Abstract:Abstract：Basin basement is one of the key factors to control basin evolution and its structural deformation. The study of basement is an important way to analyze the basin’s tectonics and structures. The northern part of Tarim basin is in the negative magnetic anomaly,suggesting that the basement is composed of meta-sedimentary rocks. Utilizing the data of zircon U-Pb chronology and geochemistry of Proterozoic schist at the core of Tugerming anticline in Kuqa depression in the north of Tarim Basin, this paper conducted the studies. The results show that zircon 206Pb/238U dating ages are concentrated on 775.3± 5.8 Ma~787.1± 6.8 Ma,which demonstrates that the schist was formed in the early Neoproterozoic,and the basement of northern Tarim basin was formed during Jinning movement. SiO2 content of schist is more than 70%,with high felsic constituents and enriched Al2O3 and K2O；the average value of ΣREE is160 ppm. Chondrite-normalized REE patterns are rightly-oblique,the rocks possess weak Eu anomalies；primitive mantle standardized trace elements characterized by LILE（Rb, Ba etc.）are relatively enriched, while HFSE（Ta, Nb, Ti etc.）are depleted. Through the restoration of the proto-rock, it can be determined that the metamorphic rock is parametamorphic rock formed from a quartz sandstone,which is in good agreement with the negative aeromagnetic anomalies in the north of Tarim Basin. The basement had low rigidity, which resulted in large-scale tectonic subsidence and intense structural deformation in the subsequent evolution of the basin.

Abstract:Abstract：In this paper, the authors have studied zircon U-Pb chronology of the high-grade metamorphic rocks on the northern margin of the Central Tianshan Microplate. The dating results show that the detrital zircons from the meta-sedimentary rocks have recorded the variable magmatic thermal events from Archean to Neoproterozoic (3320 to 530 Ma), the magmatic zircons of the meta-igneous rocks were crystallized in late Neoproterozoic of 550 Ma, whereas the metamorphic zircons were formed in Devonian of 385-360 Ma. These data demonstrate that the Central Tianshan block was probably formed in Precambrian, and subsequently subjected to Varsican orogeny. Unlike the Tarim Craton with multi-stage Proterozoic tectono-thermal events, the Central Tianshan Microplate which occurred as a single continent did not experience the Precambrian metamorphism.

Abstract:Abstract：There are 4 volcanic rock interlayers in the Permian strata of Gudongshan area, southern central Tarim Basin, but there exists no geochemical data and isotopic age constraint on the Gudongshan volcanic rock at present. Based on detailed field mapping and experiments, this paper reports field characteristics, geochemical characteristics, K-Ar dating results and zircon SHRIMP U–Pb dating results of Gudongshan volcanic rocks in the study area and also discusses the possible age and tectonic setting of Gudongshan volcanic rock. The preliminary results obtained by the authors indicate that igneous activities occurred repeatedly in Cretaceous. The youngest igneous activity age recorded by zircon SHRIMP U–Pb dating is Late Cretaceous (80.1 ± 4.3 Ma). The authors hold that the age of Gudongshan volcanic rock should be reconsidered, and is probably Cretaceous. Geochemical data show that Gudongshan volcanic rocks are rich in TiO2, FeO+Fe2O3 and P2O5, and poor in Al2O3, MgO and CaO. Both main elements and trace elements indicate that Gudongshan volcanic rocks are intraplate basalts (WPB) formed in an extensional intraplate setting.

