Geochemistry of hydrothermal and stream sedimentary rutile in the Tiegelongnan porphyry-epithermal Cu (Au) deposit, Tibet: A tool for exploration

• DOI: 10.1016/j.oregeorev.2024.105970
• Publication Date: 2024-03-07T03:44:39Z
• Authors: Chao Yang; Georges Beaudoin; Yang Song; Ju-Xing Tang; Yi-Yun Wang; Yannick Buret; Xiao-Wen Huang; Xing-Hai Lang; Bin Lin
• Keywords: Rutile

Rutile is a common and stable mineral in porphyry Cu deposits, morphology geochemistry of rutile are recognized as potential indicator for exploration. In this study, we investigate physical features chemical composition hydrothermal the Tiegelongnan porphyry-epithermal system, well stream sediments nearby to establish method apply an exploration proxy. Four stages have been identified. Potassic alteration stage (Rt1) associated with biotite, elongated acicular shape small grain size (20–50 μm). from lower temperature phyllic (Rt2), quartz veins (Rt3), advanced argillic (Rt4), has characteristic sector zoning larger (50–150 The more commonly present Rt2, Rt3, Rt4, that high-grade mineralization, incorporation W, Fe, V, Sn, Zr. earlier also geochemical signature different other three types rutile, characterized by significantly Al, Cu, Zr, Nb, Hf, higher Sc Fe contents. Low-temperature (Rt2, 3, 4) share many similarities, but Rt3 Nb Ta contents (median = 3371.0 176.0 ppm, respectively), whereas Rt4 Sb content 24.3 ppm). trace element data study literature integrated develop Partial Least Square-Discriminant Analysis (PLS-DA) multivariate statistics plots can discriminate deposit orogenic gold VHMS stages. PLS-DA predict sedimentary gold-bearing (RtSAu) adjacent derived deposit, mainly low-temperature This consistent similarity between RtSAu (Rt2 + Rt4). further confirmed U-Pb age 125.3 ± 4.7 Ma (n 24, 2σ) RtSAu, which main mineralization ∼ 120 deposit. We infer may formed during ∼120 epithermal system at Tiegelongnan, already largely eroded. general, our findings prove capability using combing texture, compositions, geochronology, tools, their spatial distribution, proxy deposits.