Metallogenic Series Related to Permian Mafic Complex in North Xinjiang:Post-collisional Stage or Mantle Plume Result?

There are four deposit types related to a Permian mafic complex in northern Xinjiang, i.e., copper-nickel sulfide deposit, vanadic titanomagnetite deposit, magnetite （-cobalt） deposit and Cu-Ni- VTiFe composite deposit. The deposits are distributed spanning tectonic units with close and consecutive metallogenic ages. A transitional deposit type can occur among the end-member deposits. Trace elements of host rocks show that they can derive from similar source area. Hence, they constitute a particular metallogenic series related to a mafic-ultramafic complex that is also a symbol series of the post-collisional stage of the Central Asia Metallogenic Province （CAMP）. The metallogenic ages of the series are between 260 Ma and 300 Ma throughout the Permian. Unlike mineralization from a mantle plume, the metallogenic period of this series spans at least 40 Ma. Compared with related deposits of the Emeishan mantle plume, the North Xinjiang series has a similar ore-forming element assemblage but has preferably developed Cu-Ni sulfide deposits rather than vanadic titanomagnetite deposits. In concomitance with this series, North Xinjiang area has developed a set of syntectonic Au-Cu-Mo metallogenic series related to a felsic volcanic-intrusive complex, which might indicate that there is no direct relationship with mantle plume activity. From early to late, i.e., the sequence of copper-nickel sulfide to magnetite （-cobalt） to vanadic titanomagnetite deposit, the host rock series evolves from mafic-ultramafic and tholeiite series to mafic and alkalic series, the ~REE content tends to increase with increasing of REE fractionation, and some of the trace elements （particularly LIL） also show an increasing tendency. The above evolutionary regularity possibly reflects a course where the magma source deepens and thermal interface moves down, energy gradually exhausts, and neo-continental crust forming in the postcollision stage tends to stabilize.

Emanation-Sedimentary Metallogenic Series and Models of the Proterozoic Rift in the Kangdian Axis

The Kangdian axis basement can be divided into two tectonic layers. The lower tectonic layer is the crystalline basement which is made up of the Archaean Dibadu Formation and early Proterozoic Dahongshan Group. The former is a kata-metamorphic basic volcano-sedimentary formation of the old geosyncline (old continental nucleus), and the latter is a medium-grade metamorphosed alkali-rich basic volcanic (emanation)-sedimentary formation of the Yuanjiang-Dahongshan marginal rift. They are in disconformable contact. The upper tectonic layer is the folded basement, and made up of the middle-late Proterozoic Kunyang Group. It is the result of Dongchuan-Yuanjiang intercontinental rifting with discordant contract with the underlying and overlying strata. Along with the evolution of Proterozoic from early to late, four types of emanation-sedimentary deposits in the Kangdian axis rift were formed in turn: emanation-sedimentary iron-copper-gold deposits related to basic volcanic rocks in the Yuanmou-Dahongshan marginal rift; emanation-sedimentary iron-copper deposits related to intermediate-basic volcanic rocks in the early stage of the Dongnchuan-Yuanjiang intercontinental rift; emanation-sedimentary copper deposits related to sedimentary rocks in the middle stage; copper deposits related to the late tectonic reworking. From early to late Proterozoic, with the evolution of the Kangdian axis rift and lowering volcanic basicity, the ore-forming elements also evolved from Fe, Cu and (Au) through Cu and Fe to Cu.

Cu－An Metallogenic Series Related to Volcanic－Intrusive Complexes in Eastern China

