The research progress in the origin of salt rocks of the Shahejie Formation of Paleogene in Dongpu Sag has been summarized， which mainly includes two parts. One aspect is the studies on salt deposition mechanism， including two contrasting viewpoints “salt deposited in deep water” and “salt deposited in shallow water”. The former， mainly based on sedimentology， paleontology， structural geology， and so on， considers that the salt is deposited in a certain waterdepth， and the brine delamination is a basic form of salt sedimentation. In contrast, the latter， mainly based on sedimentology， considers that the salt is the result of continuous lake evaporation. The other aspect is the studies on the source of salt rocks， which includes seawater from marine transgression， deep subsurface hot brine and surface fresh water. The evidence for the former one includes paleontological fossils， and the other two are supported by geochemical analysis and inferation. There are six main problems in studies of origin of salt rocks in the Paleogene Shahejie Formation in Dongpu Sag. The brine delamination model is just a hypothesis in explaining salt sedimentation in the Dongpu Sag. The evidence of “salt deposited in shallow water” is not adequate. There are great differences in explaining the same phenomenon between the two viewpoints of salt formation. It is not clear whether the quantity， distribution and analytical results of the samples truly represent the features of salt rocks in the Dongpu Sag. The marine fossils should be further identified. The channels of marine transgression remain unclear. Finally， the authors put forward that three methods can be applied to research the origin of salt rock of the Paleogene Shahejie Formation in the Dongpu Sag， which include numerical simulation of doublediffusive convection， geochemical analysis and sedimentological studies.
The Chang 8 oilbearing interval of the Upper Triassic Yanchang Formation in the northwestern Ordos Basin was deposited in a stable tectonic setting and was mainly controlled by the northwestern sedimentary systems. During its deposition， shallow water delta was developed. The shallow water environment markers， such as coal seams， plant leaves and foots， worm holes， and so on， were widely distributed in the cores indicating the relatively shallow water during its deposition(several meters to over ten meters). The Chang 8 oilbearing interval was dominated by shallow water delta front subfacies and subaqueous distributary channel was the dominant microfacies. In comparison to the typical fluvialdominated delta， the delta in the study area is characterized by its wide distribution， the gently connecting of delta plain with delta front and prodelta on the plain with no obvious transition. The delta front can be divided into the inner front and outer front deposits. The sandbodies of the Chang 8 oilbearing interval were distributed to a long distance with larger scales and were characterized by podlike distribution along the channel direction and in vertical direction. The podlike sandbodies were distributed around the lacustrine basin. The distribution of the sandbodies is mainly controlled by the lake shoreline which is obviously different from the pattern of slope break belt controlling sandbodies in the depressional lacustrine basins.
Based on a new stratigraphic division and large quantities of drilling，outcrop and core data，the authors have studied in detail the depositional system， lithofacies palaeogeographic characteristics and evolution of the Yan 9 oilbearing interval of the Yanan Formation in Huachi area， Ordos Basin. The results indicate that the Yan 9 oilbearing interval is dominated by fluvial deposits and was inherited and developed from the Yan 10 oilbearing interval. During the deposition of Yan 9， mainly braided fluvial， braided meandering fluvial and anastomosed fluvial facies were developed. Braided fluvial facies was developed in the Y39 interval and Y29 interval inherited the fuvial deposits of Y39， and formed the braided meandering fluvial facies. After the two former stages of filling process， anastomosed fluvial deposits were developed in the Y19 interval in the peneplain environment. Two fluvial depositional models were developed in the Yan 9 oilbearing interval in Huachi area，namely as， braided fluvialbraided meandering fluvial and anastomosed fluvial depositional models.