Abstract:Abstract：The late Carboniferous-Early Permian volcanic rocks in Baiyanggou of northeast Bogda orogenic belt mainly consist of sub-alkaline basalt and andesite, in which large quantities of pillow laves are excellently preserved. Pillow lavas are mainly basic lavas, whose SiO2 content is 46.65% to 52.50%, Al2O3=13.10%～16.44%，MgO=4.62%～7.89%，TiO2=1.23%～2.79%，CaO=7.06% ～13.07%，Na2O=2.76%～4.99%，and K2O=0.07%～0.89%. A group of basic lavas is enriched with large ion lithophile elements (LILE) such as Rb and Ba, and the other group is relatively depleted in LILE. In the N-MORB diagram, high field strength elements (HFSE) have significant negative anomalies of such elements as Nb and Ta. In the chondrite-normalized REE patterns, lavas show right-oblique curve with overall performance of flatness and slight enrichment of light rare earth elements (LREE); δEu=0.89～1.12. The composition of Sr-Nd-Pb isotopes shows that lavas have characteristics of the depleted mantle：εNd(t) =+2.8～+3.1, 143Nd/144Nd(i)=0.512407～0.512422, εSr(t)=-14.0～-17.5, 87Sr/86Sr(i)=0.70293～0.70317, 206Pb/204Pb(i)=17.622～17.835, 207Pb/204Pb(i)=15.374～15.463, and 208Pb/204Pb(i)=38.163～38.339. In the tectonic setting diagram, Baiyanggou volcanic rocks have the characteristics of MORB and WPB. The comprehensive regional geological data and the results of previous studies have led the authors to conclude that Late Carboniferous-Early Permian volcanic rocks of the study area might have been derived from the depleted mantle during the closure of the back-arc basin in the active continental margin of Paleo-Asian Ocean.

Abstract:Abstract：Located at the junction part between the Tianshan orogenic belt and the Tarim craton, Kuruktag area in Xinjiang is a key area for the study of the relationship between the Central Asian orogenic belt and the Tarim craton. According to structural and micro-structural investigations and Ar–Ar dating of Kuruktag area, the authors have reached the following conclusions: (1) Sinian–Early Paleozoic cap rocks were deformed obviously at the bottom with dense cleavages dipping gently northward, but they were deformed slightly at the top with sparse cleavages steeply dipping northward, forming southward spread spade-shape structural style in NS direction. (2) A decollement exists between the cover rocks and the basement stretching in EW direction with a width of 2 km, characterized by “A” type folds, mylonites, gentle mylonite foliation, whose stretching lineation plunges northwest or southeast. Studies of asymmetrical rotational structure and crystallographic preferred orientations of quartz in mylonites (EBSD analysis) indicate a movement of the hanging wall of the ductile decollement in SE direction. (3) Ar–Ar dating result of the muscovite in the mylonite from the ductile decollement shows that the decollement was formed earlier than 383 Ma. The decollement was a product of the intercontinental subduction after the collision event between the Tarim block and the Central Tianshan magmatic arc, and it means the existence of the early Paleozoic orogenic event in Kuruktag area on the northeast margin of Tarim Basin.

Abstract:Abstract：Anjihai volcanic rocks in northern Tianshan are composed of pyroclastic rocks and lavas, which include andesite crystal tuff, andesite detritus crystal tuff, dacite welded tuff, basaltic andesite and rhyolite, thus being of calc- alkaline series. Major and rare earth element compositions of basaltic andesite and rhyolite are as follows： SiO2=51.03%,77.33%, TiO2=0.76%,0.16%, CaO=10.30%,0.43%, MgO=5.19%,0.89%, Na2O=2.10%,1.27%, K2O=1.28%,2.54%, ∑REE=369.1ppm,729.0ppm, (La/Yb)N=5.0,3.5, (La/Sm)N=2.7,2.4 and δEu=0.82,0.54. The primitive mantle normalized spider diagrams of volcanic rocks are characterized by depletion of HFSE (Nb, Ta, Ti and P) and enrichment of K, Rb, U, Th, Zr and Hf. One significant difference is that Sr and Ba display insignificant positive anomalies in basaltic andesite and distinct negative anomalies in rhyolite. Isotope geochemical characteristics of basaltic andesite and rhyolite show the following values： εNd(t)=0.2,0.1, (87Sr/86Sr)t=0.70680,0.70476, (143Nd/144Nd)t=0.52224,0.51225, (206Pb/204Pb)t=17.775,17.720, (207Pb/204Pb)t=15.790,15.826 and (208Pb/204Pb)t=38.240,38.876. LA-ICPMS zircon U-Pb dating of rhyolite yielded the age of 310±2 Ma. Rhyolite was fractionated from the magma of basaltic andesite. The primary magma of volcanic rocks occurred in continental intraplate stretching setting, derived from asthenosphere (or plume)-generated continental basaltic magma, which was contaminated by lithosphere as well as upper and lower continental crust. Crystal temperature and pressure of phenocryst clinopyroxene are 1176.4℃ and 4.13 kpa respectively, equivalent to the depth of 16.7km. It is thus inferred that pyroxene phenocrysts were crystallized slowly from contaminated continental basaltic magma in middle-upper crust, and subsequently moved quickly to the surface of the earth, due to continental crust stretching.

