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Feb 3, 2012 - Logam yang tidak ditemukan dalam peridotit itu sendiri, melainkan sebagai hasil lapukan dari batuan terseb

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Sugeng Rawuh wonten ing blog kulo "The present is the key to the past"

A RS I P B UL A NA N: FE B RUA RI 2 0 1 2

Golongan Bahan Galian Ditulis pada Februari 3, 2012 Bahan galian merupakan mineral asli dalam bentuk aslinya, yang dapat ditambang untuk keperluan manusia. Mineral-mineral dapat terbentuk menurut berbagai macam proses, seperti kristalisasi magma, pengendapan dari gas dan uap, pengendapan kimiawi dan organik dari larutan pelapukan, metamorfisme, presipitasi dan evaporasi, dan sebagainya (Katili, R.J. 1966). Berdasarkan Peraturan Pemerintah (PP) No. 27 tahun 1980, bahan galian dibagi menjadi tiga golongan. Penggolongan bahan-bahan galian didasari pada : 1.Nilai strategis/ekonomis bahan galian terhadap Negara 2.Terdapatnya sesuatu bahan galian dalam alam 3.Penggunaan bahan galian bagi industri 4.Pengaruhnya terhadap kehidupan rakyat banyak 5.Pemberian kesempatan pengembangan pengusaha 6.Penyebaran pembangunan di Daerah Bahan-bahan galian tersebut digolongkan sebagai berikut : A.GOLONGAN BAHAN GALIAN YANG STRATEGIS Bahan galian Strategis berarti strategis untuk Pertahanan dan Keamanan serta Perekonomian Negara. Golongan ini terdiri dari : Minyak bumi, bitumen cair, lilin bumi, gas alam. Bitumen padat, aspal. Antrasit, batubara, batubara muda. Uranium, radium, thorium dan bahan-bahan galian radioaktip lainnya. Nikel, kobalt. Timah. 1.Minyak Bumi Minyak bumi merupakan suatu material organik dan secara kimia dikenal dua macam yaitu deretan parafin dan deretan naphtene. Pada umumnya terdapat pada sedimen-sedimen yang tebal dan tidak pernah atau jarang sekali ditemukan pada batuan metamorf atau batuan beku. Di Indonesia, endapan-endapan geosinklin pada zaman tersier banyak mengandung minyak bumi karena kondisinya yang baik. Lapisan yang mengandung minyak bumi biasanya batuan berpori seperti batupasir ataupun batugamping. Hasil olahan dari minyak bumi sangat diperlukan dan digunakan dalam kehidupan sehari-hari dan kebanyakan sebagai bahan bakar. Hasil olahannya tersebut seperti bensin, solar dan lain-lain. 2.Batubara Batubara adalah termasuk salah satu bahan bakar fosil. Pengertian umumnya adalah batuan sedimen yang dapat terbakar, terbentuk dari endapan organik, utamanya adalah sisa-sisa tumbuhan dan terbentuk melalui proses pembatubaraan. Unsur-unsur utamanya terdiri dari karbon, hidrogen dan oksigen. Batubara juga adalah batuan organik yang memiliki sifat-sifat fisika dan kimia yang kompleks yang dapat ditemui dalam berbagai bentuk. Analisa unsur memberikan rumus formula empiris seperti : C137H97O9NS untuk bituminus dan C240H90O4NS untuk antrasit. Hampir seluruh pembentuk batubara berasal dari tumbuhan. Jenis-jenis tumbuhan pembentuk batubara dan umurnya menurut Diessel (1981) adalah sebagai berikut: Alga, dari Zaman Pre-kambrium hingga Ordovisium dan bersel tunggal. Sangat sedikit endapan batubara dari perioda ini. Silofita, dari Zaman Silur hingga Devon Tengah, merupakan turunan dari alga. Sedikit endapan batubara dari perioda ini. Pteridofita, umur Devon Atas hingga KArbon Atas. Materi utama pembentuk batubara berumur Karbon di Eropa dan Amerika Utara. Tetumbuhan tanpa bunga dan biji, berkembang biak dengan spora dan tumbuh di iklim hangat. Gimnospermae, kurun waktu mulai dari Zaman Permian hingga Kapur Tengah. Tumbuhan heteroseksual, biji terbungkus dalam buah, semisal pinus, mengandung kadar getah (resin) tinggi. Jenis Pteridospermae seperti gangamopteris dan glossopteris adalah penyusun utama batubara Permian seperti di Australia, India dan Afrika. Angiospermae, dari Zaman Kapur Atas hingga kini. Jenis tumbuhan modern, buah yang menutupi biji, jantan dan betina dalam satu bunga, kurang bergetah dibanding gimnospermae sehingga, secara umum, kurang dapat terawetkan. Potensi sumberdaya batubara di Indonesia sangat melimpah, terutama di Pulau Kalimantan dan Pulau Sumatera, sedangkan di daerah lainnya dapat dijumpai batubara walaupun dalam jumlah kecil dan belum dapat ditentukan keekonomisannya, seperti di Jawa Barat, Jawa Tengah, Papua, dan Sulawesi. Di Indonesia, batubara merupakan bahan bakar utama selain solar (diesel fuel) yang telah umum digunakan pada banyak industri, dari segi ekonomis batubara jauh lebih hemat dibandingkan solar, dengan perbandingan sebagai berikut: Solar Rp 0,74/kilokalori sedangkan batubara hanya Rp 0,09/kilokalori, (berdasarkan harga solar industri Rp. 6.200/liter). Dari segi kuantitas batubara termasuk cadangan energi fosil terpenting bagi Indonesia. Jumlahnya sangat berlimpah, mencapai puluhan milyar ton. Jumlah ini sebenarnya cukup untuk memasok kebutuhan energi listrik hingga ratusan tahun ke depan. Sayangnya, Indonesia tidak mungkin membakar habis batubara dan mengubahnya menjadi energis listrik melalui PLTU. Selain mengotori lingkungan melalui polutan CO2, SO2, NOx dan CxHy cara ini dinilai kurang efisien dan kurang memberi nilai tambah tinggi. Batubara sebaiknya tidak langsung dibakar, akan lebih bermakna dan efisien jika dikonversi menjadi migas sintetis, atau bahan petrokimia lain yang bernilai ekonomi tinggi. Dua cara yang dipertimbangkan dalam hal ini adalah likuifikasi (pencairan) dan gasifikasi (penyubliman) batubara. Membakar batubara secara langsung (direct burning) telah dikembangkan teknologinya secara continue, yang bertujuan untuk mencapai efisiensi pembakaran yang maksimum, cara-cara pembakaran langsung seperti: fixed grate, chain grate, fluidized bed, pulverized, dan lain-lain, masing-masing mempunyai kelebihan dan kelemahannya. Penambangan bahan galian strategis ini cukup banyak dijumpai di Indonesia. Metode penambangan yang digunakan adalah open pit mining atau penambangan terbuka dengan alas an keberadaan endapan batubara yang tidak membutuhkan penambangan hingga bawah permukaan yang dalam, selain faktor efisiensi biaya produksi. Adapun perusahaan yang mengeksploitasi batu bara di Indonesia antara lain yaitu PT Arutmin Indonesia penambangan di Kalimantan Selatan, PT Berau Coal penambangan di Kalimantan Timur, PT Kaltim Primacoal penambangan di Sangatta Kabupaten Kutai Timur, dan beberapa perusahaan lainnya. 3.Uranium dan Thorium Endapan-endapan mineral radioaktif seperti uranium dan thorium terdapat dalam bentuk primer seperti pegmatit dan bijih, serta bentuk sekunder seperti endapan sedimen. Batuan pegmatit adalah batuan berbutir kasar yang terbentuk pada fase terakhir dari pendinginan batuan plutonik. Batuan pegmatit biasanya mengandung kuarsa dan feldspar. Mineral radioaktif biasanya dalam bentuk lensa atau kantung. Di Indonesia, belum ditemukan endapan-endapan uranium yang berharga karena kurangnya penyelidikan geologi yang dilakukan ke arah tersebut. Mineral radioaktif yang telah ditemukan yaitu monazit dan xenotim yang biasanya mengandung unsur thorium. Mineral tersebut ditemukan dalam endapan alluvial, bersama dengan bijih timah di Bangka, Belitung, pulau Berhala dan pulau-pulau timah lainnya. Deskripsi dari logam thorium yaitu sebagai sumber energi nuklir. Sebagian besar panas di bagian internal bumi merupakan hasil dari thorium dan uranium. Thorium murni berwarna putih keperakan yang stabil dari udara dan retains its luster untuk beberapa bulan. Jika terkontaminasi dengan oksida, perlahan menyublim di udaraberubah warna menjadi abu-abu hingga akhirnya hitam, memiliki titik leleh 3300oC yang juga merupakan suhu tertinggi dibandingkan oksida lainnya. Perlahan juga terubah oleh air tetapi tidak langsung larut pada kondisi asam, kecuali hidroklorik. Bubuk logam thorium umumnya pyrophoric dan disimpan dengan sangat hati-hati.ketika dipanaskan dalam air berubah menjadi ignite dan terbakar menghasilkan warna putih menyala. 4.Nikel Unsur nikel berhubungan dengan batuan basa yang disebut norit. Nikel ditemukan dalam mineral pentlandit, dalam bentuk lempeng-lempeng halus dan butiran kecil bersama pyrhotin dan kalkopirit. Nikel biasanya terdapat dalam tanah yang terletak di atas batuan basa. Di indonesia, tempat ditemukan nikel adalah Sulawesi tengah dan Sulawesi Tenggara. Nikel yang dijumpai berhubungan erat dengan batuan peridotit. Logam yang tidak ditemukan dalam peridotit itu sendiri, melainkan sebagai hasil lapukan dari batuan tersebut. Mineral nikelnya adalah garnerit. 5.Kobalt Deskripsi fisik yang ditunjukkan kobalt adalah bersifat brittle, keras, dan merupakan transisi logam dengan magnet. Kobalt juga terdapat dalam meteorit. Endapan mineralnya dijumpai di Zaire, Morocco dan Canada. Cobalt-60 (60Co) dapat membentuk isotop buatan dengan tembakan sinar gamma (energy radiasi tinggi). Garam kobalt salts berwarna biru gelap dan seperti gelas atau bening. Banyak digunakan dalam industri. Digunakan juga untuk bahan dasar perasa makanan yang mengandung vitamin B12 dalam kadar yang tinggi. 6.Timah Bijih timah biasanya terdapat dalam bentuk kassiterit atau oksida timah. Sumber timah di Bangka terdapat pada batuan granit yang berumur yura. Bijih primer terdiri dari urat kassiterit dan kuarsa kassiterit. Dikarenakan pelapukan dan konsentrasi alluvial maka kassiterit dalam endapan primer menjadi memekat sebagai lapisan berbentuk dendrit. Dua per tiga hasil timah dunia berasal dari endapan alluvial. Salah satu kegunaan timah yaitu sebagai alloy dalam pembuatan baja. Deskripsi dari mineral logam ini yaitu putih keperakan, malleable, beberapa ductile dan berstruktur sangat kristalin. Memiliki dua bentuk allotropic. Pada suhu hangat menjadi abu-abu atau timah- dengan struktur kubikal dan pada suhu 13,2°C atau timah- yaitu bentuk umum logam timah. Perubahannya juga dipengaruhi oleh pengotor aluminium dan seng, dapat dicegah dengan memberikan tambahan antimony atau bismuth. Timah tahan terhadap distilasi, air laut, dan air minum. Akan tetapi dapat terpengaruh asam kuat, mineral alkali, dan garam dari mineral asam, oksigen terlarut juga mempercepat perusakan. Ketika dipanaskan membentuk SnO2. Digunakan untuk campuran lembaran baja sebagai kaleng timah. Di Indonesia, penambangan timah yang terkenal dijalankan oleh PT Timah yang berlokasi di BangkaBelitung. Dilakukan dengan open mining pit atau penambangan terbuka. B.GOLONGAN BAHAN GALIAN YANG VITAL Bahan galian Vital berarti dapat menjamin hajat hidup orang banyak. Golongan ini terdiri dari : Besi, mangan, molibden, khrom, wolfram, vanadium, titan. Bauksit, tembaga, timbal, seng. Emas, platina, perak, air raksa, intan. Arsen, antimon, bismut. Yttrium, rhutenium, cerium dan logam-logam langka lainnya. Berillium, korundum, zirkon, kristal kwarsa. Kriolit, fluorpar, barit. Yodium, brom, khlor, belerang. 1.Besi Besi merupakan komponen kerak bumi yang persentasenya sekitar 5%. Besi atau ferrum tergolong unsur logam dengan symbol Fe. Bentuk murninya berwarna gelap, abu-abu keperakan dengan kilap logam. Logam ini sangat mudah bereaksi dan mudah teroksidasi membentuk karat. Sifat magnetism besi sangat kuat, dan sifat dalamnya malleable atau dapat ditempa. Tingkat kekerasan 4-5 dengan berat jenis 7,3-7,8. Besi oksida pada tanah dan batuan menunjukkan warna merah, jingga, hingga kekuningan. Besi bersama dengan nikel merupakan alloy pada inti bumi/ inner core. Bijih besi utama terdiri dari hematit (Fe2O3). dan magnetit (Fe3O4). Deposit hematit dalam lingkungan sedimentasi seringkali berupa formasi banded iron (BIFs) yang merupakan variasi lapisan chert, kuarsa, hematit, dan magnetit. Proses pembentukan dari presipitasi unsur besi dari laut dangkal. Taconite adalah bijih besi silika yang merupakan deposit bijih tingkat rendah. Terdapat dan ditambang di United States, Kanada, dan China. Bentuk native jarang dijumpai, dan biasanya terdapat pada proses ekstraterestrial, yaitu meteorit yang menabrak kulit bumi. Semua besi yang terdapat di alam sebenarnya merupakan alloy besi dan nikel yang bersenyawa dalam rasio persentase tertentu, dari 6% nikel hingga 75% nikel. Unsur ini berasosiasi dengan olivine dan piroksen. Penggunaan logam besi dapat dikatakan merupakan logam utama. Dalam kehidupan seharti-hari, besi dimanfaatkan untuk: Bahan pembuatan baja Alloy dengan logam lain seperti tungsten, mangan, nikel, vanadium, dan kromium untuk menguatkan atau mengeraskan campuran. Keperluan metalurgi dan magnet Katalis dalam kegiatan industri Besi radiokatif (iron 59) digunakan di bidang medis, biokimia, dan metalurgi. Pewarna, plastik, tinta, kosmetik, dan sebagainya. 2.Mangan Mangan merupakan mineral berwarna putih – abu-abu, seperti besi tapi lebih keras dan sangat rapuh. Biasanya digunakan dalam campuran baja untuk meningkatkan karakteristik campuran tersebut, seperti kekerasan. Mineral mangan juga digunakan untuk mewarnai gelas menjadi berwarna merah amethyst. Deposit bijih mangan tersebar secara luas pada dasar lapisan batugamping, dalam volcanic tuff, berksi dan sebagainya. Deposit mangan biasanya sangat kecil. Di samping dua lokasi di jawa barat dan jawa tengah, Karangunggal di selatan Tasikmalaya dan Kliripan di barat Pegunungan Progo, ada kemungkinan deposit mangan berada pada lembah batugamping di pegunungan selatan dan kemungkinan di seluruh kepulauan yang memiliki kondisi geologi yang sama dengan selatan jawa. Eksplorasi bijih mangan hanya dapat dilakukan di selatan jawa dan kalimantan bagian tenggara. Kebanyakan urat emas-perak muda di sumatera dan jawa mengandung mineral mangan, yang kadang terkonsentrasi pada zona oksidasi seperti pada sungai Pagu di sumatera. 