A Study on Palaeogeography and Metallogenic Conditions of Early Carboniferous Bauxite Deposits of Old Weathered Crust in Guizhou, Sichuan, Hunan and Hubei Provinces

There are four subtypes. namely, Ia, Ib, Ic and Id of the Early Carboniferous bauxite deposits of the old weathered crust type in Guizhou, Sichuan, Hunan and Hubei provinces. They are all distributed in the Upper Yangtze old land. As a result of the Hunan-Guizhou palaeo-faulting, the crust on the northern side of the fault was uplifted and became land, thus suffering denudation. The bauxitic substances left in the weathered crust evolved and were reworked into bauxite. On the other hand, the crust on the southern side of the fault sank and remained to be part of an ocean. The bauxite deposits of Ia and Ib subtypes were formed by in-situ enrichment of residual bauxitic substances in the weathered crust of the old land, but bauxite deposits of Ic and Id subtypes resulted from transportation, accumulation and sedimentation of allothogenous bauxitic substances on the weathered crust of the old land. The processes of transportation may be distinguished as dry transportation and wet transportation, both of which proceeded under atmospheric conditions.

Bioleaching behavior and surface property of pyrites in different metallogenic conditions

The bioleaching behaviors and surface properties of pyrites in two metallogenic conditions by Sulfobacillus thermosulfidooxidans were investigated by adsorption tests, zeta-potential measurements and bioleaching experiments. It is found that there were significant differences in the microorganism adsorption capacity, electrokinetic properties and bioleaching behaviors for the two pyrites. The S. thermosulfidooxidans adsorption capacity on high temperature hydrothermal(hy_high_temp) pyrite is larger than that on sendimentary coal(sed_coal) pyrite. It may be that more extracellular polymeric substances(EPS) is produced when it is difficult for microorganism to make use of hy_high_temp pyrite as source of energy, and get leaching bacteria attached to pyrite by means of EPS. The zeta-potential measurements indicated that zeta-potential value of hy_high_temp pyrite was higher than that of sed_coal pyrite in pH range of 2–10. After interacting with cells, the IEP(Iso-Electric Point) of hy_high_temp pyrite shifted obviously to that of bacterial. In contrast, the IEP of sed_coal pyrite remained unchanged nearly. The bioleaching results showed that hy_high_temp pyrite did not dissolve and the leaching extent was only 0.82%, while that of sed_coal pyrite was 34.59%. Attempts were taken to illustrate the remarkable difference between bioleaching results of two pyrites from a semiconductor energy band theory perspective.

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.

METALLOGENIC CONDITIONS OF GOLD-BEARING SKARN DEPOSITS ALONG THE MIDDLE-LOW ER REACHES OF THE YANGTZE RIVER

The authors discussed the metallogenic conditions of goldbearing skarn deposits along the middlelower Yangtze River reaches. Gold was enriched in mantleoriginated magmas while copper was enriched in crustoriginated magmas. So the enrichment of gold in skarn deposits was decided by the M/C ratios of the intrusive rocks. The distribution of these deposits was controlled not only by the localization of the intrusive rocks which were decided by Mesozoic Eradeveloped largescaled and deepseated faults, but also by the favorable stratigraphic horizons.

Research Progress of the Mineralization of Carbonate-Hosted Pb-Zn Deposits in the Sichuan-Yunnan-Guizhou Pb-Zn Metallogenic Province, Southwest China

The Sichuan-Yunnan-Guizhou （SYG） Pb-Zn metallogenic province in the western Yangtze Block, is a key component of the low-temperature metallogenic domain in South China. In this area, more than 400 Pb-Zn deposits have been discovered, and the total proven reserves are up to 260 million tons with lead and zinc grade reaching 10%, even up to 30%.

The Geochemical Characteristics and Metallogenic Mechanism of the Daliangzi Pb-Zn Deposit in Sichuan Province

1 Introduction Daliangzi large-sized Pb-Zn deposit,located in the Western Margin of Yangtze Plate,is typical Pb-Zn deposit in the sichuan-yunnan-guizhou polymetallic metallogenic belt.Ore bodies are hosted in Sinian

Geochemical Conditions of Metallization of the Lijiagou Pb-Zn Deposit, Gansu Province

The Lijiagou Pb-Zn deposit in Gansu Province is a syngenetic hydrothermal-depositonal and meta-morphosed hydrothermal weakly-reworked stratabound ore deposit. The metallogenic physicochemical condi-tions of the deposit are thoroughly dealt with in this paper according to its different mineralization stages.Based on the systematic study of metallogenic material sources, it is considered that the ore-forming metals, oresulphur and water of mineralizing fluids are mainly derived from the basement, reduction sulphur of marinesulfate and infiltrating heated meteoric water and partially recharged sea water, respectively. Finally, themetallogenic model of this deposit is established.

