鹽構造

鹽構造（英語：salt tectonics）是指岩石地層序列中有厚層岩鹽導致變形。這是由於鹽的密度低，不會隨著埋而增加，而且強度低^[1]。鹽構造一般分被動和主動兩種。

被動鹽構造

由重力造成。在沉積盆地內，若有早期沉積的鹽層被後期的沉積物持續增厚覆蓋，能導致重力不穩定，就會形成鹽構造。純岩鹽密度每立方米2160公斤，而一般沉積物密度通常較低，為每立方米2000公斤，但隨著加載和壓實，密度增至每立方米2500公斤，大於鹽的密度，造成上重下輕的重力不穩定。鹽層就會延覆蓋地層的構造弱點向上移動形成凸脊^[2]。凸脊的鹽由周圍鹽層提供因而形成凹陷，隨著上覆地層加厚，凸脊繼續增高，持續到周圍鹽層耗盡而形成底闢。如果原始鹽層夠厚，底闢的頂部能接近地表^[3]。

主動鹽構造

由構造活動造成。例如在伸展構造地區，斷層作用會降低上覆地層的強度並使其變薄。導致鹽層上升^[4]，在逆衝構造地區，上覆地層的灣曲將使鹽層上升到背斜的核心^[5].

參考文獻

^ Roberts, D.G. and Bally, A.W (editors) (2012). Regional Geology and Tectonics: Phanerozoic Passive Margins, Cratonic Basins and Global Tectonic Maps – Volume 1. Amsterdam: Elsevier. pp. 20–21. ISBN 978-0-444-56357-6. [
^ McGeary. D and C. C. Plummer (1994) Physical Geology: Earth revealed, Wm . C. Brown Publishers, Dubuque, p.475-476 ISBN 0-697-12687-0 [2]
^ Vendeville, B. C. and M. P. A. Jackson (1992b). The rise of diapirs during thin-skinned extension. Marine and Petroleum Geology, 9: 331-353
^ Stewart, S. A., 2007, Salt tectonics in the North Sea Basin: a structural style template for seismic interpreters, Special Publication of the Geological Society, London, 272, 361-396
^ Millán-Garrido, H. (2004). "Geometry and kinematics of compressional growth structures and diapirs in the La Popa basin of northeast Mexico: Insights from sequential restoration of a regional cross section and three-dimensional analysis". Tectonics. 23 (5). doi:10.1029/2003TC001540

[”Roberts”-1] Roberts, D.G. and Bally, A.W (editors) (2012). Regional Geology and Tectonics: Phanerozoic Passive Margins, Cratonic Basins and Global Tectonic Maps – Volume 1. Amsterdam: Elsevier. pp. 20–21. ISBN 978-0-444-56357-6. [

[”McGeary”-2] McGeary. D and C. C. Plummer (1994) Physical Geology: Earth revealed, Wm . C. Brown Publishers, Dubuque, p.475-476 ISBN 0-697-12687-0 [2]

[”Vendeville”-3] Vendeville, B. C. and M. P. A. Jackson (1992b). The rise of diapirs during thin-skinned extension. Marine and Petroleum Geology, 9: 331-353

[”Stewart,”-4] Stewart, S. A., 2007, Salt tectonics in the North Sea Basin: a structural style template for seismic interpreters, Special Publication of the Geological Society, London, 272, 361-396

[”Millán”-5] Millán-Garrido, H. (2004). "Geometry and kinematics of compressional growth structures and diapirs in the La Popa basin of northeast Mexico: Insights from sequential restoration of a regional cross section and three-dimensional analysis". Tectonics. 23 (5). doi:10.1029/2003TC001540

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