Objective The Songpan-Garze Fold Belt(SGFB),located in the eastern part of the Tibet Plateau and west of the Sichuan Basin,is an important pegmatite province in China.Some famous pegmatite type deposits occur in the S...Objective The Songpan-Garze Fold Belt(SGFB),located in the eastern part of the Tibet Plateau and west of the Sichuan Basin,is an important pegmatite province in China.Some famous pegmatite type deposits occur in the SGFB,including the Xuebaoding,Jiajika,Keeryin rare metal deposits and Danba muscovite deposit(Li Jiankang et al.,2015).The newly discovered super-large Lijiagou展开更多
The extensive Changba-Lijiagou Pb-Zn deposit is located in the north of the Xihe–Chengxian ore cluster in West Qinling. The ore bodies are mainly hosted in the marble, dolomitic marble and biotite-calcite-quartz schi...The extensive Changba-Lijiagou Pb-Zn deposit is located in the north of the Xihe–Chengxian ore cluster in West Qinling. The ore bodies are mainly hosted in the marble, dolomitic marble and biotite-calcite-quartz schist of the Middle Devonian Anjiacha Formation, and are structurally controlled by the fault and anticline. The ore-forming process can be divided into three main stages, based on field geological features and mineral assemblages. The mineral assemblages of hydrothermal stage I are pale-yellow coarse grain, low Fe sphalerite, pyrite with pits, barite and biotite. The mineral assemblages of hydrothermal stage II are black-brown cryptocrystalline, high Fe shalerite, pyrite without pits, marcasite or arsenopyrite replace the pyrite with pits, K-feldspar. The features of hydrothermal stage III are calcite-quartz-sulfide vein cutting the laminated, banded ore body. Forty-two sulfur isotope analyses, twenty-five lead isotope analyses and nineteen carbon and oxygen isotope analyses were determined on sphalerite, pyrite, galena and calcite. The δ34 S values of stage I(20.3 to 29.0‰) are consistent with the δ34 S of sulfate(barite) in the stratum. Combined with geological feature, inclusion characteristics and EPMA data, we propose that TSR has played a key role in the formation of the sulfides in stage I. The δ34 S values of stage II sphalerite and pyrite(15.1 to 23.0‰) are between sulfides in the host rock, magmatic sulfur and the sulfate(barite) in the stratum. This result suggests that multiple S reservoirs were the sources for S2-in stage II. The δ34 S values of stage III(13.1 to 22‰) combined with the structure of the geological and mineral features suggest a magmatic hydrothermal origin of the mineralization. The lead isotope compositions of the sulfides have 206 Pb/204 Pb ranging from 17.9480 to 17.9782, 207 Pb/204 Pb ranging from 15.611 to 15.622, and 208 Pb/204 Pb ranging from 38.1368 to 38.1691 in the three ore-forming stages. The narrow and symmetric distributions of the lead isotope values reflect homogenization of granite and mantle sources before the Pb-Zn mineralization. The δ13 CPDB and δ18 OSMOW values of stage I range from-0.1 to 2.4‰ and from 18.8 to 21.7‰. The values and inclusion data indicate that the source of fluids in stage I was the dissolution of marine carbonate. The δ13 CPDB and δ18 OSMOW values of stage II range from-4 to 1‰ and from 12.3 to 20.3‰, suggesting multiple C-O reservoirs in the Changba deposit and the addition of mantle-source fluid to the system. The values in stage III are-3.1‰ and 19.7‰, respectively. We infer that the process of mineralization involved evaporitic salt and sedimentary organic-bearing units interacting through thermochemical sulfate reduction through the isotopic, mineralogy and inclusion evidences. Subsequently, the geology feature, mineral assemblages, EPMA data and isotopic values support the conclusion that the ore-forming hydrothermal fluids were mixed with magmatic hydrothermal fluids and forming the massive dark sphalerite, then yielding the calcite-quartz-sulfide vein ore type at the last stage. The genesis of this ore deposit was epigenetic rather than the previously-proposed sedimentary-exhalative(SEDEX) type.展开更多
