DOI: 10.1016/j.epsl.2019.115849
论文题名: Control of fluid pressures on the formation of listric normal faults
作者: Yuan X.P. ; Leroy Y.M. ; Maillot B.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 529 语种: 英语
中文关键词: brittle upper crust
; fluid pressures
; fluid-retention depth
; Gulf of Mexico
; low-angle and listric normal faults
; Niger Delta
英文关键词: Metamorphic rocks
; Offshore oil well production
; Seismology
; Fluid pressures
; Fluid retention
; Gulf of Mexico
; Listric normal faults
; Niger Delta
; Upper crust
; Fault slips
; detachment fault
; faulting
; fluid pressure
; listric fault
; normal fault
; upper crust
; Atlantic Ocean
; Gulf of Mexico
; Niger Delta
; Nigeria
; Andersonia
英文摘要: Listric normal faults are widespread in the extension of the upper crust. Despite major advances in understanding the formation of listric faults through various experiments, the mechanical conditions that allow their formation are highly debated. In particular, Anderson's faulting theory predicts that newly formed normal faults are planar and are dipping at least at 45∘, and in practice, at 60–65∘ for most rock types. Here, we develop Limit Analysis to investigate the formation of a listric fault at the onset of slip linking a deep detachment to the topographic surface. We find that listric normal faults can occur in the brittle upper crust without appealing to viscous or ductile behaviours, nor to flexural stresses. The disequilibrium-compaction fluid pressures, typically observed in many sedimentary basins, are essential for the formation of listric faults. The fluid pressure is hydrostatic down to the fluid-retention depth ZFRD and sustains a higher gradient below this depth. Parametric studies show that the surface slope is also essential for the formation of listric faults even with a gently dipping surface slope (≤4∘), whereas a flat topographic surface leads to a simple Andersonian geometry at the onset of slip. The method is applied to two field examples in order to determine fluid overpressures that best match the fault shapes interpreted from seismic data. For the offshore Niger Delta, the simulated normal faults match the observed listric faults with a very shallow ZFRD = 0.5–0.75 km, and below ZFRD the fluid pressure has a lithostatic gradient, consistent with the observed fluid-pressure profiles. To reproduce a series of listric faults joining on one common low-angle detachment in the NW Gulf of Mexico, we demonstrate that a shallow ZFRD = 0.7–1.1 km is required, below which the fluid pressure increases to the lithostatic pressure on the detachment, in agreement with the fluid-pressure observations. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165373
Appears in Collections: 气候变化与战略
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作者单位: Laboratoire de Géologie, Ecole Normale Supérieure/CNRS UMR 8538, PSL Research University, Paris, 75005, France; Laboratoire Géosciences et Environnement Cergy, Université de Cergy-Pontoise, Cergy-Pontoise, France
Recommended Citation:
Yuan X.P.,Leroy Y.M.,Maillot B.. Control of fluid pressures on the formation of listric normal faults[J]. Earth and Planetary Science Letters,2020-01-01,529