Ore-forming Response to Syndepositional Submarine Volcanism in Langshan-Zhaertai Mesoproterozoic SEDEX Ore Belt, Inner Mongolia, China

Ore forming process of the Dongshengmiao, Huogeqi, Tanyaokou and Jiashengpan deposits in Langshan Zhaertai Mesoproterozoic SEDEX metallogenic belt is closely related to the syndepositional volcanic activities based on the following facts: (1) The Sm Nd isochron age of the basic volcanic rocks varies from 1 491 Ma to 1 824 Ma (more than or close to the model age of the lead isotope of all sulfide minerals) in these deposits, with ε (Nd, t ) =(3.48-6.40)±0.80, whose REE composition is enriched in LREE and depleted in HREE, indicating that these volcanic rocks were derived from the mantle or lower crust. (2) The REE composition of some Pb Zn Py ores is also enriched in LREE and depleted in HREE. The chondrite normalized REE patterns are similar to those of the basic volcanic rocks. (3) In the lead isotope composition diagram of Doe and Zartman, most of sphalerite, galena, pyrite, pyrrhotite and chalcopyrite are plotted on both sides of the line for the mantle or between the lines for the mantle and lower crust. (4) Cobalt content of some pyrites is much higher than their nickel content ( w (Co)/ w (Ni)= 11.91- 12.19). (5) Some volcanic blocks and debrises have been picked out from some pyrite and pyrrhotite ores. (6) All Zn Pb Cu Fe sulfide orebodies in these deposits occur in the strata overlying the metamorphic volcanic rocks in the only second ore bearing formation. The Jiashengpan deposit lacks in syndepositional volcanic rocks in the host succession, only Pb and Zn occur without Cu, but the Dongshengmiao, Tanyaokou and Huogeqi deposits with syndepositonal volcanic rocks in the host succession contain Cu, indicating the relatively high ore forming temperatures, besides Pb and Zn. The syndepositional volcanic eruption directly supplied some ore forming metals and resulted in the secular geothermal anomaly favorable for the circulation of the submarine convective hydrothermal system, and in the precipitation of deep mineralizing fluids exhaling into the anoxide basins along the syndepositional fault system in the Langshan Zhaertai rift.

Simulating Some Complex Phenomena in Hydrothermal Ore-Forming Processes by Reaction-Diffusion CNN

Complexity phenomena like dynamic and static patterns, order from disorder, chaos and catastrophe were simulated by the application of 2-D reaction-diffusion CNN of two state variables and two diffusion coefficients transformed from Zhabotinksii model. They revealed somehow the mechanism of hydrothermal ore-forming processes, and answered several questions about the onset of ore forming.

ELLIPTIC EQUATIONS IN DIVERGENCE FORM WITH DISCONTINUOUS COEFFICIENTS IN DOMAINS WITH CORNERS

We study equations in divergence form with piecewise Cαcoefficients.The domains contain corners and the discontinuity surfaces are attached to the edges of the corners.We obtain piecewise C1,αestimates across the discontinuity surfaces and provide an example to illustrate the issue regarding the regularity at the corners.

The Evolutionary History of Ore-forming Processes of Metallic Ore Deposits in Northern Guangxi

The northern Guangxi region is an important rare metal, rare earth metal and polymetallic metallogenic province. In the region there exist five metallogenic series and two metallogenic subseries, whose metallogenesis shows features of polycyclic spiral evolution throughout the geological history. As far as various cycles are concerned, mantle-derived ore substances were reduced while crust-derived ore substances increased from early to late timesfin the whole geological evolutionary history, mantle-derived substances decreased gradually while crust-derived ones increased. Meanwhile ore element associations became more and more varied. In terms of space, mineralization migrated from the old basement outwards, i.e. from west to east during the Precambrian, and from north to south during the Phanerozoic, and again from east to west during the Yanshanian.

Characteristics of the ore forming fluid from the zinc poly-metallic deposit in the Mopan mine area,Guangxi Nandan

Fluid inclusions from samples from the layered and veined mineralized belt in the Mopan mine area were studied using microscopic temperature measurements and laser Raman spectroscopy.Further studies were conducted on the nature and source of the ore forming fluid and on the mechanism of deposit formation.The results show that there are three types of inclusions that occur in both the layered and veined ore body.These are liquid inclusions,CO 2 inclusions with a liquid phase,and NaCl-H 2 O multiphase inclusions.The fluid inclusions in both the layered and veined ore bodies have similar characteristics.The ore forming fluid is strongly reducing,was exposed to low to medium temperatures,salinity,and pressures.The source of this ore forming fluid was a mix of submarine volcanic spring(blow-piping),magmatic hydrothermal jet,and underground water.

