Abstract:The fluorite deposits have been divided into three types, i.e., sedimentary- reformation type, hydrothermal fluid filling type and accompanying type on the basis of studying ore- forming process of the ore deposits and synthesizing their genetic types and industrial types. Based on an analysis of the ore- forming conditions, ore control factors and mineralization of characteristic fluorite deposits, this paper summarizes metallogenic factors. And then the sedimentary- reformation deposits and hydrothermal fluid filling deposits have been divided into subtypes. The sedimentary- reformation deposits are classified into two deposit types, the hydrothermal fluid filling deposits into five deposit types and accompanying deposits into four deposit types according to principal commodity. Ore- forming geological background, ore- forming conditions, deposit features, ore- control factor and mineralization of each deposit type are analyzed, and the secondary and necessary factors of mineralization are summarized.

Abstract:The outcropped Neoproterozoic strata are relatively complete from old to young in Lushan area, and hence this area is significant for analyzing the tectonic evolution of the whole "Jiangnan Orogen". The Hanyangfeng Formation, which exists only in Hanyang peak of the Lushan Mountain, is mainly composed of terrestrial eruptional metacrystal or phenocryst- rare rhyolite. The authors obtained the high- precision SHRIMP zircon U- Pb weighted mean age（838 ± 4 Ma, corresponding MSWD=1.12）of the metamorphic rhyolite of the Hanyangfeng Formation in the Lushan area, and also obtained LA- ICP- MS zircon U- Pb weighted mean age（852 ± 4 Ma, corresponding MSWD=0.037）of this Formation. These new data indicate that the Hanyangfeng Formation does not belong to the Banxi period. The authors initially hold that the Hanyangfeng Formation ought to be located under the tectonic transformation of the Wuling movement (820± Ma). The new research result confirms that the Hanyangfeng Formation is of the same volcanic- sedimentary strata as the Shaojiwa Formation, and therefore it may be a significant indicator to the tectonic setting. Actually, the sequence relationship of the Hangyangfeng Formation and the Shaojiwa Formation to the Xingzi Complex group shows upside- down phenomenon, suggesting that there probably existed a significant geological movement in the Lushan area during the late Qingbaikou period.

Abstract:The Haerguole seamount basalt is located in Buqingshan area on the southern margin of the East Kunlun Mountains. Detailed geochemical analysis shows that the Haerguole seamount basalt can be divided into alkaline basalts and subalkaline basalts. The REE distribution patterns of alkaline basalts are similar to those of OIB, w i t h t h e d a t a ∑ L R E E = 6 3 . 8 × 1 0 - 6 ~ 1 7 5 . 3 6 × 1 0 - 6 , ∑ HREE=14.46 × 10- 6~28.56 × 10- 6, ∑ LREE/∑ HREE=4.41~6.14, (La/Yb)N=4.14~6.71, (Ce/Yb)N=3.31~5.12, and δEu=1.03~1.17. The REE distribution patterns of subalkaline basalts are similar to those of N-MORB, with the data ∑LREE=11.07×10-6~29.95×10-6, ∑ HREE=12.56 × 10- 6~25.41 × 10- 6, ∑ LREE/∑ HREE=0.88~1.54, (La/Yb)N=0.29~0.74, (Ce/Yb)N=0.37~0.77 and δEu=1.02~1.22. These geochemical characteristics suggest that the Haerguole basalt is the association of OIB and N-MORB. The OIB of Haerguole seamount basalt was formed in a seamount or an ocean island setting near the mid-ocean ridge, and OIB magma originated from EM Ⅱ- type enriched mantle. The N- MORB was formed in a mid- ocean ridge setting and originated in depleted mantle. These data provide more evidence for the existence of ocean basin in Buqingshan area in Late Paleozoic.

