Abstract:Migration pathways of gas have close relationship with migration and accumulation of natural gas hydrate. Based on high resolution quasi-3D seismic data, and combined with practical drilling results, the authors studied the geological and geophysical features of gas migration pathways and their controlling effects associated with high saturation gas hydrate in GMGS3 drilling sites of Shenhu area. The results show that multiple types of migration pathways are developed in high saturation gas hydrate drilling sites in GMGS3 drilling area, which have favorable corresponding relation with BSR in space. Enhanced reflections occur closely beneath the BSR, and gas charging phenomena are obvious under the enhanced reflection, indicating migrating pathways exist under the gas hydrate stability zone and deep gas has migrated to shallow formations through those pathways. Deep faults, mud diapirs, gas chimneys act as vertical migrating pathways that connect deep thermogenic gases with shallow biogenic gas and pressuretemperature stability zones, and gas hydrate can be formed and accumulated just over those pathways. Shallow slump surface and high continuous sand bodies composed of channel sandstones and submarine fans provide lateral migrating pathways for the migration of shallow biogenic gas and partial thermogenic gas from deep formations, which expands the range of gas supply and increases the gas hydrate distribution scales. It is concluded that tectonic structures and regions with favorable coupling relationship between hydrocarbon migrating system and other elements are prospective targets with high saturation gas hydrate.

Abstract:Integrated investigation has revealed that the northern slope of the South China Sea (SCS) is a favorable place for gas hydrate accumulation and hence has stored a large amount of hydrate resources. Natural gas hydrates are mostly developed in areas of complex tectonic activity which are also areas of high-risk geological disasters. Potential hazard geological factors constitute great threats to the storage and commercial exploitation of gas hydrate. Based on a large number of 2D, 3D seismic profiles and multi-beam data acquired by the Guangzhou Marine Geological Survey over the years in the gas hydrate development zone in the northern part of the South China Sea, the authors conducted the seabed disaster geological study on the northern slope of the South China Sea. In this paper, the geomorphological features, the types, characteristics, genesis and distribution characteristics of the geohazards related to gas hydrate in the study area were comprehensively analyzed. The relationship between the geohazards and hydrate formation and decomposition was also discussed. The results of the study were used to predict the mineralization of gas hydrates on the northern slope of the South China Sea, thus providing a data basis for future disaster risk assessment and decisionmaking.

Abstract:With the global economic development, almost all countries are faced with a serious strategic resource crisis, and the exploitation of deep-sea mineral resources including polymetallic nodules has become a reasonable and effective way to solve this problem. With the progress of China's ocean survey, it is necessary to review the progress, status and future of polymetallic nodules resources. Deep-sea polymetallic nodule resources have attracted much attention among experts all over the world because they are the most widely distributed and most abundant metal resources in the sea floor. The occurrence of bacteria in manganese nodules is recognized and there is a general understanding that their activity may influence the formation of manganese oxide minerals.However, whether microbial activity just modifies Mn nodules or whether their activity is essential for nodule formation is still a matter of debate. The importance of metals contained in polymetallic nodules for the world economy is reflected in their patterns of consumption, their availability as primary or by-product ores in land-based deposits, and their use for merging high-and greentech applications. The research on polymetallic nodules should be carried out effectively so as to make China the leader in this field.

Abstract:The southern margin of South China Sea (SCS) has abundant hydrocarbon resources. Based on high-resolution 2D seismic data, the authors conducted the research on various focused fluid flow systems and their seismic response, implications for hydrocarbon accumulations with the purpose of understanding the characteristics and their relations with hydrocarbon. Diverse focused fluid flow systems were identified, such as mud-diapir/mud-volcano, gas chimney, pipes and the focused flow fluid related fault. Different seismic characteristics are shown for these focused fluid flow systems, which include gas-bearing high-amplitude anomalous field, low-amplitude chaotic reflection, and "drop-down"/"arch up" reflections considered to be recognition marks of focused fluid flow systems that appear frequently. Focused fluid flow systems were affected by tectonic movement and sedimentation factors and were closely related to the deep high temperature and high pressure plastic fluid. Focused fluid flow systems were preferentially developed in the weak part of the strata. Focused fluid flow systems and associated faults and fractures were often used as transport channels for hydrocarbon accumulation zones. Moreover, the strong dissolved fluid and deep hydrothermal fluid transported by the fluid movement system were beneficial to the formation of reservoirs, especially the carbonate reservoirs. Focused fluid flow systems not only served as migration passage of hydrocarbons but also could improve reservoirs. Therefore, they are of great significance for hydrocarbon accumulation.

