This paper introduces the common paragenetic minerals of skarn-type wollastonite ore and its principle of gravitation separation for purification. Through the separation experiment of concentrating table on the wollas...This paper introduces the common paragenetic minerals of skarn-type wollastonite ore and its principle of gravitation separation for purification. Through the separation experiment of concentrating table on the wollastonite ore from Xiaojipu Wollastonite Mine of Hubei province, the product has reached the reguirement of wollastonite powder used as the ceramic raw material.展开更多
Although some porphyry-skarn deposits occur in post-collisional extensional settings,the post-collisional deposits remain poorly understood.Here the authors describe the igneous geology,and mineralization history of T...Although some porphyry-skarn deposits occur in post-collisional extensional settings,the post-collisional deposits remain poorly understood.Here the authors describe the igneous geology,and mineralization history of Tuolangla,a newly-discovered porphyry-skarn Cu-W-Mo deposit in southern Tibet that belongs to the post-collisional class.The deposit is associated with Lower Cretaceous Bima Formation.It was intruded by granodiorite porphyry intrusions at about 23.1 Ma.Field investigation indicated that mineralization is spatially and temporally associated with granodiorite porphyry.Molybdenite yielded a Re-Os weighted mean age of 23.5±0.3 Ma and is considered to represent the age of skarn mineralization at the deposit.Theδ^34S values of sulfides,concentrated in a range between 0.6‰to 3.4‰,show that the sulfur has a homogeneous source with characteristics of magmatic sulfur.The Pb isotopic compositions of sulfides indicate that ore-forming metal materials were derived from the mantle and ancient crust.The granodiorite porphyry displays high SiO2(68.78%–69.75%)and K2O(3.40%–3.56%)contents,and relatively lower Cr(2.4×10^-6–4.09×10^-6),Ni(2.79×10^-6–3.58×10^-6)contents,and positiveεHf(t)values(7.7–12.9)indicating that the mineralization porphyry was derived from the partial melting of juvenile lower crust.The Tuolangla deposit is located in the central part of Zedang terrane.This terrane was once considered an ancient terrane.This terrane is in tectonic contact with Cretaceous ophiolitic rocks to its south and Mesozoic continental margin arc volcanics and intrusions of the Gangdese batholith of the Lhasa terrane to its north.Thus,the authors proposed that the Oligocene porphyry skarn Cu-W-Mo mineralization is probably associated with the Zedang terrane.This finding may clarify why the Oligocene(about 23 Ma)deposits are found only in the Zedang area and why mineralization types of the Oligocene mineralization are considerably different from those of the Miocene(17–14 Ma)mineralization.展开更多
The Sanaga iron ore prospect is a recent discovery in the Nyong Series with a resource estimated at 82.9 Mt at 32.1%Fe and whose origin remains debatable.The mineralization occurs as NE-SW oriented discontinuous lenti...The Sanaga iron ore prospect is a recent discovery in the Nyong Series with a resource estimated at 82.9 Mt at 32.1%Fe and whose origin remains debatable.The mineralization occurs as NE-SW oriented discontinuous lenticular bodies of magnetite-bearing pyroxenegneisses(MPG)hosted by ortho-derived gneisses.Rare amphibolites are observed.The MPG mineral assemblage consists of quartz-magnetite-orthopyroxene-garnet-tremolite/actinolite exhibiting a granoblastic texture,which is characteristic of granulite facies metamorphism.The granodioritic gneisses show compositional features of the tonalite-trondhjemite-granodiorite association.Their trace and REE element geochemistry indicate their protolith melt resulted from the partial melting of a subducted oceanic slab,with interaction with the overlying mantle wedge during ascent.The amphibolites show enrichment in LILE with negative Ta–Nb and Zr–Hf indicating arc-related magmas generated by partial melting of a sub-continental lithospheric mantle source with metasomatism by subduction-related fluids.The MPG exhibits oxidation-exsolution features characterized by ilmenite lamellae,with hematite fracture-fillinginmagnetite,andlacksfeatures characteristic of typical BIF such as LREE depletion relative to HREE,positive Eu,La,and Y anomalies.Based on the results of this study,we interpret the Sanaga MPG as a possible skarn-type mineralization formed by the metamorphism/metasomatism of a possible BIF protolith.The results of this study compare with similar magnetite-rich mineralization in the Sa o Francisco craton in northeastern Brazil and enhance the correlation of pre-drift reconstructions of the Sa o Francisco–Congo Cratons.展开更多
文摘This paper introduces the common paragenetic minerals of skarn-type wollastonite ore and its principle of gravitation separation for purification. Through the separation experiment of concentrating table on the wollastonite ore from Xiaojipu Wollastonite Mine of Hubei province, the product has reached the reguirement of wollastonite powder used as the ceramic raw material.