Abstract:The intrusion of diabase sills in the shales of the Xiamaling Formation is extensively developed in Yanshan Mountain area of the northern part of North China Plate. Geochemistry of the diabase is characterized by high content of TiO2(1.70%~4.29%), low content of Al2O3(11.33% ~14.98% ), MgO(4.17% ~5.86% )and Na2O>K2O. In the K2O- TiO2- P2O5 plot, all sample points almost fall into the field of continental tholeiite. REE study indicates that the diabase is enriched in light rare earth elements with abundant rare earth elements, and the fractionation between LREE and HREE is not pronounced. Meanwhile, the chondrite- normalized distribution curve is right-oblique without obvious depletion of Eu. All these characteristics in combination with the Zr-Y, Zr-Nd, Zr/Y- Zr, Ti/100- Zr- Y × 3, Ta/Hf- Th/Hf and Nd/Zr- Th/Zr diagrams indicate that the magma was derived from the transitional mantle, and the diabase was formed in an intra-continent extension setting of North China Plate during the late Mesoproterozoic.

Abstract:A detailed geological cross- sectional survey was conducted for the volcanic rocks in Zhongtanggou area on the western side of Sanchazi along Mianlue suture zone. The volcanic rocks are mainly greenschist facies metamorphic rocks, which comprise mainly metamorphic andesite rocks and subordinately metamorphic basalt and metamorphic dacite rocks, belonging mainly to the calc- alkaline series. Their REE distribution patterns are characterized by LREE enrichment, right- oblique shape and depletion of Eu. Their trace elements generally have features of enrichment of Cs, Rb and Ba, obvious depletion of Nb and Ta, and slight depletion of P and Ti. Trace elements such as Zr and Hf are relatively stable. In the La- La/Nb, Nb- Nb/Th and La/Yb- Sc/Ni discrimination diagrams, the metamorphic basalt and metamorphic andesite samples mainly fall in the region of island arc volcanic rocks. These characteristics, in combination with features of volcanic rocks, indicate that the volcanic rocks in Zhongtanggou area were formed in a typical tectonic setting of island arc. The authors hold that the material source of metamorphic andesite and metamorphic basalt rocks might have been closely related to a locally depleted area in the mantle wedge with the addition of continental crustal material. The material source of metamorphic dacite was probably related to the partial melting of the crustal granitic magma.

Abstract:The Zhougong 2 well that drilled Emeishan basalt of Zhougongshan structure in Ya'an area of western Sichuan is a typical well in basalt gas reservoirs, whose core is relatively long, fairly complete and close to the high-yield well Zhougong 1 well. Based on the petrological characteristics, the combination of macroscopic and microscopic phenomena and starting with the core, electrical, physical, and microscopic characteristics of Emeishan basalt reservoir in Zhougong 2 well core, the authors summarized its petrological characteristics, porosity type, fluid features and the distribution in the longitudinal direction in comparison with production intervals of Zhougong 1 well. The results show that the favorable reservoirs of basalt are distributed in two intervals in southwest Sichuan: one is the weathering crust, which is extensively developed at the top with the thickness of a few meters, and the other is the amygdale-rich brecciated basalt in the upper part of the cycle. The second type of reservoir has well-developed asphalt associated with quartz and extensive dissolved pores, caves and cracks, but with less permeability; the majority of its efficiency reservoir space was generated by the secondary actions. The good matching relationship between tectonism in the dormant period of eruption and the weathering and dissolution is of great importance. The open system was generally quite easily formed by the aggregation of later period tectonic cracks and joint fissures perpendicular to the bedding, and this may also be the main factor that has undermined the gas reservoir storage conditions of Zhougong 2 well.

Abstract:The southwest depression of Tarim Basin has good prospect of oil and gas resources, and it is currently the focus of the new exploration areas. The depression structure is complicated, which has zonality from east to west, sectional division from north to south, and characteristics of deformation in different stages. Hence it can be divided into four secondary tectonic units: thrust belt in the foreland of the Kunlun Mountains, Hetian-Kashi sag zone, Mageti slope, and Yutian uplift. Four sets of hydrocarbon source rocks of Cambrian- Ordovician, Carboniferous, Permian and Jurassic and their distribution characteristics were systematically analyzed, and the oil and gas source and characteristics in the area were summarized and analyzed on the basis of an analysis of reservoir and cap rock. Seven sets of favorable reservoir- cap combinations were tentatively put forward, the faults, and unconformities and permeable formations were considered to be good conducting systems. On the basis of comprehensive analysis of above accumulation conditions, in combination with the comprehensive consideration of such factors as oil and gas source, migration way and reservoir characteristics, the authors analyzed the accumulation mode, which is divided into two major types and five sorts of modes: one type is piedmont thrust belt near the source vertical migration accumulation mode, which includes exotic thrust body, wedge shaped body and primary body, whereas the other type is slope belt distant source lateral migration accumulation mode, which includes fault-propagation folds and ancient karst. On such a basis, favorable oil and gas exploration targets are further forecasted.