A Preliminary Review of the Metallogenic Regularity of Nickel Deposits in China

The nickel deposits mainly distributed in 19 provinces and autonomous regions in China are 339 ore deposits/occurrences, including 4 super large-scale deposits, 14 large-scale deposits, 26 middle- scale deposits, 75 small-scale deposits, and 220 mineralized occurrences. The prediction types of mineral resources of nickel deposits are magmatic type, marine sedimentary type and regolith type. The formation age is from the Neoarchean to the Cenozoic with two peaks in the Neoproterozoic and the late Paleozoic. The nickel deposits formed in the Neoproterozoic are located on the margin of the North China Block and Yangtze Block, and those formed in the late Paleozoic are mainly distributed in the Central Asian Orogenic Belt （CAOB）, Emeishan and the Tarim Large Igneous Provinces （LIPs）. Magmatic nickel deposits are mainly related with broken-up continental margin, post-collision extension of the orogenic belt and mantle plume. According to different tectonic backgrounds and main characteristics of magmatism, the Ni-Cu-Co-PGE metallogenie series types of ore deposits related with mantle-derived mafic-ultramafic rocks can be divided into 4 subtypes： （1） the Ni-Cu-Co- PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in the broken-up continental margin, （2） the Ni-Cu-Co-PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in mantle plume magmatism, （3） the Ni-Cu-Co- PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in the subduction of the orogenic belt, and （4） the Ni-Cu-Co-PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in post-collision extension of the orogenic belt. We have discussed in this paper the typical characteristics and metaliogenic models for Neoproterozoic Ni-Cu-（PGE） deposits related with broken-up continental margin, Cambrian marine sedimentary Ni-Mo-V deposits related with black shale, early Permian Ni-Cu deposits related with post-collision extension of the orogenic belt, late Permian Ni-Cu-（PGE） deposits related with Large Igneous Provinces （LIPs）, and Cenozoic Ni-Au deposits related with regolith. The broken-up continental margin, mantle plume and post-collision extension of the orogenic belt are important ore- forming geological backgrounds, and the discordogenic fault, mafic-ultramafic intrusion, high MgO primitive magma （high-MgO basaltic magma）, deep magmatism, sulfur saturation and sulfide segregation are 6 important geological conditions for the magmatic nickel deposits.

Geochemical Features and Metallogenic Prediction of the Caixiashan-Weiquan Area in the East Tianshan Region

The Caixiashan-Weiquan area is an important ore concentration area in the eastern Tianshan metallogenic belt. Firstly, this paper studies geochemical features of 1564 samples of 1：200000 stream sediments of the Matoutan mapsheet, where the Caixiashan and Weiquan deposits are located. Processing, analysis and explanation of exploration geochemical data play an important role in the procedure of finding the ore, which are related to whether the measured elements content of geochemical samples can effectively guide the work of mineral exploration. As a highly nonlinear dynamical system, the neural network is more analogous to the human brains in terms of principles and features compared with conventional geochemical approaches. It can adapt itself to the environment, sum up laws, complete pattern recognition. Secondly, the authors used the Kohonen neural network to classify all samples based on 10 mineralization elements of stream sediment samples in order to determine possible mineral ores, reduce the scope of ore targets and study indicator elements of the ninth group of samples, which is the mostly closest to the deposit. The results show that the neural network can delineate metallogenic prospective areas and is effective in the discovery of deep geochemical information.

Metallogenic Features and Metalogenic Model of Laterite Gold Deposits in Southern China

The modern laterite gold deposits in southern China, which belong to reworked laterite deposits, can be further divided into three subclasses and seven types. Their geological features, ore-forming conditions and regularities are discussed. A geologic-geochemical metallogenic model for laterite gold deposits has been established.

西藏昌都地区错纳Pb-Zn-Ag矿床地质特征及成矿条件分析

错纳Pb-Zn-Ag矿床是三江成矿带中段昌都地区典型的赋存于沉积岩的中型铅锌矿床。在野外调查错纳矿床成矿地质背景、矿床地质特征的基础之上,对含矿地层、控矿构造、矿体特征、矿石组构、成矿期次进行了系统研究,对其成矿条件进行了深入分析。研究结果表明,澜沧江逆冲推覆系统是该区主要的控矿构造,矿体主要赋存在逆冲推覆构造产生的次级逆断层的张性裂隙及构造破碎带中。上三叠统阿堵拉组第一岩性段石英砂岩、粉砂岩是最有利的含矿岩性。该矿床为受岩性和断裂共同控制的热液矿床。

