There were 3 subfacies including delta-front，prodelta and deep lake，and 10 microfacies including underwater distributary channel，tributary bay，channel mouth bar，distal bar，prodelta clay，sandy debris flow，turbidity current，fluidized sediment flow，slump deposit and deep lake mud of the Upper Triassic Yanchang Formation Chang 6₃ interval in Huanxian area by detailed core observation，combined with logging data integrated analysis.A series of sedimentary microfacies profile maps and sedimentary microfacies distribution maps of Chang 6₃ interval show that delta-front subfacies developed in western，northern and northeastern part of the study area，deep lake subfacies including deep lake mud，sandy debris flow and turbidity current developed in central and southeastern part of the study area.The authors firstly proposed that sand sediments can transport from shallow water area to deep water area through a series of water channels on prodelta to form the gravity flow deposit.On the comprehension of above studies，the sedimentary model of study area was established. This paper finally analyses the hydrocarbon potential and points out that underwater distributary channel and sandy debris flow sedimentary microfacies are the best reservoirs in the study area.These sand bodies generally pinch out to form big lithological traps. The study area is the favorable lithologic reservoir exploration target zone.

Based on analysis of gravity anomaly and seismic data, heavy mineral data, clastic rock data and sand body distribution were used to identify the provenance of the Member 2 of Kongdian Formation in Kongnan area, Huanghua Depression, Baihai Bay Basin. Regional Bouguer gravity anomaly field which has important referential meaning for analysis of provenance delineated the topography of Kongnan area. Sand bodies at basin margin and their fan-shaped outlines delineated the macroscopical scope of each provenance. Incised grooves surrounding the depression roughly indicated the locations of the provenances. Progradational reflection configuration on the seismic profiles confirmed the locations of the provenances. Heavy minerals included zircon, tourmaline, rutile, garnet, and magnetite. Heavy mineral assemblages and their variations indicated the directions and routes of detrital materials. Clastics consisted of abundant quartz grains, a small quantity of feldspar grains and little rock debris from the magmatic rock which was the primary source rock type. Located at the directions of southeast, southwest, northwest and northeast of the basin, the provenances were divided into ten sub-provenances at Wumaying, Yesanbo, Shenüsi and so on. These sub-provenances surrounded the lake basin and controlled the formation and distribution of sand bodies during the depositional period of Member 2 of Kongdian Formation in Kongnan area.

A great deal of seismites，which are related with earthquakes，were found in the Yaojia Formation of the Upper Cretaceous，Daqing Placanticline.By observation of cores，two major categories of seismites are identified，which are deformational structures of soft sediments(including liquefaction sand dyke，ball-and-pillow structure，vibration-induced liquefaction structure and load structure)and hard rock(including step micro-fault，autoclastic brecciated structure and structure).These deformational structures can be divided into 7 subclasses.Based on the data of core observation(Well DQ-N1，DQ-N2，DQ-N5，DQ-N7)，the vertical sequence of seismites was drawn，at the same time，different development of seismites in the sedimentary system of delta was discussed.The oil trace，which was found in the step micro-fault(Well DQ-N2)and formation breakdown(Well DQ-N5)，shows that the seismites themselves were a kind of potential reservoir，and seismic activity can efficiently enhance the porosity and permeability of the reservoir and increase new pathways for oil and gas migration.It will provide a breakthrough point to analyze the exploration and development of oil and gas resource.

Sandstone injectites are liquefied and fluidized sand bodies in deep water，which intrude into the surrounding sediments when the hydraulic fracture occurs under certain overpressure formation conditions and some trigger mechanisms.The forming processes associated with the development of sandstone injectites complexs include elevation of pore pressure，hydrofracture of sealing strata liquefaction，fluidization and injection of sand.The formation of pore overpressure is controlled by a number of factors，such as differential compaction，liquefaction caused by earthquakes，injected fluids and transmission of pressure.Once the pore pressure reaches or exceeds the fracture gradient，seal failure takes place，or overburden fracture occurs，which may be caused by earthquakes，and then the sand is fluidized and intrudes into the low permeable rock.Large amount of soft deep water sand bodies，rapid loading of low or impervious sediments，overpressure forming mechanisms and trigger events are necessary to sandstone injectites.

