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
高维多目标优化问题(many-objective optimization problem,MaOP)广泛存在于科学研究和工程应用领域.受高维目标冲突引起的非支配解集数量呈指数增加影响,传统的多目标进化算法在求解MaOP时面临计算复杂度增加、解质量降低等困难.为此,...高维多目标优化问题(many-objective optimization problem,MaOP)广泛存在于科学研究和工程应用领域.受高维目标冲突引起的非支配解集数量呈指数增加影响,传统的多目标进化算法在求解MaOP时面临计算复杂度增加、解质量降低等困难.为此,提出一种基于信息共享的改进双归档高维多目标进化算法(improved two-archive high-dimensional multi-objective evolutionary algorithm based on information sharing,Two-Arch/IS),旨在利用双归档算法计算复杂度低、收敛及多样性独立优化等优势特性,实现高维多目标优化问题的高效求解.相较于传统的算法,首先,Two-Arch/IS基于空间划分的子种群互映更新策略实现档案库的维护,进一步增强种群的多样性表现;其次,利用基于角度选择与转移密度估计的存档截断策略移除档案库中冗余解,在进化过程中保持算法的选择压力;最后,在种群进化过程中引入边界解驱动的信息补偿机制,增强收敛性存档和多样性存档间的信息交流,实现种群个体间的优势互补.将Two-Arch/IS与其他代表性的算法一同在69个具有2–20个目标的基准测试与真实世界问题上进行性能对比实验.实验结果表明,Two-Arch/IS算法在高维多目标优化问题上能够有效克服种群收敛性与多样性的冲突,并在不同性能评价指标上均表现出明显优势.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.
文摘高维多目标优化问题(many-objective optimization problem,MaOP)广泛存在于科学研究和工程应用领域.受高维目标冲突引起的非支配解集数量呈指数增加影响,传统的多目标进化算法在求解MaOP时面临计算复杂度增加、解质量降低等困难.为此,提出一种基于信息共享的改进双归档高维多目标进化算法(improved two-archive high-dimensional multi-objective evolutionary algorithm based on information sharing,Two-Arch/IS),旨在利用双归档算法计算复杂度低、收敛及多样性独立优化等优势特性,实现高维多目标优化问题的高效求解.相较于传统的算法,首先,Two-Arch/IS基于空间划分的子种群互映更新策略实现档案库的维护,进一步增强种群的多样性表现;其次,利用基于角度选择与转移密度估计的存档截断策略移除档案库中冗余解,在进化过程中保持算法的选择压力;最后,在种群进化过程中引入边界解驱动的信息补偿机制,增强收敛性存档和多样性存档间的信息交流,实现种群个体间的优势互补.将Two-Arch/IS与其他代表性的算法一同在69个具有2–20个目标的基准测试与真实世界问题上进行性能对比实验.实验结果表明,Two-Arch/IS算法在高维多目标优化问题上能够有效克服种群收敛性与多样性的冲突,并在不同性能评价指标上均表现出明显优势.