GEOLOGICAL FEATURES AND ORE- FORMING MODEL OF THE SHIZHUYUAN W-SN-MO-BI ORE DEPOSIT,HUNAN PROVINCE,CHINA

The Shizhuyuan W,Sn,Mo and Bi polymetallic ore deposit is one of the world famous superlarge ore deposits.The paper briefly introduced the geological setting and features of the ore deposit.Further,an ore－ forming model was put forward at the end of the paper.

The Forming Conditions of and Ore-searching Direction for B, Mg,Pb, Zn and Au Deposits in the Liaoji Proterozoic Rift

The Liaoji Proterozoic rift is an inter-intracontinenatl rift developed from Archean granite-greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb-Zn, Au, Ag, Co and P. These deposits were formed as the result of late mobilization, transportation and concentfation of the previously enriched ore-forming mate- rials in several ore-bearing formations formed during the rift stage. So the metallogeny of these deposits in the rift shows both inheritance and new generation of the ore-forming materials. In future ore-searching practice, attentions should be paid on the studies of the ore-bearing formations in the rift, on the multiple stages of metallogeny and and on multiple derivations of the ore-forming materials.

Global Regularity of Weak Solutions to Degenerate Eliptic Systems in Triangular Form

In this peper, using direct method, we prove the global Holder continuiy of weak solutions to degenerate eliptic systems in triangular form.

A Preliminary Review of Metallogenic Regularity of Tungsten Deposits in China

Tungsten ore resources are abundant in China with relatively complete types of deposits. Skarn type and quartz vein type deposits are dominated in the tungsten resources, whereas quartz vein type wolframite deposits are most important in terms of exploitation and utilization. Skarn type tungsten deposits are concentratedly distributed in the central Nanling region, such as South Hunan, South Anhui and the eastern Qinling region, while quartz vein type tungsten deposits occur mainly in South China, such as West Fujian, South Jiangxi, North Guangdong and South Hunan. The most important metallogenic epoch of tungsten is the Mesozoic, while the metallogenic tectonic setting is featured by an intracontinental environment after orogeny with sever tectonic movements, deep-seated faults and frequent magmatic activities, especially Mesozoic granitoids closely related to tungsten-tin mineralization. 22 metallogenic series of ore deposits characterized by or significantly related to tungsten were defined based on precise statistic information of 1199 tungsten mining areas and thorough the summary of metallogenic regularities. Based on studies of the metallogenic regularity of tungsten deposits, skarn type （or greisen type）, quartz vein type and massif-type of tungsten deposits are thought to be the key prediction types. 65 tungsten-forming belts and 22 key ore concentration areas were ascertained and a distribution map of tungsten-forming belts of China was compiled, which provided a theoretical basis for evaluation and prediction of potential tungsten resources.

POLYGENETIC COMPOUND ORE DEPOSITS AND THEIR ORIGIN IN THE CONTEXT OF REGULARITIES IN CRUSTAL EVOLUTION

Polygenetic compound ore deposits are here defined as those ore deposits which evidently possess n1any sided genetic characteristics as a comprehensive result of more than one rnineralization stages, from many rnaterial sources, and of many genetic types. They are formed most commonly during the diwa (geo(lepression) stage in the process of crustal evolution and, therefore, spread most widely in diwa regions. At the present stage of our knowledge, they may be subdivided into three principal models and many types of metallogenesis, controlled by different geotectonic conditions and being distributed in time and in space according to the corresponding regularities. This is a newly rccognizcd, third gcnetic type of ore deposits, being not reasonable to be simply referred to either pure endogenic or pure exogenic origin. They are very important and are of great study significance, becausc they comrnonly are rich and have a large amount of reserve with high economic value.