Abstract:There exist different view points about the geological structure characteristics of the Xuefeng orogen. The authors studied such aspects of this problem as deformation types, deformation epochs and intensities, geometrical and kinematic properties, dynamic mechanisms and tectonic regimes in Huaihua- Liangyaping area lying in the eastern part of the middle segment of the Xuefeng orogen through tectonic profile and regional geological survey and, as a result, reached the following conclusions: ①There existed main deformation types such as slaty cleavages, crenulation cleavages, folds, thrust faults, large-scale kink zones, normal faults and dextral strike-slip faults. ②There existed notable compressional deformations with NW to NWW compression and NE to NNE-trending folds and thrust faults in both Caledonian movement and Early Mesozoic tectonic movements (Indosinian movement and Early Yanshanian movement). Slaty cleavages and large-scale kink zones were formed in Caledonian movement. ③The middle segment of the Xuefeng orogen can be divided into the east zone and the west zone with Xupu- Jingzhou fault as the boundary, which served as the root and the middle zone of Xuefeng thrust system respectively. There existed higher deformation in the east zone than in the west zone in Caledonian movement, as evidenced by the existence of slaty cleavages in the east zone and the absence of slaty cleavage and the similarity between the Upper Palaeozoic and the underlying strata in attitude in the west zone. Unconformity, tectonic uplift and thrust faults indicate that there existed stronger deformation in the east zone than in the west zone in Early Mesozoic tectonic movement. ④Dip directions of slaty cleavages, fold axial surfaces and thrust faults indicate that there existed back- thrust structures in both Caledonian movement and Early Mesozoic tectonic movements in the east zone of the Xuefeng orogen, but the middle belts of the two period back thrust structures didn't coincide with each other, and the middle belt in Early Mesozoic was about 25km west of Caledonian. ⑤ The east side of Xupu- Jingzhou fault subsided violently in both early Nanhuan and Late Palaeozoic, suggesting that the east zone of the Xuefeng orogen was a structurally weak zone with lower strength of crust, and therefore turned into the root zone of the Xuefeng thrust system.

Abstract:Multi-stage structural events occurred in central East Kunlun tectonic belt, resulting in complex structural styles which have been preserved up till now．Very intense structural deformation and ductile shear zone exist in Hatugou, Qingshuiquan-Tatuo and Gouli areas, and there is the NWW-SEE ductile shear zone．The authors analyzed the geometry, kinematics and kinetics of the tectonic belt based on field investigation and analysis of microstructure. A quartz C-axis petrofabric analysis on Fedorov and EBSD stage indicates that the shear zone is a pressure- shear structure interface, characterized by left- handed thrust at the early stage, dextral strike- slip at the late stage, and 400~550 ℃ for the deformation temperature．The measurements of sub-grains of quartz and granularity of dynamic recrystallization indicate that the paleostress value is 153.79 MPa for the ductile shear zone in the study area. Furthermore, the closer to the central part of East Kunlun tectonic belt, the higher the Flinn index (>1), the extent of the strain and Lode parameter (absolute value) of gravel, as evidenced by the finite strain measurement of conglomerate (4 points) from Maoniushan Formation in Hatugou, which suggests a tensile deformation. Combined with regional geological data, the authors hold that the eastern segment of central Kunlun ductile shear zone was formed in Late Hercynian and Indosinian.