3.Molibden Molibdenum (MoS2, molybdenum sulfides) adalah tambang mineral utama dari molibden. Jarang ditemukan dalam bentuk Kristal, tetapi biasanya ditemukan sebagai foliated masses. Hal ini berarti mineral berbentuk lapisan seperti mika. Tingkat kekerasan 1, kilap logam dengan warna coklat, terkadang salah mengenalinya sebagai timah hitam. Molibden terbentuk pada lingkungan dengan temperatur yang tinggi seperti pada batuan beku. Beberapa molibden terbentuk ketika batuan beku mengalami kontak dengan batuan metamorf atau saat fase perubahan pada batuan. Molibden juga ditemukan pada mineral wulfenite (Pb(MoO4). Wulfenite memiliki warna orange terang, merah dan kuning Kristal. Dapat berbentuk blok atau tipis (tranparan). Kegunaan utama dari molibden yaitu untuk pembuatan peralatan baja. Molibden juga merupakan material yang penting dalam industri kimia. Molibden digunakan pula sebagai katalis, bahan cat, anti korosi, rokok. Sebagai logam yang bersih, molybden digunakan karena tingginya suhu saat pencairan yang tinggi (4,730 F) sebagai serabut dalam lampu bolam. Di USA, penghasil molibden yaitu di Colorado, New Mexico, dan Idaho. Tambang lain berada di Arizona, Montana, and Utah. Sumber terbesar molibden di USA yaitu di Climax, Colorado yaitu sekitar 5,5 m3 ton. Selain itu molibden juga banyak terdapat diberbagai Negara didunia seperti Canada, China, Chile, Mexico, Peru, Russia dan Mongolia. Jumlahnya diperkirakan mencapai 12 m3 ton. 4.Khrom Khrom merupakan elemen logam yang keras berwarna kebiruan dengan nomor atom 24 dan symbol kimia Cr. Memiliki kekerasan 4 dan berat jenis 7,21. Bentuk elemen jarang ditemukan di alam dan jarang digunakan sebagai mineral bijih. Unsur ini lebih dikenal sebagai trace element yang keberadaannya kadang memberikan warna yang berbeda pada mineral lain. Misalnya, khrom memberi warna merah pada ruby dan warna hijau pada emerald. Di alam, terdapat mineral khrom yaitu kromit (FeCr2O4, ferrous chromic oxide) yang terbentuk pada lingkungan batuan beku. Asosiasi mineral dengan intan, spinel, tembaga, dan besi. Mineral lain adalah crocoite (PbCrO4, lead chromate), yang dikenal dengan “timbal merah” karena warna merah-jingga yang indah pada kristalnya. Di Udachnaya, Rusia terdapat kimberlit kaya intan yang pada lingkungan tersebut dapat menghasilkan elemen khromium dan intan. Tambang khromit dunia diperkirakan mencapai 11 miliar ton, yang tersebar di Afrika bagian selatan, India, Kazakhstan, Turki. Jumlah ini dapat memenuhi kebutuhan dunia. Penggunaan khrom dalam kehidupan diantaranya: Alloy dengan besi yaitu Ferchromide; Cr3Fe0.4 dan chromferide; Fe3Cr0.4 Alloy kromium dengan baja membuat suatu alloy yang keras dan resisten terhadap korosi, yaitu untuk bahan stainless steel. Bahan kimia yang mengandung khrom digunakan dalam proses tanning kulit. Pigmen warna kuning dalam industry tekstil. 5.Wolfram Wolfram atau disebut pula tungsten merupakan unsur logam dengan nomor atom 74 dan symbol atom W. unsure logam ini tergolong stabil dan resisten terhadap asam maupun basa. Titik lelehnya snagat tinggi yaitu 3422 C, atau tertinggi kedua setelah karbon. Mineral utama dari tungsten adalah wolframit. Wolframit (Fe,Mn)WO4 atau besi-mangan tungstat merupakan pertengahan dari ferberit (kaya Fe) dengan huebernit(kaya Mn). Wolframit biasanya terdapat pada urat kuarsa dan pegmatit yang berasosiasi dengan granit intrusif. Sering berasosiasi dengan cassiterite, scheelite, bismuth, kuarsa, pirit, galena, sfalerit, dan arsenopirit. Mineral lain yang mengandung tungsten adalah scheelite CaWO4. Cadangan tungsten dunia terdapat di China, Kanada, dan Rusia. Campuran tungsten dan karbon adalah material yang sangat kuat dan resisten, disebut tungsten carbide. Digunakan untuk peralatan pemotong, metal, pemboran, dan konstruksi. Filament lampu terbuat dari tungsten karena titik leleh sangat tinggi. Jika dicampur dengan baja, menjadi super alloy yang sangat kuat untuk bahan mesin turbin untuk generator dan mesin jet. 6.Vanadium Vanadium memiliki nomor atom 23 dan symbol kimia V. sifat fisiknya termasuk unsur logam yang lunak, berwarna abu-abu keperakan atau merah tua. Vanadinit merupakan mineral pengandungnya, yaitu campuran dari vanadium dan timbal. Vanadium merupakan trace elements yang sering terdapat pada deposit magnetit yang juga berasosiasi dengan titanium. Juga ditemukan dalam bijih bauksit, batuan dengan konsentrasi fosforik atau batupasir dengan kandungan uranium tinggi. Vanadium juga terdapat pada deposit kaya karbon seperti batubara, oil shale, minyak mentah, atau tar pasir. Perkiraan cadangan vanadium dunia sekitar 63 juta ton, tersebar di Rusia, USA, Kanada, China, Ceko, Afsel, dan negara lain. Vanadium digunakan sebagai logam alloy dengan baja untuk bahan pembuat peralatan dan tujuan konstruksi. Ferrovanadium digunakan untuk peralatan militer dan kendaraan, atau bagian dari mesin mobil yang harus sangat kuat. Di bidang industri, vanadium pentoksida digunakan untuk gelas dan keramik, serta katalis kimia. Sekarang ini, ilmuwan telah menemukan campuran vanadium dan gallium untuk membuat magnet superkonduktif. 7.Titanium Titanium memiliki nomor atom 22 dan symbol Ti, merupakan golongan metalloid dengan sifat keras, berwarna abu-abu keperakan. Selain di kerak bumi, juga ditemukan di meteorit dan bulan. Unsur ini sangat tahan korosi, titik leleh tinggi, dan ringan. Kekuatannya sama dengan baja, namun 45% lebih ringan. Pembentukan titanium sebagai unsur native berkaitan dengan lingkungan metamorfisme bertekanan tinggi dan hanya sebagai inklusi. Berasosiasi dengan garnet dan mineral yang terbentuk dalam lingkungan serupa lain. Mineral utama pengandung titanium adalah Ilmenite (FeTiO3) dan rutile (TiO2). Mineral lain adalah sphene, brookite, anatase, pyrophanite, osbornite, ecandrewsite, geikielite dan perovskite. Ilmenit dan rutil terdapat dalam lingkungan batuan beku dan deposit pasir. Titanium ditambang di Australia, Brazil, Russia, Canada, Sri Lanka, Norway, China, South Africa, Thailand, India, Malaysia, Sierra Leone dan the United States. Penggunaan titanium adalah sebagai bahan pesawat terbang dan keperluan luar angkasa, alloy titanium, medis, batu permata buatan, perhiasan, dan kendaraan militer. TiO2 digunakan untuk pigmen warna putih dalam plastik, cat, tinta, keramik, kosmetik, kulit, dan sebagainya. 8.Bauksit Bauksit merupakan bijih utama dari aluminium (99% bijih aluminium) yaitu unsur yang keberadaannya sangat melimpah di kerak bumi. Bauksit merupakan nama umum dari mineral-mineral yang mengandung aluminium oksida terhidrasi. Mineral tersebut adalah gibbsite (Al(OH)3), diaspor dan boehmit (AlO(OH)). Sifat fisik bauksit berwarna coklat kemerahan, putih, atau kekuningan. Kilap tanah atau suram seperti clay atau soil. Terbentuk ketika batuan mengandung silika dalam aluminium (kandungan tinggi feldspar, seperti granit, gneiss, basalt, syenit, dan shale) mengalami leaching pada daerah tropis-subtropis dengan pelapukan intensif dan drainase yang baik. Bauksit lateritik tadi berbeda dengan bauksit karbonatan yang terdapat di Eropa dan Jamaika. Terbentuk karena akumulasi residual dari lapisan lempungan yang terdisolusi pada batuan karbonat. Selain bauksit, aluminium dapat terkandung pada tanah kaolin, oil shale, mineral anorthosit, dan bahkan sisa batubara. Tambang bauksit berupa surface mining. Pengolahan menjadi logam dilakukan dengan pelarutan oleh NaOH pada 150-200 C sehingga aluminate larut. Setelah disaring dari residu lumpur, gibbsite murni terbentuk saat pendinginan. Gibbsite berubah menjadi aluminium oksida oleh pemanasan. Saat meleleh pada 1000 c, ditambahkan kriolit untuk mereduksi menjadi logam aluminium. Sumber bauksit terbesar adalah Australia (40% dunia), Brasil, Guinea, Jamaika, dan USA. Sekitar 85% bauksit ditambang untuk produksi logam aluminium. 10% untuk alumina yang digunakan untuk produk kimia, abrasive, dan refraksi produk. Sisanya untuk material komponen campuran. Logam aluminium digunakan untuk berbagai kebutuhan hidup. Sebagai elemen ketiga terbesar di kerak bumi, keberadaannya tidak berbahaya bagi kehidupan. 9.Tembaga Tembaga atau copper memiliki nama kimia cuprum atau disingkat Cu. Keterdapatan tembaga di alam sebagai native copper termasuk jarang. Sebagian besar berasosiasi dengan sulfur atau produk teroksidasi dari mineral tersebut. Deposit yang biasa ditambang merupakan mineral azurite (Cu3(CO3)2(OH)2), malachite (Cu2CO3(OH)2), tennantite ((Cu,Fe)12As4S13), chalcopyrite (CuFeS2), dan bornite (Cu5FeS4). Tembaga merupakan logam yang memiliki sifat fisik malleable dan ductile. Malleable bearti dapat ditempa dan dibentuk, sedang ductile berarti dapat dibentuk menjadi seperti kabel. Kondukrtivitas termal dan elektriknya sangat tinggi. Mineral dengan nodul kaya magnesium, tembaga, dan logam lain banya dihasilkan dari aktivitas volkanik laut dalam. Sifat fisik tembaga ini memiliki warna kemerahan, dengan struktur banding. Pada kondisi liquid, memiliki kenampakan bercahaya kehijauan. Struktur electron dan posisi dalam table periodic mirip dengan logam emas dan perak. Tembaga tidak bereaksi dengan air, namun dapat teroksidasi pada suhu ruangan membentuk lapisan korosi coklat kehitaman. Sumber tembaga dunia terdapat di USA, Australia, Kanada, Chile, Meksiko, Rusia, Peru, dan Indonesia. Penggunaannya dalam bentuk murni adalah sebagai kabel transmisi, perlengkapan elektronik, pipa dan tube, peralatan rumah tangga, serta pelapis nikel, krom, dan seng. Digunakan pula sebagai campuran/ alloy dengan seng (kuningan), tembaga dengan nikel (monel), tembaga dengan timah (perunggu). 10.Timbal Timbal atau lead merupakan elemen dengan nomor atom 82. Sifat fisiknya relatif lunak, warna abu-abu kebiruan, kilap logam, mineral opak, termasuk unsur logam. Karena lunak, maka sering dijadikan campuran logam lain. Nama kimianya adalah plumbum atau Pb. Meski lunak, elemen ini termasuk berat/ densitas tinggi. Bentuk murni atau nativenya sangat jarang. Biasanya sebagai mineral, paling banyak sebagai timbal sulfida atau galena (PbS). Bentuk lain adalah anglesite PbSO4dan cerrusite PbCO3. Timbal larut dalam asam nitrit. Berasosiasi dengan mineral kalsit dan hematite. Elemen radioaktif seperti uranium dapat menjadi timbal sebagai unsur sisa. Sifatnya beracun bagi kehidupan dan organism. Sebagian besar tambangnya adalah deposit galena, dan sedikit merupakan asosiasi pada tambang seng, dan tembaga-perak. Cadangan dunia sekitar 1,5 miliar ton tersebar di USA, Kanada, Meksiko, Australia, dan Peru. Penggunaan timbale adalah sebagai bahan untuk baterai pada alat transportasi, barang elektronik, amunisi, kaca televisi, konstruksi, foil, solder, lapisan pelindung Xray, dan bahan kimia. 11.Seng Seng atau zinc adalah unsur logam dengan nomor atom 30 dan simbol kimia Zn. Sifat fisiknya berwarna abu-abu kebiruan dan kilap logam. Sifatnya rapuh pada temperatur normal, namun malleable pada 100-150C. Merupakan konduktor listrik yang baik. Perlu pelapis logam lain untuk menghindari pengaratan seng. Jika terbakar akan menimbulkan nyala merah dan awan putih oksida. Mineral seng yang signifikan adalah sphalerite (ZnS, zinc sulfide). smithsonite (ZnCO3, zinc carbonate), dan zincite (ZnO, zinc oxide). Cadangan seng dunia diperkirakan 1,9 miliar ton tersebar di USA, Australia, Kanada, Meksiko,Peru, dan negara lain. Kegunaan seng yaitu pelapis baja dan alloy dengan tembaga membentuk kuningan, senyawa kimia dalam industri obat-obatan, karet, dan cat, dan dalam bidang elektronik digunakan untuk electroplating, sekering, anoda, baterai dry cell, dan sebagainya. 12.Emas Emas merupakan elemen yang sangat dikenal sebagai logam mulia dan komoditas yang sangat berharga sepanjang sejarah manusia. Elemen ini memiliki nomor atom 79 dan nama kimia aurum atau Au. Sifat fisik unsur ini sangat stabil, tidak korosif ataupun lapuk dan jarang bersenyawa dengan unsure kimia lain. Konduktivitas elektrik dan termalnya sangat baik. Malleable sehingga dapat dibentuk dan juga bersifat ductile. Emas adalah logam yang paling tinggi densitasnya. Emas termasuk golongan native element, dengan sedikit kandungan perak, tembaga, atau besi. Warnanya kuning keemasan dengan kekerasan 2,5-3 skala Mohs. Bentuk kristal isometric octahedron atau dodecahedron. Specific gravity 15,5-19,3 pada emas murni. Makin besar kandungan perak, makin berwarna keputih-putihan. Kenampakan fisik bijih emas hampir mirip dengan pirit, markasit, dan kalkopirit dilihat dari warnanya, namun dapat dibedakan dari sifatnya yang lunak, berat jenis tinggi, dan ceratnya yang keemasan.emas berasosiasi dengan kuarsa, pirit, arsenopirit, dan perak. Emas terdapat di alam dalam dua tipe deposit. Pertama sebagai urat/ vein dalam batuan beku, kaya besi dan berasosiasi dengan urat kuarsa. Endapan lain adalah placer deposit, dimana emas dari batuan asal yang tererosi terangkut oleh aliran sungai dan terendapkan karena berat jenis yang tinggi. Selain itu, emas sering ditemukan dalam penambangan bijih perak dan tembaga. Penambangan emas dilakukan besar-besaran untuk memenuhi permintaan dunia, diantaranya ditambang di Afsel, Autralia, USA, Meksiko, Brasil, Indonesia, dan negara lainnya. Penggunaan utama emas adalah untuk bahan baku perhiasan dan benda-benda seni. Selain itu, karena konduktif, emas penting dalam aplikasi elektronik. Kegunaan lain ada di bidang fotografi, pigment, dan pengobatan. 13.Platina Platina atau platinum merupakan unsur berwarna putih – abu-abu. Biasanya berasosiasi dengan mineral lain emas, tembaga, nikel dan besi. Kebanyakan mengandung logam berat langka seperti iridium, osmium, rhodium dan palladium. Platinum sangat langka dan sangat sedikit keberadaannya. Pegunungan Ural di Rusia menghasilkan platinum sebagai placer deposit. Di Indonesia, platinum hanya ditambang sebagai produk alluvial pertambangan emas Bengkalis (sumatera tengah), distrik Meulaboh (sumatera utara) dan distrik Banjarmasin (kalimantan selatan). Di Banjarmasin, keberadaan platinum bersamaan dengan emas dan intan pada deposit alluvial. Platina digunakan sebagai perhiasan dan merupakan perhiasan yang langka sehingga memiliki nilai jual yang mahal. Dalam industri, platina diguanakan sebagai katalis. Juga digunakan sebagai peralatan laboratorium. 14.Perak Perak mulai dikenal dan digunakan sejak Zaman kuno. Terbukti disebagian kecil asia orang memisahkan perak dari timah selama 3000 BC yang lalu, seperti emas yang seharga logam, keduanya dilihat dari keindahan dan kegunaannya. Perak memiliki nomor atom 47 dengan nama kimia Argentum dan symbol Ag. Kadang ditemukan di alam dalam bentuk native dan sebagai konstituen kecil dalam emas, timbal, seng, dan tembaga. Sifat fisik dan kimia perak adalah berwarna terang-putih keperakan, kilap logam, kekerasan 2,5-3, dan berat jenis 9,6-12. Merupakan mineral opak dengan sifat ductile dan malleable. Perak adalah konduktor listrik yang sangat baik. Perak sangat resisten, tidak bereaksi dengan oksigen dan air, namun larut dalam asam sulfida dan nitrat. Perak ditemukan dalam deposit bijih timbal, seng, dan tembaga. Bijih utama perak adalah argentit(Ag2S, silver sulfide). Beberapa Negara penghasil perak dunia adalah Australia, Mexico, Peru, Chile, dan Canada. Kegunaan perak adalah sebagai perhiasan, dekorasi, maupun benda seni. Perak nitrat dan perak bromide dighunakan di bidang fotografi. Sterling merupakan alloy perak dan tembaga. Kegunaan lain untuk perangkat elektronik, cermin, katalis kimia dalam etilen, baterai, solder, dan sebagainya. 15.Air Raksa Air raksa atau merkuri adalah unsur logam dengan nomor atom 80 dan nama kimia hydrargyrum dengan symbol Hg. Pada suhu ruangan memiliki fasa liquid, berwarna keperakan dan berat jenisnya relative tinggi sekitar 13,6. Merkuri akan memadat pada suhu – 40 C. Merkuri berasosiasi dengan mineral cinnabar. Merkuri dinamakan dari nama sebuah planet. Merkuri juga dikenal dengan nama populer air raksa, yang berasal dari bahasa yunani, hydros yang berarti air dan argyros yang berarti silver karena pembentukannya terjadi pada suhu kamar sebagai cairan.. Simbol merkuri adalah Hg yang diambil dari namanya yaitu hydrargyrum.