On the basis of analyses of the regional geological background,through core observation and description and logging data, alluvial fan， fluvial flood plain， fan delta， delta and lacustrine facies were identified in the Neogene in Yiliping area of Qaidam Basin, and isoline maps of strata thickness, sandstone content, dark mudstone content and red color mudstone content were compiled. Finally， distribution maps of sedimentary facies from the Shangganchaigou Formation to Shizigou Formation were drawn. The general sedimentary characteristics indicate that shoreshallow lacustrine deposits are the main types， while flood plain， delta and fan delta occurred mainly along the basin margin. Moreover， these maps show that subsidence and depositional centres shifted from west to east in the study area. Longexisted deltas in Well Yacan 3 and Luocan 1 areas became the best areas for reservoir development. This study has an important reference significance for fine and detailed study of sedimentary facies and the exploration in Yi￣liping area.
The sedimentary characteristics of the Qingshankou Formation of Upper Cretaceous in Binbei area of Central Depression in Songliao Basin were systematically analyzed， based on studies of core and welllog facies. The planar distribution of sedimentary facies of different members of Qingshankou Formation and facies evolution were studied in detail， according to the single factor analysis and multifactor comprehensive mapping method. Maps of single factors and sedimentary facies of different members of Qingshankou Formation have been compiled. The results show that during the deposition of Qingshankou Formation，mainly two types of sedimentary facies: delta and lacustrine facies， including four subfacies， ie. delta plain， delta front， shoreshallow lacustrine and semideep-deep lacustrine facies were developed. In the study area， from the margin to the center， the facies changed from delta plain， gradually to delta front， shoreshallow lacustrine and semideep-deep lacustrine facies， from bottom to top， the facies gradually changed from semideep-deep lacustrine to shoreshallow lacustrine facies， delta front， delta plain facies. The evolution process of the Qingshankou Formation can be divided into three stages based on the distribution character，including the early， middle and late stages. The sedimentary characteristics are diffe￣rent in different stages and different tectonic units. While， as a whole， the lacustrine basin is characterized by changing from large scale to small scale from the early stage to late stage.
Well HK-2 is located 320 km northwest of Atelao City of Atelao State， western Kazakhstan. Rock types of the Middle Carboniferous in Well HK-2 include dolostone， limestone， siliceous rocks， sandstone and claystone. Siliceous rocks and claystone are the dominant types with mixed components， frequent interclayering， abundant organic materials and floating and swimming microbials of deep water facies. The Middle Carboniferous in this area was identified as deposits of a deep water environment， according to the high content of siliceous radiolarian fossils in the rocks， the complete preservation of siliceous sponge spicules， combined with high content of organic materials， dark color， finegrained components， muddy and siliceous components as the dominant ones， and single bioassemblages. It is still unclear whether deep water hydrocarbon accumulations exist in the Wulaer block where Well HK-2 is located. The authors propose that further studies should be carried out on deep water hydrocarbon accumulations. At the same time seismic profiles in this block and the adjacent blocks should be analyzed.
he Paleogene Kongdian Formation in the southern Huanghua Depression is the earliest deposited strata in the Bohai Bay rifted basin. The Kongdian Formation was distributed in the inclining graben constituted by the Cangdong fault and Xuxi fault. Based on the comprehensive analyses of the profile structural characteristics,the isopach of remnant strata thickness，the sequence configuration and fault growth index,it is concluded that the southern Huanghua Depression experienced a tectonopalaeogeography evolution from a stretching depressional basin to a stretching rifted basin during the deposition of the Kongdian Formation. During the deposition of Members 2 and 3 of the Kongdian Formation,large amounts of smallscaled normal faults were developed in the southern Huanghua Depression. These faults were evenly distributed, the moving strength was weaker and their differences were smaller. The syndepositional active faults had little influence on subsidence and deposition in the depositional area. The sequence configuration was characterized by paralleling,subparalleling pattern. Marginal facies was not developed in the upthrow of the Cangdong and Xuxi faults. These characters indicate that the Cangdong and Xuxi faults were possibly not the boundaries controlling the deposition of Members 2 and 3 of the Kongdian Formation. During the deposition of Members 2 and 3 of the Kongdian Formation, the study area was characterized by a ''depressional rift'' or ''depressional fault'' framework. During the deposition of the Member 1 of Kongdian Formation, the normal faults moved strongly and the difference of the moving strength was obvious. The stretching deformation was mainly concentrated in the inner part of the depositional area. Several largescaled trunk faults and the Cangdong and Xuxi faults were marginal faults controlling the depositional area. The deposition was dominated by a wedgelike sequence configuration. The tectonopalaeogeography was characterized by a stretching ''rift'' setting and it complicated the basin origin during the deposition of Members 2 and 3 of the Kongdian Formation.
