Metallogenic Specialization Of Gold,Copper And Molybdenum Mineralized Magmatic Rocks In Middle-Northern Great Xing'an Range And Metallogenic Prediction In Hongyan Area

The middle-northern Great Xing'an Range is roughly concluding the Great Xing'an Range and its adjacent area in the north of Ulan Hot.Its tectonic location is in the middle of the eastern part of the Xing'an Mongolian orogenic belt,is mainly composed of Ergun block and Xing'an terrane,which is bounded by NE Toudaoqiao-Elunchun fault.It has experienced the ancient Asian ocean,the Mongolian-Okhotsk sea and the circum Pacific tectonic metallogenic zone superposition,transformation and compound evolution since Paleozoic.The middle-northern Great Xing'an Range located in the north-east of the Great Xing'an Range metallogenic province,which is an important nonferrous metal and precious metal orefield in China.It owns great potential of mineralization.Due to the lower level of geological work and research in this area,the regional metallogenic regularity and metallogenic prediction need to be strengthened.So,this thesis chooses the area to study.According to the analysis the typical gold,copper and molybdenum deposits,the study of diagenesis and metallogenic specialization of metallogenic magmatite,summarizes the regional metallogenic regularity,then conduct an trial application in Hongyan area,study the diagenesis and metallogenetic advantage of magmatite,and make metallogenetic prospecting prediction.The aim is to make a phase summary for regional diagenetic-mineralization research,and providing some references for mineral exploration practice.Magmatite preferentiality of regional gold,copper and molybdenum mineralization:Dissect main gold,copper and molybdenum typical deposits of this area,included Guliku Au-Ag deposit,Zhengguang Au-Zn deposit,Duobaoshan Cu-Mo?-Au-Ag?deposit and Chalukou Mo-Zn-Pb-Ag deposit.Particularly,Guliku and Zhengguang gold deposits are studied in detail,including field geological survey,sample collection,related tests and analysis.Other deposits mainly cite previous datas and referring to existed research results to analyze the data again.The combination of theories and methods of petrology,mineralogy,geochemistry of ore deposit,fluid geology etc to discuss metallogenic magmatite preferentiality mainly in mineralogical alteration characteristics magmatite related to mineralization,metallogenic age,source of metallogenic fluid and metallogenic material,and metallogenic mechanism.Meanwhile,determines genetic types of deposits.The types of gold deposits in the region mainly are epithermal gold deposit?ED?and hydrothermal vein type gold deposit?VD?.ED-type representative deposits are Guliku Au-Ag deposit?low-sulphidation type LS?and Zhengguang Au-Zn deposit?intermediate-sulphidation type IS?.The type of copper deposit is mainly porphyry deposit?PD,PD-type copper deposit is abbreviated as PCD?,whose representative deposit is Duodoshan Cu-Mo?-Au-Ag?deposit,followed by skarn type?SD?.The type of molybdenum deposits is almost and mainly PD type?PD-type molybdenum deposit is abbreviated PMD?.Its representative deposit is Chalukou Mo-Zn-Pb-Ag deposit which belong to the Climax type.Particularly,in this paper,the genetic type of the Au-Zn deposit is identified as IS type,which is different from the previously considered LS type or structural alteration rock type.Obvious magmatic preferentiality of the major ore-forming elements assemblages of gold,copper and molybdenum deposits shows in metallogenic epoch,ore-forming tectonic setting and ore-forming materials.The Au-Zn combination exists four metallogenic period,including early Cambrian-late Ordovician,middle Ordovician,early Jurassic and late Jurassic,is mainly related to early-mid Caledonian the intermediate and intermediate-acid intrusion?porphyry?rocks in the continental margin magmatic arc setting.The ore-forming materials are dominated by mantle source,and the ore-forming fluid is atmospheric water mixed with magmatic water,and the majority is atmospheric water composition,includes a small amount of mantle sourc.The main mineral precipitation mechanism is fluid mixing,fluid boiling can be important within the scope of cryptoexplosion breccia.LS-type Au-Ag and independent Au assemblages formed in the late of eraly Cretaceous,separately related to the mid-Yanshanian acid-intermediate-acid volcanic rocks and intermediate-intermediate-acidic volcanic rocks in the large-scale extensional tectonic setting.The ore-forming materials are crust?upper crust?