Abstract:The Jurassic strata in the Chaoshan sub-basin of northern South China Sea have great potential for oil and gas exploration, and the sedimentary characteristics have obvious effect on the development of the reservoirs.Based on analyzing the latest seismic data of the study area, the authors recognized four typical seismic reflection interfaces and three seismic reflection layers and, according to the result of the sequence interface, figured out the Jurassic distribution and residual thickness. On the basis of the comparative analysis of the transformation of seismic facies-sedimentary facies, the authors determined the sedimentary facies types and distribution characteristics of the Jurassic strata in different periods and reshaped the sedimentary evolution history of the Jurassic sediments in the Chaoshan sub-basin. The study area has mainly developed five sedimentary facies and eight kinds of sedimentary subfacies, and the coastal delta front subfacies and deepwater middle-fan subfacies have controlled the development of high-quality reservoirs of the debris flow sandstone separately. In addition, the turbid sandstone reservoir is mainly controlled by the sediment supply, the more closer to the delta sand body leaves, the more the number of slump turbidite, and the larger the area. In general, the front subfacies of the delta, the subfacies of the deep water fan and the gravity flow slip turbulence constitute the facies of high-quality reservoirs in the study area. The reservoirs are fairly favorable for oil and gas accumulation due to the deep burial and the mudstone cover.

Abstract:There have existed three transgression-regression events and sedimentary evolution processes by sea level changes since late Pleistocene in the southern coast of Laizhou Bay, Bohai Sea. It is obvious that a multi-source fluvial delta sedimentary system may be more dominant for the sedimentary environment. Based on previous researchers' survey and collected data, the authors carried out research work such as division of sedimentary units, sedimentary facies analysis and stratigraphic division and correlation, with the purpose of establishing sedimentary stratigraphic framework of the Laizhou Bay. Besides, the authors focused on analyzing the sedimentary processes of the Laizhou Bay since Late Pleistocene. It is concluded that the main provenance of borehole 07 is Bailang River and the Yellow River, which have played an important role in the multi-source fluvial delta sedimentary system of the southern coast of Laizhou Bay since Late Pleistocene. The evolution can be divided into two glacial periods and three interglacial periods, corresponding to three transgression events and two regression events in Laizhou Bay since late Pleistocene. By geochemistry and provenance analysis, sediments have the characteristics of generation, segment and correlation. In 124.6-72.0 ka B.P., 60.0-24.4 ka B.P. and 10.2-4.0 ka B.P., there occurred three warm-wet periods, respectively corresponding to Cangzhou transgression, Xianxian transgression, and Huanghua transgression; In 72.0-60.0 ka B.P. and 24.4-10.2 ka B.P., which were two dry and cold periods, there was a continental sedimentary environment, corresponding to Wurm early glacier age and Wurm late glacial age. During the transgression period, there always developed littoral-neritic facies in marine area, which was gradually transitional to delta and fluvial facies in the land field, with sediments showing retrogradation superposition pattern. Contribution of short runoff rivers (Bailang river) was reduced gradually from land to sea. During the regression period, fluvial and delta facies were formed in most areas of Laizhou Bay. Terrigenous input of short runoff rivers increased, with sediments showing progradational sequences. From late Pleistocene to Holocene, the region went through sedimentary evolution of neritic facies-delta-continental facies-tidal flat-neritic facies-delta-continental facies.

