Abstract:Abstract： Researches on tectonic formation, evolution and subdivision in China have had a history of more than 100 years. There are several kinds of opinions concerning the tectonic subdivision of China, which are based on different sorts of epistemology and methodology regarding the formation and evolution of the continental crust. Tectonic subdivision blueprints guided by “three mainstream tectonic views” include Mr. Huang Jiqing's polycyclic tectonics, Mr. Wang Hongzhen's historical tectonics and Mr. Li Chunyu's plate tectonics. The ideas of these researchers have been playing a guiding role in this field and hence have had extensive and profound influence in China. Nowadays tectonic subdivision seems to be the key to the research on micro-structures of plates in that it is not only a theoretical problem in the study of plate tectonics but also a practical problem which must be solved immediately so as to help perform studies in such aspects as regional geology, metallogenic prognosis and mineral resources evaluation. In this paper, the tectonic subdivision is based on records of stratigraphic division and correlation, sedimentary formation, volcanics formation, intrusive magmatism, metamorphism and deformation, and consistent with the classic division theory of “three mainstream tectonic views” in China. Guided by theories of plate tectonics and earth dynamics, based on the requirements of metallogenic regularity and mineral energy resource prognosis, and following the main line of spatial-temporal structure analysis of tectonic facies environment of different-sized stable ancient continent block domains and different episodic orogenic systems, the authors have divided the tectonic environment of China into continent block domains and orogenic systems, which include nine first-order tectonic units and fifty-six corresponding second-order tectonic units. As there are a number of major tectonic problems in China that remain to be solved in future, a prolonged painstaking efforts are still needed for more accurate subdivision.

Abstract:Abstract：According to rheological behaviors of the lithosphere, the authors have divided the lithosphere of China into three layers. i.e., elastic upper crust, plastic lower crust and lithospheric mantle, and pointed out that they have different structures and complicated relationships. In the Xinjiang area, four basins and three ranges were formed by thrusting and overlapping in the upper crust, overlain on a series of EW-striking antiforms and synforms of the lower crust. The uplifting of the central part of the Tibetan plateau was as a whole caused by the hydraulic pressure due to the partial melting of its lower crust and lithospheric mantle, but the uplifting of the border parts is of the differential nature. In North China, the upwelling of ashenosphere material destroyed lithospheric mantle and formed a mushroom cloud structure in which the new-born mantle and the residue mantle existed side by side, and grabens occurred in the elastic upper crust. There exists no evidence for the subduction of the Pacific plate under the continent of China, except for things in a limited area of northeast China. The violent deformation of eastern China was produced by the upwelling of ashenospheric materials instead of by the subduction of the Pacific plate. So the tectonic forces nowadays in China constitute a dual system which includes the subduction of the Indian plate in the west and the uplifting of the ashenosphere in the east. The boundary of the two different tectonic forces is the north-south seismic belt. To the west of the north-south seismic belt, the lithosphere is under a compression regime, whereas to the east of the north-south seismic belt, the lithosphere is under an extensional regime. The reason for the seismicity of North China is that the elastic crust of this area was thinned by strong geothermal activity, which resulted in the considerable lowering of the elastic limit.