Abstract:The sandstone reservoir in 2nd member of the Upper Triassic Xujiahe Formation in central Sichuan Basin is the prominent representative of China's low permeability tight sandstone. Diagenesis has an important influence on sandstone's compaction. Based on the cast- slice, cathodoluminescence, electron microprobe analysis, SEM and other means of experimental analysis, the authors analyzed different types of diagenesis and features and divided diagenetic facies into six kinds according to the dominant or characteristic diagenesis that controls the porosity evolution. Quantitative evaluation of the intensities of different diagenetic activities was made, and different diagenetic facies types were distinguished by introducing such indexes as the compaction rate, the cementation rate, the microporosity and diagenetic coefficient. The porosity and permeability—diagenetic coefficient interpretation model was tentatively established with the exploratory application of robust regression method. Un-coring well's parameters were explained by the diagenetic coefficient interpretation model, the diagenetic coefficient contour map was drawn, and the regional distribution of favorable diagenetic facies was predicated. The reservoir (> 6% porosity) diagenetic coefficient contour map was drawn, and the favorable diagenetic facies- favorable reservoir development area was delineated. All these results obtained by the authors provide a possibility for realizing quantitative evaluation of diagenesis and diagenetic facies, and the rapid prediction of diagenetic facies provides a basis for the screening of favorable reservoir development areas. These achievements have guiding significance for the exploration and development of tight sandstone gas reservoirs.

Abstract:A suite of Middle Triassic turbidite with great thickness was observed in Tianlin area of Guangxi. On the basis of the sections measured in field survey, integrated with the previous researches, the authors carried out detailed studies of the lithofacies and facies associations in the study area. The results show that there exist six lithofacies which are composed of three main facies groups: Facies association 1 is dominated by sandy debris flows which represent the proximal channel- levee deposits; Facies associations 2 is dominated by typical turbidite deposits which represent the distal channel-levee deposits; Facies associations 3 is dominated by the distal turbidite deposits which represent the proximal lobe deposits. Based on the above analysis, together with the tectonic settings, provenance and the regional distribution of turbidite facies, the authors have established a depositional model for middle Triassic deep-water deposits in the study area.

Abstract:Located in Baishan City of southern Jilin Province, the Wudaoyangcha vanadic titanomagnetite deposit is a large- size magma type iron deposit lying in amphibolite layered intrusions in Archaean strata, founded for the first time in the world. The discovery of the deposit has important implications for mineral resource exploration in areas with similar geological conditions. The deposit is located in northern Banshigou greenstone belt on the southern margin of Longgang paleo-continental nucleus of the Liao- Ji paleocontinent. No. Ⅰ, Ⅱ and Ⅵ orebodies lie in Wudaoyangcha amphibolite layered intrusions, and vanadic titanomagnetite mineralization is closely related to the layered intrusions. The protolith of the layered intrusions belongs to orthometamorphite, and its tectonic environment belongs to the island arc basalts in the convergent margin of the plate. Orebodies are mainly in layered form. Ore textures include mainly crystallization texture, solid solution separation texture and sideronitic texture. Ore structures are dominated by massive structure, disseminated structure, spongy- meteoritic structure and layered structure. Magnetite- ilmenitepyrite makes up most metallic mineral association of the ore. The magnetite and ilmenite of the vanadic titanomagnetite ore was investigated by means of EPMA. The magnetite is genetically magmatic liquation titanomagnetite. The chemical composition of the ilmenite is generally consistent with the theoretical constituents of ilmenite. The authors carried out U-Pb dating and micro-scale in situ trace elements and REE research on zircons separated from the Wudaoyangcha amphibolite layered intrusions. The characteristics of trace elements and REE show that these zircons are magmatic zircons. Zircon LA-ICP-MS U-Pb dating yielded a discordant age, with the discordant upper intercept age for 28 spots of sample WCD1 being (2 526±35) Ma. This age represents the crystallization age of layered intrusions.

Abstract:The Fe-Mn carbonate breccias strata are in conformable contact with the roof and floor Jurassic volcanic complex in the Lengshuikeng Ag-Pb-Zn deposit of Jiangxi Province, with clear volcanic tuffaceous substance existent in interstitial materials. The REE distribution patterns are right- oblique, and the composition characteristics are similar to features of lower total rare earth content of normal lacustrine carbonate and positive Eu abnormal characteristics of pyroxenitic magmatic rocks. C, O isotopes show that the deformation occured in continental volcanic lakes, and continental sedimentary and magmatic rocks provided diagenetic material source. The zircon U- Pb age of the roof and floor volcanic complex is constrained around 155 Ma, and the Fe- Mn carbonate breccias underwent a diagenetic process of sedimentary-volcanic eruption of continental volcanic lakes, with the addition of the intrusion of pyroxenitic magmatic rocks.