Comprehensively using cores,logging and seismic data,the sequence stratigraphic features and sedimentary facies of the Lower Cretaceous Jiufotang Formation and Shahai Formation in Ludong Sag,Kailu Basin,have been studied systematically.Three 3rd order sequence boundaries and two 3rd order sequences are identified in the two formations.Four kinds of sedimentary facies are identified,including fan delta,proximal turbidite fan,offshore turbidite fan and lacustrine facies.Within the sequence stratigraphic framework,the depositional bodies are researched by using well drilling,logging,2D and 3D-seismic data.Furthermore, the distribution of sedimentary facies and evolution law in system tracts have been researched,and the depositional model of this period was built.According to the model,fan delta dominately developed on the steep slope,while fan delta and beach bars developed on the gentle slope belt,and off-shore turbidite fan and tempestites developed in the deep depression zones in Ludong Sag.

The types of dolostones in the Cambrian in eastern Tarim Basin include mud-sized to silt-sized crystalline dolostone，fine crystalline dolostone and medium-coarse crystalline dolostone.Based on sedimentary characteristics，order degree analysis，carbon and oxygen isotope analysis，strontium isotope analysis，cathodoluminescence and trace elements analysis，four dolomitization mechanisms were proposed for these dolostones，that is，deep water reflux penecontemporaneous dolomitization，evaporative pumping penecontemporaneous dolomitization，reflux seepage dolomitization，and burial dolomitization.Dolostones by different dolomitization mechanisms show different lithological and geochemical characteristics.Deep water reflux penecontemporaneous dolostone is mud-sized to silt-sized crystalline dolostone and occurs in eastern Tarim Basin.It results from penecontemporaneous dolomitization of lime mud by hypersaline sea water，which forms on the adjacent evaporative Tarim Carbonate Platform and flows into the deep eastern Tarim Basin along sea floor.Evaporative pumping dolostone is mud-sized to silt-sized crystalline dolostone and occurs on the carbonate rock platform.It forms in the tidal-flat environments.Reflux seepage dolostone is fine crystalline dolostone and commonly occurs beneath evaporative pumping dolostone and evaporites on the carbonate rock platform.Burial dolostone is medium-coarse crystalline dolostone.It results from dolomitization of limestone in deep burial environments by cyclic formation water rich in Mg²⁺ and Ca²⁺. Mg²⁺ and Ca²⁺ come from the dissolution of previous dolostones，rather than from compaction of shales.

In order to rationally analyze and evaluate the developing and preserving condition of penecontemporaneous dolostone caves related with evaporation in burial diagenetic environment，the petrology and geochemistry of the Middle Cambrian dolomites and their cave fillings in the Keping area，Tarim Basin have been studied in details，and the precipitation conditions of the cave fillings have been recovered.It has been discovered that the cave fillings show obvious generational features.There are at least four generations of fillings from the bedrock to the center of the cave：(1) ivory granular calcite;(2)iron dipped variegated columnar calcite;(3)achromatic transparent quartz;(4)purple fluorite.The analytical data of carbon and oxygen stable isotope，trace elements and REE compositions show that the host dolomite has these characteristics such as high Sr/Ba ratio 5.47，low U/Th ratio -0.2954<0.7，high Zr/Hf ratio 36.86，relatively high total REE，relatively high δ¹⁸O -7.444‰，salinity index Z was 120.56，which show a relatively lower temperature，oxygen rich and relatively high saline environment. The calcite fillings of the first generation has these characteristics such as low Sr/Ba 2.33，high U/Th 1.3>1.25，low Zr/Hf ratio 20.857，moderate total REE，relatively low δ¹⁸O -13.758‰，salinity index Z was 105.35<120，which shows a relatively higher temperature，hypoxia and relatively lower saline environment. The second generation has these characteristics such as relatively low Sr/Ba 2.77，high U/Th 1，in the range 0.75～1.25，relatively lower Zr/H ratio 32.08，moderate total REE，relatively low δ¹⁸O -11.344‰，salinity index Z was 116.51<120，which also shows a relatively high temperature，Oxygen-poor and low saline condition. The fluorite fillings of the fourth generation has these characteristics such as relatively low Sr/Ba 3.15，relatively high U/Th 0.8666，in the range 0.75～1.25，relatively low Zr/Hf ratio 31.875，low total REE，and the REE pattern is similar to that of the magmatic origin fluorite，which also shows a relatively high temperature，oxygen-poor and low saline precipitation condition.The precipitation conditions of cave fillings reflect that this set of strata experienced a process of burial-uplift-and then buried-and ultimately uplifting to the surface after the penecontemporaneous dolomitization.

