Geochemical Characteristics Comparison of Different Scale Sediments in the Humid and Semi-humid Hilly Area, Southern China

Abstract

Appropriate sampling grain size is very important for accurate geochemical information and better exploration effects in different landscapes. In order to determine the best sampling grain size of the sediments in the humid and semi-humid hilly landscape, a sampling experiment was carried out. Samples of two scales, -60 and-10-+80, were collected from the Hulesi—Ningguodun area in Southern Anhui Province. 40-element high-precision data, which are needed for regional geochemical exploration, were acquired by X-ray Fluorescence Spectrometry (XRF) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Results show that the contents of rock-forming elements in sediments are similar to the background values of regional rocks. Samples with grain size of-10-+80 scale are rich in As, Au, Hg, Mo, Pb and Sb. Samples with grain size of-10-+80 scale have been weakly modified by later surface weathering and reserve the original geochemical characteristics, which are remarkably better than the-60 scale in delineating anomalies of mineralization and reflecting characteristics of ore-related anomalies. Therefore, the-10-+80 scale is preferred for stream sediment surveys in the middle and lower mountains and hilly areas in southern Anhui province, which is meaningful to the choice of stream sediment sample grain size in performing geochemical exploration of similar landscapes in China.

Keywords

• sampling scale
• stream sediment
• rock-forming elements
• geochemical characteristics
• the humid and semi-humid landscape area