Late Quaternary shallow biogenic gas reservoirs have recently been discovered and exploited in the Qiantang River(QR)estuary area， northern Zhejiang Province， eastern China. The fall of global sea level during the Last Glacial Maximum enhanced the fluvial gradient and river cutting， resulting in the formation of the largescale QR incised valley. From bottom to top， the incised valley successions can be grouped into four sedimentary facies: river channel facies(Facies Ⅳ)， floodplainestuarine facies(Facies Ⅲ)， estuarineshallow marine facies(Facies Ⅱ)， and estuarine sand bar facies(Facies Ⅰ).All commercial shallow biogenic gas fields or pools occur in floodplainestuarine sandbodies of the Taihu and QR incised valleys or its branches. In the QR incised valley， the sandbodies， with burial depths of 30-80〖CS％0，0，0，0〗〖CS〗m， thicknesses of 30-70〖CS％0，0，0，0〗〖CS〗m， are surrounded by impermeable clays and may represent tidal ridges. Overlying estuarineshallow marine sediments supplied not only abundant gas， but also good preservation conditionsThe clay beds of Facies Ⅲ that serve as the direct cap beds of the shallow gas pools are mostly restricted within the QR incised valley， with burial depths ranging from 30 to 80〖CS％0，0，0，0〗〖CS〗m， remnant thicknesses ranging from 10 to 30〖CS％0，0，0，0〗〖CS〗m， and porosity of 422％〖KG-*3〗-〖KG-*5〗626％. In contrast， the mud beds of Facies Ⅱ cover the whole incised valley and occur as the indirect cap beds， with burial depths varying from 5 to 35〖CS％0，0，0，0〗〖CS〗m， thicknesses from 10 to 20〖CS％0，0，0，0〗〖CS〗m， and porosity of 506％〖KG-*3〗-〖KG-*5〗539％. The porewater pressures of clay and mud beds are higher than those of sandbodies， and the difference can be as much as 048 MPa. The maximum porewater pressure occurs at the top of the shallow gas reservoirs， just at the interface of gas reservoirs and cap beds. The porewater pressures of clay and mud beds can exceed the total porewater pressure and gas pressure of underlying sandy reservoirs. Shallow biogenic gas can be completely sealed by the clay and mud beds， whose high porewater pressures are likely the most important factor for the preservation of the shallow biogenic gas. The direct cap beds of Facies Ⅲ have better sealing ability than the indirect cap beds of Facies Ⅱ.Generally， the porewater pressure dissipation time of clay and mud beds is conspicuously long， and sometimes a steady state is even difficult to achieve. This indicates that the clay and mud beds have bad permeability and good sealing ability. With the increasing burial depth， compaction degree and sealing ability are enhanced. On the other hand， porewater pressure of sand beds tends to dissipate more rapidly than the clay and mud beds to achieve a stable state， and dissipation time does not appear to be related to the burial depth. This indicates that sand beds have better permeability and worse sealing ability. However， once the gas enters the sand lenses， the porewater pressure cant release efficiently and the porewater pressure dissipation time is longer than those of the clay and mud beds. This condition may be caused by the prompt supply of biogenic gas after the porewater pressure dissipation of the sandy reservoirs.
