Metallogenic Characteristics,Ore Genesis,Diagenesis And Metallogenic Geodynamic Process Of Precious And Non Ferrous Metals Ore Deposits In Southeast Liaoning Province

Southeastern Liaoning Province is situated within the eastern segment of the northern margin of the North China Craton?NCC?,in the northeast of china,and it contains an extensive belt of non-ferrous and precious metals,including the Maoling,Baiyun,Dayinggou,Gaojiapuzi,Qingchengzi,Huatong,and Dongbeigou deposits.This study focuses on the lithology,isotope geochemistry,fluid inclusions,and geochronology of ore deposits in the region,with the aim of understanding the regional metallogenic and geological history.In addition,the ore-genesis,fluid evolution,timing of ore formation,source of mineralization,and the metallogenesis of these deposits are examined to develop a metallogenic model.The results are combined with research on the petrology,geochronology,and geochemistry of volcanic and metamorphic rocks of the Liaohe Group,Mesozoic intrusive rocks,and previous study on the regional tectonic evolution to systematically summarize ore genesis and diagenesis and metallogenic geodynamic process of precious and non ferrous metal ore deposits.the metallogenetic law of the non-ferrous and precious metal deposits and propose a regional metallogenic model.The key findings of this study are as follows.1.Crustal evolution processes in the research area have occurred in five distinct stages:the nucleus and development of continents and the formation of crustal blocks in the Archean;the formation and evolution of a rift valley and related faulting in the Proterozoic;the tectonic evolution of the Paleo-Asian Ocean;the subduction of the Yangtze Plate beneath the North China Plate;and finally,the Mesozoic tectonic evolution of the Paleo-Pacific Ocean.Zircon U–Pb dating indicates that volcanic and metamorphic rocks of the Liaohe Group formed between 2.204 and1.898 Ga,and that the formation ages of the Liaoji granites can be divided into two stages:2.332–2.132 Ga?monzogranitic gneisses,syenogranite?,1.939–1.904 Ga?monzogranitic gneisses,syenite?,and 1.88–1.84 Ga?Great Spot,Ring Spot granites and monzogranitic gneisses?.2.This study reports the first discovery of the Dayinggou Au deposit within the Lieryu Group,which is undiscovered in this group and aids further prospecting for ore deposits in the region.3.Non-ferrous and precious metal deposits in the study area include:epithermal–mesothermal deposits?e.g.,the Maoling,Baiyun,and Dayinggou Au deposits,and the Gaojiapuizi Ag deposit?;skarn deposits?e.g.,the Huatong Cu deposit,the Yaojiagou Mo deposit,and the Wannbaoyuan Cu–Mo deposits?;sedimentary exhalative,metamorphic recrystallization,and magmatic hydrothermal deposits?e.g.,the Qingchengzzi Pb–Zn deposit?;and porphyry deposits?e.g.,the Dongbeigou Mo deposit?.4.The epithermal–mesothermal deposits are closely associated with the Dashiqiao and Gaixian formations of the Liaohe Group,along with Mesozoic magmatism.These deposits have developed as veined or lenticular ore bodies,and associated wall-rock alteration includes silicification,pyritization,sericitization,and chloritization.The skarn deposits are associated with the Dashiqiao Formation?Liaohe Group?and with intermediate–acid igneous rocks.They have developed as irregular,tumor-like,nested,or lenticular ore bodies,and wall-rock alteration includes,silicification,potassic alteration,sericitization,chloritization,kaolinization,and carbonatization.The sedimentary exhalative,metamorphic reconstruction,and magmatic hydrothermal deposits are located mainly within the Langzishan and Dashiqiao formations of the Liaohe Group.Ore bodies in these deposits are broadly distributed in simple layers and in vein form,and wall-rock alteration includes silicification,sericitization,chloritization,carbonatization,and dolomitization.The porphyry deposits are associated with moderately acidic igneous rocks.They occur in veins and net