1 Introduction Rare-metal granites are widely distributed in South China.The Daping porphyritic granitic Ta-Nb deposit,located in the Yongding area of south Fujian province,South China,is a large rare-metal deposit re...1 Introduction Rare-metal granites are widely distributed in South China.The Daping porphyritic granitic Ta-Nb deposit,located in the Yongding area of south Fujian province,South China,is a large rare-metal deposit recently discovered.Few studies have been made of its petrology,mineralogy,geochemistry,chronology and metallogeny.In recent years,several exploratory drillings have been done in this deposit.These drilling holes,from 380 to 600展开更多
The Lijiagou Pb-Zn deposit in Gansu Province is a syngenetic hydrothermal-depositonal and meta-morphosed hydrothermal weakly-reworked stratabound ore deposit. The metallogenic physicochemical condi-tions of the deposi...The Lijiagou Pb-Zn deposit in Gansu Province is a syngenetic hydrothermal-depositonal and meta-morphosed hydrothermal weakly-reworked stratabound ore deposit. The metallogenic physicochemical condi-tions of the deposit are thoroughly dealt with in this paper according to its different mineralization stages.Based on the systematic study of metallogenic material sources, it is considered that the ore-forming metals, oresulphur and water of mineralizing fluids are mainly derived from the basement, reduction sulphur of marinesulfate and infiltrating heated meteoric water and partially recharged sea water, respectively. Finally, themetallogenic model of this deposit is established.展开更多
The Songpan-Ganze orogenic belt on the northeastern margin of the Tibetan Plateau extends westward from the Songpan-Ganze terrain in western Sichuan to the Tianshuihai region in West Kunlun,Xinjiang.It hosts numerous ...The Songpan-Ganze orogenic belt on the northeastern margin of the Tibetan Plateau extends westward from the Songpan-Ganze terrain in western Sichuan to the Tianshuihai region in West Kunlun,Xinjiang.It hosts numerous giant spodumene pegmatite deposits and ore fields,including Jiajika and Ke’eryin in western Sichuan Province,Zhawulong on the border between the Sichuan and Qinghai Provinces,and Dahongliutan in Xinjiang Region.These form the Songpan-Ganze-West Kunlun(SP-GZ-WK) pegmatite-type rare-metal metallogenic belt.The pegmatite type rare-metal deposits in this belt are hosted in the metamorphic thermal domes in the metamorphosed flysh of the Triassic Xikang and Bayankalashan Groups.The mineralized pegmatites are intimately related to the Li-and volatile-rich two-mica granites that are peraluminous and have high(Li+Na+K)/(Mn+Fe+Mg+Ca+Ti) ratios.Pegmatites and granites in individual ore field throughout the belt typically form a cogenetic granite-pegmatite system,in which pegmatite dikes commonly surround granites.Spodumene is the predominant ore mineral in most pegmatites with limited hydrothermal alteration.In the granite-pegmatite systems,granitic magmas were emplaced under P-T conditions of 800–850°C and ~550 MPa,while spodumene crystallized in an alkaline environment.The granite-pegmatite systems share similar Sr-Nd-Hf-Li isotopic compositions to the metasediments of the Xikang and Bayankalashan Groups.The δ7Li values tend to increase from the granites to the Li-poor pegmatites,whereas the reverse is observed between the Li-poor and Li-rich pegmatites.These geochronological data suggest that the granite-pegmatite systems formed in the Late Triassic and tend to be progressively younger from the outer to the inner zones of the metallogenic belt.These characteristics show that the granitic-pegmatitic melts were derived from the anatexis of the Xikang and Bayankalashan Groups during the Paleo-Tethyan orogeny in the Late Triassic.The separation of pegmatitic melts from granitic magmas can be best explained using the Jiajika-style “melt-melt immiscibility” or the Ke’eryin-style “fractional crystallization+melt-melt immiscibility” model.High-maturity terrestrial sediments are of key importance for the anatexis that results in the granitepegmatite melts.The bidirectional tectonic stresses in the Songpan-Ganze orogenic belt may have caused the mineralization difference between the Jiajika deposit and the Ke’eryin ore field.These features indicate the controls of the combination of orogenic deformation,metapelites anatexis,and magmatic differentiation on the rare-metal mineralization of pegmatites.We suggest that pegmatites,pegmatite–parental granite,and their protoliths are important indicators for rare-metal mineralization in the SP-GZ-WK pegmatite type rare-metal metallogenic belt.Based on the widespread presence of fertile metasediments and well development of metamorphic thermal dome,highly differentiated granites,and regional zonation of pegmatites,the Zhawulong ore field is the most prospective area for rare metals and thus should be the priority for future exploration.展开更多