The Cu - An co - existence ore deposits related to intermediate- acidic volcanic - intrusive complexes are widespread in eastern China. They can be divided into 5 types: (1) sharn type, (2 )porphyry type, (3)vein type, (4 )breccia pipe type and (5)stratabound type. All of those have intimate spatial, temporal and genetic relations formed by the Mesozoic tertonicmatic - hydrothermal activities in certain geological environments. The magmatic and Cu-An metallogenic ager were predominately in Late Mesozoic (179-90 Ma), and in the period of 150-120 Ma the ore-forming Processes reached the Peak. The main geological Settings of Cu-An ore-forming Processes are: (1) continental margins, including the Peripheral depression of the continental Plate, (2) deep fault zones in the continental Plate,(3)continental rift belt. The magmatic activities were under the combined control of basement fault (s )and superficial fault (s ), and mostly formed the continental volcanic basins. The regional Cu-An metallogenic zones occur along the deep fault zones in WNW - EW direction,such as the Tongling metallogenic subzone, or in NE-NNE direction, such as the Dexing metallogenic subzone. Most of Cu- An ore deposits are related to subvolcanic stocks consist of quartz diorite, granodiorite, quartz porphyry, andesite porphyry, trachyte porphyry and other rocks, which belong to the calc- alkaline series and the I - type granitoid. The spatial zoning of matals from the center to periphery of the stocks is: CU (Mo )→ Cu,Au→Cu, Ph, Zn,An →Ph, Zn, Ag →Ph, Ag. There is a typical venical metallic zoning (from surface to 3 000m in depth ) in Yinshan Cu-An-Ph-Zn-Ag ore deposit, northeastern Jianxi Province.

Outline of Metallogenic Regularity of Bauxite Deposits in China

Among the abundant aluminum ore resources in China, bauxite is dominated, which is mainly distributed in 19 provinces and regions, including Shanxi, Henan, Guizhou and Guangxi. The major deposit type of bauxite is paleo-weathering crust sedimentary type, and the other one is the accumulation type. The main metallogenic period is the late Paleozoic Era followed by the Cenozoic Era. The metallogenic tectonic background is characterized by a cratonic environment. This paper summarizes the bauxite metallogenic regularity based on the characteristics of bauxite resources, bauxite deposit type, bauxite metallogenic belt and metallogenic series in China, and 15 bauxite metallogenic belts, 8 bauxite metallogenic series and 7 bauxite ore concentrated areas were identified in the study. This paper also provides a theoretical basis for the evaluation of the potential of bauxite resources.

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.

The Metallogenetic Regularities of Lithium Deposits in China

Lithium resources support the development of high-technology industries. China has abundant lithium resources which are mainly distributed in Tibet, Qinghai, Sichuan and Jiangxi. Salt lakes in China have significant lithium reserves, but lithium is mainly produced from hard rock lithium deposits because the extraction from salt lakes requires further improvements. The hard rock lithium deposits mainly occur in granitic pegmatite in the Altay region of Xinjiang and the Jiajika deposit in western Sichuan Province; they mainly formed in the Mesozoic and occurred in a relatively stable stage during orogenic processes. On the basis of the information from 151 lithium deposits or spots, 14 lithium metallogenic series were identified, and granitic pegmatite, granite, and sedimentary types were considered to be the main prediction types of lithium resources. Twelve lithium mineralization belts were divided and a series of maps showing the lithium metallogenetic regularity in China were drawn. We conclude that the hard rock and brine type of lithium resources possibly have a similar lithium source related to magmatism. The mctallogenic features of the lithium in China were related with the distinct history of tectonic-magmatic activity in China. This study benefits the assessment of, and prospecting for, lithium resources in China.

Outline of Uranium Resources Characteristics and Metallogenetic Regularity in China

Uranium,as one of twenty-six kinds of important minerals in China,is strategic resource and energy mineral,which has been thoroughly investigated in the project of National Potential Evaluation of Uranium Resource.During the implementation of this project,the authors summarized the metallogenic regularity of uranium resource in China systematically,through the researches of geological characteristics of uranium resource,uranium deposits type（genetic and prediction type）,temporal and spatial distribution,and metallogenic series.Based on the investigation of present situation and progress in uranium exploration,this paper proposes the uranium deposits in China should be divided into 4 classes,9 types,21 subtypes in genetic,and 50 types in prediction;suggests to divide China into 29 uranium metallogenic belts and 20 uranium prospective area,and constructs 20uranium-polymetallic metallogenic series,through summarizing temporal and spatial distribution characteristics and metallogenic regularity of uranium deposits in China.The above research is beneficial to the comprehensive understanding of regional uranium metallogenic regularity,and will direct the uranium exploration in the future.

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.