岩床

在地质学中，岩床（sill）是一种侵入在更老沉积岩层、火山熔岩或凝灰岩层之间，或沿变质岩叶理方向侵入的板状侵入体。“岩床”是一种整合型侵入岩层，意味着岩床不会穿过原先已存在的岩层。在高岩浆通量情况下，岩床的堆积将构建成一座岩床复合体^[1]和大型岩浆房^[2]。相较之下，岩脉则是一种穿过了更古老岩石的非整合型侵入岩板。岩床由岩脉供给岩浆^[3]，除非在特殊位置，它们形成于直接与岩浆源相连的近垂直岩层中。岩石必须是脆性和断裂的，以便能形成岩浆侵入母岩体的平面，无论是沿沉积层或火山层之间原先存在的平面，还是变质岩中与叶理相关的脆弱平面，这些平面或弱化区域可使薄片状岩浆体的侵入平行于现存的层面、整合型断裂带或叶理。

岩床平行于周围原岩中的岩层和叶理，虽然构造作用可能导致水平岩床随后向近垂直方向旋转，但它们最初可能以水平方向分布。岩床可能会与凝固熔岩流相混淆，但它们之间也有数种不同之处。侵入的岩床将显示周围原岩的部分熔化和融合，在岩床所侵入原岩的两侧接触面，能观察到加热的迹象（接触变质作用），而熔岩流只显示在较低一侧的证据。此外，熔岩流通常会显示有气体逸出到大气中的孔状结构（气泡）。而岩床因形成于地表以下，即使通常在较浅的深度（最多数公里）^[4]，上覆岩石的压力意味着岩床中几乎不会形成气泡。熔岩流的表面通常也会有风化迹象，而岩床如果仍被原岩覆盖，则通常不会。

伴生矿床

某些层状侵入体通常包含有各种重要矿物的岩床，前寒武纪的示例有南部非洲布什维尔德火成杂岩(Bushveld Igneous Complex)、因西兹瓦（Insizwa）等轴铋铂矿、“大岩墙”(GreatDyke)铬铁矿，美国苏必利尔地区的德卢斯侵入杂岩(Duluth Complex)和斯蒂尔沃特县火成杂岩；显生宙的岩床通常较小且复杂包括苏格兰拉姆岛的橄榄岩杂岩^[5]和格陵兰岛东部斯卡尔加德火成岩杂岩（Skaergaard igneous complex），这些侵入体通常含有一定丰度的金、铂、铬和其他稀有元素。

海侵岩床

尽管本质上是整合的，但许多大型岩床侵入层序内的地层水平已发生改变，侵入体的每个整合部分都由相对较短的墙状岩段连接起来。此类岩床被称为“海侵”岩床，例如暗色岩床（Whin Sill）和卡鲁盆地（Karoo basin）内的岩床^[6]^[7]。随着3D地震反射数据的使用，沉积盆地中大型岩床复合体的几何结构变得越发清晰^[8]。这些数据表明，许多岩床整体呈碟形，其他许多岩床至少已部分海侵^[9]。

另请查看

参考资料

^ Leuthold J.; Müntener O.; Baumgartner L.; Putlitz B. Petrological constraints on the recycling of mafic crystal mushes and intrusion of braided sills in the Torres del Paine Mafic Complex (Patagonia). Journal of Petrology. 2014, 55 (5): 917–949. Bibcode:2014JPet...55..917L. doi:10.1093/petrology/egu011. hdl:20.500.11850/103136 . .
^ Annen C.; Blundy J.D.; Leuthold J.; Sparks R.S.J. Construction and evolution of igneous bodies: Towards an integrated perspective of crustal magmatism. Lithos. 2015, 230: 206–221. Bibcode:2015Litho.230..206A. doi:10.1016/j.lithos.2015.05.008.
^ Meade, F. C.; Chew, D. M.; Troll, V. R.; Ellam, R. M.; Page, L. M. Magma Ascent along a Major Terrane Boundary: Crustal Contamination and Magma Mixing at the Drumadoon Intrusive Complex, Isle of Arran, Scotland. Journal of Petrology. 2009-12-01, 50 (12): 2345–2374. ISSN 0022-3530. doi:10.1093/petrology/egp081 .
^ Bell, B.; Butcher, H. On the emplacement of sill complexes: evidence from the Faroe-Shetland Basin. Geological Society, London, Special Publications. 2002, 197 (1): 307–329. Bibcode:2002GSLSP.197..307B. S2CID 128669544. doi:10.1144/GSL.SP.2002.197.01.12.
^ Emeleus, C. H.; Troll, V. R. The Rum Igneous Centre, Scotland. Mineralogical Magazine. 2014-08-01, 78 (4): 805–839 [2021-11-04]. Bibcode:2014MinM...78..805E. ISSN 0026-461X. doi:10.1180/minmag.2014.078.4.04 . （原始内容存档于2021-11-06）（英语）.
^ Hamilton M.A.; Pearson D.G. Srivastava R. , 编. Precise U-Pb Age for the Great Whin Dolerite Complex, N.E. England and Its Significance. Dyke Swarms: Keys for Geodynamic Interpretation (Springer Science & Business Media). 2011 [2021-11-04]. ISBN 9783642124969. （原始内容存档于2021-11-04）.
^ Polteau S.; Mazzini A.; Galland O.; Planke S.; Malthe-Sørenssen A. Saucer-shaped intrusions: Occurrences, emplacement and implications. Earth and Planetary Science Letters. 2008, 266 (1–2): 195–204. Bibcode:2008E&PSL.266..195P. doi:10.1016/j.epsl.2007.11.015.
^ Thomson K.; Hutton D. Geometry and growth of sill complexes: insights using 3D seismic from the North Rockall Trough. Bulletin of Volcanology. 2004, 66 (4): 364–375. Bibcode:2004BVol...66..364T. S2CID 128713713. doi:10.1007/s00445-003-0320-z.
^ Planke S.; Rasmussen T.; Rey S.S.; Myklebust R. Doré A.G.; Vining B.A. , 编. Seismic characteristics and distribution of volcanic intrusions and hydrothermal vent complexes in the Vøring and Møre basin. Petroleum geology: north-west Europe and global perspectives : proceedings of the 6th petroleum geology conference held at the Queen Elizabeth II Conference Centre, London 6–9 October 2003. 20052005. ISBN 9781862391642.