Abstract:The Lower Cretaceous strata constitute the most important oil and gas exploration horizon at present in the Eastern Subbasin of the North Yellow Sea. Accurate understanding of the Lower Cretaceous sedimentary characteristics is very important for the further strategic exploration and optimization of exploration deployment. According to drilling, well logging and seismic data and by means of paleontology, geochemistry and geophysics, the sedimentary facies types in the study area were analyzed. The sedimentary environments of paleoclimate, paleo-salinity, paleo-hydrodynamic force and provenance were studied. Finally, the sedimentary filling and evolution characteristics of the Lower Cretaceous period were discussed under the third sequences stratigraphic framework. The results show that the fan deltas and lucustrine facies were developed in the Lower Cretaceous. This period was dominated by subtropical hot and semi-arid climate, characterized by shortage of warm and humid climate. The ancient water bodies were fresh and brackish. The provenance was from north, east, southwest and some other directions. The early stratigraphic distribution of Lower Crataceous was limited, and the sedimentary facies were dominated by shore shallow lake and fan delta interbedding. After that, the lake water bodies expanded, and the sedimentary sequence of fan delta plain, fan delta front and shore shallow lake developed vertically. In the middle and late stage, influenced by the regional uplift and denudation, the strata remained only in the northwestern part of the basin, and the sedimentary facies were dominated by shore shallow lake.

Abstract:Located in the eastern part of Taiwan, the Tongao schist belongs to the northeast part of Tailuko belt and is composed of chlorite epidote schist, chlorite albite schist, mica quartz schist, quartz schist, and mica schist intercalated with graphite mica schist layer. Based on geological survey in combination with petrologic as well as major and trace element analysis, the authors hold that the original rocks were basalt, foidite or alkaline basalts and terrigenous clastic rocks. The rocks are mainly of alkaline series characterized by low Ba, high Sr and Pb, generally low total rare earth, and REE distribution patterns with features of LREE enrichment and no loss of europium. These features are similar to features of terrigenous rifting (magmatic) volcano-sedimentary rock combination. Zircons can be divided into three types, i.e., euhedral or sharply angular, subangular, and rounded ones. LAICP-MS U-Pb zircon ages have multiple peaks, in which there are four ²⁰⁶Pb/²³⁸U ratios; the minimum value is (95 ±3)Ma,representing euhedral zircons or sharply angular zircons and indicating late Cretaceous volcanic activity; the remaining three values are 118±2 Ma (Early Cretaceous), 160±5 Ma (Late Jurassic), and (250±3) Ma, Early Triassic), representing subangular and small euhedral zircons and indicating the magma age of corresponding source rock; there are two ²⁰⁷Pb/²⁰⁶Pb surface peak ages, i.e., 1838±41Ma and 2404±27Ma (Paleoproterozoic), representing rounded metamorphic zircons or magmatic zircon and indicating the age of Paleoproterozoic metamorphic basement. The Tongao schist was formed during the late Cretaceous in the Eurasian continental margin tectonic environment, being a product of volcanic-sedimentary activity.

Abstract:Hangou monzonitic granite porphyry body lies in northern Xiaoshan Mountain, western Henan Province. Petrogenetic research on Hangou rock body is important for recognizing tectonic evolution in northern Xiaoshan Mountain area, and it is also significant for estimating mineralization potential. The zircon U-Pb dating method of LA-ICP-MS was used to confirm the age of biotite monzonitic granite porphyry sample named LLHG01 from Hangou rock body. The results of 20 zircon spots are consistent with ²⁰⁷Pb/235U-²⁰⁶Pb/²³⁸U trend line, with ²⁰⁶Pb/²³⁸U ages being from 142 Ma to 147 Ma, and weighted average age being (145.1±0.7) Ma. Hangou rock body is characterized by higher SiO₂ and alkali, enrichment of K₂O, and lower MgO and CaO. Compositional spots of Hangou rock body fall into high-K calc-alkaline series in the SiO₂-K₂O diagram, and it belongs to K-rich calc-alkaline granite (KCG). In chondrite-normalized REE patterns, Hangou rock body samples have shown the characteristics of LREEenrichment and HREE depletion with trivial Eu positive anomaly, whose (La/Yb)_N ratios are from 10.41 to 11.51. Samples from Hangou rock body are enriched in large ion lithophile elements and depleted in high field-strength elements, which has formed troughs of Nb, Ta and Ti in spider diagram. Samples of Hangou rock body have higher Sr and lower Y and Yb, suggesting that Hangou rock body is adakite. According to the content of Na₂O and K₂O, Hangou rock body is C-type adakite. Hangou rock body originated from partial melting of the thickened lower crust, and its residual phases of partial melting source included garnet and rutile, with no plagioclase. North Xiaoshan Mountain area underwent the process of lithosphere delamination of different scales in~145 Ma and~130 Ma, and Hangou rock body is a product of smaller scale lithosphere delamination that occurred at~145 Ma. The formation age of Hangou rock body falls into the time interval of~145 Ma stage of acid magmatism and endogenetic mineralization in western Henan Province. In the disaster process of lithosphere delamination in Hangou area, huge deep fluids were driven and discharged rapidly, suggesting that Hangou rock body and its concealed part have large mineralization potential. There are 11 Au deposits and Au mineralization spots around Hangou rock body, which constitute the best exploration evidence.

