A constant Chinese Loess Plateau dust source since the Late Miocene

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1016/j.quascirev.2019.106042.

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Authors

Anna Bird , Ian Millar, Tanja Rodenburg, Thomas Stevens, Martin Rittner, Pieter Vermeesch , Huayu Lu

Abstract

The Pliocene-Pleistocene boundary marks a major change in global climate and East Asian monsoon dynamic. However, the role of the global atmospheric dust-cycle over this time is unclear; in particular, whether, changes in the dust cycle influenced climate change, or resulted from it. Chinese loess records past dust-cycle history and the influences of aridification and monsoon circulation over the last 40 Ma. Previous work on the Chinese Loess Plateau argue over whether changes in dust source occur at the Pliocene-Pleistocene boundary, or at 1.2 Ma, despite these intervals marking major shifts in monsoon dynamics (Ding et al., 2000; Lu, 2015). We present Sr, Nd and Hf isotope data from multiple sites and show that dust source largely remains unchanged across these boundaries. Shifts in geochemistry are due to changes in grain-size and weathering. These tracer isotopes show that dust was dominantly sourced from the Northern Tibetan Plateau, with some input from the local bedrock. This shows that a major established and constant dust source on the Tibetan Plateau has been active and unchanged since late Miocene, despite dramatically changing climate conditions. Changes in loess accumulation are a function of climate change in Tibetan Plateau source regions rather than effects from increased aridification over the Pliocene-Pleistocene boundary.

DOI

https://doi.org/10.31223/osf.io/ux82d

Subjects

Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics

Keywords

Quaternary, China, Loess, Neogene, Palaeoclimate, Radiogenic isotopes

Dates

Published: 2019-05-30 14:38

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License

CC BY Attribution 4.0 International

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