Quartz OSL chronology and dust accumulation rate changes since the Last Glacial at Weinan on the southeastern Chinese Loess Plateau

Abstract

The fine‐grained (4–11 μm) quartz O ptically S timulated L uminescence ( OSL ) dating technique was applied to the W einan section on the southeastern C hinese L oess P lateau ( CLP ) with a high luminescence sampling resolution (10‐ and 20‐cm intervals). Fifty‐eight OSL ages, spanning c. 1–74 ka, were obtained for the 10‐m loess–palaeosol sequences. The reliability of the OSL dating and the constructed chronology was confirmed by comparing the OSL ages with independent dates from other studies and by correlation with palaeoclimatic time series. The closely spaced OSL ages at W einan indicate that the mean dust accumulation rate ( DAR ) of L 1–1 ( MIS 2, 7.0±0.9 cm ka −1 ) is lower than those of L 1–3 ( MIS 4, 19.1±6.1 cm ka −1 ) and L 1–2 ( MIS 3, 16.0±0.7 cm ka −1 ) and that the mean DAR c. 30–20 ka ago (11.4±2.4 cm ka −1 ) is higher than that c. 20–10 ka ago (3.0±0.1 cm ka −1 ) in L 1–1 . The subsequent calculation of the mass accumulation rate ( MAR ) indicates that the MAR of L 1–1 (107 g m −2 a −1 ) is much lower than those of L 1–2 (247 g m −2 a −1 ) and L 1–3 (307 g m −2 a −1 ). By comparing the mean DAR results during the L ast G lacial at W einan with those at a further six sites from other studies, we observed that the mean DAR of L 1–2 is higher (lower) than that of L 1–1 on the eastern (western) CLP, and that the mean DAR during MIS 2 has an evident transition from high to low at c. 20 ka on the entire CLP . Possible mechanisms for the above mean DAR changes at orbital and sub‐orbital time scales are presented.

Quartz OSL chronology and dust accumulation rate changes since the Last Glacial at Weinan on the southeastern Chinese Loess Plateau

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