Abstract:Abstract：Researches on the ultrabasic and basic rock belt in the Kuzi Mountain on the eastern margin of eastern Southern Tianshan in Xinjiang have been very insufficient; however, the genesis and the formation of the geological setting of this rock belt is of important significance for the tectonic framework of Southern Tianshan. This belt consists of wehrlite，diabase and gabbro. The olivines in wehrlite are forsterite, whose Fo is about 93-96; the accessory mineral chrome spinel has Cr#=Cr/(Cr+Al)×100 values of 75.6-98.8 and Mg#=Mg/(Mg+Fe)×100 values of 1.8-41.4, suggesting a high chromium, low magnesium and Alaskan-type complexes in the orogenic belt. The pyroxenes in diabase are augites, whose Mg#=Mg/(Mg+Fe)×100 values show a continuous trend of evolution in decreasing order, reflecting differentiation of magma; The feldspars are composed of labradorite and andesine. The pyroxenes in gabbro are augites, the Ab values of feldspars are above 95, indicating albite. The values of K2O and TiO2 are high, and LILE content is obviously higher than HFSE content. It is considered that they are intrusions of the same orogenic belt as the wehrlite. Isotopic chronology suggests that the magmatic event might have continued from Carboniferous to Permian (331-286 Ma).

Abstract:Abstract：The helium isotopic composition of each sphere of the Earth has its characteristic isotopic ratios. These ratios show significant differences. Therefore, helium isotopes, as a tracer, are more sensitive than other isotopes to distinguishing crust from mantle materials. Up till now, geochemical behaviors of helium isotopes during the HP-UHP metamorphism have not been well studied, it led to the limited application of helium isotope in eclogites. Many HP-UHP eclogite belts have been discovered in China. These eclogites can be genetically classified into two types： one is associated with subduction of the continental slab, and the other is formed by the subduction of the oceanic slab. This paper reviewed the progresses therefore of HP-UHP eclogite facies metamorphic rocks well studied and some problems and future work of the application of helium isotope in eclogites are also discussed.

