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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]

(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]

A suite of lamprophyres, spatially associated with mafic lavas and potassic felsic intrusive rocks, was emplaced between 36.5 ± 0.2 and 33.7 ± 0.5 Ma (based on phlogopite 40 Ar/ 39 Ar dating) on the eastern side of the Ailao Shan-Red River shear zone in the western Yangtze Craton. These shoshonitic and ultrapotassic intrusive rocks post-date the ~ 60–55 Ma collisional event between the Indian and the Asian continents. They are characterized by: (1) enrichment in large-ion lithophile elements and light rare-earth elements with (La/Sm) n = 3.15–7.15; (2) strong positive Pb spikes; (3) depletion in high-field-strength elements (e.g. Nb/La = 0.08–0.98); (4) high initial 87 Sr/ 86 Sr (0.706–0.709) with negative εNd(t) values of − 10.5 to − 0.9; (5) old Nd model ages of 1542–945 Ma; and (6) radiogenic ( 207 Pb/ 204 Pb) i of 15.57–15.70 and ( 208 Pb/ 204 Pb) i (38.70–39.06). These features suggest that the mantle source was metasomatized by Proterozoic subduction beneath the Yangtze Craton. The lamprophyres have similar trace element patterns, and Sr–Nd–Pb isotope compositions, as coeval mafic lava, indicating a common source of metasomatized veined continental lithospheric mantle (CLM). Lower degree partial melting of metasomatic veins likely generated the lamprophyres, whereas the coeval mafic lava was likely derived from melting of phlogopite harzburgite. The lamprophyres and mafic lava have similar Sr–Nd isotope systematics as CLM-derived Neoproterozoic mafic rocks and Late Permian Emeishan low-Ti basalt in the region, indicating that they share the same Proterozoic source. We envisage that mantle plumes thermally eroded the Proterozoic metasomatized CLM beneath the western part of the Yangtze Craton during 825–750 Ma and 260–250 Ma, although residual metasomatized domains remained before being tapped by delamination after the India–Asia continental collision during the Paleogene period. [ABSTRACT FROM AUTHOR]