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Alterasi Epitermal Ditulis pada Februari 3, 2012 Fluida-fluida hidrotermal menyebabkan alterasi atau ubahan-ubahan pada batuan-batuan penerima (host rock) dan terjadinya mineralisasi unsur-unsur yang terbawa oleh fluida-fluida dalam bentuk antara lain: vein, veinlet, lode, stringer, stockwork, dan breksi eksplosi. Alterasi dan mineralisasi ini membentuk zone-zone yang dibedakan sebagai … Baca lebih lanjut Õ Dipublikasi di Geology | Tinggalkan Balasan

G A MB A R

David Copperfield David Copperfield (nama asli: David Seth Kotkin lahir di Metuchen, New Jersey, Amerika Serikat, 16 September 1956; umur 55 tahun) adalah pesulap dan ilusionis yang telah 21 kali memenangkan Penghargaan Emmy. Di antara ilusinya yang terkenal adalah pertunjukan “menghilangkan” Patung Liberty, “terbang” di atas Grand Canyon, dan “berjalan menembus” Tembok Besar di RRC. Biografi Copperfield mulai bermain sulap sejak berusia 12 tahun, dan menjadi pesulap termuda yang diterima sebagai anggota Society of American Magicians [1] Sewaktu berusia 16, Universitas New York sudah mengundangnya untuk mengajar kursus sulap. [2] Nama “David Copperfield” diambilnya dari tokoh fiksi bernama David Copperfield yang muncul dalam novel berjudul sama,David Copperfield karya Charles Dickens. Pada usia 19 tahun, Copperfield sudah mengadakan pertunjukan besar di Hotel Pagoda, Honolulu, Hawaii. [2] Sebagian besar penampilan Copperfield berupa acara spesial televisi dan sebagai bintang tamu dalam acara televisi. Di layar lebar, Copperfield pernah bermain sebagai Ken si pesulap dalam film horor Terror Train produksi tahun 1980. Selain itu, Copperfield pernah tampil sebagai figuran dalam film Prêt-à-Porter (1984), namun namanya tidak dicantumkan dalam daftar pemain. Pada tahun 1982, Copperfield mendirikan yayasan Project Magic [3] untuk membantu rehabilitasi pasien yang mengalami lumpuh tangan dengan mengajarkan gerakan sulap sebagai salah satu metode terapi fisik. Metode yang dikembangkannya mendapat akreditasi dariAmerican Occupational Therapy Association, dan digunakan di lebih dari 1.100 rumah sakit di 30 negara di dunia. Pada tahun 1996, Copperfield menulis antologi fiksi berjudul David Copperfield’s Tales of the Impossible yang mengambil latar belakang dunia sulap dan ilusi. Dalam penulisan buku tersebut Copperfield bekerja sama Dean Koontz, Joyce Carol Oates, Ray Bradbury, dan anggota tim yang lain. Pada tahun berikutnya terbit volume kedua, David Copperfield’s Beyond Imagination (1997). Copperfield memiliki Museum Internasional dan Perpustakaan Seni Sulap di Las Vegas, Nevada. Museum tersebut didirikan sebagai usaha Copperfield untuk melestarikan sejarah seni sulap, dan koleksi perangkat sulap antik, buku, dan benda-benda yang berkaitan dengan seni sulap. Majalah Forbes melaporkan David Copperfield memiliki penghasilan sebesar 57 juta dolar AS pada tahun 2003. Jumlah tersebut menjadikannya berada di urutan ke-10 selebritas dengan bayaran paling mahal di dunia. Pada tahun 2004, penghasilannya diperkirakan sebesar 57 juta dolar AS (urutan ke-35), sedangkan penghasilannya pada tahun 2005 tetap berjumlah 57 juta dolar AS, namun turun ke urutan ke-41 dalam daftar selebritas top dunia. [4] Setiap tahunnya, David Copperfield melakukan lebih dari 550 pertunjukan di seluruh dunia. [5] Kehidupan pribadi Copperfield pernah bertunangan dengan supermodel Claudia Schiffer. Setelah berhubungan selama 6 tahun, mereka berpisah pada tahun 1999. Ayah Copperfield yang bernama Hyman Kotkin alias Hy meninggal dunia pada bulan Februari 2006 di San Diego, California. Semasa hidupnya, Hy sering menemani anaknya sewaktu melakukan tur keliling dunia. Copperfield memiliki situs web Remember Hy untuk mengenang ayahnya. Pada bulan April 2006, Copperfield dan dua asisten wanitanya menjadi korban perampokan bersenjata di West Palm Beach, Florida. Pada waktu itu, mereka baru saja selesai melakukan pertunjukan ketika dirampok kelompok perampok muda usia. Kedua asistennya menyerahkan semua uang, paspor, dan telepon genggam yang dimiliki. Namun menurut pernyataan yang diberikannya kepada polisi, Copperfield tidak memberikan apa-apa kepada si perampok. Copperfield mengaku dirinya menggunakan kecepatan tangan pesulap untuk menyembunyikan harta bendanya. [6]

Februari 3, 2012 [https://gunoso.wordpress.com/2012/02/03/davidcopperfield/]

