Reconstruction of Stress Fields and U–Pb Calcite Dating of the Outer Zone of the South Verkhoyansk Fold-and-Thrust Belt
摘要
The U–Pb dating of carbonate rocks using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has enabled precise age determinations of vein calcite, which has found wide application in tectonic studies to obtain the age of dispalcements along faults and the corresponding stress fields. The aim of the study is to apply this approach to the fold-and-thrust structures of the southern part of the Verkhoyansk fold-and-thrust belt (VFTB) in the Belaya River basin within the Gornostakh Anticline. Based on structural analysis and paleostress reconstruction, three stages of deformation with approximately E–W compression, WNW–ESE extension with a dextral strike-slip component, and a sinistral strike-slip faulting correspondently were identified. For the first time for the South Verkhoyansk sector, U–Pb dating of the calcite vein established the age of the extension stage at about 63 Ma, which turns out to be younger than the compression stages documented in the same region (~160–70 Ma).