The response of element anomalies to the tectonic environment based on 1:50 000 stream sediment survey in North Qilian tectonic belt, Qinghai Province
WANG Jin-Shou1,2, HE Jiao2, CHEN Jing2, ZHANG Zhi-Qing2
1. Faculty of Earth Resource, China University of Geosciences (Wuhan), Wuhan 430074, China;
2. Qinghai Institute of Geological Survey, Xining 810012, Qinghai, China
Elements anomalies, such as Ag, As, Au, Ba, Bi, Co, Cr, Cu, Fe, Hg, Mo, Mn, Ni, Pb, Sn, Sb, Ti, W, Zn, from 1:50 000 stream sediment survey, North Qilian tectonic belt, vary with the tectonic evolution in different geological epochs, the elements themselves are endowed with dual properties of time and tectonic setting. According to the contrast value method, element content data of 49 303 samples from different strata were processed in combination with stratigraphic geochemical R cluster grouping. The results show that Co, Cr, Ni anomalies are in response to Paleoproterozoic post-orogenic cracking, Au, Bi and part of Cu anomalies are in response to Ordovician oceanic subduction-closing stages, Pb, Zn anomalies probably corresponded to local volcanic activity in the ocean floor in Ordovician-Silurian period. Devonian Hg, Sb anomalies have no reasonable regional tectonic interpretation, and the phenomenon of Mo element content in the Carboniferous peak indicates strong uplift and erosion on the periphery of North Qilian orogenic belt. W, Sn element anomalies reflect subduction and collision setting in Ordovician and Silurian. The regularity of the stream sediment anomalies' response to tectonic evolution suggests that the compatible ( incompatible ) features of mantle-derived elements from stream sediment survey can better distinguish tectonic environments, and the combinational geochemical approach from a large data sample and tectonic study is feasible.
王进寿, 何皎, 陈静, 张志青. 青海北祁连构造带1:5万水系沉积物元素异常对区域构造环境演化的响应[J]. 物探与化探, 2015, 39(5): 930-936.
WANG Jin-Shou, HE Jiao, CHEN Jing, ZHANG Zhi-Qing. The response of element anomalies to the tectonic environment based on 1:50 000 stream sediment survey in North Qilian tectonic belt, Qinghai Province. Geophysical and Geochemical Exploration, 2015, 39(5): 930-936.