The giant Upper Yangtze Pb-Zn metallogenic province,also known as the Sichuan-Yunnan-Guizhou(SYG)Pb-Zn province hosting>500 carbonate-hosted epigenetic Pb-Zn deposits that contain>20 Mt Pb+Zn base metal reserves...The giant Upper Yangtze Pb-Zn metallogenic province,also known as the Sichuan-Yunnan-Guizhou(SYG)Pb-Zn province hosting>500 carbonate-hosted epigenetic Pb-Zn deposits that contain>20 Mt Pb+Zn base metal reserves.The giant Maoping Pb-Zn deposit is the second largest deposit in this province and owns>5 Mt Pb+Zn metal reserves with ore grades of 12 wt.%-30 wt.%Pb+Zn.Such large tonnages and high grades make it among the top 100 similar mineral deposits in the world.The ore bodies are predominantly located within the strata of the Upper Devonian(Zaige Formation)and Lower(Baizuo Formation)-Upper(Weining Formation)Carboniferous.The principal ore minerals consist of galena(Gn),sphalerite(Sp),and pyrite(Py),while the primary gangue minerals include dolomite(Dol),calcite(Cal),and quartz(Qtz).Three mineralization stages of carbonate minerals have been identified:(1)pre-sulfide stage 1,(2)syn-sulfide stage 2,and(3)post-sulfide stage 3.Trace elements and C-O-Sr isotopes of three stages’carbonate minerals,together with S-Pb isotopes of sulfides,revealing that the metamorphic basement rocks played the role of the metal source during the early stage of Pb-Zn mineralization,whereas the metal contribution of the sedimentary wall rocks found to be more prominent during the late stage of Pb-Zn mineralization.In addition,the dissolution of marine carbonate rocks and CO_(2)degassing may have also played an important role in the formation of the Maoping deposit.Furthermore,syn-sulfide stage 2 calcite has a U-Pb age of 214±20 Ma obtained by LA-ICPMS in-situ analyses,suggesting that the hydrothermal mineralization occurred during the Triassic.Our study proposes a new coupled metallogenic model of fluid-structure-lithology assemblage and provides new insights about the formation and evolution of the Maoping deposit with significant implication for understanding and exploration of similar Pb-Zn deposits worldwide.展开更多
Tectono-geochemical analysis is one of the key technical methods for deep prospecting and prediction,but the extraction of information on weak and low degrees of mineralization remains a significant challenge.This stu...Tectono-geochemical analysis is one of the key technical methods for deep prospecting and prediction,but the extraction of information on weak and low degrees of mineralization remains a significant challenge.This study takes the Maoping super-large germanium-rich lead-zinc deposit in northeastern Yunnan as an example,systematically analyzes the mineralization element assemblages and their anomaly distribution characteristics,extracts information on low and weak anomalies at depth,clarifies the spatial distribution of ore-forming element anomalies and fluid migration patterns,and establishes tectono-geochemical deep anomaly evaluation criteria and prospecting models,thereby proposing directions for deep prospecting in the deposit.This research shows that the mineralization element assemblage of the F1 factor(Cd-Cu-Ge-Zn-Sb-In-Pb-Sr(-)-As-Hg)anomalies represents near-ore halos;the element assemblage of the F2 factor(Ni-Co-Cr-Rb-Ga)anomalies represents tail halos;the element assemblage of the F3 factor(Rb-Mo-Tl-As)anomalies represents front halos;and the element assemblage of the F4 factor(Ba-Ga)anomalies represents barite alteration anomalies.Elements such as Zn and Pb exhibit significant anomalies near the lead-zinc ore bodies.In the study area,vertical anomalies in the eastern region of the Luoze River indicate that ore-forming fluids migrated from the SE at depth to the NW at shallower levels,whereas in the western region,ore-forming fluids migrated from the SW at depth to the NE at shallower levels.Thus,the lateral extensions of different ore bodies in the eastern and western regions of the river have been determined.On this basis,tectono-geochemical deep anomaly evaluation criteria for the deposit are established,and directions for deep prospecting are proposed.This study provides scientific value and practical significance for deep prospecting and exploration engineering planning for similar lead-zinc deposits.展开更多