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Mineral-mineral Alterasi Ditulis pada Februari 3, 2012 Alterasi merupakan perubahan komposisi mineralogy batuan (dalam keadaan padat) karena pengaruh Suhu dan Tekanan yang tinggi dan tidak dalam kondisi isokimia menghasilkan mineral lempung, kuarsa, oksida atau sulfida logam. Proses alterasi merupakan peristiwa sekunder, berbeda dengan metamorfisme yang merupakan peristiwa primer. Alterasi terjadi pada intrusi batuan beku yang mengalami pemanasan dan pada struktur tertentu yang memungkinkan masuknya air meteoric untuk dapat mengubah komposisi mineralogi batuan. Adapun beberapa contoh-contoh mineral yang dapat terbentuk dari proses alterasi adalah sebagai berikut : 1. Actinolit Ca2(Mg,Fe)5Si8O22(OH)2, Mineral ini menunjukkan warna hijau gelap, sistem kristal monoklin, belahan sempurna, kilap kaca, cerat berwarna putih dan menunjukkan bentuk elongated. Terbentuk pada suhu 800 – 9000 C, dihasilkan oleh alterasi dari piroksen pada gabro dan diabas, pada proses metamorfik green schist facies. 2. Adularia KAlSi3O8, Mineral ini menunjukkan warna putih-pink, sistem kristal monoklin, belahan 2 arah, kilap kaca, cerat putih dan menunjukkan bentuk prismatik. Terbentuk pada suhu 7000 C, akibat proses hidrotermal dengan temperatur yang rendah berupa urat. 3. Albite NaAlSi3O8, Mineral ini menunjukkan warna putih, sistem kristal triklin, belahan 3 arah, pecahan tidak rata – konkoidal, kilap kaca, cerat putih. Terbentuk pada suhu 750 – 8000 C, akibat proses hidrotermal dengan suhu yang rendah dan alterasi dari plagioklas, proses metamorfik dengan temperatur dan tekanan yang rendah, proses magmatisme dan proses albitisasi. 4. Biotite K(Mg,Fe)3AlSi3O10(F,OH)2, Mineral ini menunjukkan warna hitam, sistem kristal monoklin, belahan sempurna, pecahan tidak rata, kilap kaca dan mutiara, cerat putih dan menunjukkan bentuk tabular. Terbentuk pada temperatur 700 – 800 0 C, terbentuk akibat proses magmatisme, metamorphisme dan proses hidrotermal. Dapat terbentuk pada daerah magmatisme. 5. Clinopiroxene XY(Si,Al)2O6, Mineral ini menunjukkan warna hijau, biru, sistem kristal monoklin, belahan tidak rata, kilap kaca, cerat putih dan menunjukkan betuk prismatik. Terbentuk pada suhu 900 – 1000 0 C, terbentuk akibat proses magmatik mafik dan ultramafik plutonic, pada proses metamorfisme kontak dan regional dengan temperatur yang tinggi. Dapat terbentuk pada daerah magmatisme bersifat basa. 6. Diopside MgCaSi2O6, Mineral ini menunjukkan warna hijau, biru, sistem kristal monoklin, belahan tidak rata, kilap kaca, cerat putih dan menunjukkan betuk prismatik. Terbentuk pada suhu 900 – 1000 0 C, terbentuk akibat proses magmatik mafic dan ultramafic plutonic, pada proses metamorphisme kontak. Lingkungan daerah magmatisme. 7. Dolomite CaMg(CO3)2, Mineral ini menunjukkan warna putih-pink, sistem kristal heksagonal, belahan sempurna, pecahan subkonkoidal, kilap kaca, cerat putih. Terbentuk dari proses hidrotermal pada suhu yang rendah berupa urat, juga dapat terbentuk pada lingkungan laut akibat proses dolomitisasi batugamping dan proses metamorfik (dolostone protoliths). 8. Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH), Mineral ini menunjukkan warna hijau, sistem kristal monoklin, belahan jelas 2 arah, pecahan tidak rata, kilap kaca, cerat putih dan menunjukkan bentuk prismatik. Terbentuk pada temperatur 900 – 10000 C, terbentuk akibat proses metamorphisme pada fasies green schist dan glaucophane schist dan hidrotermal (propylitic alteration). Proses magmatik sangat jarang menghasilkan mineral ini. 9. Garnet X3Y2(SiO4)3, Mineral ini menunjukkan warna hijau gelap atau merah gelap, sistem kristal rhombic dodekahedron, belahan tidak sempurna, pecahan konkoidal dan menunjukkan kenampakan tabular. Terbentuk pada suhu 1600 – 18000 C, dapat terbentuk pada zona kontak magmatic plutons dengan temperatur yang tinggi, yaitu pada mineralisasi skarn. Selain itu juga dapat terbentuk akibat proses metamorfisme. Lingkungan terbentuknya pada daerah magmatisme. 10. Heulandite (Ca,Na)2-3Al3(Al,Si)2Si13O36·12H2O, Mineral ini menunjukkan warna putih – pink, sistem kristal monoklin, belahan 1 arah, pecahan subkonkoidal – tidak rata, kilap kaca, cerat putih dan menunjukkan bentuk tabular. Terbentuk pada suhu 600 – 7000 C, akibat proses alterasi dari vitrik tuff dan proses hidrotermal berupa urat pada basalt, gneiss dan schist. 11. Illite (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)], Mineral ini tidak berwarna (bening), dan sebagian menunjukkan warna putih-abu-abu, sistem kristal monoklin, belahan 1 arah sempurna, kilap lemak, bersifat elastis dan menunjukkan bentuk tabular. Terbentuk pada suhu 700 – 8000 C, hasil dari proses magmatisme khususnya batuan beku dalam yang kaya akan alumina dan silika (pegmatit dan granit), dapat merupakan hasil proses metamorfik (mudrock sediment) dan hasil alterasi dari feldspar. 12. Kaolinite Al2Si2O5(OH)4, Mineral ini menunjukkan warna putih, sistem kristal monoklin, belahan sempurna, kilap mutiara. Terbentuk akibat adanya proses pelapukan dari mineral yang kaya Al dan hasil proses alterasi dari mineral yang kaya Al dapat terbentuk pada daerah danau. 13. Laumontite Ca(AlSi2O6)2·4H2O, Mineral ini menunjukkan warna putih – abu-abu – pink, sistem kristal monoklin, belahan 3 arah, pecahan rata, kilap mutiara, cerat putih dan menunjukkan bentuk elongated prismatik. Terbentuk pada suhu 600 – 7000 C, akibat proses hidrotermal yang mengisi rongga-rongga pada batuan beku, batuan sedimen dan metamorf. 14. Microcline (KAlSi3O8), Mineral ini menunjukkan warna putih-hijau, sistem kristal triklin, belahan 2 arah, pecahan tidak rata, kilap kaca-mutiara, cerat putih dan menunjukkan bentuk prismatik. Terbentuk pada suhu 7000 C, akibat proses magmatik yang menghasilkan plutonic rock yaitu pegmatit, proses metamorfik dengan temperatur yang rendah yaitu pada gneiss dan schist dan proses hidrotermal. 15. Montmorillonite (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2·nH2O, Mineral ini menunjukkan warna putih – abu-abu, sistem kristal monoklin. Terbentuk pada daerah beriklim tropis yang merupakan hasil alterasi dari feldspar pada batuan yang miskin silika. Hasil dari pelapukan glass volkanik dan tuff dari proses hidrotermal. 16. Prehnite Ca2Al(AlSi3O10)(OH)2, Mineral ini menunjukkan warna kehijauan, sistem kristal orthorombic, belahan sempurna, pecahan tidak rata, kilap kaca, cerat berwarna putih dan menunjukkan bentuk tabular. Terbentuk pada suhu 700 – 8000 C, akibat proses metamorfisme dan proses hidrotermal yang mengisi rongga pada batuan volkanik basalt. 17. Wairakite CaAl2Si4O12•2(H2O), Mineral ini menunjukkan warna putih, dapat terbentuk pada suhu 600 – 7000 C, akibat proses hidrotermal (geothermal environment), proses metamorfisme burial dengan suhu yang rendah, reksi dehidrasi dari laumontite pada sedimen tuff. 18. Wollastonite (CaSiO3), Mineral ini menunjukkan warna putih, sistem kristal triklin, kilap kaca, belahan sempurna 3 arah, pecahan tidak rata, cerat putih dan menunjukkan bentuk tabular. Terbentuk pada suhu 11000 C, akibat proses metamorfisme kontak pada calcareous dan marl rocks dan dapat terjadi akibat metamorfisme regional dengan tekanan yang rendah. 19. Zeolite Na2Al2Si3O10-2H2O, Mineral ini menunjukkan warna abu-abu – putih, sistem kristal monoklin, belahan sempurna 3 arah, pecahan tidak rata, kilap kaca, cerat putih dan menunjukkan bentuk elongated-prismatik. Terbentuk pada temperatur 600 – 7000 C, akibat proses hidrotermal yang mengisi urat dan rongga pada batuan beku dan proses metamorpisme burial. Dipublikasi di Uncategorized | Tag alterasi, batuan beku, pengaruh suhu | Tinggalkan Balasan

Ditulis pada Februari 3, 2012 Chairil Anwar (lahir di Medan, Sumatera Utara, 26 Juli 1922 – meninggal di Jakarta, 28 April1949 pada umur 26 tahun) atau dikenal sebagai “Si Binatang Jalang” (dari karyanya yang berjudul Aku [2]) adalah penyair terkemuka Indonesia. Bersama Asrul Sani dan Rivai Apin, ia dinobatkan oleh H.B. Jassin sebagai pelopor Angkatan ’45 dan puisi modern Indonesia. Masa kecil Dilahirkan di Medan, Chairil Anwar merupakan anak tunggal. Ayahnya bernama Toeloes, mantan bupati Kabupaten Indragiri Riau, berasal dari Taeh Baruah, Limapuluh Kota, Sumatra Barat. Sedangkan ibunya Saleha, berasal dari Situjuh, Limapuluh Kota. [1] Dia masih punya pertalian keluarga dengan Sutan Sjahrir, Perdana Menteri pertama Indonesia. [2] Chairil masuk sekolah Hollandsch-Inlandsche School (HIS), sekolah dasar untuk orang-orang pribumi waktu masa penjajahan Belanda. Dia kemudian meneruskan pendidikannya di Meer Uitgebreid Lager Onderwijs (MULO), sekolah menengah pertama Hindia Belanda, tetapi dia keluar sebelum lulus. Dia mulai untuk menulis sebagai seorang remaja tetapi tak satupun puisi awalnya yang ditemukan. Pada usia sembilan belas tahun, setelah perceraian orang-tuanya, Chairil pindah dengan ibunya ke Jakarta di mana dia berkenalan dengan dunia sastra. Meskipun pendidikannya tak selesai, Chairil menguasai bahasa Inggris, bahasa Belanda dan bahasa Jerman, dan dia mengisi jam-jamnya dengan membaca karya-karya pengarang internasional ternama, seperti:Rainer M. Rilke, W.H. Auden, Archibald MacLeish, H. Marsman, J. Slaurhoff dan Edgar du Perron. Penulis-penulis ini sangat memengaruhi tulisannya dan secara tidak langsung memengaruhi puisi tatanan kesusasteraan Indonesia. [sunting]Masa dewasa Nama Chairil mulai terkenal dalam dunia sastera setelah pemuatan tulisannya di “Majalah Nisan” pada tahun 1942, pada saat itu dia baru berusia dua puluh tahun. Hampir semua puisi-puisi yang dia tulis merujuk pada kematian. [3]. Chairil ketika menjadi penyiar radio Jepang di Jakarta jatuh cinta pada Sri Ayati tetapi hingga akhir hayatnya Chairil tidak memiliki keberanian untuk mengungkapkannya. [4] Puisi-puisinya beredar di atas kertas murah selama masa pendudukan Jepang di Indonesia dan tidak diterbitkan hingga tahun 1945. [5][6] Semua tulisannya yang asli, modifikasi, atau yang diduga diciplak dikompilasi dalam tiga buku : Deru Campur Debu (1949); Kerikil Tajam Yang Terampas dan Yang Putus (1949); dan Tiga Menguak Takdir (1950, kumpulan puisi dengan Asrul Sani dan Rivai Apin). [sunting]Akhir hidup

Makam Chairil di TPU Karet Bivak Vitalitas puitis Chairil tidak pernah diimbangi kondisi fisiknya, yang bertambah lemah akibat gaya hidupnya yang semrawut. Sebelum dia bisa menginjak usia dua puluh tujuh tahun, dia sudah kena sejumlah penyakit. Chairil Anwar meninggal dalam usia muda karena penyakit TBC[7] Dia dikuburkan di Taman Pemakaman Umum Karet Bivak, Jakarta. Makamnya diziarahi oleh ribuan pengagumnya dari zaman ke zaman. Hari meninggalnya juga selalu diperingati sebagai Hari Chairil Anwar. [sunting]Karya tulis yang diterbitkan

Sampul Buku “Deru Campur Debu” Deru Campur Debu (1949) Kerikil Tajam dan Yang Terampas dan Yang Putus (1949) Tiga Menguak Takdir (1950) (dengan Asrul Sani dan Rivai Apin) “Aku Ini Binatang Jalang: koleksi sajak 1942-1949², disunting oleh Pamusuk Eneste, kata penutup oleh Sapardi Djoko Damono (1986) Derai-derai Cemara (1998) Pulanglah Dia Si Anak Hilang (1948), terjemahan karya Andre Gide Kena Gempur (1951), terjemahan karya John Steinbeck [sunting]Terjemahan ke bahasa asing Karya-karya Chairil juga banyak diterjemahkan ke dalam bahasa asing, antara lain bahasa Inggris,Jerman dan Spanyol. Terjemahan karya-karyanya di antaranya adalah: “Sharp gravel, Indonesian poems”, oleh Donna M. Dickinson (Berkeley, California, 1960) “Cuatro poemas indonesios [por] Amir Hamzah, Chairil Anwar, Walujati” (Madrid: Palma de Mallorca, 1962) Chairil Anwar: Selected Poems oleh Burton Raffel dan Nurdin Salam (New York, New Directions, 1963) “Only Dust: Three Modern Indonesian Poets”, oleh Ulli Beier (Port Moresby [New Guinea]: Papua Pocket Poets, 1969) The Complete Poetry and Prose of Chairil Anwar, disunting dan diterjemahkan oleh Burton Raffel (Albany, State University of New York Press, 1970) The Complete Poems of Chairil Anwar, disunting dan diterjemahkan oleh Liaw Yock Fang, dengan bantuan H. B. Jassin (Singapore: University Education Press, 1974) Feuer und Asche: sämtliche Gedichte, Indonesisch/Deutsch oleh Walter Karwath (Wina: Octopus Verlag, 1978) The Voice of the Night: Complete Poetry and Prose of Chairil Anwar, oleh Burton Raffel (Athens, Ohio: Ohio University, Center for International Studies, 1993) [sunting]Karya-karya tentang Chairil Anwar

