Lacustrine carbonate rocks of the Paleogeneand Neogene in western Qaidam Basin are mainly distributed from the upper member of the Xiaganchaigou Formation to Youshashan Formation,and more developed in the  upper member of the Xiaganchaigou Formation and Shangganchaigou Formation There are three types of carbonate rocks,including  micrite limestones,algal limestones and grain limestones in western Qaidam BasinThe diamictites resulting from the mixing of lime,dolomite and terrigenous clastics are widely distributed Carbonate sedimentary facies include lime mud flats and algal flats in littoral lake,grain banks in shallow lake,algal mounds in shallow lake and marls in semideep lakeetc The typesof carbonate rocks of limemud flats in littoral lake mainly include micritic limestones,micrite limestones with terrigenous clastics and marls with terrestrial clasticsetc Those of algal flats in littoral lake mainly include algal micrite limestones and algal laminar limestones and algal micrite limestoneswith terrestrial clasticsThose of grain banks in shallow lake mainly include ooid limestones with spar or micrite,bioclastic limestones,intraclastic limestones and grain limestones Those of algal mounds in shallow lake mainly include algal stromatolitic limestones, algal clast limestones, algal micrite limestones and algalmicrite limestones with terrestrial clastics Those of marls facies in deep lake mainly include micrite limestones, marls, micrite limestones or marls with little mud and silt Carbonate sedimentary facies show a strong migration trend from southwest to northeast

The Permian in the DianQianGui Basin and its adjacent areas can be divided into three series,the Chuanshanian, the Yangxinian and the Lepingian SeriesTwo obvious unconformity surfaces, one resulting from the main episode of the QianGui structural movement at the turn from Chuanshanian Epoch to Yangxinian Epoch, and another resulting from the main episode of Dongwu structural movement at theturn from Yangxinian Epoch to Lepingian Epoch, not only become the evidentsequence boundaries of type I but also represent the important changing surfaces of palaeogeographical patterns and the characters of the sedimentary basinin the study areaThe Permian System in the DianQianＧui Basin and its adjacent areas is marked by the clear sedimentary facies differentiationThe development of coalbearing strata on the attached platform as well as the formation ofsponge reefs and grain banks in the margin of attached platform and on the isolated platforms led to a particular palaeogeographical pattern thatis characterized by “platformbasinhilltrough”.Concomitantwith the firstepisode of the Dongwu structural movement,a strong volcanic eruption occurredin the northwestern part of the study area, which led to the formation of the widely distributed “Emeishan Basalt”.At the same time,the “QinzhouFangcheng relict trough" was closedThese important events resulted in the great changes of the palaeogeographical patternsThe typical drowning event of the carbonate platforms at the turn from the Permian to the Triassic formed a typical drowned unconformityAccording to the regularities represented by the evolution succession of sediments as well as the distribution patterns of sedimentary facies, the Permian in the study area could be divided into several thirdorder sequencesThe top part of the Carboniferous and the Chuanshanian Series of the Permian form one sequence(SQ¹⁹),the Yangxinian Series includes four sequences  from SQ²⁰ to SQ²³, and the Lepingian Series could be divided into two sequences including SQ²⁴and SQ²⁵Ultimately,the complex but regular facieschanges in time and in space can be clearly illustrated by the palaeogeographical maps as well as the panel diagrams of sequence stratigraphic frameworksFirst, the main temporal facieschanging surfaces marked by the abrupt changes of sedimentary facies and the stratigraphic hiatus form the sequence boundariesDue to the different duration of stratigraphic hiatus at different locations,the diachrononism sequence boundaries of “punctuated surfaces" are formedSecond, the spatial changes of sedimentary environment as well as the migration of sedimentary facies during the temporal changing process always result in the spatial changing surfaces of sedimentary facies marking the obliqueness with chronostratigraphic surfaces and in the end the diachronism of “facieschanging surfaces" is formedThird, various faciessuccession fabric of sequences is formed in different depositional periods, and is regularly changed in space, which means different palaeogeographical backgroundsTherefore, it could be concluded that the regularity represented by “the evolutionary succession of sediments and the distributional pattern of sedimentary facies" is the key factor on the study of sequence stratigraphyOn the basis of biostratigraphic materials, this kind of regularity could be used as an indicator in the division and correlation of strata