veins,and wall-rock alteration includes silicification,sericitization,chloritization,carbonatization,and potassic alteration.5.The studies on fluid inclusions from the non-ferrous and precious metal deposits reveal that:the fluid inclusions from epithermal–mesothermal Au?Ag?deposits are mainly aqueous two-phase inclusions,along with three-phase fluid inclusions containing CO₂.The total homogenization temperature for Maoling Au deposit is range from 77³84?,with the homogenization temperature,salinity and density of mainly mineralizing stages fluids are in the range of 180³00?,6.0¹4.0 NaCleq,0.75¹.00 g/cm³,respectively;The total homogenization temperature for Baiyun Au deposit is range from 148³50?,with the homogenization temperature,salinity and density of mainly mineralizing stages fluids are in the range of 160²87?,5.51¹2.30NaCleq,0.79⁰.99g/cm³,respectively;The total homogenization temperature for Dayinggou Au deposit is range from 140³40?,with the homogenization temperature,salinity and density of mainly mineralizing stages fluids are in the range of 218³15?,1.81¹9.28 NaCleq,0.77⁰.89 g/cm³,respectively;The total homogenization temperature for Gaojiapuzi Ag deposit is range from 120²10?,with the homogenization temperature,salinity and density of mainly mineralizing stages fluids are in the range of 120¹90?,2.1⁶.0NaCleq,0.90⁰.96g/cm³,respectively.the fluid inclusions of magmatic hydrothermal stage from sedimentary exhalative,metamorphic recrystallization,and magmatic hydrothermal Zn-Pb deposits are mainly aqueous two-phase inclusions,along with daughter minerals inclusions and three-phase fluid inclusions containing CO₂.The total homogenization temperature for Qingchnegzi Zn-Pb deposit?Xiquegou?is range from 130²89?,with the homogenization temperature,salinity and density of mainly mineralizing stages fluids are in the range of 180²60?,6.16⁹.86NaCleq,0.80⁰.98 g/cm³,respectively.the fluid inclusions from skarn Cu deposits are mainly aqueous two-phase inclusions,along with pure liquid fluid inclusions.The total homogenization temperature for Huatong Cu deposit is range from 119³75?,with the homogenization temperature,salinity and density of mainly mineralizing stages fluids are in the range of 170²20?,7.3¹5.0 NaCleq,0.87¹.01 g/cm³,respectively.the fluid inclusions from porphyry Mo deposits are mainly aqueous two-phase inclusions,along with pure liquid fluid inclusions.The total homogenization temperature for Dongbeigou Mo deposit is range from 128²90?,with the homogenization temperature,salinity and density of mainly mineralizing stages fluids are in the range of 170²30?,9.21²2.09 NaCleq,0.98¹.03 g/cm³,respectively.6.Gas phase composition for fluid inclusions,and Hydrogen and oxygen isotope characteristics for group inclusions indicate that the initial ore-forming fluid for the epithermal–mesothermal Au?Ag?deposits is Na Cl-H₂O magmatic fluid of CO₂-bearing and minor H₂S,and participation of meteoric waters in the late ore-forming stage;the initial ore-forming fluid for of magmatic hydrothermal stage from sedimentary exhalative,metamorphic recrystallization,and magmatic hydrothermal Zn-Pb deposits is NaCl-H₂O magmatic fluid of CO₂,H₂S,CH₄-bearing,and participation of meteoric waters in the late ore-forming stage;the initial ore-forming fluid for the skarn Cu deposits is NaCl-H₂O magmatic fluid of CO₂ and CH₄-bearing,,and participation of meteoric waters in the late ore-forming stage;the initial ore-forming fluid for the porphyry Mo deposits is NaCl-H₂O magmatic fluid of CO₂-bearing,,and participation of meteoric waters in the late ore-forming stage.The results of the fluid inclusion study,combined with the C–H–O isotope data,indicate that fluid boiling and fluid mixing resulted in the mineralization.7.The sulfur isotope data from the four types of deposits indicate the presence of a deep sulfur source mixed with the host strata,possibly derived from the Liaohe Group and Mesozoic magmatism.The lead isotope data indicate