Can relative paleointensities be determined from the normalized magnetization of the wind-blown loess of China?

Although the wind-blown loess and interbedded paleosol sequence in the Loes s Plateau of China has been extensively studied and regarded as one of the most complete terrestrial records of both the geomagnetic field and climati c changes during the Quaternary, little attention has been paid to it as a source of relative paleointensity. In this study, we examine the Malan loes s (L1), the last glacial sediments, in the Lingtai section to determine whe ther loess is able to reliably record the relative paleointensity. Toward t hat end both the conventional normalizing method as well as the pseudo-Thel lier method [Tauxe et al., 1995] were used in conjunction with the examinat ion of the rock magnetic properties and natural remanent magnetization (NRM ). Rock magnetic properties of L1 show the uniformity in terms of magnetic mineralogy and grain size, suggesting that they may be suitable for relativ e paleointensity studies. Normalized remanences derived from L1 show highs between both 72-66 ka and 62-51 ka and lows near 63 ka, 42 ka and between 2 0 and 10 ka. Comparable results using different normalization parameters su ggest that large-amplitude variation of normalized magnetization may reflec t the intensity variation of the geomagnetic field. However, comparisons of the normalized magnetization with contemporaneous marine records show some dissimilarities. In particular, the intensity low at 20-10 ka, correspondi ng to the last glacial maximum, is not compatible with the Sint-800 composi te record. On the other hand, spectral coherence analyses of middle- and hi gh-frequency components of the normalized magnetizations suggest some clima tic influence. Thus this apparent discrepancy may be explained by climatic changes in the Loess Plateau and the resulting effect on the NRM.