Abstract:The Yanshan orogenic belt is an important Mesozoic tectonic feature in the north of the North China Craton (NCC). It was formed by the “Yanshanian Orogeny” (Wong, 1927, 1929, Bulletin of Geological Society Of China). The \"Yanshanian orogeny” has two phases (A and B) reflected by two regional angular unconformities. Both phases are characterized by crustal shortening. Phase A is marked by the unconformity beneath the andesite volcanic rocks of the Tiaojishan formation and Phase B by the unconformity beneath volcanic rocks of the Zhangjiakou formation. The end of Phase B represents the transformation of the east part of the NCC from crustal shortening to crustal extension. Although the time gap represented by the angular unconformity marking Yanshanian Phase B has constrained isotopically to be between 145Ma and 126Ma, the precise time duration for Phase B remains to be further refined. Within the central segment of the Yanshan orogenic belt, the Sihetang ductile shear zone is identified as having developed during Phase B of the Yanshanian Orogeny. We have dated the deformation of this shear zone and our work has bearings on the timing of Phase B of the Yanshanian orogeny. The Sihetang shear zone is located to the north of the Early Cretaceous Yunmengshan pluton. Shear sense indicators suggest top-to-the-SSW thrusting. The metamorphic basement, Meso- and Neo-proterozoic cover layers, and Late Jurassic to Early Cretaceous plutons are involved in the ductile shear zone deformation. Many syntectonic dykes are present in the Shihetang shear zone, and their order of emplacement during shearing is established by structural analysis. Dykes are divided into early, intermediate, and late stages, based on their geometries within the shear zone. Zircons from dykes of each stage are selected for dating. LA-ICP-MS zircon U-Pb ages for the three stages are respectively 143.0±2.1 Ma, 140.8±1.4 Ma, and 137.5±2.4 Ma, consistent with dyke emplacement order constrained from structural analysis. We suggest that 143-138 Ma should be the time period for the Sihetang ductile shear zone deformation. Considering the ages of deformed and un-deformed plutons associated with the shear zone, we suggest that the shear zone deformation represent the entire duration of Phase B. Therefore, the time period of Phase B of the Yanshanian Orogeny is 143-138 Ma.

Abstract:The ocean- continent transition period of the Carboniferous system in the north of Xinjiang has experienced the following two evolvement stages: stretch in the collision diapause--- closure of remnant ocean stage and collision stage between continent and continent in the early Carboniferous, and stretch collapse---deformation stage inside the plate after the collision at the late Carboniferous. According to the plate structure activity background of Carboniferous and combining the regional structure---sedimentary rock structure, it makes analysis and initially draws up that the types of the early Carboniferous prototype basin in the north of Xinjiang mainly include five categories: Remnant Ocean, epicontinental sinking, taphrogenic trough, rift valley and intracontinental sinking; the late Carboniferous prototype basins can be briefly divided into three categories: taphrogenic trough, epicontinental sinking and rift valley or rupture. According to the superposition alteration features at later stage of the Upper Carboniferous prototype basins, it can divide the Upper Carboniferous remnant basins and their superposition alteration categories which are preserved in the north of Xinjiang nowadays into two main types and six subtypes: above all, they can be divided into inheritance model and superposition model based on whether there is Permian system. Then according to the superposition features of Mesozoic and Cenozoic basins, they can be divided into five subtypes, which are successive inheritance model, early inheritance and early superposition model, early inheritance and late superposition model, Trias superposition model, Jurassic superposition model and cretaceous superposition model.

Abstract:Abstract: Since Shihtzupu and Pagoda formations of the middle-upper Ordovician System are named in 1920s, they had been considered to be conformable contact in the Sichuan Basin. In this study, conodont biostratigraphy and carbon isotope stratigraphy are researched in the middle-upper Ordovician in the Liangcun and Huangcao sections around the Sichuan Basin. Both biostratigraphic and chemostratigraphic results indicate a gap between the Shihtzupu and Pagoda formations. The discontinuity can be correlated with the M4/M5 sequence boundary which is a prominent unconformity in North America. Both of them probably result from the regression in the early and late Sandbian. There is also unconformity in the middle-upper Ordovician in Bachu area and Tarim Basin. The possible disconformity between the Shihtzupu Formation and Pagoda Formation is significant for our petroleum exploration in the Sichuan Basin.