Based on the identification of sequence boundary through outcrops,seismic data,well logs and analytical data,the Nadu Formation and Baigang Formation of the Eocene of Paleogene in the Baise Basin can be divided into one secondorder sequence,and further into three third order sequences The Member 3 of the Nadu Formation forms Sequence Ⅰ,the Member 2 and Member 1 of the NaduFormation form Sequence Ⅱ,and the Baigang Formation forms Sequence Ⅲ Sequences Ⅰand Ⅱ were deposited during the faulting period of the basin,during the period alluvial fan facies,fluvial facies,delta facies,fan delta facies,shore shallow lake subfacies,and deep lake subfacies were developed  Sequence Ⅱis characterized by a wide range of lake sedimentation with a great thickness,and the thick  bedded mudstones of deep lake subfacies are the main source rocks and regional cap rocks in the basin Sequence Ⅲ was deposited during the depression period of the basin,during the period alluvial fan facies,fan delta facies,fluvialfacies,delta facies,and shore  shallow lake subfacies were developed  The Paleogene in the Baise Basin experienced a process from the deposition of fluvial facies or alluvial fan facies to fluvial and delta facies,and then to lake facies (fan delta facies),and finally to fluvial facies  This indicates that the  Baise Basin experienced a complete cycle of evolution from the early rifting stage to expansion,and then to shrinkage  In the lowstand system tracts of sequences Ⅰ andⅡ,sandstones of fluvial and delta facies are well developed in the central faulted sag,the southern subsag of the Tiandong Sagand the northern faulted nose of the Nabi Uplift along  the long axis  These sandstones are in mature source rock areas with a favorable condition for reservoir formation,and are in the potential areas for the exploration ofchannel lithologic pools  In the transgressive and highstand system tracts of sequence Ⅱ,fan delta facies were developed along the northern steep slope and their sandstones are interfingered with source rocks which are favorable for the formation of hydrocarbon pools,and are easy to form a great deal of updip pinching lithologic reservoirs

The Majiacun Formation of Upper Cretaceous，with a thickness of 1 960 m，crops out in the Xixia Basin，southwestern Henan ProvinceFrom the base of the formation upwards，the succession is composed of braided river，meandering river and lacustrine sedimentsA lot of trace fossils were found in the fluvial lacustrine sediments，including Skolithos linearis,Cylindricum  ichnosp，Palaeophycus tubuaris,Jshaped burrows,vertical branchedburrows and vertically helical burrows Most of the trace fossils，in terms of their shapes，are supposed to be  domichnia,and can be classified into assemblages of Scoyenia or Arenicolites ichnofacies Based on the lithology of thehost rocks，bioturbation and the total relic fabric，the two ichnofabric typesnamed as soft ground ichnofabric and stiff ground ichnofabric can be distinguishedThe former type of ichnofabric consisted of  Skolithos linearis  and  Palaeophycus tubularis  which occurred in very finegrained sandstones and siltstones，displaying higher density and less diversity of trace fossils,while the latter type of ichnofabric dominated by Cylindricum  ichnosp,Jshaped burrows,vertical branched burrows and vertically helical burrows,occurred in siltstones and thick bed mudstones，exhibiting less density and more diverse individuals Comparedto the reported continental ichnofabrics，the fluvial ichnofabric varied apparently in the Cretaceous，and shallow lacustrine ichnofabric showed that the trace maker’sability to bioturbate the substrates increased obviously with time passing

