Geological and Geochemical Characteristics and Genesis of the Shaxi Porphyry Copper (Gold) Deposits, Anhui Province

The Shaxi porphyry copper (gold) deposits are a typical example of porphyry copper deposits associated with diorite in eastern China. Quartz diorite, which hosts the deposits, has a Rb-Sr isochron age of 127.9 ± 1.6 Ma. Geochemically, the rock is rich in alkalis (especially sodium), light rare earth elements (LREE) and large-ion lithophile elements (LILE), and has a relatively low initial strontium isotopic ratio (Isr=0.7058); thus it is the product of differentiation of crust-mantle mixing source magma. The model of alteration and mineralization zoning is similar to the Hollister (1974) diorite model. The ore fluids have a relatively high salinity and contain significant amounts of CO2, Ca2+, Na+ and ***CI?. The homogenization temperatures of fluid inclusions for the main mineralization stage range from 280 to 420°C, the δ18O values of the ore fluids vary from 3.51 to 5.52 %, the δD values are in the range between ?82.4 and ?59.8 %, the δ34S values of sulphides vary from ?0.3 to 2.49 %, and the δ13C values of CO2 in inclusions range between ?2.66 and ?6.53 %. Isotope data indicate that the hydrothermal ore fluids and ore substances of the Shaxi porphyry copper (gold) deposits were mainly derived from magmatic systems.

A new type of micro-disseminated gold deposits in association with diabase found in Yunnan and Guizhou provinces and Guangxi Zhuang Autonomous Region——Their geological characteristics and metallogenic conditions

With the continuous development of gold ore prospecting and exploration in recent years a new type of micro-disseminated gold deposits have been found in the regions of Southwest Guizhou Province and Northwest Guangxi Zhuang Autonomous Region,with the orebodies directly occurring in diabase or in the contact zone between diabase and strata.The orebodies are strictly controlled by fault structures.The discovery of this type of gold deposits has brought about new prospects for gold ore prospecting in the Yunnan-Guizhou-Guangxi Golden Triangle region.From the preliminary analysis of the geological characteristics of the Qiaoxiang gold deposit in Wangmo County,in combination with the results of research work in the adjacent areas in recent years,this paper roughly described the geological characteristics and metallogenic conditions of this type of gold ore deposits with an attempt to make more and more geologists pay enough attention to this type of gold ore deposits,so as to promote gold ore prospecting in Guizhou Province to develop toward a variety of types of gold deposits in all round way.

Geological Characteristics and Its Metallogenesis of Daolundaba Copper Polymetallic Deposits,Inner Mongolia

1 Geology Daolundaba copper polymetallic deposit occurs in West Ujimqin Banner,the Xilin Gol League of Inner Mongolia,along the west side of South part of Daxinganling ore belt,whose tectonic position just lies at the junction of Siberian Block in the south part,North China Block in the north and Songliao block in the east.The Daolundaba copper polymetallic deposit is hosted by the Lower Proterozoic Baoyintu group of biotite-plagioclase gneiss(Pt1by),upper Permian Linxi formation of sandy slate(P2l),and the Hercynian Qianjinchang pluton of biotite granite.

Geological and geochemical characteristics and metallogenic model of the Wenquan molybdenum deposit

The Wenquan molybdenum deposit is a kind of large-sized porphyry molybdenum deposit found in re-cent years.In this paper,on the basis of deposit geology,geochemistry and isotope geochronology data,the metal-logenic model of this deposit was established.The Wenquan granitic batholith belongs to the K-rich(alkali-rich) calc-alkaline rock series,which is the mineralization parent rock.The rock massif shows the characteristics of both crust-remelting granite and mantle-source granite.At the same time,the data of REE contents,hydrogen and oxygen isotopes and inclusion temperatures showed that the metallogenic hydrothermal solution is a mixed mesothermal solution of magmato-hydrothermal fluid and meteoric water.Mineralization was dated at 214±7.1 Ma,basically identical with the parent rock's age(207-226 Ma).This reflects that molybdenum mineralization has a close relation to tectonic magmatism evoked by orogenic processes,and molybdenum mineralization occurred mainly at the petrogenesis stage at the late stage of magma emplacement.Mixing with meteoric water led to a decrease in the sa-linity of magmato-hydrothermal solution and changes in other physical and chemical properties.During the tectonic process,ore-bearing hydrothermal solution ascended along favorable fault structure channels.With physicochemical changes,it filled in the surrounding rock joints on both sides of faults,forming ore deposits.