-mantle mixed source and mantle source,respectively.The ore-forming fluid are mixed with atmospheric water and magmatic water,but the majority are magmatic water and atmospheric water composition,respectively.The main mineral precipitation mechanism is fluid boiling.PD-type Cu-Mo?-Au-Ag?assemblage formed in early Ordovician,is related to the middle Caledonian intermediate-acid intrusion?porphyry?rock in continental margin magmatic arc setting.The ore-forming materials is dominated by mantle source.The ore-forming fluid is consist of the mixture of magmatic water and meteoric water,and the initial fluid is degassed magmatic fluid.The main mineral precipitation mechanism is multiphase fluid boiling.In the early stage fluid immiscibility and water rock reaction play an important role,in the later stage fluid mixing is more significant.PD-type Mo-Zn-Pb-Ag assemblage principally formed in middle-late period of late Jurassic,related to acid intrusive porphyry in the late Yanshanian extensional setting.The ore-forming materials are dominated by crust?upper crust?-mantle mixed source.The ore-forming fluid is consist of the mixture of magmatic water and meteoric water,and mainly is degassed magmatic fluid.The most important mineral precipitation mechanism is multiphase fluid boiling.Metallogenic Specialization of Gold,Copper and Molybdenum Mineralized regional Magmatic rocks:Apply theory and method of petrography,mineralogy,major and trace element petrogeochemistry,Sr-Nd-Hf isotope geochemistry,zircon U-Pb diagenesis chronology to research on pivotal chemical component characteristics,magmatic redox degree,magmatic fractionation and evolution degree,magmatic temperature,genetic type of magmatite,magmatic source,diagenesis age and metallogenetic geotectonic setting of the regional gold,copper and molybdenum mineralized magmatic rocks.Then discusses the metallogenic material specialization,metallogenic epochal specialization and metallogenic spacial specialization of these magmatic rocks.The denominations according to chemical composition of the regional gold mineralized magmatite mainly are granodiorite,diorite and granite,subvolcanic rocks mainly are dacite/trachyte-andesite/trachyandesite and rhyolite,most of which are quasi-aluminous rock?QA?and part are strongly peraluminous?SP?.The overall shows characteristics of low silicon content?SiO₂content between 51⁸4%,the average is 66%?,relatively high aluminum,low alkali and potassium?the average of total alkali content is 6.6%?.REE distribution patterns is right-inclining and no Eu anomaly to moderate negative Eu anomaly.Oxygen fugacity?calculated value by single ore deposit?between FMQ-0.5 to FMQ+3.6,the average is FMQ+1.7,the principal part of the gold ore-related magmatite is medium-strong oxidation,relatively low-medium fractionation,low-medium?-strong?evolution.relatively higher magma temperature and belong to"hot"granites?the average of saturation temperature of zircon is 814??.The genetic type of rocks are mainly I type with different degree of fractionation,a few belong to high fractionated I-type granite.Part of which are adakitic rocks or with some of the characteristics of the adakitic rock;Secondly are A type with moderate degree of of fractionation.The magma source is mainly mantle source,secondly is crust source,mainly origined from partial melting of metamorphic basalt/metamorphic tonalite?relatively poor aluminum?and metapelite.In this paper,it is believed that the concealed tonalite-porphyry of Zhengguang Au-Zn deposit mineralization and the rhyolite which has close relationship with Guliku Au-Ag deposit mineralization respectively belongs to high magnesium adakitic rocks,?high?fractionation I-type.The denominations according to chemical composition of the regional copper mineralized magmatite mainly are Granodiorite?porphyry?,followed by granite?porphyry?,most of which are weakly peraluminous?WP?.The overall shows characteristics of moderate silicon content?SiO₂content between 59⁷6%,the average is 68%?,high aluminum,relatively low alkali and potassium?the average of total alkali content is 7.0%?.REE content wholely is relatively lower,REE distribution patterns is right-inclining and no Eu anomaly to relatively weak negative Eu anomaly.Oxygen fugacity between FMQ+1.2^FMQ+5.34,the average is FMQ+3.6,the principal part of the copper ore-related magmatite is strong oxidation,the overall is low-medium fractionation and low-medium evolution.relatively lower magma temperature and belong to"cold"granites?the average of saturation temperature of zircon is 785??.The genetic type of rocks are mainly I type with low-moderate degree of fractionation,most of which are