Abstract:Abstract：The Taihu thrust system in eastern Hunan was defined in this paper on the basis of geological and borehole observations. The NE-trending thrust system is composed from northwest to southeast of such structural elements as frontal thrust fault (Luosiqiao fault), frontal belt of nappe and upper decollement structure, low ramp (Tiepuao-Longfengqiao hidden fault) and back belt of nappe, back-thrusting fault (Zhongwan fault), and rear syncline. There occurs Qingdong reversed syncline to the northwest of the frontal fault. The axial trace of the rear syncline shows an arc bulging to the northwest, and there also exist Yajiangqiao domal uplift and Indosinian Yajiangqiao pluton in the middle segment of the syncline. The midpoint of the Qingdong syncline, the bulging part of the arc rear syncline and the center of the Yajiangqiao pluton (or the Yajiangqiao domal uplift) lie on a NW-trending line coinciding with the long axis of the Yajiangqiao pluton. Based on these geological characteristics and using structural correlation analysis, the authors put forward the formation mechanisms of the Taihu thrust system, the Yajiangqiao domal uplift and the Yajiangqiao pluton as follows: Under the NW(W)-trending compressive stress during the Indosinian movement, deep and shallow detachment and thrusting took place along the low ramp, resulting in the formation of the Taihu thrust system. There also existed a middle belt extension from the Qingdong syncline to the Yajiangqiao pluton where compression and slip were more violent than the two sides when the thrust body moved northwestward. This led to the formation of the Yajiangqiao domal uplift and, controlled by back hauling, made the axial trace of the rear syncline bulge to the northwest. More intense compression-shearing and crust-thickening existed in the Yajiangqiao domal uplift, and accordingly the temperature of the deep crust rose. These factors caused the melting of the deep crust with the magmatic intrusion, and the Yajiangqiao pluton was formed with the weakening of the stress after strong compression. The Taihu thrust system gives some constraints on Mesozoic tectonic evolution in South China.

Abstract:Abstract：There occur Neoproterozoic granitic bodies in Yueyang-Pinjiang area, northeast Hunan. Zircon SHRIMP U-Pb dating of the granite from Zhangbangyuan pluton was performed, yielding an age of 816±4.6 Ma. The rocks are lightly basic with an average SiO2 content of 70.25%, have low potassium and high calcium with an average CaO content of 2.38 %, and contain poor alkali with an average Na2O+K2O content of 5.97 % and the feature Na2O＞K2O. The ASI values are 0.97～1.29 with an average of 1.16. Thus the granites are of the magnesian peraluminous calc-alkaline series. Rb and Th are rich, while Ba and Nb are poor. The rocks have low ΣREE values with an average of 130 μg/g, (La/Yb)N values of 6.76～8.50, δEu values of 0.54～0.78, εNd (t) values of -1.5～1.6, T2DM ages of 1.35～1.60 Ga, and δ18OV-SMOW‰ values of 8.1～11.1. According to the above data, the granites should belong to I-type or ACG formed by crust-mantle magmatic mixing, and the main source was derived from the depleted mantle with the participation of a small amount of crustal matter. Geochemical characteristics suggest that the granites are of the island arc volcanic system, and derived their materials from magmatism in the convergent margin of the plate instead of from mantle plume magmatism. Hence they cannot serve as the indicator of Rodinia Breakup.

Abstract:Abstract：Based on a detailed analysis of the Kaerqueka polymetallic ore deposit in Qimantage area of Qinghai Province, the authors consider that the granodiorite is closely related to the Fe-Cu-Pb-Zn skarn polymetallic mineralization. A petrological-geochemical study and SHRIMP zircon U-Pb dating of the granodiorite show that the granodiorite is composed of intermediate-acid rocks of the high-potash calc-alkaline series. The rocks are characterized by obvious fractionation of REE, enrichment of LREE, δEu values of 0.61~0.91 that indicate a weak negative Eu anomaly, high LILE (such as Rb, Th, K ) and depletion of Nb, Sr, Ti. 15 data points from SHRIMP zircon U-Pb dating show that the age is (237±2)Ma (MSWD=0.8), suggesting that the granodiorite was formed in Middle Triassic. Based on a combined study of geochronology, petrological geochemistry and evolutionary characteristics of regional structures, the authors hold that the granodiorite was formed at the post-collisional development stage in the continental orogen.

