Abstract:Abstract: Continental deformation is one of the basic contents of continental dynamics. Researches on the faults and basin?mountain evolution are the most direct and effective way to understand the continental deformation. During the late Mesozoic—Cenozoic, northern China was long influenced by northward subduction of Indian plate, westward movement of Pacific plate and blocking of Siberia plate. The crustal deformation was complex, which made northern China an ideal natural laboratory for the study of continental deformation. In this paper, based on the detailed analysis of field structures, combined with remote sensing and digital geomorphology, seismic reflection data interpretation, and low temperature thermochronology, the authors clarified the fault development sequence and tectonic stress field with the help of studying the Cenozoic faulting and the uplift history of mountain ranges in northern China. The causes of the present tectonic landform pattern difference between eastern and western China were found and the geodynamic mechanism of continental deformation was explored. NNE-striking faults were widely developed in northern China during Paleocene—Early Eocene, but they were not uniform, with larger scale and clear geomorphological features in the east. These NNE-trending faults were characterized by sinistral strike?slip, indicating NW—SE compressive stress field. The authors infer that the forming of NNE strike?slip faults was related to the NNW movement of Pacific plate in early Cenozoic. The NE dextral strike- slip and NW sinistral strike?slip faults, forming a conjugate fault system, developed in Bohai Bay region after the NNE strike?slip faults, and the direction of corresponding compressive stress field was nearly east—west. On the contrary, there were conjugate faults with NE sinistral strike?slip and NW dextral strike?slip in the west of Junggar Basin. The direction of compressive stress field was nearly north—south. These conjugate faults were superimposed on and cut the early NNE strike?slip faults. It is held that the formation of later faults in the east was related to the conversion of the movement direction of Pacific plate from north—northwest to west-northwest in 43~42 Ma. In the west, the later faults resulted from distant effect of the collision between India and Eurasia plates. With the continued northward movement of Indian plate together with the clockwise rotation, the western region maintains experienced north—northeast compressive stress field and developed a series of NW and NNW trending faults, whereas the eastern region still exhibited the EW compressive stress field. Affected by these Cenozoic faults, the mountains and basins in northern China showed a grid pattern assembled by lines and planes. Statistical analysis of apatite fission track ages shows that the eastern region experienced regional uplift?exhumation during Paleocene—Early Eocene (ca. 65~42 Ma). This tectonic event made a major contribution to the formation of present tectonic landform pattern in the east. Different from the east, the western region had undergone regional uplift?exhumation in about 8~6 Ma, hence forming the present tectonic landform pattern.

Abstract:Abstract: The Zhaxikang integrated exploration area is located in the eastern part of the North Himalayan metallogenic belt, Tibet. The most famous deposit in this belt is the Zhaxikang polymetallic deposit, which is the first large Pb?Zn?Sb?Ag association deposit discovered in southern Tibet. Deposits and ore spots in the Zhaxikang ore district exhibit significant spatial distribution. They are all in or around the Cuonadong Granitoid Pluton (CGP), from the internal part to the edge. The Sn and rare metals deposits formed at high temperature are mainly found in the internal part of CGP and its contact zone with the sedimentary cover. The mesothermal vein type Pb?Zn deposits are in the fault zones of sedimentary cover away from the CGP. The meso? epithermal Sb?Au deposits are more distant from the GCP. The distribution of deposit types are almost the same as the ore?forming element anomaly zonation determined by regional geochemical exploration of stream sediments. Based on the systematic study of the geological setting and spatial and temporal distribution of these deposits in the Zhaxikang ore district, the authors have reached the conclusion that metallogeny in the Zhaxikang ore district is closely related to CGP, and ore-controlling structures in this ore district are mainly related to the E?W extension of the Tibetan Plateau.

Abstract:Abstract: There are a few small granite porphyry plutons scattered in Houshandian and Cao’e area of central Zhejiang Province on the northeastern margin of South China block. The LA-MC-ICP-MS zircon U-Pb dating shows that they were both generated in Late Jurassic of the Mesozoic simultaneously (149.1±1.1 Ma and 150.3±1.6 Ma respectively), indicating that they both formed at the late stage of Early Yanshanian. The compositions of these two granite porphyry plutons fall into the high-K calc-alkaline category，with the A/CNK ratios being 0.96-1.28 (mostly less than 1.1). They are of metaluminous and weakly peraluminous series. They have moderate REE and strong light-heavy REE fractionation and strong Eu depletion with a slightly right inclined “sea-gull” shaped REE pattern. The spider diagrams of trace elements show that the granite porphyry samples are enriched in LILEs (e.g., Rb, Th and U) and HFSEs (e.g., Nb, Hf and Y) , but depleted in Ba, Sr, P and Ti significantly. The Houshandian granite porphyries belong to S-type granite and Cao’e granite porphyries are of A-type granite. Zircon εHf(t) values of the granites all are negative(-9.5 to -2.9 ), and two-stage Hf model ages (tHf2) range from 1364 Ma to 1783 Ma, suggesting that these granites originated from remelting of the Mesoproterozoic upper-crustal materials. Combined with the previous results, the authors infer that the Late Jurassic granite porphyries in central Zhejiang Province on the northeastern margin of South China block were formed in a post-orogenic extension environment. The formation age may represent a late stage of conversion from the Paleo-Tethys tectonic domain to the Paleo-Pacific tectonic domain.