adakitic rocks or with some of the characteristics of the adakitic rock,only individual is medium-high degree of fractionation.The magma source is mainly mantle source,secondly is crust-mantle mixed source,mainly origined from partial melting of metamorphic basalt/metamorphic tonalite?relative enrichment of aluminium?,and part origined from partial melting of metagreywacke or metapelite.The denominations according to chemical composition of the regional molybdenum mineralized magmatite mainly are granite?porphyry?,most of which are WP.The overall shows characteristics of high silicon content?SiO₂ content between 59⁸2%,the average is 74%?,low aluminum,enrich alkali and potassium?the average of total alkali content is 8.0%?.REE distribution patterns is right-inclining or seagull distribution,overwhelming majority own different degrees?weak^strong?negative Eu anomaly.Oxygen fugacity between FMQ+1.6^FMQ+5.26,the average is FMQ+3.2,overall shows moderate and strong-very strong oxidation,high-medium-low fractionation and medium-strong evolution.Belong to typical"hot"granite?the average saturation temperature of the whole rock of zircon is 839??.The genetic type of rocks are mainly I type with different degree of fractionation,majority is middle-low degree of fractionation,part of which are?high Si,high Mg?adakitic rocks,individual I type acidic intrusive rock with high degree of fractionation formed super large deposit;followed by A type,specific belong to A1 type with medium-high degree of fractionation and of high fractionation A type.The magma source is dominated by crust-mantle mixing,followed by mantle source,mainly derived from partial melting of metagreywacke and metapelite.The gold ore-related magmatite are mainly in the Yanshanian?97¹81Ma?,and concentrated in the late Yanshanian?112¹45Ma?,and there are also in mid-Caledonian?462⁴81Ma?and the early and late Hercynian?385Ma and 254Ma?.The copper ore-related magmatite can be arranged in the order of mineralization scale and number as follows:the early?late?Yanshanian?112²04Ma?,the middle of Caledonian?461⁴84Ma?,the middle and late Indosinian?218²38Ma?and the middle and late Hercynian?324³44Ma;Permian?.The molybdenum ore-related magmatite are mainly late Indosinian-Yanshanian?124²02Ma?.Among them super-large,large,medium-scale deposits are mainly formed in the Caledonian period,Indosinian and Yanshan period.In this paper,Zircon LA-ICP-MS U-Pb dating of the guanghua formation rhyolite sample,which comes from Guliku Au-Ag deposit and has close relationship with the mineralization of it,gives weighted mean ages of126.33±0.93Ma?MSWD=1.7?.Moreover,zircon LA-ICP-MS U-Pb dating of the concealed tonalite-porphyry sample,which comes from Zhengguang Au-Zn deposit and has close relationship with the mineralization of it,gives weighted mean ages of 462.1±1.8Ma?MSWD=0.34?.The former one belongs to the early of late Cretaceous,and the latter one belongs to the late of middle Ordovician.The tectonic setting of gold,copper,molybdenum ore-related magmatite mainly are continental marginal arc,post-collisional crustal extension setting,or back-arc extension.the compressional tectonic setting is more favorable for the production of copper and gold metallogenic magmatic rocks,for instance,the tectonic setting of continental margin arc can produce large scale or super-large scale Cu deposits and Au-Zn deposits;while the extension tectonic setting is more favorable for producing gold and molybdenum ore-related magmatite,for instance,the peak stage of extensional setting can produces more types of mineral assemblages and deposits,and can produce large scale Au-Te deposits;The stage changed from compression to extension can produce large scale or super-large scale Mo deposits and independent Au deposits.Metallogenic regularity of regional superiority mineral resources:The regional spatial and temporal distribution regularity of the dominance metal elements of Mo,Zn-Pb-Ag,Cu,Au and Fe deposits was summarized,the correspondence regularity of spatial distribution of gold,copper and molybdenum deposits and magmatic metallogenic material specialization are expressly analyzed.The spatial distribution of regional deposits is nonuniform.Generally,they are zonal extend in a north-east trending?zonation?or concentrated as a zone?clustering?.Inside ore deposit concentration area,There is the distribution characteristics of extending along northeast and northwest,or forming grid pattern.Metallogenic epochs of regional ore deposits are mainly in middle Caledonian,early and middle Hercynian,middle and late Indosinian and Yanshanian.The metallogenic epoch of Cu?