渤海湾盆地大港探区明化镇组多级别层序格架及砂岩型铀成矿条件

渤海湾盆地位于世界两大砂岩型铀矿成矿带之一的欧亚成矿带内,具有砂岩型铀成矿的潜力。大港探区测井结果显示明化镇组发育着大范围的高伽马异常,为探究其铀成矿条件并指明找矿方向,建立了大港探区明化镇组多级别层序格架,并开展了层序内沉积微相研究,对氧化还原带进行了划分。研究表明,依据测井曲线特征和岩石性质,将明化镇组划分为五级层序,铀异常主要见于明化镇组下段上亚段和上段下亚段2个五级层序内。其沉积微相主要发育曲流河河道、边滩、溢岸沉积和泛滥平原4种,其中铀异常主要发育于边滩、河道砂体。2个层序内的氧化还原带可划分出氧化带、过渡带和还原带,其中铀异常主要位于过渡带内。叠合沉积微相、氧化还原带展布、铀异常展布和油气分布等特征,认为油气富集带附近的过渡带中,边滩和河道微相砂体中均具有良好的铀成矿条件。综合分析认为,港东港西地区西7-14-2、西1603、港3-6-20和港8-15-1井区是大港探区砂岩型铀矿的有利找矿位置,研究结果为渤海湾盆地砂岩型铀矿勘探提供了启示意义。

甘肃北山红柳园—辉铜山地区成矿地质条件、地球化学特征及找矿新发现

甘肃北山红柳园—辉铜山地区位于甘肃北山南带,是形成铜、镍、铁、铅锌、钼、金、银等矿床的有利地区,具有较好的找矿潜力。通过开展成矿地质条件分析,总结控矿关键因素,依据水系沉积物地球化学特征,确定Au、Ag、As、Sb、Hg、W、Sn、Ni、Cu为区内主要的成矿(伴生)元素。Ni、Cu异常与基性-超基性侵入岩的分布有关,Au异常受华力西中期似斑状花岗岩及加里东晚期石英闪长岩控制明显,与区域性断裂及其旁侧平行或“入”字斜交的次级断裂关系密切。异常查证新发现铭扬铜镍矿、杨帆金矿等多处矿点及矿化线索,结合区域地质、物探、化探特征,优选出4处具较大成矿潜力的找矿远景区,尤其是早古生代铭杨铜镍矿的发现,实现了北山地区近年来铜镍矿找矿新突破。研究成果可为下一步找矿勘查部署提供重要依据。

松辽盆地克山地区航放异常特征及铀成矿条件分析

为了筛选铀成矿有利地段,探索克山地区铀成矿前景,通过开展1:5万高精度航空放射性测量异常查证工作,并结合收集整理的相关地质资料,从航放异常特征、地质特征、能谱特征及土壤氡浓度特征等几个角度,对克山地区进行铀成矿条件分析。结果表明:该地区靠近小兴安岭地区,且盆地盖层具有较高的初始铀含量,铀源条件优良;地层宽缓,断裂发育,是深部烃类向上运移的通道,地表局部剥蚀强烈,形成构造天窗,成矿有利砂体大规模发育,并伴有后生改造作用和铀富集。克山地区航放异常集中分布,航磁推断构造发育,深部放射性信息突出,为砂岩型铀矿找矿提供了有益线索,为圈定找矿有利区段提供了依据。

南秦岭安康成矿带金矿地质特征与成矿条件研究

安康金成矿远景区位处南秦岭安康成矿带,区内赋矿层位为志留系下统斑鸠关组、梅子垭组,受北西西-南东东向展布的叶坪河复式向斜构造控制,成矿类型属沉积改造型。岩石地球化学分析表明,Au元素在各地层的平均质量分数值范围为1.19×10^(-9)-~6.68×10^(-9),而经后期变质改造的各地层中(含矿层片岩类),Au元素的质量分数值升高,各变质地层Au元素的质量分数值范围为255×10^(-9)~711×10^(-9),平均值的范围为23.06×10^(-9)~26.52×10^(-9),具找矿前景,是勘查区内主要的找矿目标。认为地层岩性、构造特征、围岩蚀变、化探异常可作为该区域金矿床找矿的标志。