Abstract:The research on Lower Yangtze block in Yeshan area of Chuzhou is very insufficient. Previous researchers held that Jinniu rock mass belongs to marginal facies of Yeshan pluton. In this paper, the authors studied Jinniu pluton. Zircon U-Pb dating indicates that The Jinniu pluton of Yeshan area of Lower Yangtze block was formed at 129±2 Ma, suggesting a product of Early Cretaceous. Zircon Hf isotopic composition has relatively uniform negative εHf(t) values(-2.82——6.52) and old Hf isotopic crustal model ages (1360-1600 Ma). The Jinniu pluton is alkaline(σ:5.08-5.74)), metaluminous rock body(A/CNK:0.803-0.844), which is characterized by relatively strong differentiation between light and heavy rare earth elements, indistinct negative Eu anomalies, enrichment of LREE and LILE, and depletion of HREE and HFSE. Comprehensive comparative study of the Yeshan rock mas shows that the Jinniu rock mass and Yeshan rock mass belong to two different sources of the same period. Regional tectonic evolution characteristics and geochemistry of rocks and Hf isotope characteristics indicate that the source of the Jinniu rock mass seems to have been a mixed product of underplating water-rich basic magma from enriched lithospheric mantle and partially melted ancient lower crust due to the subduction of Paleo-Pacific Plate.

Abstract:A suite of Mesozoic strata is exposed in the Xiehe' rside area of Horqin Right Wing Middle Banner, Inner Mongolia. The lithological association is mainly composed of acidic pyroclastic rock and pyroclastic sedimentary rock intercalated with clastic sedimentary rock and acidic volcanic lava. Based on the fossil woods discovered in the upper layer of the strata by 1:50000 regional survey, the authors hold that the formation time is middle-late Jurassic. Combined with the lithological association, the authors assigned the strata to the Upper Jurassic Manketouebo Formation. In order to accurately redefine the stratigraphic age and provide a basis for the study of the age of fossil woods and the regional biostratigraphic.correlation, the authors collected zircon testing samples from the acidic pyroclastic rock in the horizon lower than that of the fossil woods, and determined that the zircon U-Pb age is (165±1) Ma, belonging to middle Jurassic. In addition, the age of the porphyritic fine-crystalline grained diorite which invaded the strata was obtained, and the zircon U-Pb age is (131±1) Ma, which defines the upper age limit of the strata. According to the regional correlation of lithological associations, dating results, time of fossil woods assemblage,and characteristics of attitude of strata, the authors conclude that the strata should be assigned to Middle Jurassic Xinmin Formation and constitute a part of the filler of Tuquan volcanic-sedimentary basin.

Abstract:The geochemical study of metamorphic rocks of the Kanas Group in Altay tectonic belt shows that the metamorphic rocks are mainly argillaceous sedimentary rocks, with small amounts of sandy sedimentary rocks, Source material is mainly of acidic continental arc volcanic rocks mixed with a small amount of other debris. Although there are differences in lithology between 16 samples, the chemical etching of the variable indexes (CIA) is almost all less than 75, indexes of compositional variation (ICV) are close to or higher than 1, indicating that the source region must have experienced a warm, humid conditions of moderate chemical weathering and the maturity was poor, being the first deposition product of active continental margin. The La, Ce, ∑REE, LREE/HREE, sigma delta Eu values of the metamorphic rocks indicate that the protolith formed in a continental arc setting. These geochemical characteristics suggest that the Kanas Group metamorphic rocks probably deposited on an active continental margin of continental island arc environment. It is inferred that Kanas Group sedimentation and metamorphism occurred between 550±18ma to 430Ma and, according to the corresponding time, the metamorphism of the Kanas Group took place in Caledonian.