[Leuthold-1] Leuthold J.; Müntener O.; Baumgartner L.; Putlitz B. Petrological constraints on the recycling of mafic crystal mushes and intrusion of braided sills in the Torres del Paine Mafic Complex (Patagonia). Journal of Petrology. 2014, 55 (5): 917–949. Bibcode:2014JPet...55..917L. doi:10.1093/petrology/egu011. hdl:20.500.11850/103136 . .

[Annenetal2015-2] Annen C.; Blundy J.D.; Leuthold J.; Sparks R.S.J. Construction and evolution of igneous bodies: Towards an integrated perspective of crustal magmatism. Lithos. 2015, 230: 206–221. Bibcode:2015Litho.230..206A. doi:10.1016/j.lithos.2015.05.008.

[3] Meade, F. C.; Chew, D. M.; Troll, V. R.; Ellam, R. M.; Page, L. M. Magma Ascent along a Major Terrane Boundary: Crustal Contamination and Magma Mixing at the Drumadoon Intrusive Complex, Isle of Arran, Scotland. Journal of Petrology. 2009-12-01, 50 (12): 2345–2374. ISSN 0022-3530. doi:10.1093/petrology/egp081 .

[BellButcher2002-4] Bell, B.; Butcher, H. On the emplacement of sill complexes: evidence from the Faroe-Shetland Basin. Geological Society, London, Special Publications. 2002, 197 (1): 307–329. Bibcode:2002GSLSP.197..307B. S2CID 128669544. doi:10.1144/GSL.SP.2002.197.01.12.

[5] Emeleus, C. H.; Troll, V. R. The Rum Igneous Centre, Scotland. Mineralogical Magazine. 2014-08-01, 78 (4): 805–839 [2021-11-04]. Bibcode:2014MinM...78..805E. ISSN 0026-461X. doi:10.1180/minmag.2014.078.4.04 . （原始内容存档于2021-11-06）（英语）.

[Hamilton&Pearson-6] Hamilton M.A.; Pearson D.G. Srivastava R. , 编. Precise U-Pb Age for the Great Whin Dolerite Complex, N.E. England and Its Significance. Dyke Swarms: Keys for Geodynamic Interpretation (Springer Science & Business Media). 2011 [2021-11-04]. ISBN 9783642124969. （原始内容存档于2021-11-04）.

[Polteauetal2008-7] Polteau S.; Mazzini A.; Galland O.; Planke S.; Malthe-Sørenssen A. Saucer-shaped intrusions: Occurrences, emplacement and implications. Earth and Planetary Science Letters. 2008, 266 (1–2): 195–204. Bibcode:2008E&PSL.266..195P. doi:10.1016/j.epsl.2007.11.015.

[Thomson&Hutton-8] Thomson K.; Hutton D. Geometry and growth of sill complexes: insights using 3D seismic from the North Rockall Trough. Bulletin of Volcanology. 2004, 66 (4): 364–375. Bibcode:2004BVol...66..364T. S2CID 128713713. doi:10.1007/s00445-003-0320-z.

[Plankeetal2005-9] Planke S.; Rasmussen T.; Rey S.S.; Myklebust R. Doré A.G.; Vining B.A. , 编. Seismic characteristics and distribution of volcanic intrusions and hydrothermal vent complexes in the Vøring and Møre basin. Petroleum geology: north-west Europe and global perspectives : proceedings of the 6th petroleum geology conference held at the Queen Elizabeth II Conference Centre, London 6–9 October 2003. 20052005. ISBN 9781862391642.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]