Abstract:

The Wuhe Shalu copper deposit is located at the northern margin of the Wuqia foreland basin in the Tianshan Mountains, Southwest Xinjiang.Large sets of Meso-Cenozoic continental sand bodies are deposited in this basin, forming important ore-bearing rock series of lead, zinc, copper, uranium, and other sandstone-type deposits.The lack of sedimentological studies on this deposit has long restricted the understanding of regional metallogeny and hindered mineral exploration.Therefore, this paper uses the Wuhe Shalu copper deposit as a case study, focusing on the clastic sedimentary rocks of the Neogene Miocene Anju’an Formation containing copper.This study primarily uses methods from sedimentology, sequence stratigraphy, lithofacies paleogeography, and clastic petrology.Samples for grain-size analysis of the lower member of Anju’an Formation in the mining area were systematically collected.Grain-size analysis and analytical methods of clastic rock were used to conduct in-depth research on the sediments in the mining area.The results show that the sedimentary facies type of Anju’an Formation is consistent with that of braided river delta.We identified two sedimentary subfacies: braided river delta plain and braided river delta front.In addition, we recognized six sedimentary microfacies in each lithologic segment: distributary channel sand bar, natural embankment on land, underwater distributary channel, interdistributary bay, estuarine sand bar, and far sand bar.The lower part of the Anju’an Formation is the main copper-rich horizon in the study area.The microfacies of the underwater distributary channel and the distributary channel sand bar are key targets for copper exploration in the Wuhe Shalu area.The sudy results provide a prospecting strategy for resource prediction on both sides and the periphery of the Wuhe Shalu copper deposit, and also serve as an important reference for searching for sandstone copper deposits in this area.

Key words: sandstone-type copper deposit, grain size characteristic, sedimentary environment, Anju’an Formation, Wuhe Shalu, Wuqia Basin