Investigation of spatially non-stationary influences of tectono-magmatic processes on Fe mineralization in eastern Tianshan, China with geographically weighted regression

摘要

The volcanic-sedimentary Fe mineralization in eastern Tianshan mineral district is controlled by a series of tectono-magmatic processes. Controlling effects of related geo-processes on Fe mineralization are varied across the space; relationships among these geo-processes are consequently spatially non-stationary. Before investigating the relationships, this paper jointly utilizes the singularity index mapping technique and principal component analysis to recognize Fe mineralization associated felsic intrusions, fault systems and the Yamansu Formation. After that, both ordinary least square and geographically weighted regression models are used to inspect the relationships that existed between Fe mineralization and these identified controlling factors. Results by geographically weighted regression quantitatively depict non-stationary influences of tectono-magmatic processes on Fe accumulation in spatial scenario, which demonstrate well the significant improvement in parameter estimation in comparison with ordinary least square regression. Examining regression coefficients, it can be inferred that Fe mineralization at different locations in eastern Tianshan mineral district was caused by interactivities of multiple geo-processes to different degrees, and these variations can be demonstrated by the results as well. Experiences derived from current study can be a useful reference to future regression analysis on geological issues.