Abstract:Abstract: Chencai Group is the main Precambrian basement at the northwest edge of Cathaysia. Researchers have focused on the study of Chencai Group over a long period of time because of its abundant information about the evolution of Jiangshan-Shaoxing suture zone. The authors divided the Chencai Group into banded biotite plagiogneiss, monzonitic granite and mafic dikes which intruded into the plagiogneiss. The zircon ages of biotite plagiogneiss are mainly concentrated around 1800 Ma, 700 Ma and 220 Ma. The age of about 1800 Ma is the peak value of inherited zircon in gneiss. The age of about 700 Ma is the minimum formation time of gneiss protolith, and the age of about 220 Ma is the metamorphism age of gneiss. Monzonitic granite crystallized at 220Ma. Metamorphism and magmation resulted from the tectonothermal event during Indosinian period, which responded to the Indosinian orogeny of South China.

Abstract:Abstract: For better understanding the Caledonian tectonic event of Cathaysia block, this paper documents a set of new zircon U-Pb geochronological and Hf isotopic analytical results for the Caledonian massive and gneissic granites from Wuyishan-Jinggangshan area. Crystallization ages of gneissic granites range from 415 Ma to 440 Ma，crystallization ages of massive granites range from 430 Ma to 449 Ma. The εHf(t) values of zircons range from -20 to 0(n=247), most data below -10. The two stage Hf model ages (tDMC) range from 1.5 Ga to 2.8 Ga. Combined with previous data, the authors revealed that the formation age, zircon Hf isotopic form and two stage Hf model ages (tDMC) of the two kinds of granite are similar. Granites were derived from crustal source of different times, which recycled during Caledonian. In addition, the addition of juvenile mantle-derived magma was insignificant. The Caledonian tectothermal event of Cathaysia block took place within an intracontinental orogenic environment. Caledonian orogen may have transformed its tectonic regime at about 430Ma, and gneissic structure resulted from synorogenic or late-orogenic deformation.

Abstract:Abstract: The Late Devonian mafic - ultramafic rocks were first discovered in Nenjiang - Heihe area. The rocks outcrop in the Hadayang tectonic mélange in Inner Mongolia. The mafic - ultramafic rocks are allochthonous rock block consisting mainly of amphibole - gabbro and amphibolite. The laser ablation inductively coupled plasma mass spectrometry (LA - ICP - MS) zircon U - Pb geochronology and geochemistry of the rocks were studied. The dating results show that the weighted average 206Pb/238U age of the amphibole - gabbro is （363.3 ± 1.2） Ma (n= 33), and the age of amphibolite is （362.09 ± 0.55 ）Ma (n =26). The ages belong to Late Devonian. The geochemical characteristics of the amphibole - gabbro show high Ti (TiO2 = 1.30%-5.04%), high Na (Na2O = 2.92%-3.14%), relatively high K (K2O = 0.31%-0.45%) and low Mg (MgO =5.94%-8.25%), the fractionation of HREE and LREE is obvious ((La/Yb)N =1.90-3.23), with the depletion of Zr, Nb and enrichment of Th and Sr. The geochemical characteristics of amphibolite show low Ti (TiO2 =0.65%-0.97%), low K (K2O=0.04%-0.12%), high Mg (MgO=20.42%-24.07%), high Fe (FeOT =11.40%-12.74%), obvious LREE and HREE fractionation ((La/Yb) N = 2.35-3.97), enrichment of Th, Hf, Ce and Nb, and depletion of Ba, Sr, K and Zr, Zr/Nb = 10.04-17.12. The characteristics of the Hadayang mafic - ultramafic rocks are similar to the features of the volcanic arc basalts. Combined with existing research results, the authors hold that the rocks probably formed in an island arc and fore arc basin above the subduction zone, and the subduction of the Nenjiang-Heihe tectonic belt already began in Late Devonian. This paper provides new evidence for the study of the tectonic evolution of the eastern part of the Hegenshan - Zhalantun tectonic belt and the Late Paleozoic Paleo - Asian Ocean of the northern Da Hinggan Mountains.