Patung dada Chairil Anwar diJakarta. Chairil Anwar: memperingati hari 28 April 1949, diselenggarakan oleh Bagian Kesenian Djawatan Kebudajaan, Kementerian Pendidikan, Pengadjaran dan Kebudajaan (Djakarta, 1953) Boen S. Oemarjati, “Chairil Anwar: The Poet and his Language” (Den Haag: Martinus Nijhoff, 1972). Abdul Kadir Bakar, “Sekelumit pembicaraan tentang penyair Chairil Anwar” (Ujung Pandang: Lembaga Penelitian dan Pengembangan Ilmu-Ilmu Sastra, Fakultas Sastra, Universitas Hasanuddin, 1974) S.U.S. Nababan, “A Linguistic Analysis of the Poetry of Amir Hamzah and Chairil Anwar” (New York, 1976) Arief Budiman, “Chairil Anwar: Sebuah Pertemuan” (Jakarta: Pustaka Jaya, 1976) Robin Anne Ross, Some Prominent Themes in the Poetry of Chairil Anwar, Auckland, 1976 H.B. Jassin, “Chairil Anwar, pelopor Angkatan ’45, disertai kumpulan hasil tulisannya”, (Jakarta: Gunung Agung, 1983) Husain Junus, “Gaya bahasa Chairil Anwar” (Manado: Universitas Sam Ratulangi, 1984) Rachmat Djoko Pradopo, “Bahasa puisi penyair utama sastra Indonesia modern” (Jakarta: Pusat Pembinaan dan Pengembangan Bahasa, Departemen Pendidikan dan Kebudayaan, 1985) Sjumandjaya, “Aku: berdasarkan perjalanan hidup dan karya penyair Chairil Anwar (Jakarta: Grafitipers, 1987) Pamusuk Eneste, “Mengenal Chairil Anwar” (Jakarta: Obor, 1995) Zaenal Hakim, “Edisi kritis puisi Chairil Anwar” (Jakarta: Dian Rakyat, 1996) Dipublikasi di Uncategorized | Tinggalkan Balasan

Vulkanisme adalah peristiwa alam akibat adanya aktivitas magma Ditulis pada Februari 3, 2012 Vulkanisme adalah peristiwa alam akibat adanya aktivitas magma Common Expressions: orogeny Expressions

Definition

Alleghenian orogeny

The Alleghenian orogeny or Appalachian orogeny is the geological mountain-forming event (orogeny) that formed the Appalachian Mountains and Allegheny Mountains. (references)

Antler orogeny

The Antler orogeny is a mountain-building episode that is named for Antler Peak, at Battle Mountain, Nevada. the orogeny extensively deformed Paleozoic rocks of the Great Basin in Nevada and western Utah during Late Devonian and Early Mississippian time. In the late Devonian, the Antler volcanic island arc, approaching the west coast of North America, which was a passive margin with deep embayments, river deltas and estuaries, in today’s Idaho and Nevada, finally reached the steep slope of the continental shelf and began to uplift deep water deposits [http://jan.ucc.nau.edu/~rcb7/devpaleo.html]. (references)

Caledonian orogeny

The Caledonian orogeny is a mountain building event recorded in the mountains and hills of northern England, Wales, Scotland, Ireland and west Norway. This event occurred during the Silurian and Devonian Periods of the Palaeozoic Era, roughly 444-416 Mya. This orogeny has been named for Caledonia, the ancient name of the Scottish highlands. (references)

Grenville orogeny

The Grenville orogeny was an episode of mountain-building (orogeny) associated with the assembly of the ancient supercontinent Rodinia. The Grenville orogeny occurred in the late Proterozoic eon, 1300-1000 million years ago (mya), as numerous continental plates collided around the edges of North America, forming folded mountains. (references)

Laramide orogeny

The Laramide orogeny was a 30 million year period of mountain building in western North America, which started in the Late Cretaceous, 70 million years ago, and ended in the Late Paleogene, 40 million years ago. The Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. The major feature that was created by this orogeny was the Rocky Mountains, but evidence of this orogeny can be found from Alaska to northern Mexico, with the easternmost extent of the mountain-building represented by the Black Hills of South Dakota. The phenomenon is named for the Laramie Mountains of eastern Wyoming. (references)

Nevadan orogeny

The Nevadan Orogeny was a major mountain building event that took place along the western edge of ancient North America between the Mid to Late Jurassic (between about 180 and 146 million years ago). The Nevadan orogeny was the first of three major mountain building episodes to transform Western North America between the Late Mesozoic and Early Cenozoic Eras, the latter two being the Sevier and Laramide orogeny, chronologically. Much like the two orogenies that followed, the Nevadan was caused by the subduction of oceanic lithosphere at a subduction zone running along the edge of the North American continent. The subduction was relatively slow due to a reduced rate of sea floor spreading, this resulted in relatively cool oceanic crust descending into the lithosphere very quickly, and steeply beneath the edge of the continent. As a result, magma rose from the melting oceanic crust producing a chain of volcanoes located close to continent’s edge. This volcanic activity over the course of several million years would form what is today the Sierra Nevada of California. (references)

Sevier orogeny

The Sevier orogeny was a mountain-building event that affected western North America between approximately 150 million years ago (Ma), and 80 Ma. The Sevier River area of central Utah is the namesake of this event, which was a result of convergent boundary tectonism; a foldthrust belt formed during this event. (references)

Taconic orogeny

The Taconic orogeny was a great mountain building period that perhaps had the greatest overall effect on the geologic structure of basement rocks within the New York Bight region. The effects of this orogeny are most apparent throughout New England, but the sediments derived from mountainous areas formed in the northeast can be traced throughout the Appalachians and midcontinental North America. (references)

Uralian orogeny

The Uralian orogeny refers to the long series of geological events that raised the Ural Mountains starting in the Late Carboniferous and Permian periods of the Palaeozoic Era, ca. 318-299 and 299-251 Mya, and ending with the last series of continental collisions in Triassic-early Jurassic times. In terms of plate tectonics and continental drift, the Uralian resulted from a southwestern movement of the Siberian Plate, catching a smaller landmass, Kazakhstania, between it and the nearly completely assembled supercontinent, Pangaea. The mountains rose as the edge of Kazakhstania rode over the European plate. This event was the last stage in the assembly of Pangaea. (references)

Variscan orogeny

The Variscan or Hercynian orogeny is a geologic mountain-building event recorded in the European mountains and hills called the Variscan Belt. This occurred in early Paleozoic times (from ~390Ma to ~310Ma) and reflects continental collision between Laurasia and Gondwana to form Pangea. This early collision was a precursor to the collision that caused the Variscan-Allegheny-Ouachita orogeny in Pennsylvanian times. (references) Top

Source: compiled by the editor from various references; see credits.

Specialty Expressions: orogeny Expressions

Domain

Definition

Algoman orogeny

Mining

Orogeny and accompanying granitic emplacement that affected Precambrian rocks of northern Minnesota and adjacent Ontario about 2.4 billon years ago; it is synonymous with the Kenoran orogeny of the Canadian classification. (references)

Appalachian orogeny

Mining

A. Late Paleozoic Era diastrophism beginning perhaps in the Late Devonian Period and continuing until the end of the Permian Period b. A period of intense mountain-building movements in the late Paleozoic Era, during which the deposits in the Appalachian and Cordilleran geosynclines were folded to form the Appalachian and Palaeocordilleran mountains. Equivalent to the Armorican and Hercynian movements in Europe. Syn: Appalachian revolution. (references)

Laramide orogeny

Mining

A time of deformation, typically recorded in the eastern Rocky Mountains of the United States, whose several phases extended from late Cretaceous until the end of the Paleocene. It is named for the Laramie Formation of Wyoming and Colorado, probably a synorogenic deposit. (references)

Nevadan orogeny

Mining

Late Jurassic-Early Cretaceous diastrophism in Western North America. (references)

Pasadenian orogeny

Mining

Mid-Pleistocene diastrophism. (references)

Taconic orogeny

Geography

Period of intense folding that affected parts of eastern North America at the end of the Ordovician. Source: European Union. (references)

Top

Source: compiled by the editor from various references; see credits.

Extended Definition: orogeny

Orogeny

Geologic provinces of the world (USGS)

Shield Platform Orogen Basin Large igneous province Extended crust

Oceanic crust: 0–20 Ma 20–65 Ma >65 Ma

Orogeny (Greek for “mountain generating”) is the process of natural mountain building, and may be studied as a tectonic structural event, as a geographical event and a chronological event, in that orogenic events cause distinctive structural phenomena and related tectonic activity, affect certain regions of rocks and crust and happen within a time frame. Orogenic events occur solely as a result of the processes of plate tectonics; the problems which were investigated and resolved by the study of orogenesis contributed greatly to the theory of plate tectonics, coupled with study of flora and fauna, geography and mid ocean ridges in the 1950s and 1960s. The physical manifestations of orogenesis (the process of orogeny) are orogenic belts or orogens. An orogen is different from a mountain range in that an orogen may be completely eroded away, and only recognizable by studying (old) rocks that bear the traces of the orogeny. Orogens are usually long, thin, arcuate tracts of rocks which have a pronounced linear structure resulting in terranes or blocks of deformed rocks, separated generally by dipping thrust faults. These thrust faults carry relatively thin plates (which are called nappes, and differ from tectonic plates) of rock in from the margins of the compressing orogen to the core, and are intimately associated with folds and the development of metamorphism. The topographic height of orogenic mountains is related to the principle of isostasy, where the gravitational force of the upthrust mountain range of light, continental crust material is balanced against its buoyancy relative to the dense mantle. Erosion inevitably takes its course, removing much of the mountains, leaving the core or mountain roots, which may be exhumed by further isostatic events balancing out the loss of elevated mass. This is the final form of the majority of old orogenic belts, being a long arcuate strip of crystalline metamorphic rocks sequentially below younger sediments which are thrust atop them and dip away from the orogenic core. History Before geology, the presence of mountains was explained in Christian contexts as a result of the Biblical Deluge, for Neoplatonic thought, which influenced early Christian writers, assumed that a perfect Creation would have to have been in the form of a perfect sphere. Such thinking persisted into the eighteenth century. Orogeny was used by Amanz Gressly (1840) and Jules Thurmann (1854) as orogenic in terms of the creation of mountain elevations, as the termmountain building was still used to describe the processes. Elie de Beaumont (1852) used the evocative “Jaws of a Vise” theory to explain orogeny, but was more concerned with the height rather than the implicit structures orogenic belts created and contained. His theory essentially held that mountains were created by the squeezing of certain rocks. Eduard Suess (1875) recognised the importance of horizontal movement of rocks. The concept of a precursor geosyncline or initial downward warping of the solid earth (Hall, 1859) prompted James Dwight Dana (1873) to include the concept of compression in the theories surrounding mountain-building. With hindsight, we can discount Dana’s conjecture that this contraction was due to the cooling of the Earth (aka the cooling earth theory). The cooling Earth theory was the chief paradigm for most geologists until the 1960s. It was, in the context of orogeny, contested hotly by proponents of vertical movements in the crust (similar to tephrotectonics), or convection within the asthenosphere or mantle. Gustav Steinmann (1906) recognised different classes of orogenic belts, including the Alpine type orogenic belt, typified by a flysch and molasse geometry to the sediments; ophiolite sequences, tholeiitic basalts, and a nappe style fold structure. In terms of recognising orogeny as an event, Leopold von Buch (1855) recognised that orogenies could be placed in time by bracketing between the youngest deformed rock and the oldest undeformed rock, a principle which is still in use today, though commonly investigated by geochronology using radiometric dating. H.J. Zwart (1967) drew attention to the metamorphic differences in orogenic belts, proposing three types, modified by W. S. Pitcher (1979); Hercynotype (back-arc basin type); Shallow, low-pressure metamorphism; thin metamorphic zones Metamorphism dependent on increase in temperature Abundant granite and migmatite Few ophiolites, ultramafic rocks virtually absent very wide orogen with small and slow uplift nappe structures rare Alpinotype (ocean trench style); deep, high pressure, thick metamorphic zones metamorphism of many facies, dependent on decrease in pressure few granites or migmatites abundant ophiolites with ultramafic rocks Relatively narrow orogen with large and rapid uplift Nappe structures predominant Cordilleran (arc) type; dominated by calc-alkaline igneous rocks,andesites, granite batholiths general lack of migmatites, low geothermal gradient lack of ophiolite and abyssal sedimentary rocks (black shale, chert, etcetera) low-pressure metamorphism, moderate uplift lack of nappes The advent of plate tectonics has explained the vast majority of orogenic belts and their features. The cooling earth theory (principally advanced byDescartes) is dispensed with, and tephrotectonic style vertical movements have been explained primarily by the process of isostasy. Some oddities exist, where simple collisional tectonics are modified in a transform plate boundary, such as in New Zealand, or where island arc orogenies, for instance in New Guinea occur away from a continental backstop. Further complications such as Proterozoic continent-continent collisional orogens, explicitly the Musgrave Block in Australia, previously inexplicable (see Dennis, 1982) are being brought to light with the advent of seismic imaging techniques which can resolve the deep crust structure of orogenic belts. Physiography The process of orogeny can take tens of millions of years and build mountains from plains or even the ocean floor. Orogeny can occur due to continental collision or volcanic activity. Frequently, rock formations that undergo orogeny are severely deformed and undergo metamorphism. During orogeny, deeply buried rocks may be pushed to the surface. Sea bottom and near shore material may cover some or all of the orogenic area. If the orogeny is due to two continents colliding, the resulting mountains can be very high (see Himalaya). Orogeny usually produces long linear structures, known as orogenic belts. Generally, orogenic belts consist of long parallel strips of rock exhibiting similar characteristics along the length of the belt. Orogenic belts are associated with subduction zones, which consume crust, produce volcanoes, and build island arcs. These island arcs may be added to a continent during an orogenic event. List of orogenies This list is incomplete; you can help by expanding it. NO RTH A ME RI CA N O RO G E NI E S