Abstract:Abstract：A set of Late Triassic acid-intermediate-basic volcanic rocks in Songsainong area is composed of basalt, andesite, dacite, rhyolite and a small amount of pyroclastic rocks as well as some other components. In the volcanic rocks, SiO2 values are in the range of 48.89-88.15% (67.44% on average), TiO2 vary between 0.22 and 1.85% (0.63% on average), and MgO range from 0.23 to 7.81%, similar to things of island arc calc-alkaline volcanic rocks. High field intensity elements such as Nb, Ta, Zr, Hf and Ti are depleted, large-ion lithophile elements like Rb, Sr and Ba are relatively concentrated, (La/Sm) n are 1.79-5.19, and LREE/HREE ratios vary mostly in the range of 4.08-6.63, suggesting a light REE enrichment type.δEu values are 0.47-0.99, Eu assumes negative anomalies, La/Nb ratios are mostly higher than 2.00, Nb/Zr> 0.04, Th/Ta> 4.41, and Th × Ta/Hf 2> 0.042, implying a margin of the volcanic arc. The above characteristics show that Late Triassic volcanic rocks in Songsainong of Zhidoi area were mostly produced in an environment where mainland collision and epicontinental arc are coexistent.

Abstract:Abstract：Multiple-layer Ordovician carbonate reservoirs have been discovered in the western plunge of Guchengxu uplift, Tarim basin, and it is important for the petroleum exploration workers to analyze characteristics and controlling factors of the reservoirs. Based on well core data and logging curves, the authors identified many kinds of reservoirs in the study area. Combined with structural evolution and karst system in the study area and compared with reservoirs in Tahe area, it is believed that the original porosity and fractures constituted the fundamental prerequisites for the formation of secondary pores, and the fractures caused by structural movement seemed to be crucial to the accelerated growth and development of karst and reservoirs. The karst reservoir grew under the depth of 6300 m in the western plunge of Gechengxu uplift. To effectively predict the karst carbonate zones, the authors also employed such technologies as amplitude variation and coherent cube analysis, which yield satisfactory results.

Abstract:Abstract：According to a comprehensive analysis of the macroscopic, microscopic and geochemical characteristics of the Qixia Formation reservoir, the major constructive diagenesis has syndepositional periods of dissolution, buried dissolution, tectonic uplift dissolution, mixed water dolomitization, buried dolomitization and recrystallization, of which the buried dissolution and the buried dolomitization seem to have made the greatest contribution to the reservoir space in that the intercrystalline pores, intercrystalline dissolution pores, dissolved holes and slits in them constitute the main reservoir space. Recrystallization possesses the second importance. Recrystallization did not make much contribution to the reservoir space, but it enhanced the effective porosity and permeability of the rocks, thus provided conditions for later dissolution. Nevertheless, the syndepositional dissolution pores have almost completely disappeared due to subsequent pore compaction, cementation and other damages.

Abstract:Abstract：The Lower Triassic Feixianguan Formation in northeast Sichuan can be divided into two third-order sequences and six system tracts in terms of sedimentary facies and sequence interfaces. Characteristics of sequence stratigraphy of the Feixianguan Formation were analyzed and sequence-palaeogeography maps were compiled. It is indicated that, influenced by regional tectonic uplifting of the Late Permian Changxing Stage in the study area during the development of SQ1 sequence, the product was formed in a regional slow transgression-regression depositional environment. The seawater that had been once deep and open became shallow, the depositional evolution changed from basin facies to open-platform facies which almost formed the platform edge or inner oolitic bank. In the second deposition of the third-order sequence cycles (SQ2), due to arider and hotter climate, sea level falling and water cycle limiting, the sedimentary facies turned into the restricted platform and evaporate platform facies, and the oolitic bank disappeared gradually. Finally, the sedimentary facies was converted to evaporate platform in which gypsum dolomite was developed. The gypsum dolomite served as an important sealant in the Feixianguan Formation, and the brine saved in the same time was helpful to the burial dolomitization in the oolitic bank to form high quality reservoirs in the Feixianguan Formation.

Abstract:Abstract：For the purpose of obtaining more comprehensive geological knowledge and providing contrast to other areas, the authors studied the Cambrian strata exposed in the Western Hill area in the aspects of sequence stratigraphy and sedimentology. In the Western Hills, Cambrian strata are composed of many carbonate rock types comprising various kinds of limestone and dolomite. In accordance with the principles of sequence stratigraphy and the working methods, combined with sequence characteristics of interfaces between the Cambrian strata, the authors defined sixteen major third-order depositional sequences：SQ1-SQ3 for type I and much more (SQ4-SQ16) for type II. The Cambrian sedimentary strata in this area are typical sediments of stable platform. As Cambrian strata were deposited in the littoral area characterized by gentle topography and stable tectonic subsidence, deep valleys and other deep-cut phenomena are not very obvious, and deposits of lowstand system tracts (LST) or shelf marginal system tracts (SMST) are not found in all sequences.