The Maoping Pb-Zn deposit(~3 Mt Pb+Zn reserves with grades of 12-30 wt%)is one of the largest Pb-Zn deposits in the Sichuan-Yunnan-Guizhou(SYG)metallogenic province,which has contributed a tremendous amount of lead an...The Maoping Pb-Zn deposit(~3 Mt Pb+Zn reserves with grades of 12-30 wt%)is one of the largest Pb-Zn deposits in the Sichuan-Yunnan-Guizhou(SYG)metallogenic province,which has contributed a tremendous amount of lead and zinc resources for China.To obtain a further understanding of the sources of ore-forming materials and ore genesis of the deposit,S-Pb isotopes of sulfides and C-O isotopes of ore-stage calcites were systematically collected from representative orebodies at different elevations with a Finnigan MAT-253 mass spectrometer.The calcites separated from the sulfides of the NoⅠand NoⅡorebodies shared identical b13 CPDB values(-5.3 to-0.8‰)andδ18OSMOW values(+14.5 to+21.8‰)with those of the calcites in the SYG region,suggesting that CO2 in regional ore-forming fluids possibly had a homologous C-O source that originated from a ternary mixture of the dissolution of marine carbonate rocks,degassing process of the Emeishan mantle plume,and dehydroxylation of sedimentary organic matter.The No.Ⅰ-1 and No.Ⅰ-2 orebody was hosted in the same strata,but the sulfur source of No.Ⅰ-1 orebody(+13.1 to+19.0‰)with equilibrated sulfur fractionation(δ34Sspbaierite-<δ34Sgalena)and No.Ⅰ-2 orebody(+18.0 to+21.8‰)with sulfur equilibrium fractionation(δ34Sspnaierite>δ34-Sgalena)were different.They were derived from the allopatry thermochemical sulfate reduction(TSR)of overlying Carboniferous sulfates in the ore-hosting strata and local TSR of sulfates in the ore-bearing Upper Devonian Zaige Formation,respectively.The narrow and uniform Pb isotopic ratios of single galena grains collected from sulfides with 206Pb/204Pb of 18.713-18.759,207Pb/204Pb of 15.772-15.776 and 208Pb/204Pb of39.383-39.467 indicate a well-mixed metal source(s)that consist of Proterozoic Kunyang and Huili Group basement rocks and Devonian to Middle Permian ore-hosting sedimentary rocks.Besides,the late Permian Emeishan basalts are difficult to contribute metals for regional Pb-Zn mineralization despite a closely spatial relationship with the distribution of the Pb-Zn deposit.This is supported by Pb isotopic ratios plotting above the average upper crustal Pb evolution curves and staying far away from that of the agecorrected Emeishan basalts.Hence,taking into account of the similarities in tectonic setting,ore-hosting rock,ore assemblage,wall rock alteration,ore-controlling structure,and ore-forming materials and the differences in relationship with regional magmatism,fluid inclusion characteristic and ore grade between the Maoping deposit and typical MVT Pb-Zn deposit,the ore genesis of the Maoping deposit should be an MVT like Pb-Zn deposit.展开更多
为定量化研究茅坪河流域农业非点源营养物质氮、磷的输出负荷，在茅坪河的亚流域陈家冲，利用2004—05～2004—10降雨期的监测数据，通过实测值和模拟值的比较对非点源污染模型SWAT（Soil and Water Assessment Tool）进行了率定和验证...为定量化研究茅坪河流域农业非点源营养物质氮、磷的输出负荷，在茅坪河的亚流域陈家冲，利用2004—05～2004—10降雨期的监测数据，通过实测值和模拟值的比较对非点源污染模型SWAT（Soil and Water Assessment Tool）进行了率定和验证，采用Nash—Sutcliffe系数（R^2）、均方根差（RMSE）和相对误差（CV）检验实测值和模拟值的拟合度．利用验证后的模型模拟了茅坪河流域营养物质氮、磷的输出负荷量．经验证径流、总氮和总磷的Nash—Sutcliffe系数分别为0．71、0．51和0．62，最小相对误差分别为1．8％、1．1％和10％，模型对氮和磷的输出模拟效果稍差，但对径流的模拟取得了较好的效果，表明该模型可运用于茅坪河流域非点源污染的模拟研究．模拟结果显示，2004—05～2004—10，茅坪河流域共有102．5t氮和9．46t磷流入长江，大量农业非点源污染的产生是造成茅坪河水质恶化的重要原因之一．展开更多
基金supported by the National Natural Science Foundation of China(41872095,U1812402 and 42172082)the Research Startup Project(YJRC4201804)of Yunnan University to J.-X.Zhou.