Wopmay orogeny Along western edge of Canadian shield, 2100-1900 mya. Hudsonian orogeny or Trans-Hudson orogeny Extends from Hudson Bay west into Saskatchewan then south through the western Dakotas and Nebraska. Result of the collision of the Superior craton with the Hearne craton and the Wyoming craton during the Proterozoic. Lasted from 2000-1800 mya. Penokean orogeny Wisconsin, Minnesota, and Michigan, U. S. A. and southern Ontario, Canada, 1850-1840 mya. Big Sky orogeny Proterozoic collision between the Hearne craton and the Wyoming craton in southwest Montana, 1770 mya. Ivanpah orogeny Mojave province, south western USA Yavapai orogeny mid to south western USA, circa 1750 mya. Mazatzal orogeny mid to south western USA, circa 1600 mya. Grenville orogeny Worldwide during the late Proterozoic, 1300-1000 mya. Associated with the assembly of the supercontinent Rodinia. Formed folded mountains in Eastern North America from Newfoundland to North Carolina, 1100-1000 mya. Taconic orogeny

Taconic orogeny Caledonian orogeny the Taconic phase in the NE U.S. and Canada during the Ordovician Period. the Acadian phase in the Eastern U.S. during Silurian and Devonian Periods. Appalachian orogeny, usually seen as the same as the Variscan orogeny in Europe. Appalachian Mountains is a well studied orogenic belt resulting from a late Paleozoic collision between North America and Africa. Taconic orogeny Acadian orogeny Alleghenian orogeny Ouachita orogeny Ouachita Mountains of Arkansas and Oklahoma is an orogenic belt that dates from the late Paleozoic Era and is most likely a continuation of the Appalachian orogeny west across the Mississippi embayment – Reelfoot Rift zone. Antler orogeny Ancestral Sierra Nevada western United States. Late Devonian – early Mississippian. Innuitian orogeny or Ellesmerian orogeny Innuitian Mountains, Canadian Arctic, extending from Ellesmere Island to Melville Island, Mississippian 345 mya. Sonoma orogeny Rocky Mountains, western North America, 270 – 240 million years ago. Nevadan orogeny Developed along western North America during the Jurassic Period. Sevier orogeny Rocky Mountains, western North America, 140 – 50 million years ago. Laramide orogeny Rocky Mountains, western North America, 40-70 Myr ago. E URO P E A N O RO G E NI E S

The Caledonian orogeny Formation of the highlands of western Norway, Britain and Ireland in the Silurian Period. Uralian orogeny Formation of the Ural Mountains, Eurasia, during the Permian Period. The Variscan orogeny (also called the Hercynian orogeny) Formation of the mountains of western Iberia, SW Ireland, SW England, central France, southern Germany and Czechoslovakia during the Devonian and Carboniferous Periods. The Alpine orogeny, encompassing: the Formation of the Alps during the Eocene through Miocene Periods. the Carpathian orogeny building the Carpathian Mountains of eastern Europe during the Miocene Period. the Hellenic orogeny in Greece and the Aegean area during Eocene through Miocene Periods. Ongoing (happening now): the Mediterranean Ridge. A S I A N O RO G E NI E S

The Aravalli-Delhi Orogen (precambrian) The Altaid Orogeny (Paleozoic) The Cimmerian and Cathayasian orogenies Active through Triassic and Jurassic Periods along south and southeast Asia. Alpine orogeny, encompassing: The Himalayan orogeny, forming the Himalaya Mountains, as a result of the ongoing collision of the Indian Plate with the Eurasian Plate. S O UTH A ME RI CA N O RO G E NI E S

Andean orogeny Andes Mountains, 0-200 Myr ago. A FRI CA N O RO G E NI E S

Pan-African orogeny (Neoproterozoic) Damaran Orogeny A US TRA L I A N O RO G E NI E S

Sleaford Orogeny (2440-2420 Ma), Gawler Craton, South Australia Glenburgh Orogeny (c. 2005 – 1920 Ma), Glenburgh Terrane, Western Australia. Kimban Orogeny (c. 1845-1700 Ma), Gawler Craton, South Australia Yapungku Orogeny (c. 1700 Ma), North Yilgarn craton margin, Western Australia Mangaroon Orogeny (c.1680 – 1620 Ma), Gascoyne Complex, Western Australia. Kararan Orogeny (1650- Ma), Gawler Craton, South Australia Barramundi Orogeny (c. 1600 Ma), MacArthur Basin, northern Australia Isan Orogeny, c. 1600 Ma, Mt Isa Block, Queensland Olarian Orogeny, Olary Block, South Australia Capricorn Orogeny, Gascoyne Complex, Western Australia Musgrave Orogeny (c. 1080 Ma), Musgrave Block, Central Australia. Edmundian Orogeny (c. 920 – 850 Ma), Gascoyne Complex, Western Australia. Petermann Orogeny (c. 550-535 Ma late Neoproterozoic to Cambrian), Central Australia Delamerian Orogeny, South Australia and Victoria, Australia, Ordovician Lachlan Orogeny, c. 540 and 440 Ma., Victoria and New South Wales Alice Springs Orogeny in central Australia, Early Carboniferous Hunter-Bowen Orogeny, (c. 260 – 225 Ma) Permian to Triassic, Queensland and New South Wales A NTA RCTI C O RO G E NI E S

Napier orogeny (4000 ± 200 Myr ago.) Rayner orogeny (~ 3500 Myr ago.) Humboldt orogeny (~ 3000 Myr ago.) Insel orogeny (2650 ± 150 Myr ago.) Early Ruker orogeny (2000 – 1700 Myr ago.) Late Ruker / Nimrod orogeny (1000 ± 150 Myr ago.) Beardmore orogeny (633 – 620 Myr ago.) Ross Orogeny (~ 500 Myr ago.) NE W ZE A L A ND O RO G E NI E S

Tuhua Orogeny (370 to 330 Myr ago) Rangitata Orogeny (142 to 99 million years ago) Kaikoura Orogeny (24 million years ago to present day) See also Continental collision Plate tectonics Common Expressions: orogeny Expressions

Definition

Alleghenian orogeny

The Alleghenian orogeny or Appalachian orogeny is the geological mountain-forming event (orogeny) that formed the Appalachian Mountains and Allegheny Mountains. (references)

Antler orogeny

The Antler orogeny is a mountain-building episode that is named for Antler Peak, at Battle Mountain, Nevada. the orogeny extensively deformed Paleozoic rocks of the Great Basin in Nevada and western Utah during Late Devonian and Early Mississippian time. In the late Devonian, the Antler volcanic island arc, approaching the west coast of North America, which was a passive margin with deep embayments, river deltas and estuaries, in today’s Idaho and Nevada, finally reached the steep slope of the continental shelf and began to uplift deep water deposits [http://jan.ucc.nau.edu/~rcb7/devpaleo.html]. (references)

Caledonian orogeny

The Caledonian orogeny is a mountain building event recorded in the mountains and hills of northern England, Wales, Scotland, Ireland and west Norway. This event occurred during the Silurian and Devonian Periods of the Palaeozoic Era, roughly 444-416 Mya. This orogeny has been named for Caledonia, the ancient name of the Scottish highlands. (references)

Grenville orogeny

The Grenville orogeny was an episode of mountain-building (orogeny) associated with the assembly of the ancient supercontinent Rodinia. The Grenville orogeny occurred in the late Proterozoic eon, 1300-1000 million years ago (mya), as numerous continental plates collided around the edges of North America, forming folded mountains. (references)

Laramide orogeny

The Laramide orogeny was a 30 million year period of mountain building in western North America, which started in the Late Cretaceous, 70 million years ago, and ended in the Late Paleogene, 40 million years ago. The Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. The major feature that was created by this orogeny was the Rocky Mountains, but evidence of this orogeny can be found from Alaska to northern Mexico, with the easternmost extent of the mountain-building represented by the Black Hills of South Dakota. The phenomenon is named for the Laramie Mountains of eastern Wyoming. (references)

Nevadan orogeny

The Nevadan Orogeny was a major mountain building event that took place along the western edge of ancient North America between the Mid to Late Jurassic (between about 180 and 146 million years ago). The Nevadan orogeny was the first of three major mountain building episodes to transform Western North America between the Late Mesozoic and Early Cenozoic Eras, the latter two being the Sevier and Laramide orogeny, chronologically. Much like the two orogenies that followed, the Nevadan was caused by the subduction of oceanic lithosphere at a subduction zone running along the edge of the North American continent. The subduction was relatively slow due to a reduced rate of sea floor spreading, this resulted in relatively cool oceanic crust descending into the lithosphere very quickly, and steeply beneath the edge of the continent. As a result, magma rose from the melting oceanic crust producing a chain of volcanoes located close to continent’s edge. This volcanic activity over the course of several million years would form what is today the Sierra Nevada of California. (references)

Sevier orogeny

The Sevier orogeny was a mountain-building event that affected western North America between approximately 150 million years ago (Ma), and 80 Ma. The Sevier River area of central Utah is the namesake of this event, which was a result of convergent boundary tectonism; a fold-thrust belt formed during this event. (references)

Taconic orogeny

The Taconic orogeny was a great mountain building period that perhaps had the greatest overall effect on the geologic structure of basement rocks within the New York Bight region. The effects of this orogeny are most apparent throughout New England, but the sediments derived from mountainous areas formed in the northeast can be traced throughout the Appalachians and midcontinental North America. (references)

Uralian orogeny

The Uralian orogeny refers to the long series of geological events that raised the Ural Mountains starting in the Late Carboniferous and Permian periods of the Palaeozoic Era, ca. 318-299 and 299-251 Mya, and ending with the last series of continental collisions in Triassic-early Jurassic times. In terms of plate tectonics and continental drift, the Uralian resulted from a southwestern movement of the Siberian Plate, catching a smaller landmass, Kazakhstania, between it and the nearly completely assembled supercontinent, Pangaea. The mountains rose as the edge of Kazakhstania rode over the European plate. This event was the last stage in the assembly of Pangaea. (references)

Variscan orogeny

The Variscan or Hercynian orogeny is a geologic mountain-building event recorded in the European mountains and hills called the Variscan Belt. This occurred in early Paleozoic times (from ~390Ma to ~310Ma) and reflects continental collision between Laurasia and Gondwana to form Pangea. This early collision was a precursor to the collision that caused the Variscan-Allegheny-Ouachita orogeny in Pennsylvanian times. (references) Top

Source: compiled by the editor from various references; see credits.

Specialty Expressions: orogeny Expressions

Domain

Definition

Algoman orogeny

Mining

Orogeny and accompanying granitic emplacement that affected Precambrian rocks of northern Minnesota and adjacent Ontario about 2.4 billon years ago; it is synonymous with the Kenoran orogeny of the Canadian classification. (references)

Appalachian orogeny

Mining

A. Late Paleozoic Era diastrophism beginning perhaps in the Late Devonian Period and continuing until the end of the Permian Period b. A period of intense mountain-building movements in the late Paleozoic Era, during which the deposits in the Appalachian and Cordilleran geosynclines were folded to form the Appalachian and Palaeocordilleran mountains. Equivalent to the Armorican and Hercynian movements in Europe. Syn: Appalachian revolution. (references)

Laramide orogeny

Mining

A time of deformation, typically recorded in the eastern Rocky Mountains of the United States, whose several phases extended from late Cretaceous until the end of the Paleocene. It is named for the Laramie Formation of Wyoming and Colorado, probably a synorogenic deposit. (references)

Nevadan orogeny

Mining

Late Jurassic-Early Cretaceous diastrophism in Western North America. (references)

Pasadenian orogeny

Mining

Mid-Pleistocene diastrophism. (references)

Taconic orogeny

Geography

Period of intense folding that affected parts of eastern North America at the end of the Ordovician. Source: European Union. (references)

Top

Source: compiled by the editor from various references; see credits.

Extended Definition: orogeny

Orogeny

Geologic provinces of the world (USGS)