Abstract:Located in the northern margin of the Tibetan Plateau, the Duolong Cu-Au ore concentration area has typical geological setting and metallogenic dynamic background, which is quite unique in porphyry copper deposits of Tibet. The effective geological exploration model for Duolong is of great significance. This paper focused on metallogenic system and exploration model in this area. Several important results were obtained through detailed field and laboratory studies: ① Copper and gold ore bodies are preserved in altered (feldspathic) quartz sandstone and volcanic rocks of Jurassic Quse Formation and Sewa Formation. Three alteration zones exist from the center of ore-bearing porphyry outwards, i.e., potassium- silicified and sericitized zone, sericitized zone, and pyritized-hornfelsic zone. ②The spacial layout of mineralization in this area finds expression in "three ore belts and five ore fields". The three belts are distributed in en echelon shape, i.e., Naruo- Sena- Gaerqin Cu- Au belt, Duobuza- Bolong- Tiegelongnan Cu-Au-Mo belt, and Dibaonamugang Cu-Au belt, whereas the five blocks are ore zones located in the three belts, i. e., Naruo- Saijiao- Rongna, Gaerqin, Dibaonamugang, Duolong- Duobuza and Tiegelongnan ore fields. ③ The model of "four effective approaches to exploration" has been summarized: (1) Iron caps, malachites and porphyry intrusions are direct indicators for porphyry coppe depositsr; (2) Low magnetic anomalies reflect the granodiorite porphyry ore rock indirectly; (3) High-polarization areas directly reflect sulfide zones surrounding both sides of the ore body, and indirectly reflect the copper ore body wrapped in the pyrite zone; (4) Copper and gold geochemical anomalies indicate regional enrichment of ore-forming elements. The application of this model to Naruo and Rongna areas led to the effective discovery of the deep-buried porphyry copper deposit. The exploration breakthrough in the Duolong area has been achieved on the basis of this exploration model.

Abstract:Located in central eastern Gangdise metallogenic belt, the Jiama polymetallic copper deposit is a giant porphyry-skarn type deposit characterized by the highest level of exploration and complex ore- forming elements and ore body types. Previous researchers have already completed a lot of research work, which includes rock and ore- controlling structure, deposit geology, geochemistry, model of the deposit and some other aspects; nevertheless, researches on metallogenic mechanism of the deposit remain very insufficient. The source of fluid materials lacks systematic study and the information lacks comprehensive rearrangement. Based on reading lots of research reports and summarizing the data obtained by previous studies, the authors carried out the oxygen isotope mapping and collected necessary additional samples of sulfur isotope along No. 16 exploration line which served as the typical cross section. A comprehensive study reveals that there existed magmatic fluid exsolution in the deep-seated porphyry concealed under the Jiama ore district, and hydrogen and oxygen isotopic combination suggests that from the early stage to the late stage of mineralization, fluid evolved gradually from the magmatic water to the atmospheric water. In addition, the oxygen isotope mapping and the distribution of uniform temperature plane of fluid inclusions demonstrate that the source of oreforming fluids was located around drill hole zk1616~zk3216 in this ore district. S, Si isotopic combination implies that the materials were mainly derived from the ore- forming magmatic rocks, and the study of lead isotope further indicates that the metallogenic materials came from the collision environment in Gangdise; the crustal thinning and the crust-mantle upwelling led to the mixture of the crust and the mantle. Based on the study of geochemistry, the authors probed into the source of fluid and metallogenic materials, and the results obtained have laid a solid foundation for the study of the genesis and the metallogenic mechanism of the Jiama ore deposit.

