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Baiyangping Pb–Zn–Cu–Ag deposit is located in Lanping basin, northwestern Yunnan province. The deposit is composed of a few ore veins and can be divided into several ore blocks. The ore bodies are primarily hosted in Mesozoic carbonate, sandstone and siltstone along the north–south-striking, NWW-striking and NE–SW-striking fault zones. There are breccia, massive, vein like and disseminated ores. The main ore minerals are sphalerite, galena, gratonite, jordanite, tetrahedrite series minerals, chalcocite, chalcopyrite, realgar, orpiment, bournonite, cobalt-bearing arsenopyrite, argentite, kongsbergite, cobaltine, siegenite. The sizes of fluid inclusions in Baiyangping deposit are generally less than 10 μm and have the shape of round, oval, irregular, etc. The ore-forming fluid system is Ca 2+ –Na + –K + –Mg 2+ –Cl − –F − –NO 3 − brine system. The freezing temperature of fluid inclusions in mineral deposits ranges from −26.4 to −0.2 °C, average −14.6 °C; the homogenization temperature is concentrated in 120–180 °C, and the salinity is between 0.35 and 24.73 wt% (NaCl eq ), average 16.9 wt% (NaCl eq ). δ 13 C PDB and δ 18 O SMOW values of hydrothermal calcite range from −4.16‰ to 3‰ and −2.5‰ to 20.4‰, respectively. δ 34 S values of sulfide minerals range from −10.2‰ to 11.2‰, average 5.6‰. The sulfide samples yield 206 Pb/ 204 Pb values of 18.609–18.818, 207 Pb/ 204 Pb of 15.548–15.842 and 208 Pb/ 204 Pb = 38.514–39.556. C–O–S–Pb isotope compositions of the Baiyangping deposit indicate a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata, the ore-forming fluid belongs to basin brine fluid system, which is mixed with the precipitate water, sulfur in sulfides and sulfosalts is derived from thermal chemical sulfate reduction, and the thermal decomposition of sulfur-bearing organic matter. The metal mineralization material is from sedimentary strata and basement. The late Pb–Zn polymetallic mineralization event superposed within early Cu–Co polymetallic mineralization event resulted in the differences of ore-forming elements for Baiyangping deposit. [ABSTRACT FROM AUTHOR]

• Fluids in the three skarn stages are characterized by complex volatile system, respectively. • Isotopic data showed a primary magmatic source, mingled with meteoric water at the late stages. • Boiling, temperature falling and f O 2 rising are the key to metal deposition at the retrograde stage. • f O 2 and temperature decreasing play role in metal precipitation at the late hydrothermal stage. Scheelite mineralization accompanied by traces of chalcopyrite occurs in skarn systems in the giant Zhuxi deposit in the Taqian area, Northeastern Jiangxi province, South China. Three paragenetic stages of skarn with ore deposition have been recognized: the prograde skarn, retrograde skarn and hydrothermal quartz-sulfide stages. Microthermometer data showed that the prograde skarn were formed at relatively high temperatures (450–>500 °C) and pressures (0.97–1.38 kbars) and low oxidation to weak reduction conditions. The Raman microprobe data demonstrated that the fluid of the stage was H 2 O–NaCl/KCl/CaCl 2 ± CH 4 /C 2 H 4 system. The retrograde skarn alteration formed at 1.24 kbars and relatively medium temperatures (280–320 °C), and the ore-forming fluid was H 2 O–NaCl/KCl/CaCl 2 system. During the hydrothermal quartz-sulfide stage, the fluids were methane-bearing aqueous, low-salinity (0.9–8.0 wt% NaCl eqv) and low homogeneous temperature (160–240 °C). Correspondingly, the minimum fluid pressures were evaluated between 75 and 252 bars. The H- and O-isotopic values from the prograde and retrograde stages implied that the mineralizing fluids were derived principally from magmatic water. The mineralizing fluids in the quartz-sulfide hydrothermal stages were mingled with magmatic water with some meteoric water as well as minor contributions of wall rocks. The sulfur and lead isotopes indicated that ore-forming materials including sulfur, lead, copper, zinc and iron in the Zhuxi deposit were derived from local magmatic and sedimentary sources. Geological, fluid inclusion and isotopic data supported that the Zhuxi deposit is a typical skarn-type W(Cu) deposit related to ilmenite-series granitic rocks and formed in a compressional tectonic environment. [ABSTRACT FROM AUTHOR]

