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The Pulang super-large porphyry Cu polymetallic deposit, located in the Sanjiang area of Yunnan Province, is one of the largest Cu deposits in China. This deposit hosts Cu resources of ~5 × 106 t and other ore-forming elements, such as Mo, Au, Ag, Pb, Zn, Pt and Pd. Recently, obvious hydrothermal vein-type Pb–Zn mineralization, with a Pb + Zn resource of ~0.4 × 106 t, has been detected in the North Ore Section of the deposit. However, the genesis of these Pb–Zn ore bodies, especially their relationship to the major Cu ore bodies in the South Ore Section, remains controversial. We conducted geologic description, fluid inclusion petrography and microthermometry, and C, H, O and S isotope studies to uncover the genesis of Pb–Zn vein-type mineralization in North Pulang. As a result, three types of Pb–Zn veins were identified: a quartz–pyrrhotite–chalcopyrite–sphalerite–galena vein, a quartz–pyrrhotite–sphalerite–galena vein, and a calcite–quartz–pyrrhotite–galena vein. All fluid inclusions in the quartz from different veins are liquid-rich inclusions, with homogenization temperatures in the range of 184 °C–235 °C and salinities between 10.4 wt.% and 17.8 wt.% NaCl eq., indicating that the Pb–Zn ore-forming fluid was a single-phase fluid with a low temperature and low-to-medium salinity. Hydrothermal quartz in different stages displays δDwater values ranging from −46.9‰ to −120.0‰ (V-SMOW), and the calculated δ18Owater values range from 2.4‰ to 4.3‰ (V-SMOW), implying that the mineralization fluids likely originated from magma, with a minor involvement of meteoric water. The δ13CCal values (−2.3‰ to −7.9‰ V-PDB) of calcite indicate that C likely originated from a deep-seated source. The δ34S values of chalcopyrite, pyrite, pyrrhotite and sphalerite reveal that S was possibly derived from magmatic rocks. Based on the above data, it is suggested that the Pb–Zn mineralization in North Pulang was the result of the northward migration of ore-forming fluids that originated from South Pulang along the NE-trending structural fractures. A strong water–rock interaction occurred during the migration process. However, the involvement of meteoric water and accompanied cooling of fluids were most likely responsible for the precipitation of galena and sphalerite. [ABSTRACT FROM AUTHOR]

The Geza arc is an important part of the Sanjiang tectono-magmatic belt and is a newly discovered copper polymetallic ore concentration area in northwest Yunnan province, Southwest China. The area comprises numerous metal ore deposits, including one super-large deposit, three large deposits, etc. The formation of these deposits was closely related to intermediate–acidic magmatic intrusions. Based on previous studies, the “big data” analysis technique was used for a comparative study of large geochemical datasets of granite related to ore-formation in the Geza porphyry copper deposit and global adakites. As a result, 1313 element combinations and 127,765 overlap ratios were obtained. The results show that the Geza porphyry has similar geochemical characteristics to global adakites (the ratios of REE and Ga to major elements are in the range of global adakites). However, the Cu, Mo, and Zn contents of the porphyry are significantly higher than those of global adakites, and the porphyry may, therefore, represent an end-member of the global range of adakite composition. In addition, the geochemistry of adakites associated with the porphyry copper deposits overlaps in part with that of global adakites, although most of the data lie outside of the range of global adakites (i.e. low Mn/Cu, Sr/Cu, Na/Cu, and Zr/Cu values, and high Th/Cu, Ba/Cu, Na/Mo, Rb/Mo, Th/Mo, Ta/Mo, Ba/Mo, Mn/Zn, and Ba/Zn values). The samples with characteristics that deviate significantly from the geochemistry of global adakites show more advanced mineralization and alteration, and a stronger relationship with Cu and Mo mineralization. The results of geochemical data mining can be used as a prospecting indicator, and provide a new scientific basis for geological prospecting of the deep levels and periphery of the Geza Cu polymetallic ore belt.

