Rock magnetism and geochemistry of two Plio-Pleistocene Chinese loess-palaeosol sequences - Implications for quantitative palaeoprecipitation reconstruction

Jan Bloemendal*, Xiuming Liu

*Corresponding author for this work

Research output: Contribution to journalArticle

113 Citations (Scopus)

Abstract

Stratigraphic and spatial variations in the magnetic properties of Chinese loess are widely accepted as reflecting changes in the intensity of soil forming processes over time and space. Recently, several workers have used statistical correlations between the magnetic susceptibility and related parameters of modern loess plateau soils and modern climate to generate transfer functions to reconstruct past temporal and spatial trends in precipitation. Here we try to assess the viability of this approach by conducting magnetic and geochemical measurements of two long (∼2.5 My) loess-palaeosol sequences from different locations on the modern precipitation gradient across the loess plateau. One site, Duanjiapo, is located on the southern humid margin of the plateau; and the other site, Luochuan, is located in a drier modern environment some 160 km further north. Our results indicate discrepancies between magnetic and geochemical indicators of weathering and soil forming intensity and that any attempt to predict palaeoprecipitation at Duanjiapo using published approaches would be significantly in error. Overall our results indicate a complex response of magnetic mineral transformations to climate, including the production of both ferrimagnetic and antiferromagnetic minerals within the same climatic interval, together with the destruction of magnetic material within some of the palaeosols. Therefore we suggest considerable caution should be exercised in generating quantitative climatic reconstructions from a single magnetic parameter.

Original languageEnglish
Pages (from-to)149-166
Number of pages18
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume226
Issue number1-2
DOIs
Publication statusPublished - 3 Oct 2005

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