Abstract:Abstract: The final suture position between North China plate and Siberia plate remains a topic of much controversy. Lots of researchers prefer describing West Lamulun River - Changchun - Yanji fault as the final suture zone of the two plates, but dispute still exists concerning the final closure time. One of the reasons is that there exists controversy concerning the Late Permian－Early Triassic stratigraphy in the Da Hinggan Mountains due to insufficient research; in particular, the study of the contact relationship between Late Permian and Lower Triassic remains very insufficient. The Early Triassic Xingfuzhilu Formation is of fluvial-lacustrine facies with red bed features and contains fossils such as ostracoda, sporopollen, conchostracan, bivalves and megaplants, which are located in southern Da Hinggan Mountains. The authors collected tuff samples and made analysis. LA-ICP-MS U-Pb dating of zircon yielded an age of (254.3±2.6) Ma. Combined with the existing volcanic dating and fossils in the upper part of the volcanic rocks, it is considered that the lower part of the third member of Xingfuzhilu Formation should be of Late Permian whereas the upper part belongs to Early Triassic, and that the Late Permian-Early Triassic strata are of continuous deposition. The Paleo-Asian Ocean experienced collision suturing and the biota mixture in late Late Permian, and the closing time of the two plates should be Early Triassic.

Abstract:Abstract: It is important to date the Quaternary volcanic rocks for understanding the neotectonic activities in Hebei plain. The 500.25 meter drill hole CK3 located near Haixing Country of Hebei Province revealed 4 layers of volcanic rocks. The 40Ar/39Ar age of the first stage of Quaternary volcanic rocks is 2.36±0.05 Ma. Combined with the magnetostratigraphy of CK3 core, the time of volcanic activities in Hebei Plain should be about 1.3 Ma, 35?70 ka and 10?15 ka, respectively.

Abstract:Abstract: The Xiangshan Group is composed of a set of marine clastic rocks with small amounts of limestone and siliceous rocks, which experienced the greenshist facies metamorphism, and is located mainly in the eastern Hexi Corridor. The comparison between the detrital zircon ages (LA-ICP-MS) of the Xiangshan Group and the Miboshan Formation shows that the youngest zircon (451±8) Ma of Miboshan Formation is younger than the youngest (525±3) Ma of the Xiangshan Group, and Xiangshan Group does not contain other young zircons as the Miboshan Formation. Therefore, the age of Xiangshan Group should be younger than (525±3) Ma and older than the Ordovician Miboshan Formation. The Xiangshan Group may be the Middle-Late Cambrian in age. Furthermore, the striking comparison between detrital zircon ages of the Xiangshan Group with the ages of magmatic and/or metamorphic events of southwest Australia, Cathsysia Block, the basement of Alxa Block, the western margin of North China Block, and the North Qilian Orgenic Belt shows that the possibility of Cathsysia Block, the basement of Alxa Block, the western margin of North China Block, and the North Qilian Orgenic Belt as the provenance of Xiangshan Group should be ruled out. Combined with paleocurrent data of the Xiangshan Group, the authods argue that the southwestern Australia might have been the main provenance of the Xiangshan Group.

Abstract:Abstract: Using the paleocurrents, gravels composition and detrital zircons age spectrum, the authors analyzed the provenance of Early Cretaceous Laiyang Group in Jiaolai basin and its geological significance. The paleocurrents show a stable northward direction in Wulian-Zhucheng, but gradually change from E-SE at the early stage to W-NW at the late stage in Laiyang-Rushan. Gravels in Wulian-Zhucheng-Jiaozhou comprise mainly granite gneiss, granite, marble and quartzite; in Laiyang-Rushan, however, granites are dominant at the early stage and multiple gravels are present at the late stage. Detrital zircons ages are primarily distributed in the ranges of 110-145 Ma, 150-180 Ma, 200-250 Ma, 600-950 Ma and 1700-2600 Ma, whereas Paleozoic zircons are rarely seen. All these features indicate that there existed three main sources for Early Cretaceous Jiaolai Basin: ① HP-UHP metamorphic rocks and shallow metamorphic complex of Sulu orogen, ② Yanshanian granites (J2-3-K1), and ③ Metamorphic rocks from the Jiaobei uplift. Additionally, the regional difference of provenance is apparent, which suggests the southern part and the northern part of Sulu orogenic belt experienced different orogenic processes. The southern Sulu orogenic belt experienced large-scale uplift and was stable, whereas the northern Sulu orogenic belt was subjected to small-scale uplift and collapsed at the late stage. It is also concluded from the provenance that the ancient landform of Jiaolai basin in the southwest was higher than in the east during the sedimentation of Early Cretaceous Laiyang Group until the late stage of the sedimentation when the east part of the basin was uplifted.