Abstract:Abstract：The structural deformation of paleo-uplifts in the cratonic basin is an ideal place to explore the deformation behaviors in the interior of the tectonic plates and the continental ductile structural geology, with the study of faulting being a breakthrough point in this aspect. Based on the newly acquired geophysical data and the recently finished exploratory wells, this paper discusses the fault systems of the north Tarim uplift of the Tarim basin, especially the geometry and kinematics of the northern boundary fault of Tarim basin. It is discovered that the Wensubei-Yeyungou fault acts exactly as the northern boundary fault, having distinct reflections in the gravitational and magnetic fields as well as along the seismic profiles. It is 600 km in length, and is composed of three segments from west to east, i.e., Wensubei fault, Wenbashi fault, and Yeyungou fault. It was first produced at the end of Early Ordovician, resulting from the breakthougth at the front limb of a large fault-related fold system caused by the subduction of the thrust fault into the basement ductile detachment zone from the south to the north. It took its shape at the end of the Caledonian movement. By the end of Permian period, responding to the strong compression from the north, the southward thrust tectonic system not only took the shape of the former detachment zone, but was also superimposed upon and modified the former Caledonian thrust tectonic system, giving rise to a large-scale anti-form thrust system consisting of a series of small-scale fault blocks, and made the whole fault zone take its shape finally. During the Himalayan movement, the tensile-torsional fault system was developed along the axial zone of the north Tarim uplift. The Wensubei-Yeyungou fault zone was subjected to sinistral transpression, and the re-activation was propagated from the east to the west. Hence it was characterized by prolonged evolution, multi-stage development, inheritance, superposition, and compounding. It had a marked trend of a strong-weak-strong evolution process, namely, the activity was strongest in the early Paleozoic, became weakened or calm in the Mesozoic-early Cenezoic period, and got stronger once again in the late Cenezoic. The faulting in the western segment was possibly much stronger than that in the eastern segment. Its formation was largely related to the collision between the Tarim continental block and the peripheral terrains due to the closing of the North Kunlun Ocean at the end of the early Ordovician, the closing of the South Tienshan Ocean at the end of Permian, and the closing of the Neo-Tethyan Ocean in the Paleogene respectively. These phenomena suggest the important influences of the adjacent plate tectonic events upon the intra-plate deformation. The fault zone seems to be an important oil and gas accumulation zone. The study of the mechanism and evolution is helpful to the expansion of hydrocarbon exploration in the area, as evidenced by the discovery of oil and gas resources in the Xiqiu anticlines.

Abstract:Abstract：The construction and reformation of carbonate platform are controlled by many factors. This paper has mainly discussed?the development and destruction of the carbonate platform under the control of fault activities. There are mainly two types of fault systems developed in Tazhong area, namely the NW-trending basement-involved fault system and the NE-trending cap rock decollement fault system. The former was mainly developed during Caledonian I episode tectonic movement in Late Early Ordovician, and it controlled the tectonic framework which had been formed when the Tazhong uplift started its formation and changed the carbonate platform from the early ramp-ramp-edge type to the isolated reef type. The latter was mainly formed during Mid-Caledonian II episode tectonic movement in Late Ordovician, and its strong activity led to the tilting movement of Tazhong area and, as a result, the eastern uplift started its reformation, which seriously destroyed the carbonate platform formed earlier.

Abstract:Abstract：The tectonic belt in the northeast margin of Tarim Basin is composed of Tianshan area of Xinjiang and most Beishan area of Gansu-Inner Mongolia border. The collision zone between Early Paleozoic Tarim Plate and Kazakhstan Plate extends from Aqikekuduke fracture zone eastwards to Sihbanjing-Xiaohuangshan ophiolite complex. The region experienced extensive magmatic events during Jinning Movement (800 Ma), and Siberian Plate, Kazakhstan and Tarim Plate once collided and connected with each other over Rodinia super-continent. The pieces broken by paleo-continent of Nanhua-Sinian period, block faulted area of Kazakhsta and Tarim Plate were dispersed into the paleo-Asian Ocean in the form of a multi-island group. The peri-continental area had features of bay sedimentary area in Sinian-Cambrian period, and was broken into a rift zone along Huaniushan-Wufengshan-Zhangfangshan line in late Ordovician period. The crust plate of paleo-Asian ocean subducted southwards along the Weinanya-Jijitaizishan-Baiyunshan-Yueyashan-Xichangjing line, forming Gongpoquan island-arc zone and arc-rear basin of Hongliuhe-Niujuanzi-Jianquanzi line. In late Silurian, granitc magmatic activities were active at the beginning stage of collision. Devonian period saw the main collision stage, during which the magmatic thermal event affected the rising orogenic belt, and the volcanic-mollasse foreland basin was formed in the south margin of Tarim Basin.