Geological characteristics and genesis of subbottom pinnoite deposit of Da Qaidam salt lake in Qaidam Basin

Da Qaidam salt lake is known for its both liquid and solid boron resource.Data from previous investigation of the Da Qaidam salt lake provided a comparable framework for this study that focused on investigating the section beneath the bottom of the perennial salt lake,including the timing,

Geological characteristics and the origin of ore-forming materials of(Laozhaiwan gold deposit, Yunnan Province

"Golden triangle"area bordered on Yunnan-Guizhou-Guangxi was one of the most important Carlin-type gold deposits concentration areas.Deep understanding of Carlin-type gold deposits in Guizhou and Guangxi Province had reached through several decades studies,but geological environment was very complex in the southeastern Yunnan,and Carlin-type gold deposits produced in the southeastern Yunnan were different from that of America,few studies were taken there.Based on a large number of field work,studies on the geological characteristics combining with geochemistry characteristics were taken,and analysis the genesis of Laozhaiwan gold deposit.The types of alteration in Laozhaiwan gold deposit were mainly silicification and pyritization,and Gold grade was high when silicification and pyritization were both occurred.It could be caculated that fluid density(g/cm3)varied from 0.7 to 4.9,salinity varied from 0.76%to 0.95%and ore-forming pressure(Pa)varied from 1.81×105 to 49.96×105 according to fluid inclusion test results,showed that Laozhaiwan gold deposit was hypabyssal hydrothermal deposit in low temperature and low salinity.According to composition of fluid inclusion analysis,combining with H-O isotope,made theδD-δ18O figure,showed that the fluid of the deposit rooted in formation water and mixed with meteoric waters later.

Genesis,Distribution and Engineering Characteristics of Recently Deposited Silts in Huaibei Plain,Anhui Province

There are two different genetic types of recently deposited silts widely distributing in Huaibei Plain of Anhui Province:flooding deposited silt of Yellow River and Huaihe River.These recently deposited silts have the following unique characteristics:new formation age,feeble consolidation degree。

A synthesis of iron deposits in the eastern Tianshan,NW China

The northern Xinjiang region is one of the most significant iron metallogenic provinces in China.Iron deposits are found mainly within three regions:the Altay,western Tianshan,and eastern Tianshan orogenic belts.Previous studies have elaborated on the genesis of Fe deposits in the Altay orogenic belt and western Tianshan.However,the geological characteristics and mineralization history of iron deposits in the eastern Tianshan are still poorly understood.In this paper I describe the geological characteristics of iron deposits in the eastern Tianshan,and discuss their genetic types as well as metallogenic-tectonic settings,Iron deposits are preferentially distributed in central and southern parts of the eastern Tianshan.The known iron deposits in the eastern Tianshan show characteristics of magmatic Fe-Ti-V(e.g.,Weiya and Niumaoquan),sedimentary-metamorphic type(e.g.,Tianhu),and iron skarn(e.g.,Hongyuntan).In addition to the abovementioned iron deposits,many iron deposits in the eastern Tianshan are hosted in submarine volcanic rocks with well-developed skarn mineral assemblages.Their geological characteristics and magnetite compositions suggest that they may belong to distal skarns.SIMS zircon U-Pb analyses suggest that the Fe-Ti oxide ores from Niumaoquan and Weiya deposits were formed at 307.7±1.3 Ma and 242.7±1.9 Ma,respectively.Combined with available isotopic age data,the timing of Fe mineralization in the eastern Tianshan can be divided into four broad intervals:Early Ordovician-Early Silurian(476-438 Ma),Carboniferous(335-303 Ma),Early Permian(295-282 Ma),and Triassic(ca.243 Ma).Each of these episodes corresponds to a period of subduction,post-collision,and intraplate tectonics during the Paleozoic and Mesozoic time.