The dark-gray，middle to thin-bedded dolostone，limestone，siltstone，and gray or black shale and mudstone，deposited in shallow to open lake settings, are mainly developed in the Middle Permian Lucaogou Formation in southern Hongyanchi section of rümqi in Xinjiang. Dolostone which is rich in organic matter is mainly composed of dolomite and ankerite with small amount of calcite and Mg-calcite.The dolomite ranges from 3 to 10μm in crystal sizes and shows homogeneously dark-red luminescence.Micromorphologies of the dolomite vary from microspherules(5～8μm in diameter)，clusters(about 2μm long)，to anhedral dolomite under the SEM.Microspherules have microlaminae structure called “growth coating” which consists of numerous nanoscale particles in the 60000 times enlarged SEM photomicrographs.Anhedral dolomite which is mainly composed of massive particles(about 0.25μm)in 40000 times enlarged SEM photomicrographs shows the features of microbial mineralization.The above morphologies of dolomite are highly similar to the typical modern microbial dolomite in experiment-culture and natural environments.The δ¹³C_PDB value of dolomite ranges from 1.8‰ to 13.8‰，and δ¹⁸O_PDB value ranges from-12.1‰ to-4.1‰.The higher δ¹³C_PDB value may be the result of isotope fractionation led by methane-producing bacteria.The characteristics of micromorphologies and stable isotope indicate that the precipitation of the Middle Permian dolomite had close relation to activities of anaerobic organisms.

The KT-Ⅰ interval carbonate unit of the Upper Carboniferours is composed of a shallow marine carbonate rock with some evaporate strata，which is dolomitized in the Coastal Caspian Sea Basin，Aktyubinsk，Kazakstan.The fine-crystalline dolostone(mud-dominated)with vug porosity is the most important oil reservoir in the KT-Ⅰ interval carbonate unit. Study shows that the KT-Ⅰ interval dolomite is characterized by micrite, silt or fine crystals with subhedral or anhedral form, ordering index of 0.336～0.504, and slight enrichment of calcium. The dolomite contains stable isotopic oxygen composition of -1.06‰～+2.45‰ PDB(average，+0.4‰)，which is positive to sea water(Carboniferous), and carbon composition of +3.36‰～+5.94‰ PDB which is approximate to sea water.Its stable isotopic strontium composition is 0.708 265～0.708 750， which is approximate to that of sea water or evaporative sea water.The trace element content of 92.57 μg/g(average) for Mn，and 447.52 μg/g (average)for Fe of the KT-Ⅰ interval dolostone，are lower than Mn and Fe content in the burial dolostone,while the trace element content of Na,K and Sr are more than those in the replaceable limestone.The above data about the KT-Ⅰ interval dolostone show that the dolomitization was formed in the near surface evaporative condition，which is characterized by seepage-reflux.

The samples of gas hydrate have been successfully obtained by drilling in the Shenhu area of northern South China Sea，it is confirmed that the Pearl River Mouth Basin is a gas hydrate-rich area.By means of quantitative basin modeling research of tectonic subsidence history of deep water area in Pearl River Mouth Basin，tectonic subsidence has been generally characterized by acceleration from north to south and from west to east in the research area since the Late Miocene.From the Late Miocene to Pleistocene，deep water area in the basin experienced the variation process of tectonic subsidence effect that was from weak to strong: The average tectonic subsidence rate was 67 m/Ma in the Late Miocene(11.6～5.3 Ma)，the average tectonic subsidence rate was 68 m/Ma in the Pliocene(5.3～1.8 Ma)，and the average tectonic subsidence rate was 73 m/Ma in the Pleistocene(1.8～0 Ma).Moreover，the major reasons which causing these changes were Dongsha tectonic event from the end of the Middle Miocene to the end of the Late Miocene and Taiwan tectonic event from the Pliocene to the Early Pleistocene: Dongsha tectonic event(10～5 Ma)makes fault block uplifting and sagging，rise area eroding，and waning of movement intensity and structural deformation from east to west，which caused stable subsidence of deep water area in the basin;Taiwan tectonic event(3 Ma)thoroughly changed the tectonic framework of deep water area in the basin，which kept on subsiding and was subsiding more southward because of gravity balance.Overlaying the developed areas of BSR and plane map of tectonic subsidence rate，it was discovered that more than 80％ Bottom Simulating Reflector(BSR) tend to be distributed in the transfer zone between uplift and depression that the average tectonic subsidence rate ranged from 75 m/Ma to 125 m/Ma and changed rapidly.

