岩株(英語:Stock(geology))在地質學中,是指露出地表小於 100 平方公里(40 平方英里)的侵入火成岩[1][2]。它與岩磐成因相似但比岩磐規模小。岩株與其侵入的岩石之間的接觸是不整合面。 許多岩株是埋在地下岩磐的的露出的圓頂。[3]。圓形或橢圓形的岩株可能是火山栓的頂[4] [5]。Boss是指小岩株[6]

一個三曡紀岩株,由nordmarkite (堿性石英正長岩) 組成, 位於 Gevanim Valley, Makhtesh Ramon, 以色列南部.

岩株是由在地殼深處的岩漿冷卻形成。 主要由長英質火成岩石類型組成,例如花崗岩、石英二長岩或閃長岩[7]

形成

岩株的表面看起來很均匀的,但是有復雜的演化歷史和結構成分。它們可由多個、不同尺寸(通常至少數公里)的火成岩體組成。需要經過年齡、成分、紋理或結構的分析,才能在其內部劃分不同岩石區塊。每個岩石區塊都是單獨從的侵入岩漿凝固而成的火成岩。

這些深成火成岩體是岩漿形成底闢上升而造成的。因為岩漿底闢是液態的並且非常熱,由於浮力讓它們穿過周圍岩石而上升。大多數岩漿底闢不會到達地表而形成火山,通常是在地下 5 至 30 公里處,冷卻凝固為深成火成岩。另一種觀點認為,深成火成岩岩體不是由大型岩漿底闢的上升形成的,而是由較小體積的岩脈聚集而成的[8]

實例

猶他州帕克城附近的阿爾塔和克萊頓峰岩株(由花崗閃長岩組成)[9]

加拿大不列顛哥倫比亞省的 Hellroaring Creek 和 Salal Creek 岩株(分別為花崗岩-花崗閃長岩和石英二長岩[10][11]

法國比利牛斯-東方的 Céret 岩株(輝長岩和閃長岩[12]

哥倫比亞 La Guajira 省的 Parashi 岩株(tonalite[13]

大加那利島 Caldera de Tejeda 的正長岩岩株[14]

在蘇格蘭的艾爾薩克雷格花崗岩小岩株,是一個火山栓[5]

參考文獻

  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.