Abstract:Abstract：The ΔTa high aeromagnetic anomaly zone lying in the central part of Tarim Basin has been a focus in discussing the composition and structure of Tarim basin and its basement. Based on a comprehensive analysis of borehole and seismic data, the authors have found that there exist large-scale seismic reflection anomaly bodies in Middle-Upper Ordovician strata of Manjiaer depression, which are related closely to the Central High Aeromagnetic Anomalies Zone (CHAAZ) and constituted mainly by eight nearly EW-trending seismic reflection anomaly bodies. The stratigraphic and seismic facies analysis shows that these seismic anomaly bodies should be igneous rocks. The anomaly bodies have vertical downward channels in seismic profiles, which are related to faults and magmatic activity channels. The CHAAZ of the basin is a product of multi episodes tectonic activities, suggesting the development of Manjiaer depression in an extensional tectonic setting in Sinian and Late Ordovician.

Abstract:Abstract：(1) There exists relatively weak left-lateral ductile-shear deformation in addition to right-lateral ductile-shear deformation in the northern Central Tianshan ductile shear zone, with local remnant late Caledonian thrust nappe ductile-shear deformation; the temperature environment of the right-lateral ductile-shear deformation is medium-low temperature, while the temperature environment of the left-lateral ductile-shear deformation is high, medium, medium-low and low temperature. (2) The southern Central Tianshan shear zone is dominated by right-lateral ductile-shear deformation together with some left-lateral ductile-shear deformation; the temperature environment of the right-lateral deformation is medium, medium-low and low temperature, whereas that of the left-lateral ductile-shear deformation is high, medium, medium-low and low temperature. (3) There exist a series of right-lateral ductile shear zones in eastern Tianshan Mountaions, and the tectonic deformations in northern and southern margins of central Tianshan Mountains might be genetically related to the deformation of such right-lateral ductile shear zones as Xingeer fault and Xingdi fault, the deformation of late Sinian-early Paleozoic syn-cleavage folded deformation in the eastern part of northern Tarim basin and the deformation of Devonian strata in southern Tianshan Mountains.

Abstract:Abstract：The Early Cambrian（corresponding to Terreneuvian and Series 2）is an important sedimentary period of marine source rocks in Tarim area．Researches on the framework of ocean and continent in Tarim area will help estimate the potential resources of the rocks．Based on previous studies，the authors investigated and analyzed 13 outcrops and 10 borehole sections，and consulted some seismic sections．By means of an analysis of stratigraphic and petrologic characteristics，the map for oceanic and continental framework and tectonic-sedimentary environment of Tarim area was compiled．It is pointed out that the area around Tiemenguan was a micro-landmass．The authors consider that both Tiemenguan micro-landmass and North Kuluketage underwater platform belonged to North Tarim passive continental margin．Furthermore，the authors divided the Tarim epeiric sea basin into different sedimentary environment areas on the basis of new data．

Abstract:Abstract：The Middle Cambrian (corresponding to Stage 5，Drumian，Early Guzhanqian of Series 3) is an important sedimentary period of gypsum-halite rocks in Tarim area. Researches on paleogeography and sedimentary environments of Tarim area will help recognize the reservoir and distribution regularity. Based on previous studies, the authors investigated and analyzed 13 outcrops and 17 borehole sections, and consulted some seismic sections. By means of an analysis of stratigraphic and petrologic characteristics, the paleogeographic framework was rebuilt and a tectonic-sedimentary environment map of Tarim area was compiled. Some conclusions have been reached：（1）The paleogeographic pattern in Middle Cambrian period inherited the characteristics of Early Cambrian, but the South Tianshan Ocean, North Kunlun Ocean and Kuluketage-Manjiaer bathyal-deep sea basin were enlarged, and the areas of Tarim epeiric sea basin was reduced in Middle Cambrian. （2）Because the climate of Tarim area was xerothermic in that period, the evaporative platform of 23×104 km2 was formed. Gypsum-halite rocks hundreds of meters in thickness were deposited in an evaporative environment, which provided high quality caprocks.