Shield Platform Orogen Basin Large igneous province Extended crust

Oceanic crust: 0–20 Ma 20–65 Ma >65 Ma

Orogeny (Greek for “mountain generating”) is the process of natural mountain building, and may be studied as a tectonic structural event, as a geographical event and a chronological event, in that orogenic events cause distinctive structural phenomena and related tectonic activity, affect certain regions of rocks and crust and happen within a time frame. Orogenic events occur solely as a result of the processes of plate tectonics; the problems which were investigated and resolved by the study of orogenesis contributed greatly to the theory of plate tectonics, coupled with study of flora and fauna, geography and mid ocean ridges in the 1950s and 1960s. The physical manifestations of orogenesis (the process of orogeny) are orogenic belts or orogens. An orogen is different from a mountain range in that an orogen may be completely eroded away, and only recognizable by studying (old) rocks that bear the traces of the orogeny. Orogens are usually long, thin, arcuate tracts of rocks which have a pronounced linear structure resulting in terranes or blocks of deformed rocks, separated generally by dipping thrust faults. These thrust faults carry relatively thin plates (which are called nappes, and differ from tectonic plates) of rock in from the margins of the compressing orogen to the core, and are intimately associated with folds and the development of metamorphism. The topographic height of orogenic mountains is related to the principle of isostasy, where the gravitational force of the upthrust mountain range of light, continental crust material is balanced against its buoyancy relative to the dense mantle. Erosion inevitably takes its course, removing much of the mountains, leaving the core or mountain roots, which may be exhumed by further isostatic events balancing out the loss of elevated mass. This is the final form of the majority of old orogenic belts, being a long arcuate strip of crystalline metamorphic rocks sequentially below younger sediments which are thrust atop them and dip away from the orogenic core. History Before geology, the presence of mountains was explained in Christian contexts as a result of the Biblical Deluge, for Neoplatonic thought, which influenced early Christian writers, assumed that a perfect Creation would have to have been in the form of a perfect sphere. Such thinking persisted into the eighteenth century. Orogeny was used by Amanz Gressly (1840) and Jules Thurmann (1854) as orogenic in terms of the creation of mountain elevations, as the termmountain building was still used to describe the processes. Elie de Beaumont (1852) used the evocative “Jaws of a Vise” theory to explain orogeny, but was more concerned with the height rather than the implicit structures orogenic belts created and contained. His theory essentially held that mountains were created by the squeezing of certain rocks. Eduard Suess (1875) recognised the importance of horizontal movement of rocks. The concept of a precursor geosyncline or initial downward warping of the solid earth (Hall, 1859) prompted James Dwight Dana (1873) to include the concept of compression in the theories surrounding mountain-building. With hindsight, we can discount Dana’s conjecture that this contraction was due to the cooling of the Earth (aka the cooling earth theory). The cooling Earth theory was the chief paradigm for most geologists until the 1960s. It was, in the context of orogeny, contested hotly by proponents of vertical movements in the crust (similar to tephrotectonics), or convection within the asthenosphere or mantle. Gustav Steinmann (1906) recognised different classes of orogenic belts, including the Alpine type orogenic belt, typified by a flysch and molasse geometry to the sediments; ophiolite sequences, tholeiitic basalts, and a nappe style fold structure. In terms of recognising orogeny as an event, Leopold von Buch (1855) recognised that orogenies could be placed in time by bracketing between the youngest deformed rock and the oldest undeformed rock, a principle which is still in use today, though commonly investigated by geochronology using radiometric dating. H.J. Zwart (1967) drew attention to the metamorphic differences in orogenic belts, proposing three types, modified by W. S. Pitcher (1979); Hercynotype (back-arc basin type); Shallow, low-pressure metamorphism; thin metamorphic zones Metamorphism dependent on increase in temperature Abundant granite and migmatite Few ophiolites, ultramafic rocks virtually absent very wide orogen with small and slow uplift nappe structures rare Alpinotype (ocean trench style); deep, high pressure, thick metamorphic zones metamorphism of many facies, dependent on decrease in pressure few granites or migmatites abundant ophiolites with ultramafic rocks Relatively narrow orogen with large and rapid uplift Nappe structures predominant Cordilleran (arc) type; dominated by calc-alkaline igneous rocks,andesites, granite batholiths general lack of migmatites, low geothermal gradient lack of ophiolite and abyssal sedimentary rocks (black shale, chert, etcetera) low-pressure metamorphism, moderate uplift lack of nappes The advent of plate tectonics has explained the vast majority of orogenic belts and their features. The cooling earth theory (principally advanced byDescartes) is dispensed with, and tephrotectonic style vertical movements have been explained primarily by the process of isostasy. Some oddities exist, where simple collisional tectonics are modified in a transform plate boundary, such as in New Zealand, or where island arc orogenies, for instance in New Guinea occur away from a continental backstop. Further complications such as Proterozoic continent-continent collisional orogens, explicitly the Musgrave Block in Australia, previously inexplicable (see Dennis, 1982) are being brought to light with the advent of seismic imaging techniques which can resolve the deep crust structure of orogenic belts. Physiography The process of orogeny can take tens of millions of years and build mountains from plains or even the ocean floor. Orogeny can occur due to continental collision or volcanic activity. Frequently, rock formations that undergo orogeny are severely deformed and undergo metamorphism. During orogeny, deeply buried rocks may be pushed to the surface. Sea bottom and near shore material may cover some or all of the orogenic area. If the orogeny is due to two continents colliding, the resulting mountains can be very high (see Himalaya). Orogeny usually produces long linear structures, known as orogenic belts. Generally, orogenic belts consist of long parallel strips of rock exhibiting similar characteristics along the length of the belt. Orogenic belts are associated with subduction zones, which consume crust, produce volcanoes, and build island arcs. These island arcs may be added to a continent during an orogenic event. List of orogenies This list is incomplete; you can help by expanding it. NO RTH A ME RI CA N O RO G E NI E S

Wopmay orogeny Along western edge of Canadian shield, 2100-1900 mya. Hudsonian orogeny or Trans-Hudson orogeny Extends from Hudson Bay west into Saskatchewan then south through the western Dakotas and Nebraska. Result of the collision of the Superior craton with the Hearne craton and the Wyoming craton during the Proterozoic. Lasted from 2000-1800 mya. Penokean orogeny Wisconsin, Minnesota, and Michigan, U. S. A. and southern Ontario, Canada, 1850-1840 mya. Big Sky orogeny Proterozoic collision between the Hearne craton and the Wyoming craton in southwest Montana, 1770 mya. Ivanpah orogeny Mojave province, south western USA Yavapai orogeny mid to south western USA, circa 1750 mya. Mazatzal orogeny mid to south western USA, circa 1600 mya. Grenville orogeny Worldwide during the late Proterozoic, 1300-1000 mya. Associated with the assembly of the supercontinent Rodinia. Formed folded mountains in Eastern North America from Newfoundland to North Carolina, 1100-1000 mya. Taconic orogeny

Taconic orogeny Caledonian orogeny the Taconic phase in the NE U.S. and Canada during the Ordovician Period. the Acadian phase in the Eastern U.S. during Silurian and Devonian Periods. Appalachian orogeny, usually seen as the same as the Variscan orogeny in Europe. Appalachian Mountains is a well studied orogenic belt resulting from a late Paleozoic collision between North America and Africa. Taconic orogeny Acadian orogeny Alleghenian orogeny Ouachita orogeny Ouachita Mountains of Arkansas and Oklahoma is an orogenic belt that dates from the late Paleozoic Era and is most likely a continuation of the Appalachian orogeny west across the Mississippi embayment – Reelfoot Rift zone. Antler orogeny Ancestral Sierra Nevada western United States. Late Devonian – early Mississippian. Innuitian orogeny or Ellesmerian orogeny Innuitian Mountains, Canadian Arctic, extending from Ellesmere Island to Melville Island, Mississippian 345 mya. Sonoma orogeny Rocky Mountains, western North America, 270 – 240 million years ago. Nevadan orogeny Developed along western North America during the Jurassic Period. Sevier orogeny Rocky Mountains, western North America, 140 – 50 million years ago. Laramide orogeny Rocky Mountains, western North America, 40-70 Myr ago. E URO P E A N O RO G E NI E S

The Caledonian orogeny Formation of the highlands of western Norway, Britain and Ireland in the Silurian Period. Uralian orogeny Formation of the Ural Mountains, Eurasia, during the Permian Period. The Variscan orogeny (also called the Hercynian orogeny) Formation of the mountains of western Iberia, SW Ireland, SW England, central France, southern Germany and Czechoslovakia during the Devonian and Carboniferous Periods. The Alpine orogeny, encompassing: the Formation of the Alps during the Eocene through Miocene Periods. the Carpathian orogeny building the Carpathian Mountains of eastern Europe during the Miocene Period. the Hellenic orogeny in Greece and the Aegean area during Eocene through Miocene Periods. Ongoing (happening now): the Mediterranean Ridge. A S I A N O RO G E NI E S

The Aravalli-Delhi Orogen (precambrian) The Altaid Orogeny (Paleozoic) The Cimmerian and Cathayasian orogenies Active through Triassic and Jurassic Periods along south and southeast Asia. Alpine orogeny, encompassing: The Himalayan orogeny, forming the Himalaya Mountains, as a result of the ongoing collision of the Indian Plate with the Eurasian Plate. S O UTH A ME RI CA N O RO G E NI E S

Andean orogeny Andes Mountains, 0-200 Myr ago. A FRI CA N O RO G E NI E S

Pan-African orogeny (Neoproterozoic) Damaran Orogeny A US TRA L I A N O RO G E NI E S

Sleaford Orogeny (2440-2420 Ma), Gawler Craton, South Australia Glenburgh Orogeny (c. 2005 – 1920 Ma), Glenburgh Terrane, Western Australia. Kimban Orogeny (c. 1845-1700 Ma), Gawler Craton, South Australia Yapungku Orogeny (c. 1700 Ma), North Yilgarn craton margin, Western Australia Mangaroon Orogeny (c.1680 – 1620 Ma), Gascoyne Complex, Western Australia. Kararan Orogeny (1650- Ma), Gawler Craton, South Australia Barramundi Orogeny (c. 1600 Ma), MacArthur Basin, northern Australia Isan Orogeny, c. 1600 Ma, Mt Isa Block, Queensland Olarian Orogeny, Olary Block, South Australia Capricorn Orogeny, Gascoyne Complex, Western Australia Musgrave Orogeny (c. 1080 Ma), Musgrave Block, Central Australia. Edmundian Orogeny (c. 920 – 850 Ma), Gascoyne Complex, Western Australia. Petermann Orogeny (c. 550-535 Ma late Neoproterozoic to Cambrian), Central Australia Delamerian Orogeny, South Australia and Victoria, Australia, Ordovician Lachlan Orogeny, c. 540 and 440 Ma., Victoria and New South Wales Alice Springs Orogeny in central Australia, Early Carboniferous Hunter-Bowen Orogeny, (c. 260 – 225 Ma) Permian to Triassic, Queensland and New South Wales A NTA RCTI C O RO G E NI E S

Napier orogeny (4000 ± 200 Myr ago.) Rayner orogeny (~ 3500 Myr ago.) Humboldt orogeny (~ 3000 Myr ago.) Insel orogeny (2650 ± 150 Myr ago.) Early Ruker orogeny (2000 – 1700 Myr ago.) Late Ruker / Nimrod orogeny (1000 ± 150 Myr ago.) Beardmore orogeny (633 – 620 Myr ago.) Ross Orogeny (~ 500 Myr ago.) NE W ZE A L A ND O RO G E NI E S

Tuhua Orogeny (370 to 330 Myr ago) Rangitata Orogeny (142 to 99 million years ago) Kaikoura Orogeny (24 million years ago to present day) See also Continental collision Plate tectonics

Common Expressions: orogeny

Expressions

Definition

Alleghenian orogeny

The Alleghenian orogeny or Appalachian orogeny is the geological mountain-forming event (orogeny) that formed the Appalachian Mountains and Allegheny Mountains. (references)

Antler orogeny

The Antler orogeny is a mountain-building episode that is named for Antler Peak, at Battle Mountain, Nevada. the orogeny extensively deformed Paleozoic rocks of the Great Basin in Nevada and western Utah during Late Devonian and Early Mississippian time. In the late Devonian, the Antler volcanic island arc, approaching the west coast of North America, which was a passive margin with deep embayments, river deltas and estuaries, in today’s Idaho and Nevada, finally reached the steep slope of the continental shelf and began to uplift deep water deposits [http://jan.ucc.nau.edu/~rcb7/devpaleo.html]. (references)

Caledonian orogeny

The Caledonian orogeny is a mountain building event recorded in the mountains and hills of northern England, Wales, Scotland, Ireland and west Norway. This event occurred during the Silurian and Devonian Periods of the Palaeozoic Era, roughly 444-416 Mya. This orogeny has been named for Caledonia, the ancient name of the Scottish highlands. (references)

Grenville orogeny

The Grenville orogeny was an episode of mountain-building (orogeny) associated with the assembly of the ancient supercontinent Rodinia. The Grenville orogeny occurred in the late Proterozoic eon, 1300-1000 million years ago (mya), as numerous continental plates collided around the edges of North America, forming folded mountains. (references)

Laramide orogeny

The Laramide orogeny was a 30 million year period of mountain building in western North America, which started in the Late Cretaceous, 70 million years ago, and ended in the Late Paleogene, 40 million years ago. The Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. The major feature that was created by this orogeny was the Rocky Mountains, but evidence of this orogeny can be found from Alaska to northern Mexico, with the easternmost extent of the mountain-building represented by the Black Hills of South Dakota. The phenomenon is named for the Laramie Mountains of eastern Wyoming. (references)

Nevadan orogeny

The Nevadan Orogeny was a major mountain building event that took place along the western edge of ancient North America between the Mid to Late Jurassic (between about 180 and 146 million years ago). The Nevadan orogeny was the first of three major mountain building episodes to transform Western North America between the Late Mesozoic and Early Cenozoic Eras, the latter two being the Sevier and Laramide orogeny, chronologically. Much like the two orogenies that followed, the Nevadan was caused by the subduction of oceanic lithosphere at a subduction zone running along the edge of the North American continent. The subduction was relatively slow due to a reduced rate of sea floor spreading, this resulted in relatively cool oceanic crust descending into the lithosphere very quickly, and steeply beneath the edge of the continent. As a result, magma rose from the melting oceanic crust producing a chain of volcanoes located close to continent’s edge. This volcanic activity over the course of several million years would form what is today the Sierra Nevada of California. (references)

Sevier orogeny

The Sevier orogeny was a mountain-building event that affected western North America between approximately 150 million years ago (Ma), and 80 Ma. The Sevier River area of central Utah is the namesake of this event, which was a result of convergent boundary tectonism; a foldthrust belt formed during this event. (references)

Taconic orogeny

The Taconic orogeny was a great mountain building period that perhaps had the greatest overall effect on the geologic structure of basement rocks within the New York Bight region. The effects of this orogeny are most apparent throughout New England, but the sediments derived from mountainous areas formed in the northeast can be traced throughout the Appalachians and midcontinental North America. (references)

Uralian orogeny

The Uralian orogeny refers to the long series of geological events that raised the Ural Mountains starting in the Late Carboniferous and Permian periods of the Palaeozoic Era, ca. 318-299 and 299-251 Mya, and ending with the last series of continental collisions in Triassic-early Jurassic times. In terms of plate tectonics and continental drift, the Uralian resulted from a southwestern movement of the Siberian Plate, catching a smaller landmass, Kazakhstania, between it and the nearly completely assembled supercontinent, Pangaea. The mountains rose as the edge of Kazakhstania rode over the European plate. This event was the last stage in the assembly of Pangaea. (references)

Variscan orogeny

The Variscan or Hercynian orogeny is a geologic mountain-building event recorded in the European mountains and hills called the Variscan Belt. This occurred in early Paleozoic times (from ~390Ma to ~310Ma) and reflects continental collision between Laurasia and Gondwana to form Pangea. This early collision was a precursor to the collision that caused the Variscan-Allegheny-Ouachita orogeny in Pennsylvanian times. (references) Top

Source: compiled by the editor from various references; see credits.