The evolution of sedimentary facies，X-rays fluorescence analysis of sandstone and mudstone，and petrographic thin section were used in the research on Fankuai and Xiaotangzi sections in Sichuan foreland basin. We found that the sedimentary environment，palaeoclimate，palaeo-salinity and clastic compositions are relevant to the Indosinian movement of the Late Triassic.The tidal sedimentary environment is developed in the early stage of late-Indosinian movement.The warm palaeoclimate and high palaeosalinity are appeared at the same time. During the depositional period of Member 2 of Xujiahe Formation，the depth of sedimentary water is shallow，and the salinity is high，and the climate changes cool.But during the depositional period of Member 3 of Xujiahe Formation，the climate changes warm again and the salinity reduces.After the Anxian tectonic movement, during the depositional period of member 4 of Xujiahe Formation,the salinity is lower than before，and the continental deposits occur in Sichuan foreland basin.The depth of the sedimentary water is shallow and the climate changes cool.The composition of sandstone,controlled by the late-Indosinian movement, shows the evolution of the provenance in front of Dabashan and Longmen Mountains.

To understand the geochemical characteristics of limestone from the Neoproterozoic Wangshan Formation and its geological background， petrological and trace elemental analyses had been carried out for the limestone collected from the Neoproterozoic Wangshan Formation in northern Anhui Province.The results showed that: the elements of U，Pb，Sr，Sm in the limestone are rich，while Nb，Pr，Zr，Hf arepoor; the REE in limestone from the Wangshan Formation are characterized by the lower total REE(6.68～42.78 μg/g)，light LREE depletion(Nd_SN/Yb_SN=0.65～0.91)，slight fractionation between LREE and HREE，and various degree in positive La and Y anomaly.It can be inferred that the ancient seawater is anoxic and high salinity，and the palaeoclimate is drought by the information from U，Th，V，Sr/Ba and Sr/Cu，respectively.The limestone from the Wangshan Formation might be deposited in the continental arc environment indicated by diagrams of the La-Th-Sc and Th-Sc-Zr/10.

The present paper investigated the total sulfur(TS) content，total organic carbon(TOC) content，chloridion ion concentration and pH value in 12 sediment sections(2.5 m long for each)from different geomorphologic units of the southern Changjiang delta plain.The regression line slopes of TS/TOC plots were also calculated for sediments from the lacustrine plain，delta plain，and modern tidal flat.We tend to examine the major factors for sulfur distribution in the Changjiang estuary and assess the feasibility of applying TS-TOC in distinguishing sedimentary environments.The results demonstrate that average values of TS/TOC of sediment sections H2～H8 from the delta plain vary from 0.026 to 0.044.There is a significant correlation between TS and TOC and the regression line slope being 0.027.TS/TOC values are 0.029～0.032 and regression line slope is 0.037 in sediment sections H10～H12 from the lacustrine plain.TS/TOC is much higher，being 0.130 in H9 from the modern tidal flat of the Hangzhou Bay.Regression slope is also significantly higher as being 0.117.For H1 located at the modern tidal flat of Chongming island，the average value of TS/TOC is 0.055 and the regression slope is 0.054.The distribution of TS/TOC and the regression slope of TS-TOC plots indicates that it could be a useful tool to distinguish sedimentary environments in the Changjiang River delta.In addition，the values of TS/TOC and regression slope of TS-TOC plots of the study area are clear lower than those of other brackish coastal deposits，reflecting the characteristics of large river mouth with huge quantity of freshwater and sediment discharge.