A Preliminary Review of Metallogenic Regularity of Gold Deposits in China

Gold is one of the most important mineral resources in China with its rich mineral resources. In recent years, significant progress has been made on the process of gold resource exploration. Some large and giant gold deposits were newly found and some important expansions in the main mining regions were also been completed. Studies on metailogenic regularity of gold deposits in China also have made achievements with a long-term work. This review aims to conclude the achievements of research on gold metallogenic regularity in China. Based on the data of about 2000 gold deposits and other ore （mineralized） occurrences, gold deposits in China were classified into five prediction types： gold deposits genetically related to granite-greenstone formation, gold deposits related to sedimentary formation （including the Carlin type and the metamorphosed clastic rock related vein gold deposit）, gold deposits genetically related to volcanic rocks （including the continental and marine types）, gold deposits genetically related to intrusions （including the porphyry type and the inner intrusion and contact zone related gold deposit）, gold deposits of supergenesis （including fracture zone-altered rock gold deposit, placer gold deposit, gossan type gold precise chronology data of gold deposits indicate deposit and soil type gold deposit）. Statistics on that there occurred 5 main periods of gold- mineralization in geological history of China. They were Neoarchean to Paleoproterozoic, Meso- Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic. Gold deposits in China mainly formed in the Mesozoic and the Cenozoic. On the studies of the spatial-temporal distribution characteristics of gold deposits, 53 gold-forming belts were delineated in China. The metallogenic regularity of gold deposits was preliminarily summarized and 71 gold metallogenic series were proposed in China. This suggests that it is necceary to deepen the study on metallogenic regularity of gold deposits and to provide the theory guide for the ore-prospecting for gold resources in China.

New Technology “Flotation to Form Agglomerates and Magnetic Separation” Allows Great Breakthrough for World Low-Grade Light Rare Earth Ores

Rare earth resources are relatively scarce worldwide, but their global consumption is increasing year-by-year. At present, China has about 36% of the global rare earth reserves, but provides 90% of the world＇s supply, which has generally met world demand and promoted the development of the world economy. In order to continuously and stably supply rare earths to international markets, the Chinese Government has financially supported the Institute of Multipurpose Utilization of Mineral Resources within the China Geological Survey to study the utilization of low-grade rare earth ores. Following many years of experimental research, the project has developed a new technology entitled ＂Flotation to Form Agglomerates and then Magnetic Separation＂, which will bring a technological revolution to the world＇s light rare earth ore dressing.

云南开远市吉德金矿地质特征及成矿模式

吉德金矿矿体主要呈似层状、透镜状产于峨眉山玄武岩与下伏灰岩岩溶不整合面、玄武质火山碎屑岩夹层及次级构造破碎带中,有红土型和岩溶角砾岩型两种类型,金以微粒自然金为主,目前矿床规模较小、地质研究程度较低。通过总结成矿规律、构建成矿模式,对矿区及外围寻找红土型和岩溶角砾岩型金矿具有指导作用。

龙陵县新寨-茅草园稀土矿特征及控矿条件浅析

龙陵新寨-茅草园地区花岗岩风化壳离子吸附型稀土矿床受内生地质和表生地质条件双重控制,主要赋存于白垩纪花岗岩体全风化层中下部及强风化层上部,V 1-1矿体分布面积38.59km 2,单工程控制矿体品位(SREO)0.035%~0.128%,平均0.047%;V 1-2矿体分布面积16.85 km 2,单工程控制矿体品位(SREO)0.035%~0.110%,平均0.048%,达大型远景规模,具有较好的勘查开发前景。

西藏锑矿分布、类型及其成矿规律研究

【研究目的】锑是中国战略性矿种之一,构建新的锑矿资源基地势在必行。本文对西藏地区锑、锑−金、锑−铅−锌等矿床的地质特征、矿床类型、时空分布、成矿物质来源等进行分析与归纳,初步总结了西藏锑矿的成矿规律,对指导新一轮找矿突破具有重要意义。【研究方法】文章通过搜集、整理国内外已公开发表的西藏锑矿资料,结合最新区域地质调查成果,从地质特征、成因类型、地球化学等方面厘清西藏锑矿床(点)成矿作用与青藏高原形成演化之间的关系。【研究结果】西藏地区锑矿床类型以热液型为主,矿体主要赋存在碎屑岩和碳酸盐岩围岩中,地幔物质参与成矿,成矿时代集中在早白垩世至中新世(20 Ma左右)。成矿作用主要与碰撞型花岗质岩浆活动和碰撞后伸展期的岩浆作用有关。西藏地区锑矿的分布受各种层状构造、断裂、褶皱等构造联合控制,赋矿地层为上三叠统和侏罗系—白垩系。【结论】西藏锑矿具有分带性展布特征,从西向东划分出藏西、藏南、藏北和藏东4大锑成矿带。新生代是西藏地区锑矿最重要的成矿期,青藏高原强烈隆升后的陆内伸展背景有利于锑成矿。根据西藏锑矿成矿特征提出实用性的勘查模型,为锑矿找矿突破提供科学依据。