Geology and mineralization of the Dayin’gezhuang supergiant gold deposit(180 t)in the Jiaodong Peninsula,China:A review

The Dayin’gezhuang gold deposit is located in the central part of the Zhaoping Fault metallogenic belt in the Jiaodong gold province-the world’s third-largest gold metallogenic area.It is a typical successful case of prospecting at a depth of 500-2000 m in recent years,with cumulative proven gold resources exceeding 180 t.The main orebodies(No.1 and No.2 orebody)generally have a pitch direction of NNE and a plunge direction of NEE.As the ore-controlling fault,the Zhaoping Fault is a shovel-shaped stepped fault,with its dip angle presenting stepped high-to-low transitions at the elevation of -2000-0 m.The gold mineralization enrichment area is mainly distributed in the step parts where the fault plane changes from steeply to gently,forming a stepped metallogenic pattern from shallow to deep.It can be concluded from previous studies that the gold mineralization of the Dayin’gezhuang gold deposit occurred at about 120 Ma.The ore-forming fluids were H_(2)O-CO_(2)-NaCl-type hydrothermal solutions with a medium-low temperature and medium-low salinity.The H-O isotopic characteristics indicate that the fluids in the early ore-forming stage were possibly magmatic water or mantle water and that meteoric water gradually entered the ore-forming fluids in the late ore-forming stage.The S and Pb isotopes indicate that the ore-forming materials mainly originate from the lower crust and contain a small quantity of mantle-derived components.The comprehensive analysis shows that the Dayin’gezhuang gold deposit was formed by thermal uplifting-extensional tectonism.The strong crust-mantle interactions,large-scale magmatism,and the material exchange arising from the transformation from adakitic granites to arc granites and from the ancient lower crust to the juvenile lower crust during the Early Cretaceous provided abundant fluids and material sources for mineralization.Moreover,the detachment faults formed by the rapid magmatic uplift and the extensional tectonism created favorable temperature and pressure conditions and space for fluid accumulation and gold precipitation and mineralization.

新疆中亚造山带铁矿床地质特征、时空分布和找矿方向

在前人研究和野外调查基础上,文章综述了新疆中亚造山带铁及铁多金属矿地质特征、时空分布规律、构造环境和找矿方向。铁及铁多金属矿主要为岩浆型、海相火山岩型、矽卡岩型、IOCG型、岩浆热液脉型、沉积变质型和沉积型,其中海相火山岩型和矽卡岩型是主要类型,主要分布于南阿尔泰、东天山和西天山,少量分布在准噶尔、北山和西南天山。6个主要成矿期:新元古代青白口纪、中-晚志留世、泥盆纪(376~411 Ma)、石炭纪(301~337 Ma)、早-中二叠世(262~295 Ma)和晚三叠世—中侏罗世,其中泥盆纪和石炭纪为主要成矿期。新疆中亚造山带在前寒武纪陆块、洋-陆俯冲增生、陆-陆碰撞、后造山伸展和陆内等地质过程形成了不同类型的铁矿床。泥盆纪—石炭纪为与板块俯冲有关的大洋岛弧和陆缘弧环境,主要形成海相火山岩型和矽卡岩型;二叠纪为后碰撞环境,主要形成岩浆型和矽卡岩型;晚三叠世—中侏罗世为陆内伸展环境。今后的找矿部署是主攻西天山阿吾拉勒,深化南阿尔泰、东天山阿齐山-雅满苏-沙泉子和梧桐沟-天湖矿集区,加快评价准噶尔北缘、伊什基里克和莫托沙拉-库米什矿集区。