Abstract:Abstract：The outcrops of Keping area in Tarim basin,where the lower Silurian depositional sequence is continuous and perfectly exposed, constitute a preferable study area for marine clastic deposition. However, depositional system types of the lower Silurian sediments deserve further discussion. Based on detailed outcrop observation and laboratory tests, the authors analyzed the lower Silurian depositional system types and their characteristics in Keping area. As a result, deltas and clastic coast systems composed of tidal flat and offshore were detected, and river-dominated deltas and tide-influenced deltas were recognized from the Lower Silurian strata in Keping area. Large scale river-dominated delta systems are developed in Kepingtage Formation, whereas tide-influenced delta systems and tidal flat systems are developed in Tataertage Formation. On such a basis, the depositional characteristics and differences of various depositional systems are studied and compared with each other.

Abstract:Abstract：The Cambrian-Ordovician dolomite in Tarim basin is characterized by old age, deep burial and complex diagenesis. The space of the dolomite reservoir is mainly composed of pores and cracks. The pores can be further divided into such types as intercrystal pores, intercrystal dissolved pores, intracrystal pores, moldic pores and dissolved holes, while the cracks can be further divided into satures, weathering fractures and structural fractures. According to the characteristics of reservoir space, dolomite reservoirs can be divided into four kinds, i.e., pores, vuggies, fracture-pores and fractures, in which pore and fracture reservoirs are better than others. Based on the origin, dolomite reservoirs can be divided into three types, namely syngenesis, burial, structure-hydrothermal solution and weathering-crust corrosion, among which the last two types and their combinations often formed high quality reservoirs.

Abstract:Abstract：The Ordovician Yinshan Formation in Tarim basin has been regarded as the focus layer for breakthrough in oil and gas exploration. Through comprehensive use of cores, slices, logging, analytical and test data and three-dimensional seismic data, the authors analyzed the reservoir characteristics and influencing factors of Yinshan Formation. Some conclusions have been reached： the lithology of Yingshan Formation is generally composed of fine-grained dolomite,calcarenite and limy dolomite, whereas the reservoir space comprises mainly dissolved pores and cracks; the top of the Formation is the weathered crust reservoir with the development of dissolved pores and cracks, while the lower part of the Formation is the fractured reservoir, whose space is mainly cracks; in vertical direction, the upper part is mainly composed of pores and cracks, whereas the lower part comprises mainly cracks with strong heterogeneous nature; the tectonic unconformity formed in the first episode of the middle Caledonian tectonic movement seems to have been the important factor responsible for reservoir development; the faults and tectonic fractures formed during the middle Caledonian tectonic movement and the Early Sea West tectonic movement were the key factors for the reservoir development; during the early Permian period, the karst baking associated with volcanism and the burial dissolution exerted a positive effect on the reservoir development

Abstract:Abstract：This paper has analyzed the natural gas components, carbon isotope composition and natural gas genetic types of the Hetianhe gas field, with the emphasis placed on the differences between the eastern part and the western part. Studies show that methane content of the natural gas is extremely high, mainly in the range of 64.19%～86.86%，being 79.36% on average; C2+ content is 0～3.75%; the dry coefficients vary in the range of 95.52～99.4，97.34 on average; CO2 content is high. There exists remarkable difference in natural gas conditions between the eastern part and the western part, resulting mainly from multi-period accumulation, reaction of TSR and westward migration. As for the genesis of the natural gas, there are oil-cracked gases in the eastern part, with the Ma 2 well being mixed gases of the oil-cracked gases and the kerogen-cracked gases, whereas kerogen-gases are dominant in the western part.

