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• The wavelength 1455 nm is important for the mineralization. • Silicification variation can indicate the fluid flow direction. • Illite crystallinity is associated with mineralization and metallogenic environment. • Illite mapping with SWIR can judge whether low sulfidation epithermal deposit is. Field measurements using shortwave infrared (SWIR) reflectance from drill hole samples provided an effective method to map variations in illite crystallinity and the illite assemblage minerals associated with hydrothermal alteration zonation of the Sinongduo low sulfidation epithermal Ag-Pb-Zn deposit, Tibetan Plateau, China. The SWIR mineral spectral information was combined with electron probe micro-analysis (EPMA) measurements, and microscope observations to provide geological insights into: (a) the likely metallogenic fluid nature of the mixture of magmatic fluids and a cooler water source; (b) the illite physico-chemical properties of the associated hydrothermal fluids; (c) the illite, montmorillonite and sericite evolutionary interactions among these fluids, country rocks, and alteration minerals; and (d) the alteration minerals relationships and illite crystallinity to the economic mineralization. The results suggest that illite characterizations can be used as an indicator for epithermal deposit prospecting. [ABSTRACT FROM AUTHOR]

[Display omitted] • SIMS U-Pb dating of Jiama intrusives brackets magmatic event related to Jiama porphyry-skarn mineralization in 1.3 Myr. • Zircon O-Hf isotopic compositions suggest Jiama ore-forming magmas were derived from melting of the newly formed Tibetan lower crust. • No significant magma mixing has been observed during the magmatic evolution from diorite to granite. The post-collisional Gangdese metallogenic belt with over 45 Mt Cu has attracted worldwide attention. We report the whole-rock geochemistry, zircon SIMS U–Pb geochronology, and in situ zircon Hf–O isotopic compositions of the Jiama deposit in the Gangdese belt. The intermediate to the felsic intrusive rocks are characterized by high SiO 2 (64.8 to 78.8 wt. %) and Al 2 O 3 (12.1 to 16.3 wt. %) contents, high Sr/Y ratios (43–74), showing the geochemical characteristics of adakites. Zircons from four intrusives yield U–Pb ages of 16.19 ± 0.20 Ma, 15.67 ± 0.32 Ma, 15.44 ± 0.16 Ma, and 14.90 ± 0.16 Ma, respectively, which brackets magmatic event related to mineralization in 1.3 Myr (16.19 to 14.90 Ma). Magmatic zircons have intermediate δ18O (+5.21 to + 7.18‰), and depleted Hf isotopic values (εHf(t) = 1.8 to 9.4). In combination of whole rock, plagioclase, and zircon geochemistry, we suggest the main ore-forming magma was derived from the remelting of the newly formed lower crust. During the whole journey of magma ascending from lower crust to the surface, no significant injection or mixing of mafic melt from different source has been observed. This is supported by three lines of evidence: 1) There is no clear reverse zonation in plagioclase, 2) the major and trace element compositions of continuous lithologies from diorite to granite shows no significant mixing, 3) there is no significant change of the zircon O and Hf isotope among different intrusions. Our study suggests that the formation of the giant porphyry deposits such as Jiama in post-collisional setting likely form in a short-term (<1.5 Myr) without significant magma mixing during magmatic evolution from diorite to granite. [ABSTRACT FROM AUTHOR]