Origin, weathering, and geochemical composition of loess in southwestern Hungary

摘要

Loess geochemistry generally reflects paleo-weathering conditions and it can be used to determine the average composition of the upper continental crust (UCC). In this study, major and trace element concentrations were analyzed on loess samples from southwestern Hungary to determine the factors influencing their chemical compositions and to propose new average loess compositions. All studied loess samples had nearly uniform chemical composition, suggesting similar alteration history of these deposits. Chemical Index of Alteration values (58-69) suggested a weak to moderate degree of weathering in a felsic source area. Typical non-steady state weathering conditions were shown on the Al2O3-CaO+Na2O-K2O patterns, indicating active tectonism of the Alpine-Carpathian system during the Pleistocene. Whole-rock element budgets were controlled by heavy minerals derived from a felsic magmatic or reworked sedimentary provenance. Geochemical parameters indicated that dust particles must have been recycled and well homogenized during fluvial and eolian transport processes. (C) 2008 University of Washington. All rights reserved.