Abstract:Abstract： Dashanpu of Zigong City in Sichuan Province is world-wide famous for its dinosaur fossils, particularly the concentrative burial of a large quantity of dinosaurs. The cause of their concentratrative burial remains a problem of much controversy. Based on an analysis of such characteristics of the strata in the Zigong Dinosaur Museum and its surrounding areas as the lithofacies, depositional environment, shape of sandstone, and deposition background, this paper deals with the taphonomic environment of dinosaur faunae in Dashanpu and the cause of their concentrative burial. The authors consider that dinosaur remains were buried in frontal river mouth sand bar of lacustrine delta after their depth due to an unknown cause and river transport of their bodies instead of being buried in situ after their death due to poisoning.

Abstract:Abstract：Platinum-group element (PGE) contents and distribution patterns of different mantle peridotites from ophiolite masses (blocks) are to some extent different. Relative to things of the primitive mantle, PGE in Langcuo and Dongpo masses don't show distinct anomalies. The curves of primitive mantle-normalized distribution patterns are approximately even, and there exists no strong fractionation between PPGE and IPGE. On the whole, the PGE characteristics are similar to those of mantle peridotites from Xigaze, Alps and Eastern Mediterranean regions. However, PPGE contents of Dangqiong masses vary in a wide range and don't show a strong fractionation between PPGE and IPGE. PGE contents and distribution patterns of clinopyroxenite dykes differ greatly from those of the mantle peridotite：Os, Ir, Ru and Rh are depleted whereas Pt and Pd are enriched. The pattern curve declines to the left. These characteristics suggest that clinopyroxenite dykes were probably formed by the high degree of partial melting as well as melting segregation. PGE contents of chromitite are high and vary in a very wide range of 19.7-5526 ppb. The average ∑PGE (729.33ppb) is equal to 25.6 times its value in primitive mantle. Os, Ir, Ru and Rh are enriched but Pt and Pd have experienced both enrichment and depletion as compared with their values in the primitive mantle. The pattern curves are scattered and decline to the right. There exists a strong fractionation between IPGE and PPGE, and Pt in most of samples assumes negative anomalies. These characteristics are similar to those of chromitite in ophiolites from China's Luobusha, Greece, Yugoslavia, Cyprus and some other regions in the world. PGE contents of chromitite are not related to base metal sulfides (BMS) contents in the same samples. PGE don't mainly exist in BMS. It is thought that PGE mostly occur in platinum-group element minerals (PGM), which remain to be investigated and found in future.

Abstract:Abstract：At present, Re-Os isotopic dating of molybdenite is one of the direct ways to acquire the ore-forming age. Using TJA X-series ICP-MS, the authors dated five molybdenite samples collected from the Chilu molybdenum deposit and obtained model ages. The results show that the ore-forming age is about 105-106 Ma, quite close to the emplacement age of porphyritoid granite, adamellite and feldspar graphic granite (115±4 Ma, Rb-Sr isochron age), which are intimately related to the ore-forming processes in this area. This indicates that they are all products of late Yanshanian magmatism. The above outcome provides direct evidence not only for the research of late Yanshanian magmatism and mineralization in the Pucheng-Ningde NW-trending ore belt but also for the comparative study between the Pucheng-Ningde ore-forming belt and the Shanhang-Yuenxiao ore-forming belt, thus contributing to mineral exploration in these two belts.

