Late Paleozoic provenance shift in the east-central Ordos Basin: Implications for the tectonic evolution of the north China Craton
2021
Abstract Detrital minerals are important recorders of sedimentary transport and provenance, both of which have significant implications for basin genesis and tectonics. By integrating detrital zircon U-Pb dating and Lu-Hf isotopic analyses, quantitative mineralogy of heavy minerals, and paleocurrent analysis, we identified here two Late Paleozoic provenance shifts in the east-central Ordos Basin, North China. The Late Paleozoic sandstones in the Liulin section of the Ordos Basin reveal detrital zircon U-Pb age peaks at 2.5 Ga, 1.85 Ga and 0.3 Ga. The ca. 0.41–0.42 Ga age populations are observed in the late Carboniferous Benxi Formation and late Permian Shiqianfeng Formation, respectively, yet are missing in the early-middle Permian Taiyuan, Shanxi and Shihezi Formations. The Precambrian detrital zircons show highly variable Lu-Hf isotopic compositions, with eHf(t) values ranging from negative to positive (−22.1 to +15.5). In contrast, the Phanerozoic detrital zircons present enriched Hf isotopic signatures, indicating magma sources with considerable ancient crustal components. Combined with heavy minerals and paleocurrent analysis, this study demonstrates that the major sedimentary provenance of the early-middle Permian Taiyuan, Shanxi and Shihezi Formations was the Yinshan orogenic belt. Sedimentary provenance for the late Carboniferous Benxi Formation and late Permian Shiqianfeng Formation could have been the Yinshan orogenic belt and the southern margin of the North China Craton (NCC). The first early Permian provenance shift may have been initiated by the uplift of the Yinshan orogenic belt, while the uplift of the southern margin of the NCC (associated with the Qinling orogenic belt), might have precipitated the second shift.
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