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岩株

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一个三叠纪岩株,由nordmarkite (堿性石英正长岩) 组成, 位于 Gevanim Valley, Makhtesh Ramon, 以色列南部.

岩株(英语:Stock(geology))在地质学中,是指露出地表小于 100 平方公里(40 平方英里)的侵入火成岩[1][2]。它与岩磐成因相似但比岩磐规模小。岩株与其侵入的岩石之间的接触是不整合面。 许多岩株是埋在地下岩磐的的露出的圆顶。[3]。圆形或椭圆形的岩株可能是火山栓的顶[4] [5]。Boss是指小岩株[6]

岩株是由在地壳深处的岩浆冷却形成。 主要由长英质火成岩石类型组成,例如花岗岩、石英二长岩或闪长岩[7]

形成

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岩株的表面看起来很均匀的,但是有复杂的演化历史和结构成分。它们可由多个、不同尺寸(通常至少数公里)的火成岩体组成。需要经过年龄、成分、纹理或结构的分析,才能在其内部划分不同岩石区块。每个岩石区块都是单独从的侵入岩浆凝固而成的火成岩。

这些深成火成岩体是岩浆形成底辟上升而造成的。因为岩浆底辟是液态的并且非常热,由于浮力让它们穿过周围岩石而上升。大多数岩浆底辟不会到达地表而形成火山,通常是在地下 5 至 30 公里处,冷却凝固为深成火成岩。另一种观点认为,深成火成岩岩体不是由大型岩浆底辟的上升形成的,而是由较小体积的岩脉聚集而成的[8]

实例

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犹他州帕克城附近的阿尔塔和克莱顿峰岩株(由花岗闪长岩组成)[9]

加拿大不列颠哥伦比亚省的 Hellroaring Creek 和 Salal Creek 岩株(分别为花岗岩-花岗闪长岩和石英二长岩[10][11]

法国比利牛斯-东方的 Céret 岩株(辉长岩和闪长岩[12]

哥伦比亚 La Guajira 省的 Parashi 岩株(tonalite[13]

大加那利岛 Caldera de Tejeda 的正长岩岩株[14]

在苏格兰的艾尔萨克雷格花岗岩小岩株,是一个火山栓[5]

参考文献

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  1. ^ Gabler, R.E. et al. (2009) Physical Geography (9th edition), Cengage Learning Inc., page 390.
  2. ^ Whittow, John (1984). Dictionary of Physical Geography. London: Penguin, 1984, p. 513. ISBN 0-14-051094-X.
  3. ^ Albert, Fay H. (1947). A Glossary of the Mining and Mineral Industry. Washington, D.C.: Government Printing Office. p. 200
  4. ^ Kikauka, Andris (1996). Geological, Geochemical, and Diamond Drilling Report on the Salal 1-6 Claims, Pemberton, B.C. (Report). Sooke, British Columbia: Geo-Facts. p. 7.
  5. ^ 5.0 5.1 Gillen, C. (2003). Geology and Landscapes of Scotland (2nd edition). Dunedin. ISBN 978-1780460093.
  6. ^ Coash, John R. (1967). "Geology of the Mount Velma Quadrangle, Elko County, Nevada". Nevada Bureau of Mines Bulletin. 68: 16.
  7. ^ Petersen, James F.; Sack, Dorothy; Gabler, Robert E. (2017). Physical Geography (11th ed.). Boston: Cengage Learning Inc. p. 614. ISBN 978-1-305-65264-4.
  8. ^ Hall, Clarence A. Jr. (2007). Introduction to the geology of southern California and its native plants. Berkeley: University of California Press. p. 22. ISBN 9780520249325.
  9. ^ Cook, Stephen J.; Bowman, John R. (1994). "Contact metamorphism surrounding the Alta stock: Thermal constraints and evidence of advective heat transport from calcite + dolomite geothermometry" (PDF). American Mineralogist. 79: 513–525.
  10. ^ S.G. Soloviev (2011). Compositional Features and Rare Metal Mineralization of the Hellroaring Creek Stock, Southeastern British Columbia (NTS 082F/09) – Geological Fieldwork 2011, Paper 2012-1 (PDF). British Columbia Ministry of Energy, Mines and Petroleum Resources. pp. 181–198.
  11. ^ Mustard, D. K.; Campbell, C. B. (1971). Salal Creek Molybdenum Property (Report). Government of British Columbia. pp. 6, 7, 8, 9.
  12. ^ Aguilar, C.; Liesa, M.; Reche, J.; Powell, R. (2016). "Fluid-fluxed melting and melt loss in a syntectonic contact metamorphic aureole from the Variscan eastern Pyrenees". Journal of Metamorphic Geology. 34 (4): 379–400. doi:10.1111/jmg.12187.
  13. ^ Martínez, Lina Fernanda; Zuluaga C., Carlos A. (2010). "Thermal modeling of pluton emplacement and associated contact metamorphism: Parashi stock emplacement in the Serranía de Jarara (Alta Guajira, Colombia)". Earth Sciences Research Journal. 14 (2).
  14. ^ Pérez Torrado, F.J.; Carracedo, J.C. (2002). "Cenozoic volcanism II - the Canary Islands – Gran Canaria". In Gibbons, W.; Moreno, T. (eds.). The Geology of Spain. The Geological Society. p. 448. ISBN 1-86239-110-6.