Low‐Angle Normal Faults on the NW Shelf of Australia: Implications for Late Paleozoic Rifting
Low‐Angle Normal Faults on the NW Shelf of Australia: Implications for Late Paleozoic Rifting
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澳大利亚西北陆架的低角度正断层：对晚古生代裂谷的影响
DOI：
10.1029/2021tc007088
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发表时间：
2022-06
期刊：
影响因子：
4.2
通讯作者：
Catherine Belgarde
中科院分区：
文献类型：
--
作者：
Hongdan Deng;Ken McClay;Catherine Belgarde
晚古生代澳大利亚西北陆架裂谷作用形成了一个广泛的盆地，从根本上控制了中生代大陆裂谷作用和被动边缘发育；然而，与这种伸展过程相关的构造样式仍然没有得到很好的约束。在此，我们将高分辨率地震数据与NW陆架近端区域的井资料相结合，表明Dampier次盆地东部的Mermaid断裂系统是一条大尺度（~ 80 km长）、低角度（5-20°）的正断层，在晚古生代裂陷期间形成了长达10 km的偏移。在其北部和南部域中，美人鱼断层呈平面几何形状，具有典型的伸展构造特征。在其中央区域，上地壳的向海倾斜的多米诺骨牌式正断层向下延伸，进入一个高反射地震带，该地震带向上拱起，形成一个椭圆形的圆顶。上盘半地堑的生长地层和下盘基底反射表明，美人鱼断裂起源于高角度正断层，在伸展过程中受到下盘掘出的旋转作用。沿Mermaid断裂及其下方的基底内变形以中~高振幅半连续地震反射为特征，与上覆基底单元的透明反射特征不同。将美人鱼断裂系统与变质核复杂背景下研究充分的滑脱断裂进行比较，揭示出惊人的相似性。因此，我们认为美人鱼断裂是作为一个新生变质核杂岩的一部分发展起来的，下盘温暖到热，在晚古生代大陆裂陷期间，可能是由古特提斯洋向南俯冲引起的，使中下地壳流动成为可能。
Late Paleozoic rifting of the NW Shelf of Australia formed a wide basin that fundamentally controlled the Mesozoic continental rifting and passive margin development; however, structural style associated with this extensional process remains poorly constrained. Here, we integrate high-resolution seismic data with well data from the proximal domain of the NW Shelf to show that the Mermaid fault system in the eastern Dampier Sub-basin is a large-scale (∼80 km long), low-angle (5–20°) normal fault with up to 10 km offset formed during the Late Paleozoic rifting. In its northern and southern domains, the Mermaid fault has a planar geometry with characteristic extensional structures. In its central domain, seaward-dipping, domino-style normal faults in the upper crust extend downward into a highly reflective seismic zone that arches upward to form an elliptical dome. Growth strata in the hangingwall half-graben and footwall basement reflections indicate that the Mermaid fault initiated as a high-angle normal fault and was rotated by footwall exhumation during extension. Intrabasement deformation along and below the Mermaid fault is characterized by moderate- to high-amplitude, semi-continuous seismic reflectors that are distinct from transparent reflection character in the overlying basement unit. Comparison of the Mermaid fault system to well-studied detachment faults in metamorphic core complex settings reveals striking similarities. We therefore suggest that the Mermaid fault developed as part of a nascent metamorphic core complex with a warm to hot footwall that enabled middle-lower crustal flow during the Late Paleozoic continental rifting, likely induced by southward subduction of the Paleo-Tethys Ocean.
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影响因子：
4.9
作者：
D. Whitney;C. Teyssier;P. Rey;W. Buck
通讯作者：
D. Whitney;C. Teyssier;P. Rey;W. Buck
影响因子：
1.2
作者：
N. Direen;H. Stagg;P. Symonds;J. Colwell
通讯作者：
N. Direen;H. Stagg;P. Symonds;J. Colwell
影响因子：
9
作者：
N. Kusznir;G. Karner
通讯作者：
N. Kusznir;G. Karner
DOI：
10.1071/aj93046
发表时间：
1994
期刊：
The APPEA Journal
影响因子：
--
作者：
Geoff Hill
通讯作者：
Geoff Hill
DOI：
--
发表时间：
1994
期刊：
--
影响因子：
--
作者：
H. Stagg;J. Colwell
通讯作者：
H. Stagg;J. Colwell