云南新平米底莫铁铜矿成矿机理及找矿标志

米底莫铁铜矿床位于红河断裂与绿汁江断裂的三角区域,是不同时期构造-岩浆运动和变质作用的产物。为探索米底莫铁铜矿床成矿规律,在总结区域成矿背景、矿床地质特征的基础上,对矿化规律及控矿因素进行分析总结。研究表明:矿区出露早元古代大红山群,上覆晚三叠统盖层,总体为浅—中等变质的钠质火山岩系,其中大红山群曼岗河组是主要的含矿层位;矿区继承了区域构造-岩浆特征,火山喷发中心为火山气液、后期热液叠加部分,火山岩厚度自喷发中心往外逐渐减小,矿床富集程度也随之降低;区内大红山群岩系经受了浅—中等程度的区域变质作用,变质矿物主要为角闪石、绿帘石、铁铅榴石、黑云母等,并伴随着硅化、绢云母化、电气石化、钠长石化等围岩蚀变;矿床具有严格的成矿专属性,并受控于火山活动中心、火山喷发-沉积旋回及地质构造,邻近的火山机构及相似的地层岩性和近矿围岩蚀变可作为有力的找矿标志。

贵州务—正—道地区铝土矿含铝岩系中稀土元素富集规律及赋存形式

务川-正安-道真(务-正-道)地区是贵州省重要的铝土矿集区,提交铝土矿石资源储量超过7亿吨。区内铝土矿含铝岩系为下二叠统大竹园组,其中广泛富集稀土元素,由于这类稀土元素富集规律和赋存形式尚存在较大争议,综合利用和地质勘探依然缺少实际理论依据。本文通过对该区铝土矿含铝岩系的地质特征及其中伴生稀土元素研究,以总结分析稀土元素地球化学特征和富集规律,并讨论其赋存形式。研究结果表明,务-正-道地区含铝岩系中稀土元素基本呈右倾的配分模式,LREE表现为明显富集,Eu负异常明显。该套含铝岩系中上部样品普遍具有Ce正异常,而底部绿泥石泥岩则为Ce负异常。总体而言,稀土元素在研究区北西部和南东部向斜中的含量相对较高,而在中部向斜含铝岩系中相对较低。稀土元素主要赋存在底部的绿泥石泥岩中。其赋存形式可能主要以离子吸附或类质同象置换的形式赋存于铝矿物和黏土矿物表面或晶格中,也存在稀土元素的独立矿物。本研究为该类资源地质勘探和综合利用提供地质地球化学依据。

豫南信阳地区珍珠岩、膨润土矿成矿规律与成矿远景评价

在充分收集、研究地质勘查资料的基础上,对豫南信阳地区珍珠岩、膨润土非金属矿成矿地质特征及成矿规律进行归纳、总结,对豫南信阳地区珍珠岩、膨润土非金属矿成矿体系的建立做了有益的补充。基于信阳地区珍珠岩、膨润土矿的成矿规律和资源潜力,圈定了豫南信阳地区膨润土矿床成矿远景预测区5处,并作出了成矿远景评价,为扩大豫南地区非金属矿找矿成果提供借鉴。

河南省石墨矿产资源分布特征及成矿规律分析

河南省石墨矿产资源丰富,但由于其资源禀赋特征以及经济市场环境等因素的影响,致使其利用率整体较低。概述了石墨矿资源的储量、分布情况和利用现状,探讨了石墨矿床的成因类型,以区域变质型为主,约占95%,接触变质型石墨矿床较少。通过对矿床成因类型、主要矿石类型及可利用性的研究,初步分析了河南省石墨矿成矿区带的划分和成矿规律,指出河南省石墨矿床的形成受多期次构造-岩浆活动事件的影响,具有明显的区域性和分带性,为河南省今后石墨矿产资源的开发利用前景以及科学部署进一步勘查等工作指明了方向。