南岭成矿带中段成矿规律与找矿前景分析

【研究目的 】南岭中段是中国重要的有色金属、能源矿产、非金属和水气矿产资源基地,成矿地质条件优越、矿产类型丰富、成矿作用类型复杂,深入理解其成矿规律是开展区域成矿理论研究和实现找矿突破的关键。【研究方法 】本文基于前人丰硕的成果资料,对南岭成矿带中段成矿规律和找矿方向进行了总结分析。【研究结果 】此次研究明确了南岭中段主要控矿地质条件,厘定了区域两种构造格架体系的控矿作用;依据矿产资源特征,总结了成矿特征、规律及其演化,进一步探讨了区域岩浆演化和成矿潜力;整理出了南岭成矿带中亚带目前发育的50个矿种、872处矿产地和15种矿床类型,并探讨了主成岩作用特征、演化及其成矿潜力。【结论 】南岭中段找矿的主攻方向为:寻找接触带附近的铀矿、煤矿的滑覆构造、受变质和硫铁矿区风化型铁矿、有色金属组合的综合预测和寻找缺位类型,寻找新类型稀有、稀散矿和独立金矿,保护和开发伴生宝石矿。围绕着骑田岭及周边、乐昌—韶关—翁源远景区,有望实现钨锡钼铋铜铅锌铀稀土等矿产的找矿突破。

辽宁省本溪县红旗沟地区成矿条件分析及找矿靶区预测

通过对辽宁省本溪县红旗沟地区区域典型矿床成矿相关岩体的成矿属性及构造、围岩等成矿条件对比分析,认为研究区内热液石英脉型金(铜)矿床、矽卡岩型、斑岩型铜金钼多金属矿床、与基性岩有关的铜金钴镍金属矿床的极具找矿潜力。运用有利成矿条件信息的赋值统计方法,对研究区进行金铜钼等找矿靶区预测工作。

塔里木盆地巴楚隆起上新统砂岩型铀成矿条件及找矿方向

为明确巴楚隆起上新统砂岩型铀矿找矿方向,文章通过研究构造、断裂、岩性及岩石地球化学、沉积相和砂体、外部铀源、地层含铀性、深部铀源等,分析了砂岩型铀成矿条件,指出:巴楚隆起上新统发育构造缓坡,后生氧化作用时间短,原生为红杂色层,外部铀源和地层含铀性差,不利于形成大规模层间氧化带型铀矿。沟通深部烃源岩和上新统的断裂发育,上新统与下伏地层之间为区域性不整合面,断裂和不整合面构成良好的渗出型流体的运移通道。发育后生还原的灰色砂体,为渗出型铀成矿良好的容矿空间;古生界发育富铀烃源岩,为渗出型铀成矿良好的铀源。巴楚隆起渗出型铀成矿条件优于渗入型铀成矿条件,渗出型铀矿为巴楚隆起上新统下一步主要的找矿类型。

鄂尔多斯盆地与四川盆地砂岩型铀矿成矿条件对比初探

为了研究砂岩型铀矿成矿条件,使其勘探工作能进一步拓展,通过总结北方鄂尔多斯盆地和南方四川盆地的主要控矿因素,较系统地对比了二者砂岩型铀矿铀成矿条件。研究表明,二者在盆地类型、规模及展布特征、铀源、盆地演化史和矿床成因类型等方面具有相似性,但在构造活动性、控矿沉积体系和古气候演化三大方面存在明显差异。四川盆地具备良好的铀成矿条件,成矿潜力巨大,是实现我国南方陆相盆地砂岩型铀矿找矿突破的重要基地,也为后期围绕差异性控矿因素详细开展成矿理论和成矿规律研究提供参考方向。

松辽盆地中央坳陷区长岭地区上白垩统姚家组砂岩型铀矿成矿条件分析

近年来,在松辽盆地南部的开鲁坳陷和西南隆起带中相继发现大型砂岩型铀矿,如何在含矿层地质条件相似的中央凹陷区姚家组中取得找矿突破,对其砂岩型铀矿成矿条件展开研究是亟待解决的问题。文章通过对油气勘探开发资料的二次利用,基于沉积学和铀成矿理论的指导,对松辽盆地南部中央坳陷区长岭地区砂岩型铀矿的成矿条件进行综合分析,认为:长岭地区位于背斜构造之上,其中南北向为缓坡,东西向为陡坡,靠近西北部陡坡一带发育一系列沿北北西向展布的断层,可能连通构造天窗,使含铀含氧水更易深入;研究区内主要铀源体为西部蚀源区的黑云母花岗岩和白岗质花岗岩,U含量最高可达9.1×10^(-6),浸出率可达37.5%,说明铀成矿过程中可能有大量来自外部的铀资源供给;姚一段主要发育浅水三角洲前缘亚相水下分支河道微相,河道砂体连通性较好、延伸距离远;与地沥青相伴生的黄铁矿、渗透性砂岩段的油气后期还原褪色蚀变以及砂岩中的褐铁矿化、赤铁矿化作用,说明姚家组一段具有较好的氧化还原条件。综合分析认为长岭地区乾深2井一带为Ⅰ类砂岩型铀矿远景区,乾深4井一带为Ⅱ类砂岩型铀矿远景区。