The Mufushan Complex(MFSC),located in northeastern Hunan,is a significant producer of Nb-Ta-Li-Be rare metals in South China.The present study examines the genetic relationship,material provenance,fluid evolution,and ...The Mufushan Complex(MFSC),located in northeastern Hunan,is a significant producer of Nb-Ta-Li-Be rare metals in South China.The present study examines the genetic relationship,material provenance,fluid evolution,and metallogeny of the co-developed ore-free pegmatite(OFP)and ore-bearing pegmatite(OBP)in granite-related pegmatite-type Nb-Ta rare-metal deposits in MFSC.Three minerals(columbite-tantalite(coltan),zircon,and monazite)were chosen for analysis.The coltan grains display both primary crystallization structures(crystal homogeneity,oscillatory zonings,and primary growth rims)resulting from equilibrium and disequilibrium reactions due to localized changes in the physicochemical conditions and environment,as well as later replacement structures(alteration rims,patches,irregular zonations,and complex zonations)from metasomatic replacement processes related to hydrothermal fluid activity.The coltan yielded two weighted mean^(206)Pb/^(238)U ages of 138.1±2.1 Ma and 125.3±2.0 Ma corresponding to magmatic and hydrothermal Nb-Ta mineralization ages.For the OFP,zircons also yielded two weighted mean^(206)Pb/^(238)U ages of 138.4±0.8 Ma and 131.5±0.7 Ma,whereas monazite gave a weighted mean U-Pb age 142.9±1.2 Ma.The ages of 142-138 Ma and 131 Ma represent the early and late stages of OFP crystallization and barren pegmatites in the MFSC,respectively.Zircon Lu-Hf isotopic compositions link rare-metal metallogenesis to the Lengjiaxi Group,which was the source material to the Mufushan composite batholith.Calculatedε_(Hf)(t)values and TDM2 ages from the OFP(-7.6 to-3.6 and 1676-1418 Ma,respectively)and the OBP(-14.1 to+4.9 and 2976-1548 Ma,respectively)are akin to those of schists and metasandstones of the metasedimentary Lengjiaxi Group.We propose a long-lived(ca.13-Myr)event involving two metallogenic episodes of Nb-Ta mineralization in the Mufushan region.This study demonstrates the potential of zircon,coltan,and monazite for fingerprinting minerals and classifying the mineralization potential of pegmatite veins.展开更多
基金funded by the Natural Science Foundation of China (grant No. 41702074)Sichuan Education Department Foundation (grant No. 17ZA0039)+2 种基金Young and Middle-Aged Teacher Foster Program of Chengdu University of Technology (grant No. JXGG201701)Opening Foundation of Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation, Ministry of Land and Resources (grant No. gzck2018003)Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration in Guilin University of Technology (grant No. 12-071-20)
文摘Objective The Songpan-Garze Fold Belt(SGFB),located in the eastern part of the Tibet Plateau and west of the Sichuan Basin,is an important pegmatite province in China.Some famous pegmatite type deposits occur in the SGFB,including the Xuebaoding,Jiajika,Keeryin rare metal deposits and Danba muscovite deposit(Li Jiankang et al.,2015).The newly discovered super-large Lijiagou
基金supported and funded by the Special Research Funding for Public Benefit sponsored by MLR(Grant No.200911007-21)the Fundamental Research Funds for the Central Public Welfare Research Institutes(Grant No.K1612 and K1607)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.300102279401)the Geological Survey Project(Grant No.N1916)and(Grant No.DD20190368)。