-Mo?-Fe-Au deposits mainly in Paleozoic,and PD?-ED?-SD are the genetic types of ore deposit.While,VMS is the characteristic genetic type of ore deposit in the late Paleozoic.The Mesozoic is characterized by Mo-Pb-Zn-Ag-Cu-Au-Fe polymetallic mineralization,and genetic types of ore deposits are dominated by PD-VD-ED.Low fractionation I type?LFI?and high?-moderate?fractionation I type?H?-M?FI?magmatite all possess gold,copper and molybdenum metallogenic material specialization,and the former is particularly significant.They control the distribution of most gold,copper and molybdenum deposits,as NE trending zonal distribution respectively in the Eergu'na block and Duobaoshan-Yi'ershi continental-margin magmatic arc zone?copper and gold deposits?,or as areal distribution widely in the central area?molybdenum deposits?;Moderate-low fractionation A type?M-LFA?and high-moderate fractionation A type?M-HFA?magmatite is respectively only possess gold and molybdenum metallogenic material specialization,and control the distribution of minority of gold and molybdenum deposits.Metallogenic advantage of magmatite in Hongyan area:Hongyan area is situated in the east slope of Middle-Northern Great Xing'an Range.Its tectonic location is in Duobaoshan-Zhalantun island arc which is conjoining zone between Xing'an terrane and Songnen terrane.magmatite are widely developed,intrusive rocks of which are mainly?alkaline?acidic rocks,and they all are Hercynian,volcanic rocks are mainly intermediate?basic?and acid volcanic lava and whose tuff,and they are middle Hercynian and middle Yanshan.Analyzed the intrusive rocks and volcanic rocks in this area,appling petrography,major and trace element petrogeochemistry,zircon U-Pb diagenesis chronology,zircon Hf isotope geochemistry,major and trace element geochemistry of zircon to research the diagenesis age of magmatite,magmatic redox degree,magmatic fractionation degree and evolution degree,magmatic temperature,genetic type of magmatite,magmatic source and diagenetic geotectonic background.Compared them with the ore-related magmatite of regional superior minerals on rock-forming age,temporal and spatial metallogenic specialization,and the material metallogenic specialization of gold,copper,molybdenum ore-related magmatite,then evaluate the metallogenic specialization of each magmatite unit;Make use of element content data of soil geochemical survey?1:50000?to analyze ore-bearing potential of main intrusions and volcanic rocks in Hongyan area;Furthermore,combine metallogenic specialization and ore-bearing potential to evaluate metallogenic advantage of the magmatites.Combining previous studies,ascertain there are at lest seven period of magmatic activity in Hongyan area.They are middle-late devonian(383.8³89.8Ma,Shitougou D_2-3?pluton and Yihede D_2-3??pluton),late devonian?374.0Ma,Qi'anchuoluo D₃??pluton?,early stage of early Carboniferous?356.0Ma,C₁m intermediate-acidic volcanic rock?,late stage of early Carboniferous?323.5Ma,Lapao C₁??pluton?,late Carboniferous?305.3Ma,Hadayang C₂??pluton?,early stage of early Permian?290.9²97.6Ma,Shanshengfu P₁??pluton and P₁??pluton?and late stage of early Cretaceous?124.7²7.5Ma,K₁gh intermediate-basic volcanic rock and K₁b acidic volcanic rock?.Middle-late Devonian?383.8³74.0Ma?is in the post-collision to post-orogenic and partly strike-slip extension setting.Late Devonian to early Carboniferous?363.3³52.5Ma or³34.3Ma?is in the continental margin arc-syn-collision compressional setting;early-late Carboniferous?323.5³05.3Ma?is in post-collisional crustal extension setting;early Permian?297.6²90.9Ma?is in post-extension setting of active continental marginal arc;late Jurassic?¹45.7Ma?in transition stage from compression to extension;early Cretaceous?127.5¹24.7Ma?is in superimposed setting of continental collision and post-arc extension-thinning system.Qi'anchuoluo D₃??belong to low fractionation I type,is from the mixture of crust and mantle;the rest of granites(including Shanshengfu P₁??,Hadayang C₂??,Shitougou D_2-3?,Lapao C₁??and Yihede D_2-3??pluton)are the alkaline A sub-type?AAG?which is a sub-classes of A2 sub-type of the higher-high fractionation A-type,The first four are from the mixture of crust and mantle and dominated by crust source material,the latest is mainly from crust source material.The rhyolite of Baiyingaolao Formation?K₁b?is A1 sub-type of the higher-high fractionation A-type,is mainly from crust source material,it combined with alkaline basalts of the Ganhe Formation?K₁gh?constitute bimodal volcanic rocks,which is from enriched lithospheric mantle