Abstract:Mesoproterozoic and Epiproterozoic carbonate strata are widely distributed in southern Zhangjiakou. Located in the Wumishan Formation in Chicheng County, the Liangjiagou Pb-Zn-Ag polymetallic deposit is a typical polymetallic deposit in the carbonate sedimentary cover of southern Zhangjiakou. Due to lack of data of ore-forming epoch of the deposit, there long exist two viewpoints concerning the genesis of the deposit, i.e., syngenetic sedimentation and epigenetic transformation. The ages of the Liangjiagou deposit were determined by the Rb- Sr isochron method for sphalerite and a group of mineral assemblage samples (pyrite and sphalerite), and the results are 126 Ma and 130.7 Ma respectively. The ages of the Liangjiagou deposit were also determined by the Sm-Nd isochron method for sphalerite and a group of mineral assemblage samples (sphalerite and pyrite), and the results are 130.5 Ma and 131 Ma respectively. The metallogenic epochs measured by the Rb-Sr and Sm-Nd isochron methods are very close to each other. Combined with regional geological background of Zhangjiakou, the authors hold that the mineralization resulted from hydrothermal activities in the Yanshanian tectonic movement period.

Abstract:The Xingjiashan Mo-W deposit is the only large- size molybdenum deposit in Jiaodong, which is well known for numerous gold orefields. In order to find out the ore- forming mechanism of this deposit, the authors conducted systematic geological survey and geochemical analysis in the Xingjiashan Mo deposit. The results show that the Xingjiashan Mo deposit has experienced magmatic hydrothermal period (comprising skarn stage, quartz- sulfides stage and carbonates stage) and supergene oxidation period. Molybdenite mainly occurs in garnet-vesuvianite skarn of the quartz- sulfidies stage. Geochemical data indicate that substances like SiO₂, Al₂O₃, TiO₂ and Fe₂O₃ migrated into the skarn from Xingfushan monozie granite, while CaO and MgO were brought outward. The migration of oxides provided enough substance for the formation of skarn minerals. The obvious similarity of REE patterns and spider diagrams between skarn rocks, stock and marble implies a closely genetic link between them. Besides, the values of δEu and δCe rising from ores to remote Pb-Zn mineralization marble might record the environment change from reducing to oxidizing in the post- ore stage. The C-O isotopic compositions of calcite veins also show the granitic origin features. In addition, the low Re content in molybdenum of this deposit may indicate that Mo was derived from the lower crust. The Xingjiashan Mo deposit is a typical contact metasomatic skarn deposit formed in early Yanshanian period.

Abstract:The skarn type Pb-Zn ore body of the Bangpu superlarge Mo polymetallic ore deposit is hosted in the skarn and marble of the Lower Permian Luobadui Formation. The orebodies occur as stratoids or lenses, and lots of skarn minerals are developed in the ore deposit. In order to further clarify the species of skarn minerals and types of the skarn and analyze the forming environment of skarn and its relationship with the mineralization types, the authors studied the chemical composition of the main skarn minerals by using electron microprobe technology based on the systematic microscope observation. Electron microprobe analyses show that the end member of garnet is mainly andradite with a small amount of spessartite and grossularite. Pyroxene comprises mainly diopside and hedenbergite with a certain amount of johannsenite. Pyroxenoids consist mainly of ferrobustamite, and the end member of amphiboles is dominated by calcium actinolite. Fe and Mg content of epidote is very low. Skarn mineral assemblages show that the skarn of the Bangpu deposit has characteristics of both calcic skarn and manganoan skarn. The skarn of the early stage formed in a strong oxidizing environment, so did the ore- forming magmatic fluid. The discovery of manganoan skarn mineral assemblages indicates that the prospecting potential of Ag in the Bangpu polymetallic ore deposit is promising, and this study provides some theoretical support for the next step prospecting work.

Abstract:The gold, silver and polymetallic deposits in Shihu area are located in the mid-northern Taihang Mountains and occur in Archean Fuping Group metamorphic rock series around Yanshanian Mapeng granitic intrusion. The gold, silver and polymetallic deposits in Shihu area have attracted the attention of many geologists, and their metallogenesis has long been in dispute. The authors chose pyrite and quartz samples from these deposits in Shihu area to analyze their helium, argon, carbon, hydrogen and oxygen isotopic composition of fluid inclusions and the hydrogen, oxygen and carbon isotopic composition of the quartz in the same ore sample. The analytical results show that 3He/4He ratios in pyrite range from 0.43 to 2.40 Ra, and 40Ar/36Ar ratios range from 477 to 879.The composition of helium and argon isotopic system suggests that the source of ore- forming hydrothermal fluids was the mixture of mantle- derived fluids and crust- derived fluids. It is estimated that the δDV- SMOW values of the ore- forming fluid responsible for the formation of the quartz are -62‰~-105‰, and the δ18OV-SMOW values of the fluid inclusions of the quartz are 9.6‰ ~13.8‰, showing that the ore-forming hydrothermal fluids were formed by the mixture of magmatic water and meteoric water. The δ13CPDB values of quartz vary in a relative narrow range of -3.5‰~-5.0‰, showing that the ore-forming hydrothermal fluids were derived from the mantle. The relationship between hydrogen, oxygen, carbon and helium and the argon isotopic systems of oreforming hydrothermal fluids show tracing consistency in gold, silver and polymetallic deposits of Shihu area. All the noble gas isotopic data, combined with stable isotopic data from five deposits, demonstrate that the ore-forming fluids were a mixture between mantle-derived fluids and crustal-derived fluids.