文摘The extensive Changba-Lijiagou Pb-Zn deposit is located in the north of the Xihe–Chengxian ore cluster in West Qinling. The ore bodies are mainly hosted in the marble, dolomitic marble and biotite-calcite-quartz schist of the Middle Devonian Anjiacha Formation, and are structurally controlled by the fault and anticline. The ore-forming process can be divided into three main stages, based on field geological features and mineral assemblages. The mineral assemblages of hydrothermal stage I are pale-yellow coarse grain, low Fe sphalerite, pyrite with pits, barite and biotite. The mineral assemblages of hydrothermal stage II are black-brown cryptocrystalline, high Fe shalerite, pyrite without pits, marcasite or arsenopyrite replace the pyrite with pits, K-feldspar. The features of hydrothermal stage III are calcite-quartz-sulfide vein cutting the laminated, banded ore body. Forty-two sulfur isotope analyses, twenty-five lead isotope analyses and nineteen carbon and oxygen isotope analyses were determined on sphalerite, pyrite, galena and calcite. The δ34 S values of stage I(20.3 to 29.0‰) are consistent with the δ34 S of sulfate(barite) in the stratum. Combined with geological feature, inclusion characteristics and EPMA data, we propose that TSR has played a key role in the formation of the sulfides in stage I. The δ34 S values of stage II sphalerite and pyrite(15.1 to 23.0‰) are between sulfides in the host rock, magmatic sulfur and the sulfate(barite) in the stratum. This result suggests that multiple S reservoirs were the sources for S2-in stage II. The δ34 S values of stage III(13.1 to 22‰) combined with the structure of the geological and mineral features suggest a magmatic hydrothermal origin of the mineralization. The lead isotope compositions of the sulfides have 206 Pb/204 Pb ranging from 17.9480 to 17.9782, 207 Pb/204 Pb ranging from 15.611 to 15.622, and 208 Pb/204 Pb ranging from 38.1368 to 38.1691 in the three ore-forming stages. The narrow and symmetric distributions of the lead isotope values reflect homogenization of granite and mantle sources before the Pb-Zn mineralization. The δ13 CPDB and δ18 OSMOW values of stage I range from-0.1 to 2.4‰ and from 18.8 to 21.7‰. The values and inclusion data indicate that the source of fluids in stage I was the dissolution of marine carbonate. The δ13 CPDB and δ18 OSMOW values of stage II range from-4 to 1‰ and from 12.3 to 20.3‰, suggesting multiple C-O reservoirs in the Changba deposit and the addition of mantle-source fluid to the system. The values in stage III are-3.1‰ and 19.7‰, respectively. We infer that the process of mineralization involved evaporitic salt and sedimentary organic-bearing units interacting through thermochemical sulfate reduction through the isotopic, mineralogy and inclusion evidences. Subsequently, the geology feature, mineral assemblages, EPMA data and isotopic values support the conclusion that the ore-forming hydrothermal fluids were mixed with magmatic hydrothermal fluids and forming the massive dark sphalerite, then yielding the calcite-quartz-sulfide vein ore type at the last stage. The genesis of this ore deposit was epigenetic rather than the previously-proposed sedimentary-exhalative(SEDEX) type.
基金supported by MOST of China 2016YFC0600408Investigation of Rare Metal, Rare Earth, and Rare-scattered Mineral Resources in South China (DD20160056)
文摘1 Introduction Rare-metal granites are widely distributed in South China.The Daping porphyritic granitic Ta-Nb deposit,located in the Yongding area of south Fujian province,South China,is a large rare-metal deposit recently discovered.Few studies have been made of its petrology,mineralogy,geochemistry,chronology and metallogeny.In recent years,several exploratory drillings have been done in this deposit.These drilling holes,from 380 to 600
文摘The Lijiagou Pb-Zn deposit in Gansu Province is a syngenetic hydrothermal-depositonal and meta-morphosed hydrothermal weakly-reworked stratabound ore deposit. The metallogenic physicochemical condi-tions of the deposit are thoroughly dealt with in this paper according to its different mineralization stages.Based on the systematic study of metallogenic material sources, it is considered that the ore-forming metals, oresulphur and water of mineralizing fluids are mainly derived from the basement, reduction sulphur of marinesulfate and infiltrating heated meteoric water and partially recharged sea water, respectively. Finally, themetallogenic model of this deposit is established.
