Geochemical and magnetic characteristics of aeolian transported materials under different near-surface wind fields: An experimental study

摘要

By combining field investigations, field sampling, wind-tunnel experiments, and laboratory measurements, the relationships between near-surface winds and the geochemical and magnetic characteristics of windtransported materials were statistically analyzed. Our study was conducted using bulk surface samples from a major potential dust source area in Central Asia (the Ala Shan Plateau). Under near-surface wind velocities ranging from 8 to 22 m/s, the coefficients of variation ranged between 1.6% and 14.9% for chi(if), 1.4% and 11.0% for chi(ARm), and 0.7% and 123% for SIRM of the transported materials. For the 26 elements and oxides investigated, the coefficients of variation of Ti, Cr, As, Zr, Ce, Pb, and Cu in the samples were greater than 10%. No consistent patterns were found between magnetic characteristics and elemental and iron oxide concentrations as a function of variations in near-surface wind velocities. In potential dust source areas under near-surface wind velocities, there are variations in the relationships between magnetic and geochemical characteristics in the fine fractions of transported materials with different particle sizes. Given the wide variation in magnetic and geochemical characteristics of aeolian-transported materials under different near-surface winds, their use as proxies for past climate reconstruction must be carefully appraised. (C) 2015 Elsevier B.V. All rights reserved.