西藏多龙斑岩-浅成低温热液型铜(金)矿集区地质特征及找矿潜力分析

本文在总结多龙矿集区地质特征的基础上,开展了矿山深边部的潜力分析,以期为下一步的找矿预测提供勘查思路。多龙斑岩-浅成低温热液型铜(金)矿集区位于西藏班公湖-怒江成矿带的北西侧,主要由铁格隆南超大型斑岩-浅成低温热液型铜(金)矿床,拿若大型斑岩-隐爆角砾岩筒型铜(金)矿床,多不杂、波龙、多不杂西大型斑岩型铜(金)矿床,尕尔勤、地堡那木岗高硫化浅成低温热液型铜(金)矿点组成,共探获铜资源量超过1500万t,伴生金超250 t,伴生银3900 t。多龙矿集区形成于早白垩世(120 Ma)班公湖-怒江洋盆北向俯冲的陆缘弧环境,物质源区为壳幔混合源,成矿岩浆岩主要为中酸性的闪长玢岩-花岗闪长斑岩-花岗斑岩系列,具有弧岩浆特征。俯冲板片的折返是多龙矿集区深部岩浆形成和侵位的主要动力学机制,成矿后安山质火山岩(110 Ma)的覆盖对矿床起到重要的保存作用。多不杂矿区F2逆断层将矿体分割成上、下两部分,下部分矿体是找矿的重点方向。铁格隆南矿区深钻揭露了由南向北的逆冲断层,该逆冲断层将矿体错断并推覆到“红层”沉积之上,其下盘是寻找另一半隐伏矿体的方向。尕尔勤矿区大面积发育指示浅成低温热液成矿系统的“硅帽”,明显富集Au、Ag、As、Sb、Bi、Cu等元素,Au、As、Sb、Hg等呈现较好的元素组合异常,具有寻找浅成低温热液型矿床的潜力。地堡那木岗矿区发育高硫化浅成低温热液型蚀变(高岭石化、地开石化、明矾石化等)和矿物组合(铜蓝、蓝辉铜矿、斑铜矿等),且物探、化探、遥感异常套合良好,是未来矿产勘查的重点。区内逆冲断层对矿床的改造作用是未来研究的重点,对进一步的勘查评价具有重要的指导意义。

河南银洞坡金矿“三位一体”找矿预测地质模型及应用示范

河南银洞坡金矿位于河南省桐柏县朱庄镇,为一特大型金矿床,同体共生银、铅锌。运用勘查区找矿预测方法与理论,构建成矿地质体、成矿构造与成矿结构面和成矿作用特征标志为主的“三位一体”找矿预测地质模型。野外调查和矿床学研究认为,矿床成因为与早白垩世岩浆作用有关的中低温岩浆热液矿床,主成矿阶段温度介于200~350℃之间,碳、氢、氧、硫同位素研究表明,成矿物质和成矿流体主要来源于岩浆。确定成矿地质体为矿区深部隐伏早白垩世花岗岩体;成矿结构面为岩性界面(硅/钙面)、褶皱成矿构造系统结构面、沉积成岩结构面;成矿作用特征标志主要为矽卡岩化、钾化、黄铁绢英岩化、硅化、铁白云石化、萤石矿化、碳酸盐化。由此建立了银洞坡金矿找矿预测地质模型,圈定了找矿靶区,施工的钻孔见矿率达到85%,对该地区及邻区进一步找矿具有现实的指导意义。

安徽宿松县柳坪磷矿地质特征及找矿标志

柳坪磷矿是宿松地区典型磷矿床之一,其矿床资源储量规模达中型,其磷矿赋存于宿松岩群的柳坪岩组中,分为上下四层。该磷矿为“海州式”沉积变质型矿床,受岩层和次级褶皱的控矿条件制约,具有地层、岩性组合、磷锰共生、地球化学异常等找矿标志。矿区部分地段深部延伸稳定且未完全控制,显示深部仍然具有较大找矿潜力。

新疆西昆仑—喀喇昆仑地区锂多金属成矿带地质特征及资源潜力

通过对新疆西昆仑—喀喇昆仑地区的地质背景、矿床类型及资源现状进行综合分析,揭示了其作为我国重要战略资源基地的潜力。该地区地质构造复杂,受特提斯构造域北缘的影响,历经多期构造活动,形成了丰富的锂多金属矿产资源。矿床类型主要为花岗伟晶岩型。目前,该区域的锂资源开发正处于起步阶段,大多数矿区仍未被充分开发。鉴于全球对清洁能源和新能源汽车的需求持续增长,该地区的锂多金属资源有望成为未来重要的供应基地。