Abstract:Abstract: On the basis of the detailed drilling data and the core characteristics at the macro and micro level, by means of analyses about characteristics and distribution rules of sedimentary facies, in combination with reef?banks syn?sedimentary corrosion reservoir characteristics,and according to the ancient sedimentary geomorphic units combined with lithofacies, the authors established the syn?sedimentary corrosion model of reef?banks in the Middle Ordovician Yijianfang Formation in the western Tabei uplift of Tarim Basin. According to the results obtained, first, the open platform facies of Yijianfang Formation contain platform?interbank, interbank sea and platform?inter patch reef, and the plane distribution of facies is stable; second, Yijianfang Formation exhibits obvious characteristics of the syn?sedimentary corrosion and widely reflects the characteristics of the intermittent exposure of bank: boring pores and corrosion pores are filled with ancient mud soil formed by the exposure of reef banks, the intertidal zone fossil fragment accumulation and traces of soft?bodied organisms activities are common, the corrosion cycle from seepage to undercurrent belt can be identified by core observation and Image Logging. According to the model, the banks and patch reefs of Yijianfang Formation are classified into five geomorphic units, i.e., supralittoral long?term exposure bank, intertidal intermittent exposure bank, subtidal high?energy bank, Calathium baffles tone and tideway.

Abstract:Abstract：Genetic types of sedimentary sand bodies affect oil and gas exploration in the Heshui-Ta’erwan area of Ordos Basin. Based on outcrop and core characteristics analysis, combined with well logging data, the authors recognized various types of sedimentary facies of the Chang6-Chang10 intervals in the study area, i.e., normal delta, braided delta, lacustrine system and slump fan, and made a detailed discussion on the subfacies. The turbidite and sandy debris flow sediments are the major gravity flow deposition systems. The primary braided delta deposits came from the southwest, the minor normal delta deposits came from the northeast, and the slump fan developed in the middle. The study area experienced transgression and regression during the deposition of Chang6-Chang10 intervals. The southwestern braided delta kept retrograding and slump fan developed in the front in deep water ultimately. The northeastern normal delta deposits are found mainly in the Chang6 and Chang8 intervals. It is revealed that source rocks developed in the Chang7 interval, and both underwater distributary channels in the Chang6 and Chang8 interval and gravity flow sediments in the Chang7 and Chang6 interval are potential exploration targets.

Abstract:Abstract：Based on core description, thin section observation, SEM and cathodoluminescence analysis, combined with regional?geological?setting, the authors tried to recover the diagenetic environments of limestone in Early Miocene Zhujiang Formation of Pearl River Mouth Basin by identifying?the?diagenetic?fabrics and analyzing the diagenetic characteristics. Some conclusions have been reached: 1) No epigenesis is developed in Zhujiang Formation limestone because of the transgressive background and gradual burial history. However, frequent changes in sea level result in the influence of meteoric water on limestone in the high part of the palaeo-geomorphology. The main diagenetic environments developed in Zhujiang Formation limestone include marine phreatic environment, fresh water phreatic environment, fresh water vadose environment and burial diagenetic environment. 2) Marine phreatic environment is the first and foremost environment that the Zhujiang Formation limestone have experienced during the diagenetic process, in which the main diagenesis includes the encrustation of red algae and mutual crusting effect between red algae and other organisms, the development of organism borings, early lithification of micrite and the formation of micrite envelope, glauconite formation, and the cementation of fringing fibrous calcite, bladed spar calcite and syntaxial calcite. Fresh water phreatic environment is characterized by the cementation of equant and massive calcite and mosaic sparry calcite in optical continuity with enclosed echinoderm fragment, and limited solution, while fresh water vadose environment is lack of cementation but has typical features of non-fabric selective solution and geopetal structure. Chemical compaction, development of stylolite, late leaching and oil emplacement are common in the middle to deep burial diagenetic environment.