• Coqen zircon xenocrysts were originated from ancient recycled continental crustal. • Zircons record the temporal evolution of magmatism and crustal thickness in Coqen. • Lhasa terrane evolutionary process is restored by these zircon xenocrysts. The Cenozoic volcanic rocks of Coqen are located in the western central Lhasa subterrane, where knowledge of the regional lithospheric architecture and related magmatic processes is still lacking. To address this issue, we used in situ U–Pb dating, Lu–Hf isotopic and mineral inclusion analysis in zircon xenocrysts among trachyandesite. These zircons from volcanic samples yielded wide U–Pb ages from 18 Ma to 2424 Ma, showing three significant age peaks at ∼ 246 Ma, 193 Ma, and the most intense one at 128 Ma, which represent three major magmatic processes that developed in the area. The earliest zircon dates suggest the age of volcanic eruption in the Coqen area was not earlier than 18 Ma. Zircon xenocrysts trace elements data point to the continental crust origin of central Lhasa subterrane. We provide the evidence for evolutive magmatism of the Lhasa terrane by calculating ΔFMQ, and show that the oxygen fugacity goes from reduced to oxidized (Cambrian to Miocene). The very low ε Hf (t) indicate a long-term magmatic event sequence, with the Zenong Group having the most vigorous magmatic activity. The old U–Pb ages and T DM C confirmed that an ancient basement of the Precambrian exist in the middle Lhasa terrane. Our work also restores the tectonic and crustal thickness evolutionary process of Coqen area even entire Lhasa terrane. In the back of a series of thickening and thinning processes, the Tibetan crust drastically thickened at ∼ 54 Ma, and gradually created what is now believed to be the thickest crust in the world. [ABSTRACT FROM AUTHOR]

(a) Main crustal processes within magmatic plumbing system underneath the ultrapotassic Zhuopan pluton. (b) Petrogenetic model for the 37–30 Ma mafic potassic–ultrapotassic volcanic and plutonic rocks in western Yunnan, highlighting their distinct magmatic ascent paths and processes in the crust. [Display omitted] • Clinopyroxene zoning and textures record a complex magma history. • Clinopyroxenes crystallized at two crustal levels with distinct depths. • Crustal contamination and magma recharge took place in the magma system. • The Zhuopan pluton originated from a metasomatized lithospheric mantle. • Potassic–ultrapotassic volcanic and plutonic rocks differ in element systematics. Ultrapotassic rocks that are rare and volumetrically minor have attracted much attention due to their genetic link with the terrestrial mantle evolution and specific tectonic settings. However, crustal processes that may be involved in the generation of these rocks are poorly known despite extensive studies on their mantle sources. The ultrapotassic Zhuopan pluton in western Yunnan, southeastern Tibetan Plateau, consists chiefly of clinopyroxene-rich mafic–intermediate rocks and well preserves clinopyroxene textures and zoning, implying its potential record of valuable information on crustal processes. This pluton was emplaced at ∼ 36 Ma, suggesting its formation in the post-collisional setting associated with the India–Asia collision. Clinopyroxenes have three distinct types and form complex zoning patterns, with colorless clinopyroxene at the core, pale green at the mantle, and dark green at the rim. The clinopyroxene–liquid thermobarometer indicated that the clinopyroxenes crystallized in two magma reservoirs at depths of ∼ 18 and ∼ 10 km. The in situ clinopyroxene Sr isotopes revealed that wall-rock contamination had taken place and then was punctuated by recharge with a relatively evolved magma, leading to the resorption of pre-existing clinopyroxenes. The Zhuopan plutonic rocks were formed through evolution within multi-stage crustal reservoirs from the primary mafic magma derived from a subduction-metasomatized lithospheric mantle. Together with the coeval (37–30 Ma) potassic–ultrapotassic volcanic counterparts, we determined that the two differ in elemental systematics. This may have resulted from distinct magmatic ascent paths and processes in the crust. We also concluded that the generation of these coeval potassic–ultrapotassic rocks was triggered by massive lithospheric delamination. [ABSTRACT FROM AUTHOR]