文摘山东省鲁西隆起区是我国重要铁矿集区之一,其中矽卡岩型铁矿是其优势矿种,主要分布于济南、莱芜、淄博等地区(段壮,2019)。2013年以来,山东省地质调查院等地勘单位在德州市齐河—禹城地区郭店、李屯、大张等地进行了异常查证并取得重大找矿突破,发现多处大中型富铁矿床;因研究区属超深覆盖区(新生界厚度大于530 m).
文摘Although some porphyry-skarn deposits occur in post-collisional extensional settings,the post-collisional deposits remain poorly understood.Here the authors describe the igneous geology,and mineralization history of Tuolangla,a newly-discovered porphyry-skarn Cu-W-Mo deposit in southern Tibet that belongs to the post-collisional class.The deposit is associated with Lower Cretaceous Bima Formation.It was intruded by granodiorite porphyry intrusions at about 23.1 Ma.Field investigation indicated that mineralization is spatially and temporally associated with granodiorite porphyry.Molybdenite yielded a Re-Os weighted mean age of 23.5±0.3 Ma and is considered to represent the age of skarn mineralization at the deposit.Theδ^34S values of sulfides,concentrated in a range between 0.6‰to 3.4‰,show that the sulfur has a homogeneous source with characteristics of magmatic sulfur.The Pb isotopic compositions of sulfides indicate that ore-forming metal materials were derived from the mantle and ancient crust.The granodiorite porphyry displays high SiO2(68.78%–69.75%)and K2O(3.40%–3.56%)contents,and relatively lower Cr(2.4×10^-6–4.09×10^-6),Ni(2.79×10^-6–3.58×10^-6)contents,and positiveεHf(t)values(7.7–12.9)indicating that the mineralization porphyry was derived from the partial melting of juvenile lower crust.The Tuolangla deposit is located in the central part of Zedang terrane.This terrane was once considered an ancient terrane.This terrane is in tectonic contact with Cretaceous ophiolitic rocks to its south and Mesozoic continental margin arc volcanics and intrusions of the Gangdese batholith of the Lhasa terrane to its north.Thus,the authors proposed that the Oligocene porphyry skarn Cu-W-Mo mineralization is probably associated with the Zedang terrane.This finding may clarify why the Oligocene(about 23 Ma)deposits are found only in the Zedang area and why mineralization types of the Oligocene mineralization are considerably different from those of the Miocene(17–14 Ma)mineralization.
文摘The Sanaga iron ore prospect is a recent discovery in the Nyong Series with a resource estimated at 82.9 Mt at 32.1%Fe and whose origin remains debatable.The mineralization occurs as NE-SW oriented discontinuous lenticular bodies of magnetite-bearing pyroxenegneisses(MPG)hosted by ortho-derived gneisses.Rare amphibolites are observed.The MPG mineral assemblage consists of quartz-magnetite-orthopyroxene-garnet-tremolite/actinolite exhibiting a granoblastic texture,which is characteristic of granulite facies metamorphism.The granodioritic gneisses show compositional features of the tonalite-trondhjemite-granodiorite association.Their trace and REE element geochemistry indicate their protolith melt resulted from the partial melting of a subducted oceanic slab,with interaction with the overlying mantle wedge during ascent.The amphibolites show enrichment in LILE with negative Ta–Nb and Zr–Hf indicating arc-related magmas generated by partial melting of a sub-continental lithospheric mantle source with metasomatism by subduction-related fluids.The MPG exhibits oxidation-exsolution features characterized by ilmenite lamellae,with hematite fracture-fillinginmagnetite,andlacksfeatures characteristic of typical BIF such as LREE depletion relative to HREE,positive Eu,La,and Y anomalies.Based on the results of this study,we interpret the Sanaga MPG as a possible skarn-type mineralization formed by the metamorphism/metasomatism of a possible BIF protolith.The results of this study compare with similar magnetite-rich mineralization in the Sa o Francisco craton in northeastern Brazil and enhance the correlation of pre-drift reconstructions of the Sa o Francisco–Congo Cratons.