Abstract:Abstract The Jiangligou granitic pluton that is Monzonitic granite distributed in the northern part of West Qinling and intruding into the Daguanshan Formation is consist mainly of plagioclase， quartz，potassium feldspar，biotite. Major and trace elements studies show that the pluton is characterized by typical Himalaya granite features with SiO2=71.76% ~ 75.86%，Al2O3=11.67% ~ 14.84%，MgO=0.35% ~ 0.70%，Sr=58×10-6~223×10-6，Y=1.2×10-6~16.1×10-6，Yb=1.21×10-6~ 1.76×10-6.Rittmann index is between 1.42 and 2.08 and belongs to high K calc-alkaline series in the K2O-SiO2 diagram . The research also showed that the pluton is characterized with A / CNK=1.05~1.1，suggesting that the Jiangligou pluton belongs to the Peraluminous Granites. Primitive manlte normalized trace elements patterns reveal that large ion lithophile elements ( LILE ) K，Th，Rb，Ba is enriched，but strength element ( HFSE ) Nb，P，Ti，Y，Yb are depleted compared with adjacent elements. chondrite-normalized REE distribution pattern show an strong enriched LREE distribution and a relative depleted of HREE distribution with obviously Eu negative anomaly(LREE/HREE=6.3~16.2，(La/Yb)N =4.9~17.4，δEu=0.38~0.66). CL images and LA-ICP-MS isotopic dating show that zircon U-Pb isotopic age of the Jiangligou granitic pluton is 264.0 ±1.4Ma belong to Middle Permian. Based on the previous studies and the analysis revealed Jiangligou granitic pluton was formed in the thickened crust envitonment and was associated with the result of the subduction and collision of the distance effect in the closing process of A’nyemaqen oceanic basin，making extrusion effect in this area . It causes the crust thickness increase as temperature and provides dynamic conditions and magmatic activity space for deep crustal material remelting emplacement in the area.

Abstract:The Heishantou Formation volcanic rocks occurred in the area of Barleik, West Junggar, consisting of gray purple (vesicular) almond andesite and almond shaped basaltic andesite, belonging to sub-alkaline series. High-precision LA-ICP-MS zircon U-Pb dating has revealed that they were formed at the age of 349±8Ma, MSWD=0.14 (95% conf.), the time belongs to the Early Carboniferous. These rocks have moderate Mg# (23.82~50.4) values, relatively high alkali (Na2O+K2O=3.74%~8.02%), and relative enrichment in sodium. Their LREE are relatively enriched ((La/Yb)N=2.87~13.41) and well fractionated ((La/Sm)N=1.46~3.41)), while HREE fractionation is weak ((Gd/Yb)N=1.46~3.48)). Only some of the samples have weak negative Eu anomalies (δEu=0.82~1.47). All samples are characterized by large ion lithophile elements (LILEs, eg., Ba, Th, K and Sr) enrichment, especially Ba and K, high field-strength elements (HFSEs, eg., Nb, Ta, and Ti) depletion, while Zr, Hf slightly enriched. Geochemical features indicate that the volcanic rocks are products of metasomatism between subduction-zone fluids and lithospheric mantle. Comprehensive analysis indicates that the volcanic rocks were derived from active continental margin. The determination of the age and tectonic environment information of volcanic rocks from Heishantou Formation provides new evidence for further understanding of the tectonic evolution in the area of Barleik in the West Junggar.

