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The Jiama deposit, a significant porphyry‐skarn‐type copper polymetallic deposit located within the Gangdese metallogenic belt in Tibet, China, exemplifies a typical porphyry metallogenic system. However, the mineral chemistry of its accessory minerals remains under‐examined, posing challenges for resource assessment and ore prospecting. Utilizing electron microprobe analysis and LA‐ICP‐MS analysis, this study investigated the geochemical characteristics of apatite in ore‐bearing granite and monzogranite porphyries, as well as granodiorite, quartz diorite, and dark diorite porphyries in the deposit. It also delved into the diagenetic and metallogenic information from these geochemical signatures. Key findings include: (1) The SiO2 content, rare earth element (REE) contents, and REE partition coefficients of apatite indicate that the dark diorite porphyry possibly does not share a cogenetic magma source with the other four types of porphyries; (2) the volatile F and Cl contents in apatite, along with their ratio, indicate the Jiama deposit, formed in a collisional setting, demonstrates lower Cl/F ratios in apatite than the same type of deposits formed in a subduction environment; (3) compared to non‐ore‐bearing rock bodies in other deposits formed in a collisional setting, apatite in the Jiama deposit exhibits lower Ce and Ga contents. This might indicate that rock bodies in the Jiama deposit have higher oxygen fugacity. Nevertheless, the marginal variation in oxygen fugacity between ore‐bearing and non‐ore‐bearing rock bodies within the deposit suggests oxygen fugacity may not serve as the decisive factor in the ore‐hosting potential of rock bodies in the Jiama deposit. [ABSTRACT FROM AUTHOR]

Jurassic sandstones in the Xiongcun porphyry copper–gold district, southern Lhasa subterrane, Tibet, China were analysed for petrography, major oxides and trace elements, as well as detrital zircon U–Pb and Hf isotopes, to infer their depositional age, provenance, intensity of source-rock palaeo-weathering and depositional tectonic setting. This new information provides important evidence to constrain the tectonic evolution of the southern Lhasa subterrane during the Late Triassic – Jurassic period. The sandstones are exposed in the lower and upper sections of the Xiongcun Formation. Their average modal abundance (Q21F11L68) classifies them as lithic arenite, which is also supported by geochemical studies. The high chemical index of alteration values (77.19–85.36, mean 79.96) and chemical index of weathering values (86.19–95.59, mean 89.98) of the sandstones imply moderate to intensive weathering of the source rock. Discrimination diagrams based on modal abundance, geochemistry and certain elemental ratios indicate that felsic and intermediate igneous rocks constitute the source rocks, probably with a magmatic arc provenance. The detrital zircon ages (161–243 Ma) and εHf(t) values (+10.5 to +16.2) further constrain the sandstone provenance as subduction-related Triassic–Jurassic felsic and intermediate igneous rocks from the southern Lhasa subterrane. A tectonic discrimination method based on geochemical data of the sandstones, as well as detrital zircon ages from sandstones, reveals that the sandstones were most likely deposited in an oceanic island-arc setting. These results support the hypothesis that the tectonic background of the southern Lhasa subterrane was an oceanic island-arc setting, rather than a continental island-arc setting, during the Late Triassic – Jurassic period. [ABSTRACT FROM AUTHOR]

• The host volcanic rocks of the Sinongduo Ag–Pb–Zn deposit erupted at approximately 61.9 Ma. • The sphalerite rich in Ag, In and Cd is a kind of Fe-poor sphalerite that is commonly found in IS epithermal deposits. • The Sinongduo Ag–Pb–Zn deposit is an IS epithermal deposit rather than a LS epithermal deposit. The Sinongduo Ag–Pb–Zn deposit was first defined as a typical low sulfidation (LS) epithermal deposit in the widespread Linzizong volcanic succession (LVS), Gangdese belt, Tibet. This paper we describe the lithology, mineralization, and hydrothermal alteration based on current advances in exploration, and use multiple chemical and geochronology methods, including whole-rock geochemistry (major and trace elements) of ores and the lithocap, the mineral chemistry of sphalerite, and the LA–MC–ICP-MS zircon U–Pb dating of host volcanic rocks to better constrain the genesis of the Sinongduo deposit and give some exploration advice. In the Sinongduo deposit, the host crystal tuff yields a zircon U–Pb age of 61.9 ± 0.4 Ma, indicating nearly simultaneous diagenesis and mineralization. The metallic minerals are mainly FeS-poor sphalerite, galena, pyrite, and minor chalcopyrite, along with silver and silver-based precious minerals. These minerals, particularly FeS–poor sphalerite, pyrite, and chalcopyrite, represent IS states. Mineral chemistry shows that the content of FeS in sphalerite is lower than 4.94 mol% and the Ag concentration is quite high, ranging from 16 to 1798 ppm with a mean concentration of 245 ppm. Low Ga/in ratios (<1) and enrichment of In and Sn in sphalerite imply that the ore-forming fluid is dominated by magmatic water with intermediate temperature. Gangue minerals include the silicic group (quartz and chalcedony), carbonates group (calcite, siderite, ankerite, etc.), and hematite. Alterations, including illite, montmorillonite, and sericite, are widely distributed. The results suggest that the Sinongduo deposit is not a LS epithermal deposit but a typical IS epithermal deposit and we believe that there is potential for Au and Ag exploration. [ABSTRACT FROM AUTHOR]