Relationship between the Altyn Tagh strike-slip fault and the Qaidam Basin:New insights from superposed buckle folding in Hongsanhan

摘要

The relationship between the sinistral strike-slip Altyn Tagh Fault (ATF) and the internal tectonic deformation of the Qaidam Basin remains a controversial issue. Uncovering the relationship between the structures along the southern slope of the ATF is a viable solution to this problem. The 'snake-like' Hongsanhan superposed fold is located on the southern slope of the ATF. The Hongsanhan structure is controlled by the superposition of two generations of folds. The first-generation NW-SE-trending f(1) fold, which developed during the Oligocene, constitutes the principal component of the present-day Hongsanhan fold, while the second-generation NE-SW-trending f(2) folds formed during the middle Miocene. The structure of the Hongsanhan superposed fold proves that the large-scale sinistral strike-slip movements along the ATF began during the Oligocene. In addition, a flower structure associated with the ATF continuously extends into the Qaidam Basin.