Abstract:Abstract: The Yuanling-Mayang basin is a giant Mesozoic continental basin in the middle segment of Xuefeng orogen. At present, the features of the Mesozoic-Cenozoic faults and folds in the basin is lack of systematic and deep research. The authors studied such aspects of this problem as Mesozoic-Cenozoic structural framework, characteristics of the faults and folds, deformation sequences and epochs and regional tectonic settings through tectonic profile and field geological investigation, and reached the following conclusions: (1) The principal tectonic framework of the Yuanling-Mayang basin is composed of NNE- to NE-trending normal faults, thrust faults and gentle folds, accompanied by other folds and faults of different trends and natures. In the western and middle basin, main deformations are normal faults which formed complex horst-graben structure, with weak fold deformation. On the east margin of the basin, controlled by the Huaihua-Yuanling fault belt, there occur strong deformations, such as thrust faults which mostly dip east and subordinately dip west, often accompanied by overturned tight folds. (2) The basin has undergone several tectonic events since Middle Triassic: ① Regional NW to NWW-striking compression in late Middle Triassic Indosinian movement which formed NE to NNE-trending folds and thrust faults. ② Regional NS-striking compression during Late Triassic-Early Jurassic which formed EW-trending folds and kinks. ③ Regional NWW to EW-striking compression in late Middle Jurassic Yanshanian movement which formed NS- and NNE-trending folds and thrust faults involving Upper Triassic and Lower-Middle Jurassic on the east margin of the basin. ④Regional NW-SE striking extension in Early Cretaceous which formed NE- to NNE-trending normal faults of different scales. ⑤ Regional NS-striking extension in Late Cretaceous which formed EW-trending normal fault. ⑥ Regional NE-striking compression during middle-late Paleogene which formed NW-trending folds and thrust faults, NEE- to NE-trending sinistral strike-slip faults, NNE-trending dextral strike-slip faults, and NEE- or NNE-trending conjugated shear joints involving Cretaceous and early layers. ⑦Regional NW compression during late Late Paleogene-Early Neogene which formed NE-trending folds, NE- to NNE-trending thrust faults and NS-trending thrust faults involving Cretaceous and early layers. Among them, the most important deformations are normal faults which originated from the NW-SE-striking extension in Early Cretaceous, the folds and thrust faults originated from the NW-striking compression during late Late Paleogene-Early Neogene. (3) The klippes located in the eastern basin and east periphery, defined by Previous researchers, such as Wangbinpo, Huangjin’ao, Tanwan and Mayang, do not exist. The so-called “klippes” are actually faulted blocks with deep roots, and the Banxi Group located in Paleozoic and Mesozoic were related to the movement of thrust faults or normal faults.

Abstract:Abstract：Based on the geological-tectonic characteristics in Beijing plain，combined with the problems that have emerged in the study of active faults in recent years，the authors carried out the division of “small blocks” in Beijing plain, and recognized 7 small blocks, which are Machikou-Shahe small block, Xiaotangshan small block, Shunyi small block, Pinggu small block, Fengtai-Laiguangying small block, Daxing-Tongzhou small block and Fangshan small block. In accordance with active faults and the Quaternary sedimentary characteristics in the small block, the small block was further divided into several micro blocks. It is suggested that, in analyzing the activity, the viewpoint should be changed from active fault to active block. The authors revealed the activity of interactional microblocks and their sedimentation during the Quaternary period. This model plays an important role in city planning and construction and provides valuable reference for reducing geological hazards, thus ensuring the safety of urban geology.

Abstract:Abstract: The Zhuxi tungsten?copper deposit, discovered in northern Jiangxi in recent years, is a potential superlarge skarn deposit. Based on the geological setting and geological features of the ore deposit, the authors analyzed the rare earth and trace elements of the magmatite and skarn ores in the drill holes. Combined with the ore-bearing properties of the granitoid, the mineralization zoning, and the pre-existing geochronological data, this paper preliminarily discusses the geochemical characteristics of the granite and their constraints on mineralization of the Zhuxi tungsten-copper deposit. It is suggested that the granite is closely related to metallogenesis, and the mineralization of Zhuxi tungsten?copper polymetallic deposit is controlled by the crustal remelting granite which may have resulted from the large?scale lithospheric extension of southern China during the Mesozoic.

Abstract:Abstract:Petrology and major-trace elements analysis shows that Xiankou pluton is a compound granitic body characterized by high SiO2, high K and slightly peraluminous nature, thus belonging to the high-K calc-alkaline series. Chondrite-normalized REE patterns are characterized by right-inclined shape, rich light rare earth, significant negative europium anomalies, and more obvious fractionation of LREE than that of HREE. Trace elements are characterized by rich Rb, Th, U, Pb, Ta, Nd, Hf, obviously poor Nb, Ce, Pr, Zr, Ba, and significant variation of Rb/Sr ratio（0.92～6.52）, with the average uranium content being 19.55ppm, suggesting that the pluton belongs to uranium-rich granite. The tectonic setting discrimination diagram of trace elements and main elements shows that Xiankou pluton is a uranium-rich granite formed in an environment of intraplate post-orogensis. The discovery of Xiankou pluton provides a new train of thought for resolving the uranium source problem of the Xiangshan uranium orefield, and might guide the prospecting for granite type uranium deposits in southern Xiangshan.

Abstract:Abstract: Li, Ga and Sc are important rare noble metal resources, which are widely distributed in the bauxite. More than ten large-sized bauxite deposits have been found in the Wuchuan?Zheng’an?Daozhen bauxite ore district in northern Guizhou Province, and the associated Li, Ga and Sc resources are very abundant. The authors chose the typical Wachangping, Xinmin and Xinmu?Yanxi bauxite deposits in Wuchuan-Zheng’an-Daozhen area as the study case, investigated the distribution regularity of Li, Ga and Sc by analyzing their content in ore-bearing rocks and their overlying and underlying rocks. The results show that the values of Li, Ga and Sc decrease from the central ore-bearing rock series to the bottom and then to the upper part vertically. In addition, the values of Li in massive ores are higher than those in clastic ores, and they are all higher than values in earthy ores; Ga is concentrated in earthy and massive ores, whereas Sc is concentrated in clastic ores. Additionally, the regional distribution of Ga, Li and Sc is higher in the north and lower in the south, suggesting their relationship with lithology, weathering and sedimentary differentiation. Ga, Li and Sc mainly exist on the surface of rutile, zircon and xenotime. Hence these heavy minerals are very important for comprehensive utilization of Li, Ga and Sc. The distribution regularities of Li, Sc and Ga suggest that the bauxite was formed in a continental lacustrine basin environment.