Abstract:Abstract：Hydrothermal alteration is caused by fluid-rock interaction in the migration process of the ore-bearing hydrothermal fluids. The hydrothermal alterations of the Qianhe gold deposit might be divided into seven types, namely potash feldspathization, propylitization, sericitization, silicification, pyritization, carbonation and fluoritization. The alteration-mineralization process and the alteration zones can be divided respectively into six stages and three zones, in order of botite-potash feldspar stage→propylite stage→phyllic stage→pyrite-quartz stage→quartz-pyrite stage→carbonate-halide stage, forming outer, central and inner zones. Analyses of major and trace elements for five typical altered rocks indicate that, during phyllic alteration, Si, K, Pb increased considerably and HREE concentrated a bit with the slight decrease of REE. Negative anomalies of δEu and δCe were present in each alteration-mineralization stage. These factors might be responsible for gold precipitation. The metasomatic characteristics of fluid-rock interaction at every ore-forming stage are also reflected in chemical composition variation of chlorite.

Abstract:Abstract：The Zhuyuangou ore deposit is a large-sized tungsten-molybdenum deposit discovered in recent years in East Qinling area. Its geological features were studied in this paper on the basis of the geological background. The distribution of ore bodies is related to folds, fractures, lithology and intensity of wall-rock hydrothermal alteration in the ore district, and the ore bodies are controlled by the Huangbeiling anticline and the endo-exocontact zones of the northwest-pitching Shibaogou porphyritic adamellite intrusive. The ore deposit is genetically of the porphyry-skarn type. Ore-searching criteria and prospects are indicated in this paper, which are of some significance for further ore-searching work.

Abstract:Abstract：The Yangpingwan gold deposit was found after the discovery of the Huanglong and Luming gold deposits in the northern Shiquan-Hanyin area of the Qinling orogenic belt. The study of regional gold prospecting and gold metallogeny is of great importance. Geological and geochemical characteristics were studied in this paper through field investigation and laboratory experiment. Gold mineralization occurs in schist of the Lower Silurian Meiziya Formation (S1m). The northern and southern ore-forming belts which contain three ore bodies have been delineated. Gold mineralization is characterized by silicon and pyrite. Gold exists mainly as visible gold between mineral grains or in cracks. Gold mineralization is controlled by schist strata intercalated with quartzite layer and shearing structure. Metallogenic temperature of fluid inclusions is 170-220℃, suggesting mesothermal-epithermal mineralization. D and O isotopes show that ore-forming fluids were derived from precipitation and metamorphosed water. S values vary in the range of 7.5‰-11.7‰, implying that metallogenic materials came from strata. Geological and geochemical characteristics indicate that the Yangpingwan gold deposit is a sedimentary-reformation type deposit formed at middle-low temperatures.

Abstract:Abstract：The experimental results of fluid inclusion microthermometry, material constituents, H-O isotopes and ore-forming fluids in the Daxigou gold deposit suggest that there exist three types of fluid inclusions in the ore deposit, namely gas inclusions (V type), gas-liquid inclusions (V-L type) and liquid inclusions (L type). Fluid inclusions occur in vein quartz, with their homogenization temperature, salinity, fluid density and ore-forming depth being 175～275℃, 2%～7%, 0.804～0.959g/cm3 and 1.01～2.24 km respectively. The gases in fluid inclusions are chiefly composed of H2O and CO2. As for liquid composition, the cations are mainly Na+ and subordinately Ca2+ and K+, and the anions are mainly comprised of SO2-4 and Cl- with minor amounts of F-. The δ18O H2O values of quartz from the ore-forming fluids range from 2.1‰ to 5.8‰, and δD values from -87‰～-103.67‰, indicating a mixed source of magmatic water and atmospheric precipitation. The gas fugacity determinations show that Au was transported in the form of complex compound [Au（HS）2]- in the ore-forming fluids. In addition, the mixing process and the hydrothermal alteration contributed to gold deposition and concentration.

