The affinity between the North China Craton and the microcontinent Alxa Block during the Paleo-Mesoproterozoic: From a perspective of the stratigraphy and provenance analysis

Abstract

The extension or fragmentation of supercontinents can lead to sedimentary depositions in continental interiors or margins. Analyzing the provenance of these deposits is crucial for understanding the source and tectonic affinity between different terranes. The relationship between the North China Craton (NCC) and the Alxa Block has been a subject of controversy, with previous studies primarily focusing on magmatism, paleomagnetism, and localized qualitative provenance analysis. To address this problem comprehensively, this review synthesizes detrital zircon geochronological and Lu-Hf isotopic data to conduct a quantitative comparison of the provenance associated with Mesoproterozoic sediments across various regions of the NCC and Alxa Block. The analysis reveals that Mesoproterozoic sediments in the Helanshan area exhibit a similar provenance to those found in the Dunzigou and Nuorigong groups in the Alxa Block, as well as the Zhartai Group in the northern NCC. These findings suggest that Mesoproterozoic sedimentary series in the western NCC and Alxa Block, displaying comparable stratigraphic patterns, were formed through rift-to-marginal deposition within similar tectonic settings. Consequently, it is inferred that the NCC and Alxa Block were coherent units during the fragmentation of the supercontinent Nuna/Columbia. This quantitative approach to provenance analysis contributes valuable insights, shedding light on the nature of the relationship between these geological entities during a critical period in Earth’s history.