Abstract:Abstract: The Jingshansi iron deposit in Henan Province is located in the southeastern part of the North China Craton. The orebodies occur in nearly bedded and lenticular forms, and the iron ores are predominantly banded, with minor massive ones. Taihua Group Tieshanmiao Formation marbles are developed as main wall rocks and interlayers among the orebodies. Geochemical studies of carbon, oxygen and silicon isotopes of the ore deposit were carried out to investigate the ore?forming fluid nature and its potential sources. The results show that δ13CV?PDB values of ore?forming calcite range from ?5.2‰ to ?1.4‰, δ18OV?SMOW values range from 8.5‰ to 16.9‰, δ13CV?PDB values of carbonate host rocks calcite range from ?1.0‰ to 1.6‰, and δ18OV?SMOW values range from 20.3‰ to 23.4‰, the C and O isotope evolution indicates that drastic water?rock interaction took place at the ore?forming stage, and isotope exchange took place between ore?forming fluids and carbonate host rocks. The carbon isotope components were mainly provided by the marine carbonate rocks through dissolution, influenced by middle?low temperature alteration. The characteristics of δ18O[H2O] indicate that the hydrothermal solution is?the?mixture?of?magmatic?water?and?seawater.?The δ30Si NBS?28 values of iron ore quartz range from ?1.9‰ to ?0.4‰, and the δ30Si value of leptite quartz is 0‰, which indicates that the silicon isotope were derived from volcanic?exhalation. The Si isotope fractionation took place in the ore?forming process. A comprehensive analysis shows that the Jingshansi iron deposit?was?formed?in?a submarine?volcanic?eruptions?sedimentary?environment?in Precambrian.

Abstract:Abstract: To find out the distribution regularity and organic geochemical characteristics of the hydrocarbon source strata in Niutitang Formation and Wufeng-Longmaxi Formation in northern Guizhou and its adjacent areas in combination with the specific field geological investigation and previous research results, the authors conducted detailed analysis and investigation, and the result shows that the distribution of the hydrocarbon source strata in Niutitang Formation was controlled by the deposition and depression or taphrogenic trough in early Cambrian. Two hydrocarbon generation depressions were formed in northern Guizhou, which are respectively located along Dafang- Qianxi- Qingzhen area and to the east of Tongzi- Suiyang- Meitang area. The thickness of hydrocarbon source rocks (TOC>1.0%) is 80-110 m. The average organic carbon in Niutitang Formation in northern Guizhou is 1.36%-10.01%; the organic carbon isotope is -34.90‰ to -28.19‰, the organic matter is of I type, and Ro is 1.77%-4.53%. The hydrocarbon source rocks with the thickness larger than 20 m in Wufeng- Longmaxi Formation are mainly distributed to the east of Tongzi- Renhuai-JiaoYuan- Xiashui area, with the average organic carbon being 3.0%-5.0%, and the organic carbon isotope being -31.92‰ to -28.97‰, the organic matter is orⅠ~Ⅱ1 type, and the vitrinite reflectance is 1.73%-2.38%. As shown in the comprehensive analysis, the shale gas in Wufeng- Longmaxi Formation is controlled by the distribution of shale containing organic matters under certain preservation conditions. The areas favorable for shale gas exploration in Longmaxi Formation include the positive tectonics with medium buried depth and the broad and gentle syncline areas. The shale gas accumulation in Niutitang Formation is controlled by the thickness of hydrocarbon source rocks, the formation position of paleokarst in the late Sinian System, the quality of physical properties of rocks in Dengying Formation, the lamellation fracture in Niutitang Formation, the preservation conditions and other factors. The thickness of hydrocarbon source rocks in Niutitang Formation in some anticlines of Qianxi depression is larger than 80 m, with the buried depth being 1500-2000 m. The attitude of the strata on two sides of the anticline is gentle, without the development of fractures but with certain preservation conditions, and hence this area is the target area favorable for shale gas exploration in Niutitang Formation.

