气候变化领域集成服务门户(CCPortal): Growth folds above propagating normal faults

CCPortal

DOI	10.1016/j.earscirev.2019.102885
	Growth folds above propagating normal faults
	Coleman A.J.; Duffy O.B.; Jackson C.A.-L.
发表日期	2019
ISSN	00128252
卷号	196
英文摘要	Growth folds above the upper tips of normal faults are ubiquitous in extensional settings, especially during the early phases of extension and in salt-rich basins. As slip accumulates on the underlying normal fault, the geometry and size of the fold changes. These changes reflect the dip, throw, displacement and propagation rate of the underlying normal fault, as well as the thickness and rheology of the overlying cover. These changes also have a marked impact on the architecture and distribution of synkinematic sediments, as well as the styles of secondary deformation accommodating strain within the growing fold. Here, we analyse a large dataset of natural, and physically- and numerically-modelled growth folds to: (i) characterise their diagnostic features; (ii) investigate the controls on their geometry, size and differences; and (iii) describe how they grow with increasing extensional strain. We demonstrate that larger fault throws and a thicker and weaker cover are associated with larger growth folds. In contrast, small fault throws as well as thin and strong brittle cover are associated with smaller growth folds. We show that the geometry and size of growth folds vary through time; the width (and thus, the wavelength) of the fold is established relatively early during fold growth, whereas fold amplitude increases gradually with increasing fault throw. Fold width and amplitude become increasingly similar during fold evolution, until the fold is breached by the underlying normal fault. We also derive a number of preliminary empirical relationships between readily observable structural and stratigraphic parameters in our dataset that may help estimate the geometry and size of poorly exposed (i.e. in the field) or imaged (i.e. in the subsurface) growth folds. In addition, we discuss how fault growth models (i.e. constant-length vs. propagating) may impact the three-dimensional evolution of growth folds. Finally, our work shows that growth folds are likely more common than previously thought. For example, although they are well-documented in areas characterised by weak, ductile cover strata and low strain rates, our dataset illustrates that growth folds may also occur in brittle, relatively strong rocks and in regions with high strain rates. However, the underlying controls on fold occurrence remain elusive. © 2019 Elsevier B.V.
关键词	Extension Fault-propagation fold Fault-related fold Forced fold Growth fold Normal fault Rift Salt-influenced rift
英文关键词	fault propagation; fold; normal fault; rifting; strain rate
语种	英语
来源期刊	Earth Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203408
作者单位	Basins Research Group (BRG), Department of Earth Science and Engineering, Imperial College, Prince Consort Road, London, SW7 2BP, United Kingdom; Bureau of Economic Geology, The University of Texas at Austin, University Station, Box X, Austin, TX 78713-7508, United States
推荐引用方式 GB/T 7714	Coleman A.J.,Duffy O.B.,Jackson C.A.-L.. Growth folds above propagating normal faults[J],2019,196.
APA	Coleman A.J.,Duffy O.B.,&Jackson C.A.-L..(2019).Growth folds above propagating normal faults.Earth Science Reviews,196.
MLA	Coleman A.J.,et al."Growth folds above propagating normal faults".Earth Science Reviews 196(2019).