文摘The giant Upper Yangtze Pb-Zn metallogenic province,also known as the Sichuan-Yunnan-Guizhou(SYG)Pb-Zn province hosting>500 carbonate-hosted epigenetic Pb-Zn deposits that contain>20 Mt Pb+Zn base metal reserves.The giant Maoping Pb-Zn deposit is the second largest deposit in this province and owns>5 Mt Pb+Zn metal reserves with ore grades of 12 wt.%-30 wt.%Pb+Zn.Such large tonnages and high grades make it among the top 100 similar mineral deposits in the world.The ore bodies are predominantly located within the strata of the Upper Devonian(Zaige Formation)and Lower(Baizuo Formation)-Upper(Weining Formation)Carboniferous.The principal ore minerals consist of galena(Gn),sphalerite(Sp),and pyrite(Py),while the primary gangue minerals include dolomite(Dol),calcite(Cal),and quartz(Qtz).Three mineralization stages of carbonate minerals have been identified:(1)pre-sulfide stage 1,(2)syn-sulfide stage 2,and(3)post-sulfide stage 3.Trace elements and C-O-Sr isotopes of three stages’carbonate minerals,together with S-Pb isotopes of sulfides,revealing that the metamorphic basement rocks played the role of the metal source during the early stage of Pb-Zn mineralization,whereas the metal contribution of the sedimentary wall rocks found to be more prominent during the late stage of Pb-Zn mineralization.In addition,the dissolution of marine carbonate rocks and CO_(2)degassing may have also played an important role in the formation of the Maoping deposit.Furthermore,syn-sulfide stage 2 calcite has a U-Pb age of 214±20 Ma obtained by LA-ICPMS in-situ analyses,suggesting that the hydrothermal mineralization occurred during the Triassic.Our study proposes a new coupled metallogenic model of fluid-structure-lithology assemblage and provides new insights about the formation and evolution of the Maoping deposit with significant implication for understanding and exploration of similar Pb-Zn deposits worldwide.
基金National Natural Science Foundation of China(42472127,42172086)Yunnan Major Science and Technological Projects(202202AG050014)+2 种基金the Yunnan Major Project of Basic Research(202401BN070001-002)Yunnan Mineral Resources Prediction and Evaluation Engineering Research Center(2011)Yunnan Provincial Geological Process and Mineral Resources Innovation Team(2012).
文摘Tectono-geochemical analysis is one of the key technical methods for deep prospecting and prediction,but the extraction of information on weak and low degrees of mineralization remains a significant challenge.This study takes the Maoping super-large germanium-rich lead-zinc deposit in northeastern Yunnan as an example,systematically analyzes the mineralization element assemblages and their anomaly distribution characteristics,extracts information on low and weak anomalies at depth,clarifies the spatial distribution of ore-forming element anomalies and fluid migration patterns,and establishes tectono-geochemical deep anomaly evaluation criteria and prospecting models,thereby proposing directions for deep prospecting in the deposit.This research shows that the mineralization element assemblage of the F1 factor(Cd-Cu-Ge-Zn-Sb-In-Pb-Sr(-)-As-Hg)anomalies represents near-ore halos;the element assemblage of the F2 factor(Ni-Co-Cr-Rb-Ga)anomalies represents tail halos;the element assemblage of the F3 factor(Rb-Mo-Tl-As)anomalies represents front halos;and the element assemblage of the F4 factor(Ba-Ga)anomalies represents barite alteration anomalies.Elements such as Zn and Pb exhibit significant anomalies near the lead-zinc ore bodies.In the study area,vertical anomalies in the eastern region of the Luoze River indicate that ore-forming fluids migrated from the SE at depth to the NW at shallower levels,whereas in the western region,ore-forming fluids migrated from the SW at depth to the NE at shallower levels.Thus,the lateral extensions of different ore bodies in the eastern and western regions of the river have been determined.On this basis,tectono-geochemical deep anomaly evaluation criteria for the deposit are established,and directions for deep prospecting are proposed.This study provides scientific value and practical significance for deep prospecting and exploration engineering planning for similar lead-zinc deposits.