Abstract:

Extracting concealed metallogenic information is a fundamental task in exploration geochemistry. The Huangshan-jing’erquan Ni-Cu metallogenic belt, in the eastern Tianshan, Xinjiang, is chosen as a study case to identify concealed local anomalies from complex geochemical background by singularity mapping technique. The results illustrate that the Ni concentration value in the geochemical map according to primary Ni contents is obviously different from that in the geochemical map by singularity mapping technique. In the former, the Ni concentration value is high in the Tuha basin and medium to low in the tectonic-magmatic belt. While in the later, there are adverse features. Due to geological analysis, high concentration value of the element Ni is resulted from intruding of mafic-ultramafic intrusions. These intrusions are of low-degree differentiation and unfavorable to form deposits in Tuha basin so that there occur large-area anomalies in the basin. However, in the tectonic-magmatic belt, though intrusions are small and with medium to low geochemical anomalies, they are differentiated well and favorable to form deposits. The concentration-aera (C-A) method is used to analyze singularity value and delineate anomalies. Because delineated anomalies fit well with known Ni-Cu deposits, they can provide geochemical evidence for delineating target regions.

Key words: singularity mapping technique, geochemistry, Huangshan-jing’erquan, Ni-Cu deposit, Xinjiang