Abstract:The Kanling lead-zinc deposit is one of the typical lead-zinc deposits in south Tianshan orogen, Xinjiang. It is located in the Kalpin uplift belt on the northwestern margin of the Tarim plate. Geological survey and isotope studies show that the host rocks of the deposit with epigenetic genesis are Upper Cambrian-Ordovician carbonate rocks, and the orebodies exhibit veined, stratoid and lenticular forms, mainly controlled by the fault and strata. Galena and sphalerite are the main ore minerals, with weak wall rock alteration. The characteristics of the sulfur isotope (in the range of -1‰-12.2‰) imply that the sources of sulfur was mainly derived from the deep mantle and sedimentary strata, the Pb isotopic composition of the ore is more homogeneous, and the ²⁰⁶Pb/²⁰⁴Pb ratios range from 17.262 to 17.269, ²⁰⁷Pb/²⁰⁴Pb from 15.571 to 15.675, and ²⁰⁸Pb/²⁰⁴Pb from 38.062 to 38.396; the ore-forming metals were mainly derived from the sedimentary strata as compared with the Pb isotopic characteristics of the ore and the host rocks. Geological and geochemical characteristics of the deposit indicate that the Kanling lead-zinc deposit is a MVT deposit, which is hosted in the platform carbonate rocks.

Abstract:Erlian basin has rich coal, oil, natural gas and uranium resources, but the targeting and breakthrough of the prospecting for sandstone-type and sedimentary uranium deposits remain a focus in uranium resources exploration of this basin. Hurenbuqi depression is a subordinate depression on the Bayinbaolige uplift in the northern part of Erlian basin, which is a relatively independent geological tectonic unit. It deposited thick Mesozoic-Cenozoic strata above the Paleozoic basement. The Lower Cretaceous Saihan Formation deposited a set of fan delta-lacustrine coal-bearing clastic rocks. The burial depth of the strata is fairly shallow, the thickness is stable, the mud-sand-mud structure is developed, the sand body is especially well developed, and the rock has black and gray primary geochemical characteristics. Using the new idea of employing the data of coalfield drilling for second-round development of uranium resources, the authors conducted comprehensive research on the coalfield logging data collected from a certain area on the northwest margin of the basin and, as a result, delineated large-scale and continuous radioactive anomalies in the Lower Cretaceous Saihan Formation, showing a good prospecting prospect. Through a systematic study of tectonic conditions, stratigraphic facies, lithology, palaeoclimate, geomorphology, and palaeohydrology, the authors chose uranium anomaly holes in the coalfield to make drilling verification and found a uranium ore hole with the industrial significance. Two stable uranium mineralization layers were found in the Saihan Formation. The first layer is controlled by the phreatic oxidation zone, is located in the mudstone at the bottom of the interface of the phreatic oxidation zone, and belongs to the vertical oxidation type mineralization type. The second layer of uranium mineralization is a mudstone formation, and belongs to the typical interlayer oxidation type. The authors finally point out the direction of the next exploration work.

Abstract:Kalatag area of Xinjiang is located in the east Tianshan metallogenic belt, where mineral resources are abundant, and copper, gold and polymetallic ore deposits have great prospecting potential. Copper and gold mineralization and surface mineralized alteration phenomena are obvious, and limonite mineralization + jarosite + sericitization assemblage has formed abnormal spectral reflectance characteristics, which are favorable for the utilization of hyperspectral remote sensing ground-air integrated prediction method to detect copper and gold mineralization alteration information. In this paper, the authors carried out air high spectrum and ground spectrum in search for copper gold polymetallic deposits. HyMap aviation imaging spectrometer and FieldSpec Pro FR spectrometer were adopted and, as a result, HyMap aviation high spectral resolution data, ground quasi-synchronization calibration data and ground hyperspectral data were obtained in the study area, whereas extracting and filtering were conducted based on HyMap aerial hyperspectral image of metallogenicl favorability alteration information. On such a basis, the air-ground hyperspectral comprehensive analysis was made for the Hongshan copper and gold deposit in the study area and, in combination with the geological background of the deposit, a hyperspectral remote sensing ground-air integrated prospecting model was established for the Hongshan copper gold deposit. On the basis of comparison and analysis, two prospecting targets were delineated. The application of hyperspectral remote sensing ground-air integrated prediction method in the study area shows a good application effect.

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