[Display omitted] • Hydrothermal apatite U–Pb age (208.1 ± 6.5 Ma) is coeval with peripheral intrusions. • C–O–S–Pb isotopes indicate a magmatic source for the ore fluid and material. • The Qukuleke is classified as a sediment-hosted intrusion-related deposit. • Intrusion-related Au ore system is a valuable target for regional exploration. Genetic classification of sediment-hosted Au deposits is often disputed in many orogenic belts around the world. The marine sediment-hosted Qukuleke Au deposit (>5 t Au) is an example of this, which has been attributed to orogenic or intrusion-related type. This paper addresses its metallogeny through detailed geologic and petrographic studies, together with apatite U–Pb dating and C–O–S–Pb isotopes. The hydrothermal paragenesis at Qukuleke is divided into three stages (I to III): Stage I (pre-ore) sheeted quartz veins; Stage II (main ore) pervasive sericite ± carbonate ± apatite ± pyrite ± arsenopyrite alteration associated with quartz–calcite ± stibnite veins; Stage III (post-ore) barren calcite veins. LA-ICP–MS hydrothermal apatite U–Pb dating on Stage II disseminated Au ore yielded 208.1 ± 6.5 Ma, coeval with the Late Triassic post-collisional intrusions from the periphery of Qukuleke deposit. Carbon–oxygen isotopes of Au–Sb ore-related hydrothermal calcite show that the hydrothermal fluids were derived from the marine carbonate ore host with considerable magmatic input. Lead–sulfur isotopes of the Au–Sb ore-related are consistent with those of coeval intrusions around the deposit, but different from those of the local sedimentary strata. Our age and geochemical data suggest the presence of a magma source that supplied the hydrothermal fluids, sulfur and metals for the mineralization. Combining the low sulfide content and the Au–As–W–Sb–Mo assemblage characteristics, the Qukuleke is best classified as a sediment-hosted intrusion-related Au deposit. Considering also the discovery of the large coeval Qukukekedong Au deposit nearby, we propose that Late Triassic intrusion-related Au system is a high-potential exploration target in the western EKOB. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metallogenic materials and reduced sulfur primarily originated from ore-bearing carbonate rocks. • The precipitation of sulfides was jointly controlled by the W/R reaction and TSR process. • The metallogenic fluids exhibit an evolutionary trend from the metamorphic basement to ore-hosting carbonate rocks. • The Maoping deposit was formed within the late Triassic compressive tectonic setting, with the involvement of Emeishan magmatism. The Maoping Pb-Zn deposit is spatially associated with the late Permian Emeishan basalts and structurally controlled by the NE-trending reverse fault-anticline tectonic system. Nevertheless, there remains limited comprehension of its genetic association with the Emeishan magmatism, as well as the coupling relationship between the overall metallogenic processes and geodynamic evolution. In order to clarify these scientific issues, the syn -ore hydrothermal calcites, sulfides, and sulfates were systematically collected from the representative No. I ore body at different elevations in the Maoping deposit for bulk C-O-S and in situ S-Pb isotopic analyses. Bulk C-O isotopic compositions of syn -ore calcite (δ13C V-PDB = − 4.94 to −0.81‰, δ18O SMOW = +17.66 to +21.16‰) and associated fluids (δ13C V-PDB = −4.56 to −0.48‰, δ18O SMOW = +8.63 to +12.13‰) indicate that C in fluids was mainly derived from ore-bearing carbonate rocks, whereas O was generated by fluid/rock (W/R) interaction process between initial fluids and carbonate rocks. Such process also triggered carbonate dissolution and syn -ore calcite precipitation. In situ Pb isotopic ratios of galena (208Pb/204Pb = 39.116–39.425, 207Pb/204Pb = 15.742–15.767 and 206Pb/204Pb = 18.603–18.753) are more comparable with those of ore-bearing sedimentary rocks, while in situ and bulk S isotopic compositions (δ34S Py+Sp = +20.06 to +23.86‰; δ34S Gn = +17.26 to +18.44‰) of sulfides exhibit high consistency with those of sulfates (δ34S Brt = +17.01 to +19.07‰) within the ore-bearing strata. This suggests that the majority of metallogenic materials and reduced sulfur originated from this source. Meanwhile, the S-Pb isotopic data and relatively high ore-forming temperature (206 ℃) further reveal that the ore-bearing fluids underwent gradual migrated and evolved from the basement to the ore-hosting strata. The Emeishan magmatism not only provided the majority of the thermal power for the fluid circulation, but also contributed a portion of the ore-forming fluids and materials. During the late Triassic, ore-forming fluids migrated along compresso-shear reverse faults to coeval secondary extensional ore-hosting structures due to regional compressive tectonic stresses caused by the Indosinian orogeny and Xuefengshan intraplate orogeny. The mixing of metal-rich hydrothermal fluids with the marine evaporites (mainly gypsum) within sedimentary rocks first triggered thermos-chemical sulfate reduction (TSR) process. The subsequent continuous W/R interaction resulted in a decrease in fluid acidity and temperature, ultimately leading to the precipitation of metal sulfides. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal activity at Mengxing can be divided into three stages: pre-ore stage, syn -ore stage (Stage I and Stage II), and post-ore stage. • Fluid inclusion data show a trend of decreasing of homogenization temperature and salinity from stage I to stage II. • The H-O-S-Pb isotopic compositions are similar to skarn deposits and epithermal deposits, but significantly different from the MVT deposits in Sanjiang region, indicating Mengxing deposit is a hydrothermal deposit closely related to magmatism. The Mengxing Pb-Zn deposit is located in the central-southern Baoshan block, SW China, which contains over 1.02 Mt metals with the average Pb + Zn grade of 12.12 %. In this deposit, the orebodies are mainly stratabound and developed in the Silurian limestone of the Shangrenheqiao Formation. The mineral assemblage is mainly consisted of sulfides, quartz, calcite and barite. Based on petrographic observation, three mineralization stages have been recognized, including the pre-ore, syn -ore (including stage I and II) and post-ore stages. Fluid inclusion study shows that the ore-forming fluid in Mengxing deposit belongs to a NaCl-H 2 O-(CO 2) system with medium–high temperature (187.3–320.1 °C) and medium–low salinity (2.1–17.9 wt% NaCl equiv.). H-O-S-Pb isotopic studies reveal that the ore-forming fluid dominantly originated from magmatic water, and reacted with organic matter preserved in sedimentary strata at stage I and mixed with metamorphic/meteoric water at stage II. The sulfur for mineralization was mainly contributed by magmatic sulfur. Marine sulfates preserved in Silurian sedimentary strata also contributed some ore-forming sulfur in stage II. The ore-forming metals in Mengxing deposit were jointly contributed by sedimentary strata and deeply concealed granitic magmatism. Based on these geological and geochemical characteristics, we suggest that the Mengxing Pb-Zn mineralization is Epithermal type and formed in multiple stages. [ABSTRACT FROM AUTHOR]

[Display omitted] • Luerma is the firstly discovered porphyry in western Gangdese. • The metallogenic of Luerma occurred at ca. ∼ 212 Ma, which thus represents the oldest known porphyry deposit in the Gangdese belt. • Five stages of porphyry copper (molybdenum-gold) mineralization has been put forward in Gangdise porphyry copper belt. Due to the difference of lithospheric structure between the eastern and western segment of Gangdese metallogenic belt, it is generally believed that porphyry copper deposits are mainly developed in the east. However, the newly discovered of Luerma porphyry copper deposit in the western segment of Gangdese provides an excellent research object for us to supplement this understanding. The molybdenite re-Os isotope dating of two samples from quartz veinlet ores (ca. 213.1 ± 5.2 Ma and ca. 212.0 ± 3.7 Ma), combined with the LA-ICP-MS zircon U-Pb dating of three ore-bearing quartz monzonite porphyry samples (ca. 212.7 ± 0.9 Ma, 213.1 ± 1.1 Ma, and ca. 211.8 ± 1.8 Ma), indicates a new generation of Late Triassic Luerma copper porphyry-type mineralization events in the western Gangdese magmatic belt. The Luerma porphyry is a strongly peraluminous shoshonite series rock, is rich in silicon total alkalis, potassium and aluminum, has low contents of calcium, magnesium, and iron. It is enriched in light rare earth elements and large ion lithophile elements, relatively depleted in heavy rare earth elements and high field strength elements, and has negative Eu anomalies and no Ce anomalies. The porphyry exhibits relatively low (87Sr/86Sr) i values (0.705617 on average), high ε Nd (t) values (0.63 on average), high ε Hf (t) values (11.98 on average), and young two-stage Hf model ages. The Luerma ore-related porphyries are most likely generated dominantly from partial melting of juvenile crust that formed by metasomatized mantle during the subduction of the NeoTethys Ocean to the Lhasa terrane and underwent crystal fractionation during the process. The deposit is currently the oldest and westernmost porphyry deposit in the Gangdese porphyry copper belt, providing evidence that porphyry copper mineralization in this belt began in at least the Late Triassic. [ABSTRACT FROM AUTHOR]