Abstract:Abstract: Based on the test data including the observation and measurement of mud shale in the field geological sections and a well, the result of organic geochemistry experiment, physical analysis and the component analysis of the rock mineral samples, the authors systematically investigated the characteristics of sedimentary environments, the scale of development, geochemistry and reservoir of Upper Sinian Doushantuo Formation black shale in the north of middle Yangtze region. The results show that the thickness of black mud shale is approximately 53.3-114.7 m with an average of 87.3 m, the mud shale is mainly developed in the intra-platform basin, the total organic content is generally over 1.0%, the main organic type is I-Ⅱ1, the average value of organic material maturity is 1.85%, Tmax is mainly in the range of 353-609 ℃, and the black mud shale is mainly composed of detrital minerals and clay minerals. In addition, the average content of detrital minerals is 56.3%, the ingredients are mainly quartz and feldspar, the average content of clay minerals is 26.1%, the ingredients are mainly illite and smectite mixed layer minerals, the average of porosity is 2.32%, and the average permeability is 0.031857×10-3 μm2. Compared with the indicators of the main mud shale gas production areas in the USA and China, Upper Sinian Doushantuo Formation mud black shale in the north of Middle Yangtze region has a larger thickness, relatively?low organic matter, higher thermal evolution degree, higher brittleness mineral content, lower clay mineral content, lower shale porosity and permeability, and better preservation?condition. The study area which has the basic geological conditions for producing shale gas is one of the main marine shale gas prospecting?areas in China.

Abstract:Abstract: Based on the base-level cycle principle, the authors studied high-resolution sequence stratigraphic characteristics and coal accumulation of Taiyuan Formation in the Datong coalfield by using borehole, logging and geological data. One long-term base level cycle, three medium-term base level cycles and seven short-term base level cycles were identified. Various sedimentary facies sequences, structure and stacking pattern of short cycle sequences and controlling factors for coal accumulation in different middle cycle sequences were analyzed emphatically and, as a result, the distribution features and log responses of sand bodies and coal seams in the interior were obtained. The research results also show that the accumulation of the coal of Taiyuan Formation was controlled by medium-term base-level changes under the conditions of slight extension and slow subsidence of tectonic setting and humid climate. The late rising half medium-term base-level was favorable for depositing wide and thick coal seams, while thin layers of carbonaceous mudstone and coal were developed in the early-to-middle period of the rising half medium-term base level or the late period of the falling half level, where the coal seams were distributed sporadically with poor continuity laterally.

Abstract:Abstract: The Duobuza porphyry copper deposit was discovered in recent years in Tibet. It is located in the western part of the Bangong Co-Nujiang River metallogenic belt. From the interior to the outer part of this deposit, there exists zoning of potassic alternation, phyllic alteration and propylitization. Potassic alternation is mainly developed in the granodiorite porphyry outcropping area, sericitization is developed surrounding the potassic alteration zone and superimposed upon the potassic alteration zone, and propylitization occurs in lamps on the western side of the deposit. This paper expounds the relationship between the grade tendency line of Cu in the drill hole and the orderly zoning in the Duobuza deposit, and further demonstrates that the potassic alteration zone and the orebody have a close corresponding relationship. Based on the pyrite distribution trend and the actual ore comparative analysis as well as the study of rock geophysical properties the authors reached the preliminary conclusion that the ore-bearing granite diorite porphyry is characterized by high resistivity and polarizability. On such a basis, method test and geochemical data processing were conducted in typical deposits. According to the inferred results and actual orebody position, it is held that the orebody mainly occurs in the high resistivity, high polarizability and magnetic field gradient zone, whereas Cu-As-Sb-Au high background area is located in the shallow part. The results obtained by the authors further improve the method choice and provide the basis for the prognostic work in the Duobuza porphyry deposit.

Abstract:Abstract: Located in the northeast of Zhangjiakou-Chengde metallogenic ore district along the Fuxin-Jining metallogenic belt, the Xinzhangzi area shows a good ore-prospecting potential. Based on the 1∶50000 stream sediment survey, the authors primarily investigated the geochemical features of Xinzhangzi area. Element parameter study, R mode cluster analysis, factor analysis and element anomalies show that the study area might be a prospective area for Au, Ag, Cu, Pb and Zn. Combined with the metallogenic background in the aspects of strata and structure, the authors summed up the work of lineation, selection, ranking and interpretation of geochemical anomalies, and then delineated Shihu and Panjiadian gold metallogenic prospective areas as well as Lutonggou and Rongjiazhuang polymetallogenic prospective areas.

Abstract:Abstract: According to the?1: 200000 geochemical data obtained from Beiya area and analysis of the?enrichment regularity of?main ore?forming elements of?Ag, Au, Cu, Pb, Zn, the authors studied the?element distribution features, anomaly?characteristics, correlation and abnormal?element composition, and determined the?favorable prospecting?composite?index. Through the comparison of the?typical?metallogenic geological and geochemical characteristics of the Beiya gold ore district, combined with the?formation, magmatite?and other criteria,?the prospecting area was predicted. The results?show that, through an integrated?study of the?regional formation, structure, magmatite?and mineral resources data, the establishment of the?ore-forming elements?anomaly?zoning?is feasible, which can effectively reflect the?anomalies and highlight the mineralization information. According to?the regional metallogenic setting of?single?elements Au, Ag, Pb, Zn, Cu?and the combination of?elements?geochemical characteristics of anomalies, the target areas for further exploration were delineated, which provides?guidance?for ore prospecting.

