錐狀岩板
錐狀岩板（英語：cone sheet）是一種淺成岩的火成岩侵入體，常出露在部分被侵蝕的火山雜岩中心。錐狀岩板是由較薄的傾斜岩板構成，通常只有幾米厚，形狀如同向下指向的圓錐體。 從空中看，它們通常是圓形到橢圓形。 最初被命名是在英國第三紀火山省 Ardnamurchan、Mull 和其他在中央的複合體。
分佈
錐狀岩板分佈很廣，各大洲都有，分佈的地質年代從晚古生代到第三紀。岩性以淺成岩最多，深成岩亦有，包括輝綠岩 [1] ， 粗面岩[2], 响岩[3], 辉长岩[4], 流紋岩[5], 二长岩[6], 碱性玄武岩[7],，花崗岩[8]。
形成
錐狀岩板常與放射狀岩脈共存，兩者均屬板狀侵入岩。若在同一火山系統在，大都共享同一岩漿來源。兩者都由于岩漿的向上拱壓而造成。放射狀岩脈是侵入岩充填由張力造成的裂縫。而錐狀岩板是侵入岩充填由剪切力造成的裂縫[9]。
圍岩結構和和區域應力場也控制侵入岩的幾何形狀[10]。且區域應力場是隨時間變化，也受岩漿房的形狀、深度和內部壓力的控制[11]。一些錐狀岩板（例如Ardnamurchan）是多次侵入岩形成的，每層錐狀岩板的構造形狀不同，表明來自不同的岩漿房。岩漿侵入時，先形成岩床再膨脹成岩蓋，導致上覆岩層被迫向上隆起，並引起錐形張裂。引入岩漿侵入[12][13]。
參考文獻
- ^ Geldmacher, Jörg; Haase, Karsten M.; Devey, Colin W.; Garbe-Schönberg, C. Dieter (1998). "The petrogenesis of Tertiary cone-sheets in Ardnamurchan, NW Scotland: petrological and geochemical constraints on crustal contamination and partial melting". Contributions to Mineralogy and Petrology. 131 (2–3): 196–209. doi:10.1007/s004100050388.
- ^ Donoghue, Eleanor; Troll, Valentin R.; Harris, Chris (2010). "Fluid–Rock Interaction in the Miocene, Post-Caldera, Tejeda Intrusive Complex, Gran Canaria (Canary Islands): Insights from Mineralogy, and O- and H-Isotope Geochemistry". Journal of Petrology. 51 (10): 2149–2176. doi:10.1093/petrology/egq052.
- ^ Ancochea, Eumenio; Huertas, María José; Hernán, Francisco; Brändle, José Luis (2014). "A new felsic cone-sheet swarm in the Central Atlantic Islands: The cone-sheet swarm of Boa Vista (Cape Verde)". Journal of Volcanology and Geothermal Research. 274: 1–15. doi:10.1016/j.jvolgeores.2014.01.010.
- ^ Johnson, S. E.; Paterson, S. R.; Tate, M. C. (1999). "Structure and emplacement history of a multiple-center, cone-sheet–bearing ring complex: The Zarza Intrusive Complex, Baja California, Mexico". Geological Society of America Bulletin. 111 (4): 607–619. doi:10.1130/0016-7606(1999)111<0607:SAEHOA>2.3.CO;2.
- ^ Branch, C.D. (1959). Progress Report on Upper Palaeozoic Intrusions Controlled by Ring Fractures near Kidston, North Queensland (PDF). Bureau of Mineral Resources Geology and Geophysics, Department of National Development, Commonwealth of Australia.
- ^ Rodriguez-Losada, J.A.; Martinez-Frias, J. (2004). "The felsic complex of the Vallehermoso Caldera: interior of an ancient volcanic system (La Gomera, Canary Islands)". Journal of Volcanology and Geothermal Research. 137 (4): 261–284. doi:10.1016/j.jvolgeores.2004.05.021.
- ^ Geshi, N. (2005). "Structural development of dike swarms controlled by the change of magma supply rate: the cone sheets and parallel dike swarms of the Miocene Otoge igneous complex, Central Japan". Journal of Volcanology and Geothermal Research. 141 (3–4): 267–281. doi:10.1016/j.jvolgeores.2004.11.002.
- ^ Ahmed, F. (1977). "Petrology and Evolution of the Tehilla Igneous Complex, Sudan". Journal of Geology. 85 (3): 331–343. doi:10.1086/628303
- ^ Phillips, W.J.（1974）The dynamic emplacement of cone sheets, Tectonophysics,Volume 24, Issues 1–2,Pages 69-84, ISSN 0040-1951,https://doi.org/10.1016/0040-1951(74)90130-9. (https://www.sciencedirect.com/science/article/pii/0040195174901309)
- ^ Macdonald J.G. (1989) Cone sheets. In: Petrology. Encyclopedia of Earth Science. Springer, Boston, MA. https://doi.org/10.1007/0-387-30845-8_41
- ^ Galland, O., Burchardt, S., Hallot, E., Mourgues, R., and Bulois, C. (2014), Dynamics of dikes versus cone sheets in volcanic systems, J. Geophys. Res. Solid Earth, 119, 6178– 6192, doi:10.1002/2014JB011059.
- ^ Walter, Thomas R.; Troll, Valentin R. (2001-06-01). "Formation of caldera periphery faults: an experimental study". Bulletin of Volcanology. 63 (2): 191. doi:10.1007/s004450100135. ISSN 1432-0819.
- ^ Magee C.; Stevenson C.; O'Driscoll B.; Schofield N.; McDermott K. (2012). "An alternative emplacement model for the classic Ardnamurchan cone sheet swarm, NW Scotland, involving lateral magma supply via regional dykes" (PDF). Journal of Structural Geology. 44: 73–91. doi:10.1016/j.jsg.2012.08.004.