乌毛蕨叶光谱特征对矾山铜钼矿区钼金属找矿指示意义

针对植被覆盖区遥感技术在矿产勘查中的实际问题,提出了一种利用金属元素迁移规律和金属胁迫后植被光谱发生变异的特点开展植被覆盖区地质找矿的遥感新方法。该方法基于植被叶片光谱曲线反射和吸收特征的原理,结合地球化学数据,间接实现重金属元素分布遥感制图。采集矿区和矿区周围背景区乌毛蕨叶样本及对应光谱数据,基于化学分析测定获得矿区和背景区乌毛蕨叶钼元素含量,明确矿区乌毛蕨叶受到了钼元素影响。对比分析矿区和背景区乌毛蕨叶在波形、红边位置、叶绿素及水吸收、植被指数上的差异,结果表明,受钼金属胁迫后矿区乌毛蕨叶光谱在光谱曲线和水吸收特征方面较背景区均存在明显差异,其中970 nm处的水吸收特征差异最明显。研究成果可为遥感技术在植被覆盖区开展地质找矿提供新思路。

福建省尤溪县卓坑钼矿床元素迁移特征及矿床成因

福建尤溪县卓坑斑岩型钼矿床位于浙闽火山断陷带构造单元内,圈定的17个钼矿体均赋存于晚侏罗世似斑状中细粒二长花岗岩岩体中。本文为了厘定成矿过程中物质迁移规律,对其矿体和同时代似斑状二长花岗岩进行了主微量元素测试分析,并采用标准化Isocon图解法计算元素迁移特征。结果表明,卓坑钼矿床在热液蚀变过程中Au、Ag、As、Na_(2)O等组分发生一定程度的迁出,而SiO_(2)、K_(2)O、CaO、MgO、P_(2)O_(5)、Cu、Pb、Zn、Co、Sn、Bi等组分发生迁入;这些主微量元素迁移特征表明热液蚀变作用是矿区Mo沉淀的主要机制,钼矿化与钾长石化和硅化蚀变关系密切。结合华南地区中生代构造背景,认为卓坑钼矿床是太平洋板块向欧亚板块俯冲背景下形成的斑岩型钼矿床,含矿流体沿岩体内原生裂隙和构造裂隙运移至浅部断裂中沉淀成矿;NE向断裂内及其次级断裂内为其找矿构造标志,似斑状中细粒二长花岗岩体中钾长石化和硅化叠加发育为矿化蚀变标志,石英细脉和网状裂隙为找矿的岩脉标志。

肯尼亚沃伊矿区高岭土矿床地质特征及成因探讨

本文在对肯尼亚沃伊矿区高岭土矿进行专项地质调查和综合研究的基础上,分析了高岭土矿床的地质特征和矿床成因,总结了找矿标志。研究认为:肯尼亚沃伊矿区高岭土矿床赋存于前寒武纪长英质变粒岩中,是优质的高岭土矿石,可满足各类工业应用要求;该矿床为风化残积型高岭土矿床;区内高岭土一般为白色高岭土,白色的黏土矿物为本区高岭土找矿直接标志,富含有长石的基岩为高岭土矿的间接找矿标志。研究结果为肯尼亚高岭土的找矿工作提供参考。

不同计算方法的云南省永胜县下院滑坡堰塞湖沉积物粒度特征及沉积历史重建

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福建大田县元山高岭土矿床成矿地质特征及开发利用前景

通过福建大田县元山高岭土矿床的成矿地质特征及开发利用价值的分析,认为:元山高岭土矿产出于流纹斑岩风化壳内,矿石质量尚佳,埋藏浅,适宜露天分台阶开采;矿物主要为高岭石和石英,高岭石多为集合体,少量为他形片状单体;高岭土应用领域广泛,元山高岭土矿床具有较大的经济价值,具有较好的开发利用前景。