A two-stage plume-induced rifting in the Neoproterozoic North Tarim: Evidence from detrital zircon study and seismic interpretation

A rift basin developed in the Neoproterozoic Tarim Craton and it provides a key perspective for understanding the breakup of Rodinia. The rift-related successions with glacial deposits spanning ca. 200 m.y. in the North Tarim are studied through detrital zircon U-Pb dating and seismic interpretation. A total of 1503 ages from 11 samples are reported and two kinds of age distribution patterns are recognized. Samples of the Qiaoenbrak Group show unimodal distribution with most ages at 900-800 Ma; samples of the upper two formations show bimodal distribution: One age range at 900-600 Ma and another at 2000-1800 Ma. The emergence of Paleoproterozoic zircons indicates uplift and exhumation of the basement, which is compatible with plume upwelling. We find that there are prominent gaps between depositional ages and crystalline ages of detrital zircons, which corresponds with a plume environment instead of a back-arc environment. Besides, seismic and well data show that the Qiaoenbrak Group was deposited in (half-)grabens controlled by normal faults. The lower Sinian was less restricted but still affected by these faults, while the Upper Sinian thickens prominently towards the outer edge of the basin. Together, we propose a new two-stage plume-induced model for the Neoproterozoic rift in the Tarim Craton in which two different evolution paths are recognized: From rift to aulacogen for the Nanhua Qiaoenbrak Group, and from rift to passive margin for the Sinian System