Geochemical Characteristics of Trace Elements in the Early Cambrian Zhuzhusi Formation, Qujing Region, Yunnan Province, and Their Implications for Sedimentary Environment

Abstract

This study investigates the climate, water salinity, and redox conditions during the deposition of the Early Cambrian Zhuzhushi Formation in Qujing, Yunnan Province, China. Utilizing elemental geochemical methods, we reconstruct the paleoenvironment of the Early Cambrian Zhuzhushi Formation in the Qujing area. Results indicate: Li content ranged from 1.5 to 56.3 μg/g, with Sr/Ba ratios between 0.09 and 0.56, indicating a predominantly freshwater environment during the Zhuzhushi Formation's deposition in the study area. V/(V+Ni) values ranged from 0.66 to 0.91 (mean 0.79), U/Th ratios from 0.75 to 15.45 (mean 4.33), and δU values from 1.38 to 1.96 (mean 1.73), collectively indicating a predominantly anoxic-reductive environment during the Zhuzhushi Formation deposition; Paleoclimate indices C ranged from 1.09 to 4.48, and Sr/Cu ratios from 1.16 to 9.30, indicating a predominantly warm and humid climate during the Chuzhusi Formation deposition. Babio values ranged from 200 to 1309.98, and P/Ti ratios from 1.59 to 62.5, suggesting high productivity levels throughout the Chuzhusi Formation deposition period. The concentrations of Ba, Ni, Co, Mn/Fe (average 0.005), and Rb/Zr (average 2.27) indicate shallow water depth during the Zhuzhushi Formation deposition. Sr content indicates an average paleowater temperature of 30.38°C, suggesting a warm water environment.