Abstract:Abstract：The attributes of reflection seismic data are closely related to the ultimate goal of oil and gas exploration. The utilization of the oil and gas accumulation-related code concealed in the attributes of reflection seismic data to detect oil and gas is a new technology for oil and gas detection. Where oil and gas occur, there exist local unconventional variations in seismic attributes, and the prospecting for the differences in such variations is a means for oil and gas detection. This means provides the basis for geophysical evaluation of oil and gas traps. The test in the Tarim oilfield shows that the analytical technology for detecting the variations in oil and gas attributes is effective. It is suggested that oil and gas detection and trap evaluation be conducted prior to oil and gas drilling so as to reduce risks and raise the success rate of oil and gas exploration.

Abstract:Abstract：The prospecting extent in the whole Bachu uplift of Tarim Basin is relatively low, which however is a potential area for oil and gas exploration. The poor near-surface shooting conditions, deeply buried target areas and deep geological conditions result in the serious seismic data static correction problem, highly-developed interference wave, difficulties in correct recognition of multiple wave, improvement of the energy of deep reflection wave and accurate obtaining of the velocity and migration imaging. Low S/N ratio data and poor quality have greatly restricted the capability of solving the geological problem by using seismic data. Through an analysis of newly acquired seismic data, the authors accurately built a near-surface model for calculating accurate static values and enhancing pre-stack attenuation. Various amplitude energy compensation methods were used for accurate velocity analysis to improve the precision of the velocity field, and inner mute was adopted in near traces. Integrated application of cascade methods was adopted to eliminate multiple interference, migration method was chosen for improving the imaging quality of deep weak signal and S/N ratio in this low S/N ratio area and, as a result, event continuity and structure imaging quality were greatly enhanced and improved, thus attaining superior applying results.

Abstract:Abstract：The analysis and processing of 12-second deep reflection seismic data obtained from Bachu to Tazhong in Tarim basin show that, in NS direction, the basement is gradually uplifted from He-3 well through Hetian-1 well to He-4 well, with the basement becoming deeper from He-4 well southwards; in EW direction, the basement of Bachu uplift is relatively shallow, and becomes deeper at Tazhong. Through processing, the authors have found that, besides commonly seen reflection structures of T4-T9 layers, effective reflection can also be seen in the deep layers beneath the basement. Based on preliminary interpretation and geological analysis, the authors hold that the processed profile has good continuity of phase axis, high signal-to-noise ratio and homing accuracy and reliable deep reflection information. The tectonic framework reflected by the profile is clear and of fairly large scale. The authors’ work has confirmed the underground structure along the deployed survey line of the work area, and also revealed structures or structural manifestations which had not been detected by previous researchers, thus enriching the understanding of the structural characteristics and structural evolution in this region.

Abstract:Abstract：Using data collected from an 750-kilometer-long seismic array and receiver function method, we obtain an image of the crust and upper mantle along the Hotan-Baicheng section across the Tarim basin. In the image, Hotan depression, Markit slope, Bachu uplift, Awat depression, Tabei uplift, Kuqa depression and the boundary faults of these blocks are clearly seen. The crust is divided into six layers that are Neogene-Quternary deposition, Sinian-Paleogene deposition, upper crust crystalline basement, mid-crust low density layer, lower crust high density layer, and lower crust low density layer. Generally, the density increase with depth, but two layers are abnormal. The density of the mid-crust is lower than the upper crust crystalline basement, and in the lower crust the density of the lower layer is lower than the upper layer. The mid-crust low density layer is a discontinuous 3~9-km-thick layer, at about 25 km depth. The lower crust low density layer is a continuous 5~10-km-thick layer, at about 45km depth. The depth of Moho is 40~50 km in the northern basin and 50~60km in the southern basin. The depth of the underside of lithosphere is 75~85 km. The lithosphere mantle of the Tarim block underthrust the West Kunlun block, but does not the crust. It indicates the decoupling between the crust and the mantle. In the north of the Tumxuk fault, the North Tarim block is deformed weakly. In the south, the South Tarim block is deformed intensively. The Hotan-Markit-Bachu block is whole and deformed intensively. The five large decollements or thrusts cause imbrication and shortening of the lower crust. But, the sedimental covers deformed very little indicating that the deformation in the South Tarim block had occurred before Sinian or Devonian. Since Neogene, these large decollements or thrusts became active again.