Abstract:The Yinjiagou pyrite-polymetallic deposit of Henan Province, located in the Huaxiong block of the southern margin of the North China craton, is the largest pyrite-polymetallic deposit in the East Qinling orogenic belt. The deposit is characterized by abundant pyrite resources and complicated paragenetic and associated elements, which is different from most molybdenum deposits characterized by Mo and W in the East Qinling area. From early to late, the ore-forming process can be divided into three periods of skarn, sulfide and epigenetic epochs, including seven ore-forming stages, representing as magnetite, vein quartz-molybdenite, quartz-pyrite-chalcopyrite-bornite-sphalerite, stockwork quartz-molybdenite, quartz-sericite-pyrite, calcite-galena-sphalerite and chalcedony-limonite stages, respectively. Three types of fluid inclusions are distinguished in quartz phenocryst, various quartz veins and calcite vein based on petrographic and microthemometric criteria, namely aqueous two-phase, CO2-bearing three-phase and daughter mineral-bearing multiphase inclusions. Fluid inclusions in quartz phenocryst of K-feldspar granite porphyry are mainly aqueous two-phase and daughter mineral-bearing multiphase inclusions with minor CO2-bearing three-phase inclusion, their homogenization temperatures and salinities vary from 341℃ to >550℃ and from 0.4% to 44.0% NaCl equivalent, respectively. Fluid inclusions in quartz of vein quartz-molybdenite stage are composed of aqueous two-phase and daughter mineral-bearing multiphase inclusions with homogenization temperatures and salinities vary from 382℃ to 416℃ and from 3.6% to 40.8% NaCl equivalent, respectively. Fluid inclusions in quartz and calcite of quartz-calcite pyrite-chalcopyrite-bornite-sphalerite stage consist of aqueous two-phase and daughter mineral-bearing multiphase inclusions, their homogenization temperatures and salinities vary from 318℃ to 436℃ and from 5.6% to 42.4% NaCl equivalent, respectively. Fluid inclusions in quartz of stockwork quartz-molybdenite stage are mainly composed of aqueous two-phase inclusion with minor daughter mineral-bearing multiphase inclusion, their homogenization temperatures and salinities vary from 321℃ to 411℃ and from 6.3% to 16.4% NaCl equivalent, respectively. Fluid inclusions in quartz of quartz-sericite-pyrite stage are aqueous two-phase and daughter mineral-bearing multiphase inclusions, with homogenization temperatures and salinities varying from 326℃ to 419℃ and from 4.7% to 49.4% NaCl equivalent, respectively. From skarn orebody to porphyry orebody, ore-forming temperature gradually reduces without evident salinity changes. The ore-forming fluid of the Yinjiagou deposit is characterized by high temperature and high salinity, roughly belonging to H2O-NaCl±CO2 system. The δ18OH2O values of the ore-forming fluid vary from 4.0‰ to 8.6‰, and δ18DV-SMOW values vary from -64‰ to -52‰, indicating that the ore-forming fluid was mainly derived from magmatic fluid. The δ18SV-CDT values of sulfides range from -0.2‰ to 6.3‰, with an average of 1.6‰, suggesting that the ore-forming material mainly came from deep sources and most likely came from lower crustal composed of poorly differential igneous material, in addition, the dolomite of the Guandaokou Group also provided part of the heavy sulfur. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of 35 sulfide samples vary from 17.331 to 18.043, 15.444 to 15.575 and 37.783 to 38.236, respectively. These lead isotopic data are roughly consistent with those of the Yinjiagou intrusion occurring in the Yinjiagou ore district, implying that the ore lead of the Yinjiagou deposit was mainly originated from the felsic-intermediate intrusive rocks, with a small amount of lead from strata. To the conclusion, the Yinjiagou deposit belongs to porphyry-skarn deposit, the boiling action of ore-forming fluid is the dominant factor for metallic sulfide deposition, probably occurred in a transitional tectonic setting from nearly EW-trending to nearly NNE-trending tectonic regimes during the Mesozoic era.