The Saihantala Sag is one of the main hydrocarbon enrichment sags in Erlian Basin， with an area of 2300 km2 and proved geological reserves of 14580 000 tons. According to the basic theories of sequence stratigraphy， 5 sequence stratigraphic boundaries were recognized by seismic profile and drilling data， and as a result，the Lower Cretaceous of Saihantala Sag was classified into 4 thirdorder sequences. The systems tracts were subdivided with first flooding surfaces and maximum flooding surfaces within each stratigraphic sequence and thus the sequence stratigraphic framework was established for the Lower Cretaceous of Saihantala Sag. Reservoirforming factors in different sequences， such as hydrocarbon source and reservoir condition，and so on，were comprehensively analyzed by studies of depositional systems and their evolution， and 3 sets of sourcereservoircap rock assemblages were established in the Lower Cretaceous of Saihantala Sag. The sandbodies of sublacustrine fan and turbidite fan of the LowerMiddle Aershan Formation and middle part of Member 1 of the Tenggeer Formation， which were connected with source rocks in vertical direction，are able to form effective lithologic traps around the oil generating center of Saihantala Sag. Thus they are the most favourable hydrocarbon accumulation zones and the main exploration targets of the Saihantala Sag.
The total organic carbon(TOC)， acid volatile sulfide(AVS)， and heavy metal elements content for four sediment cores, which were collected from the Licun Estuary of Jiaozhou Bay near Qingdao， Shandong Province were measured by instruments. Their environmental responses were discussed. It was found that the distribution of TOC，AVS and heavy metal elements was controlled by the distance away from the estuary and facies distribution. Near the entrance of the river， TOC content was relatively high and was controlled by terrestrial input. The AVS and heavy metal elements content were relatively high. The quantity of active Fe controlled the formation of AVS， and most reactive metals relied on AVS. A short distance away from the entrance of the river， sediments were coarser and its TOC content was lower than those near the entrance， and it was controlled by both marine and terrestrial sources. The AVS and heavy metal content were relatively low. The quantity of TOC controlled AVS production， and most reactive metals relied on the Fe form. Based on the sedimentary characteristics， the environmental responses of these elements were separated into three areas and five types， ie. the subaqueous distributary channel and distributary bay in type 1 area， the subaqueous distributary channel and distributary bay in type 2 area， and the delta front sandbodies in type 3 area.
To retrieve the Holocene history of climatic and environmental changes in the coastal area of Fujian Province， we conducted a multiproxy survey of a lake core(eggrain size， magnetic susceptibility， C/N ratio) of the core from the Longhu Lake in Jinjiang with a chronological support of three AMS dates. The chronostratigraphic data show that the Longhu Lake was initiated from a floodplain at about 5580 calaBP. and lasted for about 4370 years(till about 850 calaBP). The lake transformed to a marsh at about 850 calaBP and the marsh then reverted to a lake at about 470 calaBP. The record of the past about 400 years is absent because the corresponding sediments were removed by a massive dredging in 1958. The proxy data indicate that the climatic wetness fluctuated relatively dramatically since the formation of Longhu Lake in Fujian coastal area. They also show that typhoonrelated precipitation intensity has been decreasing for the past 5500 years， suggesting that the declining trend in the intensity of typhoon might have resulted from the declining trend of the solar insolation. The marsh sediment indicates that the precipitation decreased further. According to the AMS14C data， the date of marsh environment can be correlated to the events of the Sun activity， the ice raft， Asian monsoon and so on， indicating that the formation of the marsh was related to the global abrupt climate event which was superimposed on the long timescale natural climatic changes. The sediment records from Longhu Lake suggest that during the cold periods the precipitation related to typhoon along the coastal area of Fujian decreased， and vice verse， the global warming will cause the increase of typhoon precipitation there.
ean relative humidity from April to May was estimated based on tree ring width data of Pinus tabulaeformis from 1900 onwards in the Liupan Mountains area. The radial growth of Pinus tabulaeformis in this region was significantly affected by the mean relative humidity in spring. On the basis of response analysis， the mean relative humidity changing succession from April to May was reconstructed， and the reconstruction equation was of good stability with correlation coefficient of 0557. As indicated by the spectral analysis， the reconstructed series displays significant cycles of 4-7 years. Its clear that there are four relatively dry periods: 1905-1916， 1918-1932， 1941-1946 and 1955-1962， and four relatively wet periods: 1900-1904， 1934-1939， 1948-1953 and 1964-1973. The most dry periods are 1905-1915 and 1922-1932. tree rings， relative humidity， Liupan Mountains