Abstract:Abstract: To better explore the best working technical conditions of geo-electrochemical extraction techniques in the cold plateau area, the authors chose 7 line sections of the engineering-controlled Gardaban copper polymetallic deposit in Qinghai for the contrastive experimental study with geo-electrochemical extraction technology, and designed a set of suitable geo-electrochemical extraction technologies for the cold plateau area. Through comparative tests, the authors determined the technical indicators: the extraction time is forty-eight hours, the service voltage is 9 V, the concentration and dosage of extracting solution are 15% and 1000 ml respectively, the pole pitch of extraction is 1 m, and the material of extraction is foam plastic. The optimal working technical conditions were adopted, and the prognostic work for concealed orebodies was conducted in the unknown area in the southeast part of the ore district. As a result, four favorable ore-prospecging targets were delineated, which can play the guiding role in the further ore-prospecting work.

Abstract:Abstract: It has been identified that a high geochemical background of some heavy metals including Pb exists in the southeastern part of China. There is a potential eco?geochemical hazard risk from heavy metal mobilization caused by soil acidification due to acid precipitation and improper manure. The main production area of Tieguanyin tea was selected for this study. Surface and sub?surface soils as well as tea leaves were collected from totally 79 tea gardens. Heavy metals in soils and tea leaves, major elements and physicochemical indicators of soil samples were determined. It is found that Hg, Pb, Se and Zn in tea garden soils are higher than their geochemical backgrounds of national soils, and this is attributed mainly to soil?parent rocks controlled by geological setting. However, soil properties including particle composition, organic material content and pH also play important roles in trace element concentration. Some non?nutrition elements for vegetation including As, Cd, Cr, Hg, Se, Pb and F are accumulated in matured leaves compared with their values in sprouts. Nutritive elements such as Cu, Ni and Zn seem to accumulate in sprouts to meet the demand of tea growth. Although the relationships between soil and tea leaves are quite complicated for most elements, there exists obvious positive correlation between soils and tea leaves in Cr and Pb content. This discovery provides the mathematical basis for establishing a model for forecasting lead impact on ecosystem.

Abstract:Abstract: Geothermal activity is an important form of earth degassing, which is frequently accompanied by a large number of greenhouse gas emissions. Taking Mapamyum of non?volcanic geothermal region in Tibet as a study case, the authors evaluated the degassing flux of geothermal soil CO2 based on the Fick's law of diffusion. The results indicate that the soil CO2 degassing flux is from 0.167 to 0.771 kg /(m2·a), while the fumarole CO2 degassing flux is from 2.054 to 7.877 kg/(m2·a) which is 18.9 times that of the soil; Compared with global volcanic soil (0.001 ~ 2.25 Mt/(km2·a), the soil CO2 degassing flux is significantly lower in value but larger than the Alpine grassland ecosystem soil CO2 emissions in the Tibetan Plateau (187.46 g(m2 a)?1)). Combined with tectonic setting, the authors evidently hold that CO2 in the geothermal system is mainly derived from magma degassing and hydrothermal fluid with walk rock alterations such as feldspathization. The low zone of soil CO2 degassing flux is constrained by the poor permeability clastic sedimentary cover.

Abstract:Abstract: Eighty water samples were collected from different geothermal fields in Beijing and the following five kinds of characteristics of deuterium excess parameters were analyzed: (1) The average d value of geothermal water is 5.40, the average d value of cold groundwater is 6.04, which is bigger than that of the geothermal water, so the oxygen isotope exchange caused by water?rock interaction is easier in geothermal water than in cold groundwater. (2) The oxygen isotope has remarkable isotope exchange process, and the d value increases with the age of the geothermal groundwater. When the age of the water is (12.76±0.13) ka, the d value is 11.2; when the age of the water is (38.96±0.63) ka, the d value is 14.6. (3) The d value decreases with the depth of the geothermal groundwater in the same area; when the depth is 3221 m, the d value is 3.03; when the depth is 125.13 m, the d value is 5.72. (4) The d value decreases from the recharge area to the discharge area. The average d value is 7.31 in northern recharge area, 5.68 in Beijing depression, and ?9.20 at the southern edge of Beijing plain. The velocity of flow decreases with the difference d values. (5) The d value increases with the redox potential when it is smaller than 200 mV. When the redox potential is ?326 mV, the d value is ?9.20; when the redox potential is 158 mV, the d value is 7.48. The d value decreases with the redox potential when it is bigger than 200 mV.