气候变化领域集成服务门户(CCPortal): Using paleomagnetism to test rolling hinge behaviour of an active continental low angle normal fault, Papua New Guinea

CCPortal

DOI	10.1016/j.epsl.2021.116745
	Using paleomagnetism to test rolling hinge behaviour of an active continental low angle normal fault, Papua New Guinea
	Watson E.J.; Turner G.M.; Little T.A.; Piispa E.J.
发表日期	2021
ISSN	0012821X
卷号	558
英文摘要	Metamorphic core complexes (MCCs) have been attributed to slip on long-lived detachment faults in extensional environments. At the surface, such faults are typically shallow dipping (<30°). This is inconsistent with Andersonian faulting theory, which requires that normal faults should nucleate and slip at steeper dips. One possible solution to this mechanical problem is a “rolling hinge” evolution for the fault during its slip history. In this model, faults initiate at steep dips (e.g. 60°) and back-tilt to shallower dips due to flexure and isostatic uplift in response to unloading of the footwall during slip. The Mai'iu fault is an active, rapidly slipping (∼1 cm/yr) low-angle (dip 20-22° at the surface) normal fault. Sampling of the footwall Goropu Metabasalt revealed a consistent normal-polarity component of magnetisation with moderate inclination that we interpret to have been acquired during uplift and cooling of the footwall rocks during the Brunhes chron. Comparison of the direction of the normal component with the expected average (geocentric axial dipole) direction at the site latitude indicates 23.9° ± 2.6° (1σ) of back-tilting of the footwall about the strike of the Mai'iu fault, consistent with a rolling hinge style of rotation. This indicates an original fault dip of 41.3-48.5°, as is consistent with independent estimates of original fault dip from fault-bedding cut-off angles and microseismicity at depth. This study is the first of its kind to demonstrate, using paleomagnetism, large-scale horizontal-axis rotations consistent with a rolling hinge evolution for a continental MCC. © 2021 Elsevier B.V.
关键词	continental extension detachment faults metamorphic core complex paleomagnetism rolling hinge Woodlark Rift
英文关键词	Geomagnetism; Hinges; Unloading; Detachment fault; Horizontal axis rotation; Isostatic uplift; Mechanical problems; Metamorphic core complex; Microseismicity; Normal component; Papua New Guinea; Fault slips; cooling; detachment fault; extensional tectonics; footwall; magnetic inclination; metamorphism; normal fault; paleomagnetism; tectonic evolution; uplift; Papua New Guinea
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203334
作者单位	School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand; School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand
推荐引用方式 GB/T 7714	Watson E.J.,Turner G.M.,Little T.A.,et al. Using paleomagnetism to test rolling hinge behaviour of an active continental low angle normal fault, Papua New Guinea[J],2021,558.
APA	Watson E.J.,Turner G.M.,Little T.A.,&Piispa E.J..(2021).Using paleomagnetism to test rolling hinge behaviour of an active continental low angle normal fault, Papua New Guinea.Earth and Planetary Science Letters,558.
MLA	Watson E.J.,et al."Using paleomagnetism to test rolling hinge behaviour of an active continental low angle normal fault, Papua New Guinea".Earth and Planetary Science Letters 558(2021).