a mixed source of crustal and mantle components?mainly from subduction-related mantle lead?,indicating that the mineralization and enrichment resulted from interaction between magma and the surrounding wall-rock.8.Accurate mineralization ages for these deposits were obtained for the first time in this study.Pyrite Rb–Sr isochron ages from the Dayinggou and Wulong Au deposits are 137.0±2.0Ma and 119.1±2.0 Ma,respectively.A quartz Rb–Sr isochron age from the Jinchanggou Au deposit is 159.0±29.0 Ma,and a sphalerite Rb–Sr isochron from the Diannan Pb–Zn deposit yielded an age of 2217±6.9 Ma.In addition,biotite ⁴⁰Ar/³⁹Ar dating indicates that the Maoling Au deposit formed at 188.9±1.2 Ma,and pyrite Re–Os isotope data indicate that the Baiyun Au deposit formed at 225.3±7.0 Ma.Finally,the molybdenite Re–Os isochron ages of the Huatong Cu deposit and the Dongbeigou Mo deposit are 127.4±0.7 Ma and 128.1±5.1 Ma,respectively.We identified three epochs of mineralization,which had four stages for the non-ferrous and precious metal deposits.The Lvliang comprising the Paleoproterozoic?1800Ma±?,the Indosinian comprising the Triassic?239²09Ma?,the Yanshannian comprising the Early-Middle Jurassic?189¹68Ma?and Early Cretaceous?119¹34Ma?.the Indosinian and the Yanshannian are the most important.9.Major and trace element,and Sr–Nd–Pb–Hf isotopic data indicate that the Indosinian magmatic rocks associated with mineralization in the region formed as a result of subduction of the Yangtze Plate beneath the North China Plate.In addition,this study confirms that the thermal source driving magmatism and metallogenesis was basaltic magma derived from partial melting of the upper mantle.The Yanshanian Early–Middle Jurassic magmatism and metallogenesis occurred during a period of compression related to subduction of the Paleo-Pacific Plate.The heat source for mineralization during this period was likely provided by basaltic magma derived from the mantle wedge,which had been previously metasomatized by fluids derived from the subducted slab.The Yanshanian?Early Cretaceous?magmatic rocks were formed during rollback of the Paleo-Pacific Plate and the heat source for mineralization was provided by basaltic magma derived from the mantle or the lithospheric mantle,which had been previously metasomatized by fluids derived from the subducted slab.10.Geodynamic evolution model in different metallogenic epochThe Lvliang Pb-Zn and Cu-Co metallogenic epoch distributed in a Paleoproterozoic rift geodynamic setting.The Yangtze plate crust which subducted beneath the North China Craton during Indo-China movement period,then rolled back and stretched,leading to the Au-Ag-Pb-Zn mineralization.The Yanshanian Au-Cu-Pb-Zn-Mo mineralization distributed in a stretching setting and roll-back of plate after compression triggered by subduction of Paleo-Pacific plate and Eurasian plate.Primary Pb-Zn-Cu-Co ore bodies and source bed formed by exhalation under seafloor in a rift shallow sea setting in this region in Paleoproterozoic.The source bed activated to layered ore bodies by regional metamorphism in the rift evolution.The Yangtze plate subducted beneath the North China Craton in Permian,the process lead to a roll-back and break of the Yangtze plate then triggered intrusion of the ore-bearing intermediate-acid magma.The magma rose and extracted materials in country rock,then deposited in Indo-China metallogenic epoch.The Paleo-Pacific Ocean plate subducted under the Euraisan plate,which lead to thicken of the crust.The thicken crust then delaminated and formed ore-bearing intermediate-acid magma in Early-Middle Jurassic.The magma rose and extracted materials in country rock,then deposited in the Yanshanian metallogenic epoch.A stretching geodynamic setting caused by subdution plate in this area in Early Cretacous.The fluid metasomatism between subduction plate and lithosphere mantle forming ore-bearing magma,which triggered large scale mineralization in this region.