The Hongshan complex, located in the southern part of the Taihang Mountains in the central part of the North China Craton, consists of syenite stocks (including fine-grained biotite aegirine syenite, medium-grained aegirine gabbro syenite, coarse-grained aegirine gabbro syenite, syenite pegmatite, and biotite syenite porphyry), with monzo-diorite and monzo-gabbro dikes. This paper presents zircon U-Pb ages and Hf isotope data and whole-rock geochemical data from the Hongshan complex. LA–ICP-MS zircon U–Pb age from the fine-grained biotite aegirine syenite, monzo-diorite, and monzo-gabbro are 129.3 ± 2.0 Ma, 124.8 ± 1.3 Ma, and 124.1 ± 0.9 Ma, respectively, indicating their emplacement in the Early Cretaceous when the North China Craton was extensively reactivated. The monzo-diorite and monzo-gabbro have low SiO2 contents (48.94–57.75 wt%), total alkali contents (5.2–9.4 wt%), and εHf (t) values of −22.3 to −18.4 and are enriched in MgO (4.0–8.2 wt%), Al2O3 (14.3–15.8 wt%), light rare earth elements (LREEs) and large ion lithophile elements (LILEs). Interpretation of elemental and isotopic data suggests that the magma of monzo-diorite and monzo-gabbro were derived from partial melting of the enriched lithospheric mantle metasomatized by slab-derived hydrous fluids. Syenites with high alkali (K2O + Na2O = 9.4–13.0 wt%) and Sr contents (356–1737 ppm) and low Yb contents (0.94–2.65 ppm) are enriched in Al (Al2O3 = 16.4–19.1 wt%), but depleted in MgO (0.09–2.56 w%), Cr (Avg = 7.16 ppm), Co (Avg = 6.85 ppm) and Ni (Avg = 9.79 ppm), showing the geochemical features of adakitic rocks associated with thickened lower crust. Combining zircon 176Hf/177Hf ratios of 0.282176 to 0.282359, εHf(t) values of −18.3 to −11.8 and εNd (t) values of −11.1 to −8.2, we conclude that the syenite magma was derived from the mixing of the thickened lower crust and the enriched lithospheric mantle magma. These magma processes were controlled by Paleo-Pacific plate subduction and resulted in the destruction and thinning of the central North China Craton.
The Biliya Ag-Pb-Zn polymetallic (SLZP) deposit (16.5 Mt, @ 52.9 g/t Ag, 2.6% Pb and 2.3% Zn) lies in the Great Xing'an Range, Northeast China. Breccia-, veinlet- and vein-type Ag-Pb-Zn ore bodies are primarily hosted in the quartz porphyry, trachyandesite and rhyolitic tuff. They are spatially and temporally related to andesitic porphyry. Three mineralization processes are identified: stage I: grey quartz - pyrite + tawny sphalerite (high Cd2+), stage II: grayish white quartz - pyrite + grey sphalerite (high Fe2+) + galena + argentite + tetrahedrite, stage III: white quartz-pyrite. The alterations consist of quartz + sericite, illite + quartz, fluorite + calcite + opal and chlorite zone. The silver-lead–zinc mineralization primarily corresponds to stage II. Five sulfide samples from stage II yielded a well-fitted isochron age of 131.3 ± 2.4 Ma (MSWD = 2.4), marking the timing of Ag-Pb-Zn polymetallic mineralization. CO2-bearing NaCl-H2O (C), gaseous CO2 (V); vapour-liquid H2O-NaCl (WL) and fluid-phase H2O-NaCl (L)-type of fluid inclusions were distinguished. Their petrographic and microthermometric features and H-O isotopic data suggest that the hydrothermal fluids were initially originated from magmatic source, with intensive mixing with meteoric water and that their temperatures and salinities are 254–130 ℃ and 7.15–1.22 wt% NaCl eqv, respectively, belonging to a reduced fluid (CO2-H2O-NaCl ± CH4) system. In-situ S and bulk Pb isotope analyses indicate that the metal materials were related to andesitic magma from the lower crust. The deposit geology, fluid inclusions, stable isotopes and chronology results suggest that the Biliya deposit belongs to a low-sulfidation (LS) epithermal SLPZ deposit. Boiling and fluid immiscibility coupled with suddenly decreasing in temperature, pressure, logfS2 of the hydrothermal fluids are likely to play important roles in Biliya SLPZ ore deposition.
Abstract: Based on the data base of 1285 mineral deposits of 22 commodities in 121 countries of 6 continents of the world, the authors use the linear trend analysis for their reserves to determine the cut‐off limited order of reserves to select 36 exceptional superlarge (as peak mineral), 95 superlarge and 314 large deposits as new recognized intellect for their quantitative change. We have projected above 445 large‐superlarge deposits on (1:5 M) global tectonic background map and divided 4 metallogenic domains, 21 metallogenic belts. Global metallogeny of large‐superlarge deposits are: unity by endogenic, exogenic metamorphic and epigenetic in origin; speciality in different metallogenic domains and belts; preferentiality to ore‐forming elements of Cu, Au, Fe, Ag, Cr, Mn, Zn, Pb, Sb, Hg, to continental margins or plate convergent belts, to Intra‐continental tectono‐magmatic complex belts and Large ductile shear zones; abnormality by the global oxyatmversion (excess oxygen atmospheric event) in Archean, redoxyatmversion (lack oxygen atmospheric event) in Proterozoic‐Paleozoic, and tectonosphere thermal erosion (great amount of tectonic magmatic event) in Mesozoic‐Cenozoic.
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Based on the data base of 1285 mineral deposits of 22 commodities in 121 countries of 6 continents of the world, the authors use the linear trend analysis for their reserves to determine the cut-off limited order of reserves to select 36 exceptional superlarge (as peak mineral), 95 superlarge and 314 large deposits as new recognized intellect for their quantitative change. We have projected above 445 large-superlarge deposits on (1:5 M) global tectonic background map and divided 4 metallogenic domains, 21 metallogenic belts. Global metallogeny of large-superlarge deposits are: unity by endogenic, exogenic metamorphic and epigenetic in origin; speciality in different metallogenic domains and belts; preferentiality to ore-forming elements of Cu, Au, Fe, Ag, Cr, Mn, Zn, Pb, Sb, Hg, to continental margins or plate convergent belts, to Intra-continental tectono-magmatic complex belts and Large ductile shear zones; abnormality by the global oxyatmversion (excess oxygen atmospheric event) in Archean, redoxyatmversion (lack oxygen atmospheric event) in Proterozoic-Paleozoic, and tectonosphere thermal erosion (great amount of tectonic magmatic event) in Mesozoic-Cenozoic.
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