Abstract:The Lengshuikeng orefield has a complex combination of shallow porphyry type orebody and deep stratiform orebody. The stratiform orebody is hosted in (Fe, Mn) carbonatite breccia layer which is sandwiched in crystal tuff of the Upper Jurassic Daguding Formation. This paper has discussed and analyzed the characteristics of Fe-Mn carbonatite breccia in the aspects of main material composition, trace elements composition, distribution, attitude and its relationship with the orebody on the basis of basic geological features of the Fe-Mn carbonatite breccia. In combination with X- ray powder analysis of minerals, carbon- oxygen isotopes and hydrogen-oxygen isotopic evidence, the authors have reached the conclusion that the Fe-Mn carbonatite breccia is of the deep lake facies volcanogene sedimentary origin closely associated with the formation of stratiform orebody, and the early volcanogene sedimentary carbonatite rock had been subjected to the superimposed reformation of later porphyry magma emplacement and fluid activity, which formed Zn-Ag-rich deposits genetically associated with porphyry.

Abstract:The Beiya gold deposit is located in southwest Sanjiang alkali porphyry belt with complex geological structure, welldeveloped Variscan marine basalt and Himalayan alkali- rich porphyry. The Variscan marine basalt generally contains the hydrothermal mineralization, whereas the Himalayan alkali-rich porphyry has a close relationship with gold, iron, lead, zinc, silver. With the Beiya iron gold deposit as the study object, the authors utilized the magnetic anomalies delineated by high resolution magnetic survey in combination with audio magnetotelluric method, (the two methods are mutually complementary), followed the principle of "from known to unknown", and depended on geological data. As a result, deep geological structure and spatial location of the orebody were detected, which can provide a strong guidance for the project layout.

Abstract:Using 1∶50 000 high precision aeromagnetic data in combination with the regional geological background, the authors analyzed aeromagnetic anomaly features in Da Hinggan Mountains. On the basis of geological, geophysical and geochemical data and the distribution of ore deposits (ore spots) as well as metallogenic regularity, quite a few aeromagnetic anomalies were delineated through sieving. According to the latest high precision aeromagnetic map and the anomaly characteristics of the known ore deposits in combination with comparative study and comprehensive verification, a magnetite deposit and lots of nonferrous metal deposits were discovered. verification was made on the basis of summarizing the experience, and the future prospecting targeting based on aeromagnetic data was pointed out.

Abstract:Based on the 1:200000 geochemical exploration data of southern Huanggang- Ganzhu’ermiao metallogenic belt, the authors employed the singular- value decomposition technique and geochemical blocks methods to extract geochemical synthetic anomalies and assess the Sn and Zn mineralizing potential. The conclusions drawn by the authors are as follows: (1) The intersections of structures in different directions and the area where structure truncates the geochemical anomalies or the superimposed area of anomalies in different directions are favorable positions for Mo, Sn, W, Cu, Pb, Zn prospecting. (2) Most of the deposits in the study area have a close spatial relationship with the Permian strata, especially the contact zone between the Permian strata and the rock mass or the contact zone between the Permian strata and strata of other epochs with well-developed faults. (3) A Sn geochemical block, a regional anomaly and eight local anomalies as well as a zinc geochemical block, a regional anomaly and seven local anomalies were delineated. With 1 000 m as the thickness of the block, the total potential mineral resource of Sn is 211.92 million tons, and the potential mineral resource of Zn is 146.42 million tons in the study area. (4) By analyzing the structures of the geochemical blocks and anomalies, three first-order Sn prospective areas, four second-order Sn prospective areas and two third-order Sn prospective areas, along with three first-order Zn prospective areas, two second-order Zn prospectiveareas and two third-order Zn prospective areas, were delineated according to the metallogenic conditions.

