Detrital Zircon U-Pb Dating for Clastic Rocks from Boreholes in the Eastern Junggar Basin: Constraints on Permian Tectonics in the Southern Central Asian Orogenic Belt

Abstract

Permian sedimentary successions, widely distributed in the eastern Junggar Basin, may record key details on the closure of the Paleo-Asian Ocean in this region. Results of boreholes show that Permian strata is mainly composed of mudstone, sandy mudstone, siltstone, sandstone, sandy conglomerate, dolomite, and limestone. Detrital zircon U-Pb dating results of three sandstone samples yielded the calculated maximum ages of 296 Ma, 278 Ma and 293 Ma, indicating they possibly deposited during the Early Permian. Permian strata in the eastern Junggar Basin show similar rock associations and detrital zircon age data distribution patterns. Our new and compiled age data for sandstone samples in the eastern Junggar Basin and Bogda region yield predominant Paleozoic ages, close to their sedimentary ages. Such detrital zircon age data distribution patterns support the hypothesis that these Early Permian meta-clastic rocks in the eastern Junggar Basin and Bogda region were deposited in a subduction-related basin, and indicate an Early Permian Ocean prevented Precambrian detritus from the Central Tianshan block from depositing in the eastern Junggar Basin and Bogda region.

Keywords

detrital zircon U-Pb dating / tectonostratigraphy / Junggar Basin / Paleo-Asian Ocean

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2024 Geological Society of China