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1812402 and 41673056)。
文摘The Maoping Pb-Zn deposit(~3 Mt Pb+Zn reserves with grades of 12-30 wt%)is one of the largest Pb-Zn deposits in the Sichuan-Yunnan-Guizhou(SYG)metallogenic province,which has contributed a tremendous amount of lead and zinc resources for China.To obtain a further understanding of the sources of ore-forming materials and ore genesis of the deposit,S-Pb isotopes of sulfides and C-O isotopes of ore-stage calcites were systematically collected from representative orebodies at different elevations with a Finnigan MAT-253 mass spectrometer.The calcites separated from the sulfides of the NoⅠand NoⅡorebodies shared identical b13 CPDB values(-5.3 to-0.8‰)andδ18OSMOW values(+14.5 to+21.8‰)with those of the calcites in the SYG region,suggesting that CO2 in regional ore-forming fluids possibly had a homologous C-O source that originated from a ternary mixture of the dissolution of marine carbonate rocks,degassing process of the Emeishan mantle plume,and dehydroxylation of sedimentary organic matter.The No.Ⅰ-1 and No.Ⅰ-2 orebody was hosted in the same strata,but the sulfur source of No.Ⅰ-1 orebody(+13.1 to+19.0‰)with equilibrated sulfur fractionation(δ34Sspbaierite-<δ34Sgalena)and No.Ⅰ-2 orebody(+18.0 to+21.8‰)with sulfur equilibrium fractionation(δ34Sspnaierite>δ34-Sgalena)were different.They were derived from the allopatry thermochemical sulfate reduction(TSR)of overlying Carboniferous sulfates in the ore-hosting strata and local TSR of sulfates in the ore-bearing Upper Devonian Zaige Formation,respectively.The narrow and uniform Pb isotopic ratios of single galena grains collected from sulfides with 206Pb/204Pb of 18.713-18.759,207Pb/204Pb of 15.772-15.776 and 208Pb/204Pb of39.383-39.467 indicate a well-mixed metal source(s)that consist of Proterozoic Kunyang and Huili Group basement rocks and Devonian to Middle Permian ore-hosting sedimentary rocks.Besides,the late Permian Emeishan basalts are difficult to contribute metals for regional Pb-Zn mineralization despite a closely spatial relationship with the distribution of the Pb-Zn deposit.This is supported by Pb isotopic ratios plotting above the average upper crustal Pb evolution curves and staying far away from that of the agecorrected Emeishan basalts.Hence,taking into account of the similarities in tectonic setting,ore-hosting rock,ore assemblage,wall rock alteration,ore-controlling structure,and ore-forming materials and the differences in relationship with regional magmatism,fluid inclusion characteristic and ore grade between the Maoping deposit and typical MVT Pb-Zn deposit,the ore genesis of the Maoping deposit should be an MVT like Pb-Zn deposit.
文摘为定量化研究茅坪河流域农业非点源营养物质氮、磷的输出负荷，在茅坪河的亚流域陈家冲，利用2004—05～2004—10降雨期的监测数据，通过实测值和模拟值的比较对非点源污染模型SWAT（Soil and Water Assessment Tool）进行了率定和验证，采用Nash—Sutcliffe系数（R^2）、均方根差（RMSE）和相对误差（CV）检验实测值和模拟值的拟合度．利用验证后的模型模拟了茅坪河流域营养物质氮、磷的输出负荷量．经验证径流、总氮和总磷的Nash—Sutcliffe系数分别为0．71、0．51和0．62，最小相对误差分别为1．8％、1．1％和10％，模型对氮和磷的输出模拟效果稍差，但对径流的模拟取得了较好的效果，表明该模型可运用于茅坪河流域非点源污染的模拟研究．模拟结果显示，2004—05～2004—10，茅坪河流域共有102．5t氮和9．46t磷流入长江，大量农业非点源污染的产生是造成茅坪河水质恶化的重要原因之一．
