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Yumen conglomerate ages in the South Ningxia Basin, north‐eastern Tibetan Plateau, as constrained by cosmogenic dating
Author(s) -
Shi Wei,
Hu Jianmin,
Chen Peng,
Chen Hong,
Wang Yongchao,
Qin Xiang,
Zhang Yu,
Yang Yong
Publication year - 2020
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3510
Subject(s) - conglomerate , geology , neogene , unconformity , plateau (mathematics) , paleontology , structural basin , paleogene , cosmogenic nuclide , cenozoic , pleistocene , tectonic uplift , early pleistocene , quaternary , geomorphology , mathematical analysis , mathematics , physics , cosmic ray , astrophysics
The South Ningxia Basin, as the outermost Cenozoic basin on the north‐eastern margin of the Tibetan Plateau, is characterized by a series of convex to the north‐east arcuate structural belts. Constraining the final formation time of the belt has been an ongoing focus in geologic research of the Tibetan Plateau. A set of early Pleistocene conglomerates, the Yumen conglomerate, overlying the folded pre‐Quaternary formations are widely distributed throughout the whole basin, and the latest folded formation is the upper Pliocene Ganhegou Formation, marking the termination of folding uplift in the north‐eastern Tibetan Plateau. Based on 1:50,000 geological mapping, a set of early Pleistocene alluvial fan conglomerates overlying the folded Palaeogene–Neogene strata were recognized and agree well with the Yumen conglomerate. Here, the Yumen conglomerate formation ages were determined to be 0.6–1.04 Ma using cosmic nuclide burial dating. Combined with the upper limit age of the latest strata beneath the unconformity with the latest palaeomagnetic age of 2.77 Ma, the crustal shortening event is restricted to the period 2.77–1.04 Ma, indicating that it is the most intense tectonic shortening event along the north‐eastern margin of the Tibetan Plateau.