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

ABSTRACT

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 f₁ fold, which developed during the Oligocene, constitutes the principal component of the present-day Hongsanhan fold, while the second-generation NE–SW-trending f₂ 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.

KEYWORDS:

• Cenozoic tectonic
• Altyn Tagh Fault
• Qaidam Basin
• superposed fold
• Hongsanhan fold

Acknowledgments

Thanks to Dr. Robert j. Stern for the help in submitting this paper for review. Many thanks to the three reviewers for their helpful suggestions. We are indebted to Qiquan Zhang and Chuanwu Wang for their assistance in data analyses. We thank Changhao Zhang for assistance in the field.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by the grants from the National Science and Technology Major Project [Grant No.2017ZX05008-001] and the National Natural Science Foundation of China [Grant No.41930213].