基金supported by the Chinese National Key R&D Program (Grant No. 2019YFC0605200)the National Natural Science Foundation of China (Grant Nos. 41872096 and 42002109)the China Geological Survey Project (Grant Nos. DD20221684 and DD20230289)。
文摘The Songpan-Ganze orogenic belt on the northeastern margin of the Tibetan Plateau extends westward from the Songpan-Ganze terrain in western Sichuan to the Tianshuihai region in West Kunlun,Xinjiang.It hosts numerous giant spodumene pegmatite deposits and ore fields,including Jiajika and Ke’eryin in western Sichuan Province,Zhawulong on the border between the Sichuan and Qinghai Provinces,and Dahongliutan in Xinjiang Region.These form the Songpan-Ganze-West Kunlun(SP-GZ-WK) pegmatite-type rare-metal metallogenic belt.The pegmatite type rare-metal deposits in this belt are hosted in the metamorphic thermal domes in the metamorphosed flysh of the Triassic Xikang and Bayankalashan Groups.The mineralized pegmatites are intimately related to the Li-and volatile-rich two-mica granites that are peraluminous and have high(Li+Na+K)/(Mn+Fe+Mg+Ca+Ti) ratios.Pegmatites and granites in individual ore field throughout the belt typically form a cogenetic granite-pegmatite system,in which pegmatite dikes commonly surround granites.Spodumene is the predominant ore mineral in most pegmatites with limited hydrothermal alteration.In the granite-pegmatite systems,granitic magmas were emplaced under P-T conditions of 800–850°C and ~550 MPa,while spodumene crystallized in an alkaline environment.The granite-pegmatite systems share similar Sr-Nd-Hf-Li isotopic compositions to the metasediments of the Xikang and Bayankalashan Groups.The δ7Li values tend to increase from the granites to the Li-poor pegmatites,whereas the reverse is observed between the Li-poor and Li-rich pegmatites.These geochronological data suggest that the granite-pegmatite systems formed in the Late Triassic and tend to be progressively younger from the outer to the inner zones of the metallogenic belt.These characteristics show that the granitic-pegmatitic melts were derived from the anatexis of the Xikang and Bayankalashan Groups during the Paleo-Tethyan orogeny in the Late Triassic.The separation of pegmatitic melts from granitic magmas can be best explained using the Jiajika-style “melt-melt immiscibility” or the Ke’eryin-style “fractional crystallization+melt-melt immiscibility” model.High-maturity terrestrial sediments are of key importance for the anatexis that results in the granitepegmatite melts.The bidirectional tectonic stresses in the Songpan-Ganze orogenic belt may have caused the mineralization difference between the Jiajika deposit and the Ke’eryin ore field.These features indicate the controls of the combination of orogenic deformation,metapelites anatexis,and magmatic differentiation on the rare-metal mineralization of pegmatites.We suggest that pegmatites,pegmatite–parental granite,and their protoliths are important indicators for rare-metal mineralization in the SP-GZ-WK pegmatite type rare-metal metallogenic belt.Based on the widespread presence of fertile metasediments and well development of metamorphic thermal dome,highly differentiated granites,and regional zonation of pegmatites,the Zhawulong ore field is the most prospective area for rare metals and thus should be the priority for future exploration.
基金the National Natural Science Foundation of China(No.92162103)the Natural Science Foundation of Hunan Province(No.2021J30699)+2 种基金the Geological Exploration Project of the Hunan Provincial Institute of Land and Resources Planning(Grant No.20190604)the Science and Technology Innovation program of the Hunan Province(Grant No.2021RC4055)the Fundamental Research Funds for the Central Universities of Central South University(Grant No.CX20200310).
文摘The Mufushan Complex(MFSC),located in northeastern Hunan,is a significant producer of Nb-Ta-Li-Be rare metals in South China.The present study examines the genetic relationship,material provenance,fluid evolution,and metallogeny of the co-developed ore-free pegmatite(OFP)and ore-bearing pegmatite(OBP)in granite-related pegmatite-type Nb-Ta rare-metal deposits in MFSC.Three minerals(columbite-tantalite(coltan),zircon,and monazite)were chosen for analysis.The coltan grains display both primary crystallization structures(crystal homogeneity,oscillatory zonings,and primary growth rims)resulting from equilibrium and disequilibrium reactions due to localized changes in the physicochemical conditions and environment,as well as later replacement structures(alteration rims,patches,irregular zonations,and complex zonations)from metasomatic replacement processes related to hydrothermal fluid activity.The coltan yielded two weighted mean^(206)Pb/^(238)U ages of 138.1±2.1 Ma and 125.3±2.0 Ma corresponding to magmatic and hydrothermal Nb-Ta mineralization ages.For the OFP,zircons also yielded two weighted mean^(206)Pb/^(238)U ages of 138.4±0.8 Ma and 131.5±0.7 Ma,whereas monazite gave a weighted mean U-Pb age 142.9±1.2 Ma.The ages of 142-138 Ma and 131 Ma represent the early and late stages of OFP crystallization and barren pegmatites in the MFSC,respectively.Zircon Lu-Hf isotopic compositions link rare-metal metallogenesis to the Lengjiaxi Group,which was the source material to the Mufushan composite batholith.Calculatedε_(Hf)(t)values and TDM2 ages from the OFP(-7.6 to-3.6 and 1676-1418 Ma,respectively)and the OBP(-14.1 to+4.9 and 2976-1548 Ma,respectively)are akin to those of schists and metasandstones of the metasedimentary Lengjiaxi Group.We propose a long-lived(ca.13-Myr)event involving two metallogenic episodes of Nb-Ta mineralization in the Mufushan region.This study demonstrates the potential of zircon,coltan,and monazite for fingerprinting minerals and classifying the mineralization potential of pegmatite veins.
