--> --> Effects of Fault Throw and Mechanical Stratigraphy on Fault Architecture in the Lenghu Fold-Thrust Belt, Qaidam Basin, NE Tibet
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AAPG ACE 2018

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Effects of Previous HitFaultNext Hit Throw and Mechanical Stratigraphy on Previous HitFaultNext Hit Architecture in the Lenghu Fold-Thrust Belt, Qaidam Basin, NE Tibet

Abstract

Understanding the detailed Previous HitfaultNext Hit architecture at an outcrop scale of reverse faulting is critical for understanding the processes involved in fold-thrust belts as well as predicting the degree of Previous HitfaultNext Hit compartmentalisation, the relationship between folds and faults, the distribution of strain and sub-seismic faulting deformation. Although previous studies have investigated the relationship between faults and folds developed within compressional systems, the detailed Previous HitfaultNext Hit architecture of thrust faults remain poorly constrained, particularly at an outcrop scale. Not only are sub-seismic faults poorly imaged but even seismically resolvable structures are poorly imaged because of either steep dipping nature of reflections or complexity of Previous HitfaultNext Hit architecture at an outcrop scale, which makes it difficult to predict the Previous HitfaultNext Hit zone geometry precisely. The detailed Previous HitfaultNext Hit architecture analysis of an exceptionally well-exposed fold-thrust belt in the Qaidam Basin is reported.

The Lenghu fold-thrust belt, provides an exceptionally well-exposed outcrop example of a reverse Previous HitfaultNext Hit-propagation fold, which enables high-resolution fieldwork to collect multiple scale data, including stratigraphy, strikes/dips, shallow subsurface profiles and detailed Previous HitfaultNext Hit outcrop maps. Detailed stratigraphic logging coupled with high-resolution profiles provides a unique insight into the 3D geometry of a thrust Previous HitfaultNext Hit at both regional and an outcrop scale. Integrating the high-resolution Previous HitfaultNext Hit system mapping, we observe that 85-90% of the estimated throw is accommodated on the main Previous HitfaultNext Hit zone, which has sufficient throw to be imaged on a seismic profile, while 15-20% of the throw is accommodated on smaller scale folds and faults that are beyond seismic resolution. The exceptionally exposed outcrops of the Lenghu thrust Previous HitfaultNext Hit was mapped in detail, which allows us to understand the Previous HitfaultNext Hit architecture patterns regarding to the Previous HitfaultNext Hit throw (ranging from tens of centimeters to tens of meters). Previous HitFaultNext Hit outcrops with comparable Previous HitfaultNext Hit throw but different level of mechanical heterogeneity also allow us to evaluate the control of mechanical stratigraphy on Previous HitfaultNext Hit zone deformation. By coupling the structural observations within a stratigraphic context, we can demonstrate that although the main Previous HitfaultNext Hit controls the overall strain in the system, the local stratigraphy plays a critical role in how the strain is accommodated and whether it is partitioned into single faults, multiple-Previous HitfaultTop splays or folding.