Abstract:The Hardat Tolgoi Pb-Zn Deposit is located in the assembly belt of the North China plate and the Siberia plate, is a new medium-sized Pb-Zn deposit in the Erenhot-Dongwuqi polymetallic ore belt. This paper reports fluid evolution and metallogenic mechanism of the ore deposit by fluid inclusions measurement and stable isotopic compositions. Microthermometric study suggests that fluid inclusions the mineralization homogenization temperature is 195 ℃ to 408 ℃ with average 332.5 ℃, the salinity is 1.40 % to 11.93 %.NaCl eq. with average 4.87 %NaCl eq., and the density is 0.61 g/cm3 to 0.89 g/cm3 with average 0.72 g/cm3. There are two peak values range of homogenization temperature histogram diagram, one peak values from 230 ℃ to 250 ℃ is close related with the metallogenisis, another peak value from 350 ℃ to 370 ℃ is representing the early metallogenic fluid temperatrue. It is estimated that fluid formed under the pressure of about 13.0 Mpa and the depth of about 1.3 km. Test results of the laser Raman analyses indicate that the ore forming fluids belong to the H2O-NaCl system with little CO2. The hydrogen and oxygen compositions indicate that the ore forming fluid of the Hardat Tolgoi Pb-Zn deposit mainly derived from magmatic water mixed with meteoric water. The sulfides has a very uniform S and Pb isotopic composition, with δ34S is 4.0 ‰ to 6.1 ‰；w(206Pb)/w(204Pb) is 18.311 to 18.467，w(207Pb)/w(204Pb) is 15.590 to 15.636，w(208Pb)/w(204Pb) is 38.253 to 38.393. Both the S and Pb isotopic compositions of ore indicate that the metallogenic materal were derived from magma. All of this suggest that the Hardat Tolgoi Pb-Zn deposit is a shallow mesothermal deposit.

Abstract:Based on the result of national mineral resources potential evaluation, there is a large number of bauxite resource in southeast of Chongqing city. Therefore , it has important guidance significance to study the geophysics exploration method adapted to this area. First, this study expounded the metallogenic regularity and orebody characteristics of the area. Summed up the storage mode of bauxite. Then based on metallogenic regularity and storage modes, combined with the experience of other predecessors and regional physical differences, a program which to use electromagnetic sounding method to determine the spatial form distribution of Liangshan group stratum in order to help buried bauxite exploration is put forward. Selected Chepan mining area as a test site, did a test respectively use of controllable source (person workshop source) audio magnetotelluric sounding method (CSAMT) and high-frequency magnetotelluric sounding method (EH4) in the same profile. The data acquisition and data quality evaluation are introduced. At last, two kinds of electromagnetic sounding data were inversed by the two-dimensional continuum inversion of the human-computer interaction, and combined with the borehole data, analysis and discussed the two profiles of frequency—resistivity, then lased out the inferred geophysical results diagram.

Abstract:Continental margins, which locate in the continental crusts and oceanic crusts, record the processes of the continental breakup and the ocean opening. It is important for the research on the geodynamics. The Cenozoic basins in deep water of northern margin of South China Sea located on the continental margin. The Cenozoic basin can be divided into three structural layers. They are rift layer, post-rift depression layer and post-rift subsidence of ocean basin layer. Rift basin layer performed as a series of graben and half graben. The character of post-rift depression layer is thick in the middle and thin on both side which looks like a disk. The thickness of post-rift subsidence of ocean basin layer changed greatly, it thick on the continental slope and thin on the ocean basin which showed the character as a “flexing basin”. The basin in deep water of northern margin South China Sea has experienced three evolution stages and showed the different geodynamic mechanisms. Influenced by the upwelling of the mantle, the basin mainly performed as horizontal extensional and formed the extensional structural styles in rift stage. In post rift stage, the basin subsided widely. In the third stage, the basin bended towards the South China Sea which controlled by the subsidence of ocean basin. The structural framework of continental shelf — continental slope — ocean basin is formed in the stage of ocean basin subsided. The activity difference of mantle material which under the basin of northern margin and the ocean basin is the main influence factors of the geodynamics.

Abstract:Based on well drilling and seismic data, the characteristics and cause of lateral buried hill transformation belt are studied. The result shows that Raoyang buried hill transformation belt is based on Mesozoic differential tectonic erosion, formed by Cenozoic differential tectonic erosion; in response to different tectonic subsidence between tectonic units, which are above on bedrock detachment surface as a carrier, a series of buried hills collapse in order from east to west. Logging, oil test, laboratory analysis data confirm that buried hill transform zones are characterized by “multiphase filling of oil and gas in time, heterologous oil accumulation in plane, differential hydrocarbon accumulation in profile” and form multiple oil and gas accumulation zone, which are mostly buried hill hydrocarbon reservoir and the next is Tertiary hydrocarbon reservoir. Strong tectonic deformation of buried hill transform zones offer favorable conditions for formation of trap and reservoir. Under the guidance of “oil and gas differential accumulation principle”, we exact analyze the distribution of inner hydrocarbon reservoirs of buried hills in space and search for favorable exploration target and extend prospecting area of buried hill in Jizhong depression.