source,and contaminated by the crust material.The intermediate-basic to intermediate to intermediate-acidic calc-alkaline volcanic rocks of Mo'ergenhe Formation?C₁m?are low-fractionation I-type,intermediate-basic volcanic rocks of which are from enriched mantle wedges,while intermediate-acidic volcanic rocks are differentiated mantle derived magma,and both contaminated by crust material.Most granites?except Qi'anchuoluo D₃???possess poor Mo metallogenic material specialization.However,Magmatic oxygen fugacity of Qi'anchuoluo D₃????FMQ_D is 2.4?,Yihede D_2-3????FMQ_D is-0.4?and Shanshenfu P₁??pluton??FMQ_D is 0.3?relatively higher,and their metallogenic material specialization,temporal and spatial specialization are consistency to varying degrees.Their metallogenic specialization?the former is Au and Cu,the last two are Au and Mo?are more reliable and mineralization possibility are higher.All volcanic rocks possess Au metallogenic specialization.There is a certain or preferable consistency in metallogenic material specialization,temporal and spatial specialization of early Carboniferous and early Cretaceous volcanic rocks.The metallogenic specialization of the latter is more reliable,and early Carboniferous volcanic rocks aslo possesses Cu metallogenic specialization.Late Jurassic and early Cretaceous acid volcanic rocks aslo possess ED-type Ag-Pb-Zn metallogenic specialization.The regional main ore-forming elements Au,Ag,Mo,W,Cu and Pb with intense fractionation and relative enrichment in Hongyan area,therefore their metallogenic possibility are higher.Yihede D_2-3??and Qi'anchuoluo D₃??pluton possess the most metallogenic advantage to form Au deposites,followed by J₃mk acid volcanic rocks,C₁m intermediate-basic to intermediate to acid volcanic rocks and K₁b acid volcanic rocks.Shanshenfu P₁??and Shitougou D_2-3?pluton also possess a relatively great Au metallogenic advantage.Ag and Au may have a similar origin,so they usually are paragenetic or concomitant.Habei C₂??pluton relatively possesses the most Cu metallogenic advantage,followed by Qi'anchuoluo D₃??pluton and C₁m intermediate-basic to intermediate to acid volcanic rocks,then J₃mk acid volcanic rocks and C₂P₁bl¹ intermediate volcanic rocks.Hadayang C₂??pluton relatively possesses the most Mo and W metallogenic advantage.While,J₃mk acid volcanic rocks relatively possesses the most Pb metallogenic advantage.Metallogenic prospective prediction in Hongyan area:Base on element content data of1:50000 soil geochemical measurements in Hongyan area.Employ the traditional method to obtaine the anomalous limits of elements,then delineate single element anomaly.The paragenetic elements anomalous combination was delineated as a comprehensive anomaly.Analyze,sort and classify these anomalys,then assessed their possibility of mineralization and necessity to carry out mineral inspection.Combining regional diagenesis-mineralization characteristics and metallogenetic regularity with the specific favorable mineralizing condition and information in Hongyan area to confirm the main prospecting mineral varieties and ore deposit types in this area.And then synthesize anomalous information of geology,geochemical prospecting,geophysical prospecting and remote sensing,of which on the important basis of metallogenic advantage of magmatite,delineating metallogenic prospective area in Hongyan area.The data statistics of 1:50000 soil geochemical measurements in Hongyan area shows variation coefficients of Au,Cu,Mo and Ag are higher,accordingly their mineralization probability is higher.In this case,delineated ten geochemical anomalous combination,of which elements anomalous combination As-Au-Cu?HS-4-?₂?and Sb-As-Cu-Pb?HS-5-?₂?possess an excellent metallogenic conditions and great prospecting potential.In order of importance,the main prospecting mineral varieties are Au,Cu,Ag,Mo,Pb and W.The main prospecting ore deposit types are ED-type Au?-Cu-Ag?deposits related to volcanism,VD-type Au and Mo?-W?deposits related to intrusion,and PD-type Cu?-Au-Ag?deposits.Delineate three I-level metallogenic prospective areas which are Shanshenfu-Fendousandui gold,copper,tungsten and molybdenum polymetallic metallogenic prospective area,Xiaoheishan-Shitougou copper,gold,silver and lead metallogenic prospective area,and Jiangtun-Gangyao gold,copper and silver polymetallic metallogenic prospective area.By means of mineral inspecting in later mineral prospecting work,find Fendou Au-Cu-Ag ore occurrence and Xiaoheishan Cu-Au ore occurrence in further delineated prospecting target areas within the former two metallogenic prospective areas.