Abstract:On the basis of 1∶50000 stream sediment survey，the geochemical characteristics of the arctic-alpine zone in Heku area were tentatively analyzed. The distribution of the elements，the elements relation in single anomaly and the features of the anomaly were also studied. The result shows that the method of geochemical stream sediment survey is obviously effective in the area of complicated topography，as evidenced by the successful delineation of two Pb-Zn-Cd-V ore-forming places.

Abstract:Carbon storage or sequestration is important in studying the global carbon cycle and budget. To evaluate carbon accumulation rate of S. salsa marsh along the vegetation coverage gradient, the authors collected 7 core samples from Liaohe Delta in May, 2010. The sediment accretion rate was calculated by 210Pb dating method. The laboratory analyses focused on water content, bulk density, nutrient contents, Mehlich III extractable nutrients and carbon concentration. Remarkably, carbon concentration is significantly related to nutrient contents（p<0.01）, implying that organic matters can effectively accumulate nutrient elements and support the growth of wetland vegetation, which favors carbon sequestration in the wetland soils. The results showed that total carbon concentration, about 83% of which is organic carbon, varies within 10.5- 14.6 g/kg and carbon accumulation rates are in the ranges of 98.02-260.37 g/m2/a（for total carbon）and 81.17-229.98 g/m2/a（for organic carbon）respectively with the average accumulation rate of 171.84 g/m2/a for TC and 141.29 g/m2/a for Corg. Carbon accumulation rates are likely affected by sediment accretion rate which is significantly related to the elevation of each wetland（p<0.01）. The implication is that not every wetland in different geological conditions and vegetation coverages is equally effective in sequestering carbon; it is important to address differences in wetland elevation, geological conditions and vegetation coverages when assessing the role of wetlands as carbon sinks in global carbon budgets.

Abstract:The improvement of soil capacity of carbon sequestration has great significance for reducing global greenhouse effect. Using two phases' data of organic carbon in surface soil in second soil survey and multi-purpose regional geochemical survey in south Songnen plain and employing variation tendency of organic carbon content in soil in different soil types and land uses in the past 20 years, the authors estimated soil carbon sourcing and gathering potential in different soil types and different land uses in south Songnen plain. The results show that, if the current land use, climate conditions, tillage, and planting technique are fixed, the carbon sequestration potential of soil in the depth of 0-20 cm of cultivated land in Songnen plain is -1.229 Tg C, and the carbon sequestration potential of soil in forestry land is positive in Songnen plain. The data obtained show that the forestry land is a carbon storage area, whose total carbon sequestration potential is 3.169 Tg C, whereas in natural pasture, the data of carbon sequestration potential adds up to - 2.235 Tg C, and the values are mostly negative, indicating a carbon resource area. It is estimated that the carbon sequestration potential of Songnen plain is totally -0.917 Tg C.

Abstract:In this paper, the topsoil environmental quality and nutrient quality were evaluated by the calculation techniques of single factor index and integrated factors on the basis of topsoil heavy metal elements and nutrient elements data with high accuracy provided by the multi-purpose geochemistry survey in Shouning County of Fujian Province in the light of the environmental quality standard for soils（GB15618—1995）and relative industrial standard. On such a basis, the lands were graded according to the geochemical quality. Some conclusions have been reached: the land quality is comparatively good on the whole, i.e., the land mainly belongs to the third and fourth grade, which accounts for 80.80% of the whole area, with the soil being comparatively clean; Seenriched soil is distributed in the soil of the third and fourth grade, accounting for 10.46% of the survey area, and it is suitable for the development of general agriculture and selenium- enriched agriculture. The next is land of the first and second grade quality, accounting for 13.13% of the survey area, and such land is suitable for development of green or pollution-free agricultural products, and should be protected and utilized reasonably. The area of land of fifth and sixth grade quality is rather insignificant, only accounting for 6.07% of the survey area.