Abstract:Traditionally TSR-solid bitumens (pyrobitumen) have been recognized as direct, stable products of the thermochemical process. Compared with hydrogen sulfide (H2S), the presence of these solid bitumens has not been considered an important factor in TSR In this paper, activated carbon (C) was selected as a model compound for solid bitumen (pyrobitumen), and thermochemical reduction of calcium sulfate (CaSO4) by activated carbon (C) was carried out under hydrothermal conditions at elevated temperatures. Thermodynamic characteristics of the system of CaSO4-C-H2O were investigated. According to the experimental results, CaCO3, H2S and CO2 were determined as the main TSR products. The threshold temperature for initiating TSR in the present study was only 300 ℃, which was much lower than those of most previous TSR simulations using hydrocarbons and in accordance with the further thermodynamic calculations. Process simulation of TSR was conducted using the software of HSC Chemistry 5.0. It was found that at reservoir temperatures of 25℃-200℃, TSR in the system of CaSO4-C-H2O was totally controlled by kinetic factors. Under a constant temperature, the increasing pressure was unfavorable to the initiation of TSR. The intensity of TSR was closely associated with the amount of water. The small amount of water may contribute to better oxidizing conditions. The influence of water content on TSR may be related to the saturation concentration of CaSO4. When pH≤2, sulfate reduction rates are dependent upon the decrease of pH at a certain temperature. However, in the pH range of sedimentary basin formation water (pH>4), effect of pH on TSR is negligible. TSR in the system of CaSO4-C-H2O was an exothermic process. The released heat increased with the increasing temperatures, which was estimated as about12.9 J-133 J/(mol)CaSO4 at 25 ℃-200 ℃. Thermodynamic studies and the experimental results implied that solid bitumens (pyrobitumen) more easily involved in TSR than gaseous or liquid hydrocarbons.

Abstract:Dangxiongcuo salt lake, which locates in the southwest plateau of Tibet, has the moderate carbonate-type brine, with the good industrial exploitation prospect and value. The natural evaporation is the basis work of the salt field solar evaporation technology application, and basing on the relative results of the isothermal evaporation experiment of brines indoor, this paper studied the field solar evaporation experiment with brine from Dangxiongcuo salt lake in winter. Through investigating the enrichment of the chemical elements in the liquid and the crystallization regularity of the salt minerals, the collecting and distributing behaviors of Li+, B+, K+ were analyzed in detail, and the controlling conditions of salt separating had also been explored according to the enrichment of the chemical elements, the evaporated water, the crystallization order, variety and amount of the salt precipitated during the evaporation process of brine. By referring to the metastable diagram of the quinary system Na+, K+/CO32-, SO42-, Cl--H2O at 25℃, the crystallization paths and precipitation regularities of salts in the process of solar evaporation with brine from Dangxiongcuo salt lake in winter had been drawn. The crystallization sequence of the primary salts from the solar natural evaporation of brine is Halite (NaCl), Natron (Na2CO3•10H2O), Trona (Na2CO3•NaHCO3•2H2O), Borax (Na2B4O7•10H2O), Sylvite (KCl), Zabuyelite (Li2CO3). Some low-temperature products such as Mirabilite (Na2SO4•10H2O) and Natron can be precipitated or entrained within the mother liquor in advance. The brine rich in Li+ can be prepared through the low-temperature evaporation in winter, and the mother liquor at the later evaporation stage can also be used to extract the Borax and the Sylvite. All these provide the foundation for the engineering design of salt field and brine preparation operation technology for the large-scale exploitation of the valuable resource from Dangxiongcuo salt lake.