Abstract:
Changba area, Gansu Province is located in Changba-Yeshuiheariscan and Indosinian Pb-Zn-Ag-Au metallogenic zone. During the implementation of the project titled
Prospecting Prediction of Changba Ore Concentration Area,
Gansu Province initiated by the Development and Research Center of China Geological Survey, the existing data on geology, geophysics, geochemistry, remote sensing, mineral distribution, and prospecting indicators of Changba area, were further processed. Most importantly, a 1∶50 000 tectonic-geochemical survey of Shilipu and Huangzhuguan Map-sheets was carried out. A total of 8694 samples were mainly collected from altered rocks and fillings in structures, with a mean sampling density of 13.02 samples per km
2. Among them, 2911 samples were used for tectonic-geochemical analysis. Nineteen elements (i.e. Au, Ag, Cu, Pb, Zn, As, Sb, Bi, Hg, W, Sn, Mo, Cd, Cr, Co, Ni, Mn, Ba, and B) were analyzed using the inductively coupled plasma-mass spectrometer (ICP–MS), atomic fluorescence spectroscopy (AFS) and perpendicular electrode- emission spectrometry (ES). As a result, the distribution regularity of major metallogenic elements (i.e. Pb, Zn, and Au) and their associated elements were generally ascertained, the relations of these elements with stratum and structures were identified, and three prospecting areas were proposed. Based on this, a 1∶50 000 geochemical dataset of Shilipu and Huangzhuguan Map-sheets, Gansu Province (also referred to as the Dataset) was finally developed. It consists of one data table and an atlas. The former is composed of the primary analysis data of 19 elements for 2911 samples and the later includes one sampling point bitmap, 19 element geochemical maps, five element-association anomaly maps, one integrated anomaly map, and one interference and interpretation map. A total of 344 single-element geochemical anomalies and 24 integrated anomalies were newly discovered in Changba area. Meanwhile, Combining with the information on geology, minerals, geophysical prospecting, geochemical prospecting and remote sensing, one Au prospecting target and two Pb-Zn prospecting targets were delineated. The Dataset could provide geochemical information for mineral geological surveys and serves as an important reference for deep mineral prospecting prediction and basic geological research of Changba and its surrounding areas.