Abstract:Abstract：Located in Qingshuiquan area neighboring the southern Altun UHP metamorphic belt, the Qingshuiquan mafic-ultramafic intrusion consists of three to four magmatic cycles and exhibits the features of layered mafic-ultramafic intrusion. LA-ICP-MS U-Pb isotopic dating of zircon from hornblende gabbro in the intrusion with Th/U ratios of 0.32~1.16（0.64 on average）and magmatic oscillatory bands was conducted, and the results show that its age is 467.4±1.4 Ma (MSWD=2.5), which is younger than the age of UHP metamorphic rocks (504~487 Ma) and older than the age of A-type granites (~425 Ma) in southern Altun orogen. Meanwhile, the distribution of bimodal magma intrusion at ~465 Ma and contemporary metamorphic thermal events in southern Altun area suggest that the southern Altun orogen was in the tectonic stage of post-collision rifting or extending at ~465Ma.

Abstract:Abstract：Wonderful Hexagonal columns (columnar joints) of Cretaceous High Island Formation (Kkh) volcanic rocks make up the key landscape of the Sai Kung Volcanic Rock Region in southern Hong Kong National Geopark, but whether they belong to lava or pyroclastic rock has been disputing. On the basis of field geological investigation and rock thin section observation, these volcanic rocks are determined to be a specific lava—rhyolitic porphyroclastic lava which is characterized by common columnar joints, porphyroclastic & pearl-rim textures of phenocrysts, and felsitic texture & flow structure in groundmass. They are not only the latest Mesozoic products in Hong Kong but also constitute a large central extrusive facies dome within the Sai Kung Caldera. This porphyroclastic lava dome is inferred to be the largest one (～150 km2) so far known in the world, and its residual parts after long-term erosion are current landscape which can be seen in the Sai Kung Volcanic Rock Region.

Abstract:Abstract：In consideration of the poor hydrocarbon exploration of the study area，the authors firstly studied the petrologic characteristics and reservoir characteristics，and divided diagenesis into two types on the basis of an analysis of diagenesis and diagenetic sequence，and then conducted the quantitative analysis of the E1t1上and E1t1下 separately，which developed the porosity evolution model and deepened the understanding of the reservoir formation procedure as well as the influencing factors. The result shows that the porosity evolution features were controlled jointly by the sedimentary environment，material source，parent rock properties of the provenance，diagenesis，and tectonic process.

Abstract:Abstract：Bottom sediments from the Songhua River were analyzed to determine the total content and distribution patterns of 16 main polycyclic aromatic hydrocarbons (PAHs). The PAHs concentrations vary from 226.86 to 10079.68 ng·g-1, with the mean value being 2230.04 ng·g-1. The 4～6 rings PAHs possess 61.6 %, whereas 2～3 rings PAHs possess 38.4%, suggesting the derivation of PAHs mainly from pyrogenic (coal, oil, natural gas and wood) burning in the Songhua River. Petroleum sources only exist in the downstream of the Nenjiang River in Qiqihar City and the main stream of the Songhua River in western Zhaoyuan County. For evaluating the potential ecological risk of PAHs in the Songhau River, the potential ecological risk of PAHs was assessed on the basis of Effects Rang-Low (ERL), from low ring to high ring. There are components containing more PAHs than the ERL in the upstream and downstream of the Second Songhua River in Jilin City; Nap, Ace, Fl in the Nenjiang River of southeastern Tailai County and DBA in the Songhua River in Bayan County are higher than the ERL too. It should be noticed that such high levels of PAHs in the bottom sediments will result in potential ecological risk for the environment.