Specialty Expressions: orogeny

Expressions

Domain

Definition

Algoman orogeny

Mining

Orogeny and accompanying granitic emplacement that affected Precambrian rocks of northern Minnesota and adjacent Ontario about 2.4 billon years ago; it is synonymous with the Kenoran orogeny of the Canadian classification. (references)

Appalachian orogeny

Mining

A. Late Paleozoic Era diastrophism beginning perhaps in the Late Devonian Period and continuing until the end of the Permian Period b. A period of intense mountain-building movements in the late Paleozoic Era, during which the deposits in the Appalachian and Cordilleran geosynclines were folded to form the Appalachian and Palaeocordilleran mountains. Equivalent to the Armorican and Hercynian movements in Europe. Syn: Appalachian revolution. (references)

Laramide orogeny

Mining

A time of deformation, typically recorded in the eastern Rocky Mountains of the United States, whose several phases extended from late Cretaceous until the end of the Paleocene. It is named for the Laramie Formation of Wyoming and Colorado, probably a synorogenic deposit. (references)

Nevadan orogeny

Mining

Late Jurassic-Early Cretaceous diastrophism in Western North America. (references)

Pasadenian orogeny

Mining

Mid-Pleistocene diastrophism. (references)

Taconic orogeny

Geography

Period of intense folding that affected parts of eastern North America at the end of the Ordovician. Source: European Union. (references)

Top

Source: compiled by the editor from various references; see credits.

Extended Definition: orogeny

Orogeny

Geologic provinces of the world (USGS)

Shield

Oceanic crust:

Platform

0–20 Ma

Orogen

20–65 Ma

Basin

>65 Ma

Large igneous province Extended crust Orogeny (Greek for “mountain generating”) is the process of natural mountain building, and may be studied as a tectonic structural event, as a geographical event and a chronological event, in that orogenic events cause distinctive structural phenomena and related tectonic activity, affect certain regions of rocks and crust and happen within a time frame. Orogenic events occur solely as a result of the processes of plate tectonics; the problems which were investigated and resolved by the study of orogenesis contributed greatly to the theory of plate tectonics, coupled with study of flora and fauna, geography and mid ocean ridges in the 1950s and 1960s. The physical manifestations of orogenesis (the process of orogeny) are orogenic belts or orogens. An orogen is different from a mountain range in that an orogen may be completely eroded away, and only recognizable by studying (old) rocks that bear the traces of the orogeny. Orogens are usually long, thin, arcuate tracts of rocks which have a pronounced linear structure resulting in terranes or blocks of deformed rocks, separated generally by dipping thrust faults. These thrust faults carry relatively thin plates (which are called nappes, and differ from tectonic plates) of rock in from the margins of the compressing orogen to the core, and are intimately associated with folds and the development of metamorphism. The topographic height of orogenic mountains is related to the principle of isostasy, where the gravitational force of the upthrust mountain range of light, continental crust material is balanced against its buoyancy relative to the dense mantle. Erosion inevitably takes its course, removing much of the mountains, leaving the core or mountain roots, which may be exhumed by further isostatic events balancing out the loss of elevated mass. This is the final form of the majority of old orogenic belts, being a long arcuate strip of crystalline metamorphic rocks sequentially below younger sediments which are thrust atop them and dip away from the orogenic core. History Before geology, the presence of mountains was explained in Christian contexts as a result of the Biblical Deluge, for Neoplatonic thought, which influenced early Christian writers, assumed that a perfect Creation would have to have been in the form of a perfect sphere. Such thinking persisted into the eighteenth century. Orogeny was used by Amanz Gressly (1840) and Jules Thurmann (1854) as orogenic in terms of the creation of mountain elevations, as the termmountain building was still used to describe the processes. Elie de Beaumont (1852) used the evocative “Jaws of a Vise” theory to explain orogeny, but was more concerned with the height rather than the implicit structures orogenic belts created and contained. His theory essentially held that mountains were created by the squeezing of certain rocks. Eduard Suess (1875) recognised the importance of horizontal movement of rocks. The concept of a precursor geosyncline or initial downward warping of the solid earth (Hall, 1859) prompted James Dwight Dana (1873) to include the concept of compression in the theories surrounding mountain-building. With hindsight, we can discount Dana’s conjecture that this contraction was due to the cooling of the Earth (aka the cooling earth theory). The cooling Earth theory was the chief paradigm for most geologists until the 1960s. It was, in the context of orogeny, contested hotly by proponents of vertical movements in the crust (similar to tephrotectonics), or convection within the asthenosphere or mantle. Gustav Steinmann (1906) recognised different classes of orogenic belts, including the Alpine type orogenic belt, typified by a flysch and molasse geometry to the sediments; ophiolite sequences, tholeiitic basalts, and a nappe style fold structure. In terms of recognising orogeny as an event, Leopold von Buch (1855) recognised that orogenies could be placed in time by bracketing between the youngest deformed rock and the oldest undeformed rock, a principle which is still in use today, though commonly investigated by geochronology using radiometric dating. H.J. Zwart (1967) drew attention to the metamorphic differences in orogenic belts, proposing three types, modified by W. S. Pitcher (1979); Hercynotype (back-arc basin type); Shallow, low-pressure metamorphism; thin metamorphic zones Metamorphism dependent on increase in temperature Abundant granite and migmatite Few ophiolites, ultramafic rocks virtually absent very wide orogen with small and slow uplift nappe structures rare Alpinotype (ocean trench style); deep, high pressure, thick metamorphic zones metamorphism of many facies, dependent on decrease in pressure few granites or migmatites abundant ophiolites with ultramafic rocks Relatively narrow orogen with large and rapid uplift Nappe structures predominant Cordilleran (arc) type; dominated by calc-alkaline igneous rocks,andesites, granite batholiths general lack of migmatites, low geothermal gradient lack of ophiolite and abyssal sedimentary rocks (black shale, chert, etcetera) low-pressure metamorphism, moderate uplift lack of nappes The advent of plate tectonics has explained the vast majority of orogenic belts and their features. The cooling earth theory (principally advanced byDescartes) is dispensed with, and tephrotectonic style vertical movements have been explained primarily by the process of isostasy. Some oddities exist, where simple collisional tectonics are modified in a transform plate boundary, such as in New Zealand, or where island arc orogenies, for instance in New Guinea occur away from a continental backstop. Further complications such as Proterozoic continent-continent collisional orogens, explicitly the Musgrave Block in Australia, previously inexplicable (see Dennis, 1982) are being brought to light with the advent of seismic imaging techniques which can resolve the deep crust structure of orogenic belts. Physiography The process of orogeny can take tens of millions of years and build mountains from plains or even the ocean floor. Orogeny can occur due to continental collision or volcanic activity. Frequently, rock formations that undergo orogeny are severely deformed and undergo metamorphism. During orogeny, deeply buried rocks may be pushed to the surface. Sea bottom and near shore material may cover some or all of the orogenic area. If the orogeny is due to two continents colliding, the resulting mountains can be very high (see Himalaya). Orogeny usually produces long linear structures, known as orogenic belts. Generally, orogenic belts consist of long parallel strips of rock exhibiting similar characteristics along the length of the belt. Orogenic belts are associated with subduction zones, which consume crust, produce volcanoes, and build island arcs. These island arcs may be added to a continent during an orogenic event. List of orogenies This list is incomplete; you can help by expanding it. NO RTH A ME RI CA N O RO G E NI E S

Wopmay orogeny Along western edge of Canadian shield, 2100-1900 mya. Hudsonian orogeny or Trans-Hudson orogeny Extends from Hudson Bay west into Saskatchewan then south through the western Dakotas and Nebraska. Result of the collision of the Superior craton with the Hearne craton and the Wyoming craton during the Proterozoic. Lasted from 2000-1800 mya. Penokean orogeny Wisconsin, Minnesota, and Michigan, U. S. A. and southern Ontario, Canada, 1850-1840 mya. Big Sky orogeny Proterozoic collision between the Hearne craton and the Wyoming craton in southwest Montana, 1770 mya. Ivanpah orogeny Mojave province, south western USA Yavapai orogeny mid to south western USA, circa 1750 mya. Mazatzal orogeny mid to south western USA, circa 1600 mya. Grenville orogeny Worldwide during the late Proterozoic, 1300-1000 mya. Associated with the assembly of the supercontinent Rodinia. Formed folded mountains in Eastern North America from Newfoundland to North Carolina, 1100-1000 mya. Taconic orogeny

Taconic orogeny Caledonian orogeny the Taconic phase in the NE U.S. and Canada during the Ordovician Period. the Acadian phase in the Eastern U.S. during Silurian and Devonian Periods. Appalachian orogeny, usually seen as the same as the Variscan orogeny in Europe. Appalachian Mountains is a well studied orogenic belt resulting from a late Paleozoic collision between North America and Africa. Taconic orogeny Acadian orogeny Alleghenian orogeny Ouachita orogeny Ouachita Mountains of Arkansas and Oklahoma is an orogenic belt that dates from the late Paleozoic Era and is most likely a continuation of the Appalachian orogeny west across the Mississippi embayment – Reelfoot Rift zone. Antler orogeny Ancestral Sierra Nevada western United States. Late Devonian – early Mississippian. Innuitian orogeny or Ellesmerian orogeny Innuitian Mountains, Canadian Arctic, extending from Ellesmere Island to Melville Island, Mississippian 345 mya. Sonoma orogeny Rocky Mountains, western North America, 270 – 240 million years ago. Nevadan orogeny Developed along western North America during the Jurassic Period. Sevier orogeny Rocky Mountains, western North America, 140 – 50 million years ago. Laramide orogeny Rocky Mountains, western North America, 40-70 Myr ago. E URO P E A N O RO G E NI E S

The Caledonian orogeny Formation of the highlands of western Norway, Britain and Ireland in the Silurian Period. Uralian orogeny Formation of the Ural Mountains, Eurasia, during the Permian Period. The Variscan orogeny (also called the Hercynian orogeny) Formation of the mountains of western Iberia, SW Ireland, SW England, central France, southern Germany and Czechoslovakia during the Devonian and Carboniferous Periods. The Alpine orogeny, encompassing: the Formation of the Alps during the Eocene through Miocene Periods. the Carpathian orogeny building the Carpathian Mountains of eastern Europe during the Miocene Period. the Hellenic orogeny in Greece and the Aegean area during Eocene through Miocene Periods. Ongoing (happening now): the Mediterranean Ridge. A S I A N O RO G E NI E S

The Aravalli-Delhi Orogen (precambrian) The Altaid Orogeny (Paleozoic) The Cimmerian and Cathayasian orogenies Active through Triassic and Jurassic Periods along south and southeast Asia. Alpine orogeny, encompassing: The Himalayan orogeny, forming the Himalaya Mountains, as a result of the ongoing collision of the Indian Plate with the Eurasian Plate. S O UTH A ME RI CA N O RO G E NI E S

Andean orogeny Andes Mountains, 0-200 Myr ago. A FRI CA N O RO G E NI E S

Pan-African orogeny (Neoproterozoic) Damaran Orogeny A US TRA L I A N O RO G E NI E S

Sleaford Orogeny (2440-2420 Ma), Gawler Craton, South Australia Glenburgh Orogeny (c. 2005 – 1920 Ma), Glenburgh Terrane, Western Australia. Kimban Orogeny (c. 1845-1700 Ma), Gawler Craton, South Australia Yapungku Orogeny (c. 1700 Ma), North Yilgarn craton margin, Western Australia Mangaroon Orogeny (c.1680 – 1620 Ma), Gascoyne Complex, Western Australia. Kararan Orogeny (1650- Ma), Gawler Craton, South Australia Barramundi Orogeny (c. 1600 Ma), MacArthur Basin, northern Australia Isan Orogeny, c. 1600 Ma, Mt Isa Block, Queensland Olarian Orogeny, Olary Block, South Australia Capricorn Orogeny, Gascoyne Complex, Western Australia Musgrave Orogeny (c. 1080 Ma), Musgrave Block, Central Australia. Edmundian Orogeny (c. 920 – 850 Ma), Gascoyne Complex, Western Australia. Petermann Orogeny (c. 550-535 Ma late Neoproterozoic to Cambrian), Central Australia Delamerian Orogeny, South Australia and Victoria, Australia, Ordovician Lachlan Orogeny, c. 540 and 440 Ma., Victoria and New South Wales Alice Springs Orogeny in central Australia, Early Carboniferous Hunter-Bowen Orogeny, (c. 260 – 225 Ma) Permian to Triassic, Queensland and New South Wales A NTA RCTI C O RO G E NI E S

Napier orogeny (4000 ± 200 Myr ago.) Rayner orogeny (~ 3500 Myr ago.) Humboldt orogeny (~ 3000 Myr ago.) Insel orogeny (2650 ± 150 Myr ago.) Early Ruker orogeny (2000 – 1700 Myr ago.) Late Ruker / Nimrod orogeny (1000 ± 150 Myr ago.) Beardmore orogeny (633 – 620 Myr ago.) Ross Orogeny (~ 500 Myr ago.) NE W ZE A L A ND O RO G E NI E S

Tuhua Orogeny (370 to 330 Myr ago) Rangitata Orogeny (142 to 99 million years ago) Kaikoura Orogeny (24 million years ago to present day) See also Continental collision Plate tectonics

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