Abstract:Abstract：Geothermal resources are very rich in the geothermal field of eastern Liaocheng, Shandong Province. Geological-structural conditions and geothermal reservoirs there are relatively favorable for the exploitation of these resources. Based on drilling data and recent research results, the author considers that the Liaocheng geothermal field belongs to the karst fissure layered conductive type, with the regional geological structures being mainly composed of Liaokao fault and Chiping fault, and the hot reservoir chiefly comprised of limestone strata of Ordovician Majiagou Formation. The geothermal gradient of the area is controlled mainly by structure, the structural heat conduction is a key factor for the formation of this area, the mineralization intensity of the geothermal water is low, and the geothermal water contains some useful mineral components. Some suggestions concerning the reasonable development of geothermal resources and some policies for solving problems in current exploitation work are also put forward in this paper.

Abstract:Abstract：The clay minerals and major elements of two basaltic weathering crusts and a tuffaceous crust in the Weizhou Island and the Xieyang Island were identified and measured by means of X-ray diffraction and X-ray fluorescence analysis. The results show that 7×10-10 m halloysite is the main constitutent in the clay minerals of every weathering profile, and goethite and hematite are also extensively existent. This suggests that these weathering crusts are in a fairly high degree of weathering. The abnormal variations of chemical indicators in surface weathering profiles and the existence of secondary calcite in one of the profiles imply the effect of compound alkalization on the weathering crust. Underground water has also made these profiles considerably different from the normally-developed weathering crust. Tropical monsoon climate has remarkably controlled the development of weathering crusts, but the specific compound alkalization of the island and the underground water have also exerted their influence on the development of the weathering crusts.

Abstract:Abstract：Sanghe area is an important oil-bearing zone in the Baiyinchagan Sag. Oil exploration in the Baiyinchagan Sag has been carried out for many years, but fundamental geological data of Sanghe area remain insufficient. Based on a comprehensive analysis of core and logging data, regional geological setting, sedimentary facies types of the 1st Member of Lower Cretaceous Duhongmu Formation in Sanghe area of Baiyinchagan Sag, the authors made a systematical study of their distribution and evolution characteristics. The results show that three types of sedimentary facies are developed in this area, namely fan delta, lacustrine fan and slump turbidite fan facies. From the margin to the center, the granularity of sediments becomes finer and the facies are gradually developed from fan deltas or shore-shallow lake to semi-deep lake. The same evolution regularity is observed from the bottom to the top. Based on an analysis of clastic particle types and heavy minerals of the sandstone, the authors hold that the sediments of the 1st Member of Duhongmu Formation in Sanghe area must have come from Bayinbaolige swell situated in the north of the Baiyinchagan Sag, with the characteristics of multiphase, spasm and being adjacent to the source rocks. The results also suggest that the source rocks are mainly sedimentary rocks and subordinately igneous rocks as well as small amounts of metamorphic rocks.

Abstract:Abstract：Three debris flow gullies, i.e., Sunjia, Muchang and Yangjuan, are distributed along the mountains behind Luding County seat, Sichuan Province. In the past years, debris flows frequently occurred and serious damaged and threat Luding County seat. In this paper, the distribution of debris flow gullies and some disaster events are described, their formation conditions such as solid materials, landform and rainfall are analyzed, and their occurrence characteristics are discussed in the aspects of time, space and magnitude. On such a basis, the countermeasure system against debris flows is established, and some corresponding prevention advices are put forward.

Abstract:Abstract：Based on the alteration mineral information derived from the ASTER data, combined with a typical ore-prospecting model, the authors studied the ore prognostic method that utilized the data-driven model and remote sensing data obtained from Yanyuan area, Sichuan Province. Different logical models were used to analyze alteration mineral abundances and oxide contents on the basis of such means as Bool logic, overlay index and fuzzy logical method. As a result, the prospecting target was delineated, and the interpretation result was well verified in field work.

Abstract:Abstract：Groundwater is the main source of water supply in many cities of China. Excessive exploitation of groundwater has brought about lots of environmental problems, such as groundwater level declining, land subsidence, and land crack. Research on the groundwater level early-warning system plays an important role in the development and utilization of groundwater resource. This paper suggests a groundwater level early-warning system based on the numerical model for Linfen basin. The result of the research provides a scientific basis for the sustainable utilization of groundwater resource.