Water depth is an important index for research on the paleoenvironmental evolution and basin analysisThe authors made research on the quantitative relationship between the planktonic foraminifera content and water depth in modern sediments in the western South China Sea，which providesareference for paleoenvironmental studyMore than 300 samples of surface sediments were collected systematically from the western South China Sea (4°～18°N，1085°～115°E) for foraminifera identificationThe abundance of benthonic foraminifera decreases from the continental shelf to the deep sea basin with increasing water depth，while planktonic foraminifera reach the highest abundance in the upper slope，with water depth between 200 m to 2000 m，and decrease toward both the coast and deep sea basinThere is a distinct relationship between the content of planktonic foraminifera (P) and water depth (D) which is apparently different in the shelf and in the slope to deep sea basinThe content of planktonic foraminifera increases rapidly on the shelf with the increasing of water depthand their relative equation is shown as lnD＝0021P＋3.208，but a negative relation from the slope to deep sea basin is shown by D＝-526.3P＋52105.2It is mainly because the planktonic foraminifera increase as the water depth increasing in the shelf，however，the dissolution of carbonate becomes the main reason to control the contents of the planktonic foraminfera in the ocean at the depth of more than 200 mThe planktonic foraminifera are easier to dissolve than benthic foraminifera

The obvious conformability of basinmountain topography with the crustal structure in northwestern China is an important characteristic of current basinmountain tectonicsIn this paper，we discuss the palaeogeographical appearances and the process of the development and evolutionin different periods of the MesoCenozoic in basinmountain area in northwestern ChinaBased on their evolutionary process since the Mesozoic，we know that，there were different palaeogeographical features in different periods of the MesoCenozoic，and they continuously developed with the tectonic evolution of the crust and the upper mantleThe basinmountain tectonics was controlled by the activities and evolution of crustUsually，the main mountains in northwestern China are thePaleozoic or the Early Mesozoic orogenic zones，but the formation of such huge mountains happened in the Late CenozoicThe tectonic evolution history of Tianshan is an exampleIn the Triassic，it was once uplifted to form the mountains with thick molasse accumulation on both its sides，Junggar and Tarim BasinsThen it became a peneplain by the exposion and deplanation in the Jurassic，forming the widespread coalbearing strata which can be correlatedFrom the Cretaceous to the Early Cenozoic，it was uplifted again，until the Quaternary to build huge mountains with two large sedimentary basins on both sidesThere were similar development and evolution histories for other mountains in northwestern China，such as Qilian and Kunlun mountainsAt last，the basic factor controlling the process is the tectonic evolution of the crust，even of the whole lithosphere in this region

Based on analyzing lithofacies palaeogeography andstratigraphy from the Carboniferous to Triassic of North China Block and South China Block in easternChina，the TanLu Fault Zone can be divided into two main development stages since the HercynianFirst stage is a fault zone in broad senseIt is a boundary of a rifted cratonic margin (or basin) that spreads in a wide arcshape along the northeastern margin of the Yangtze Block during the Hercynian It is a collision suture between the Yangtze Block and North China Block during the Indosinian period，a thrustnapping fault zone belonging to the Tethyan regimes in broad sense Second stage isa wrench fault system，which belongs to the Pacific Ocean cycle regime in narrow sense during the Yanshanian and Himalayan periodsBased on analysis of the lithofacies palaeogeography from the Late Carboniferous to the Early Triassic，the collision between the YangtzeBlock and North China Block started in the early age of the Late Permian The lifting time of the Yangtze Block started from south to north or from southeast to northwest in directionThe TanLu Fault Zone was a “S”shaped border trending northeast or northnortheast as a suture of the blocks collision It is a thrustnapping zone from NNW to SSE The tectonic deformation of the suture was shown as the Zhangbaling structural belt and the foreland foldingthrusting belt that belongs to the midupper tectonic layer of the DabieSulu orogenic belt

According to the analysis on historical documents and research on borehole sections in Juye,Liangshan and Daimiao and the investigation of lake basal sediments in Dongping Lake,the sedimentary records of Dayeze Lake,Liangshanpo Lake,Anshan Lake and Dongping Lake are determined and the authors propose that the Dongping Lake was evoluted from Dayeze Lake,Liangshanpo Lake and Anshan LakeBy analyzing the relationship between the evolution of Dongping Lake and the crevases and shifting ofthe Yellow River，it is suggested that the evolution process of Dongping Lake inhistorical periods was closely related with the Yellow RiverDuring the crevasesand shifting of the Yellow River,water poured into and lake expanded,river shifted and lake shrankThe Yellow River poured into it during itsfirst shifting stage and flowed across Dayeze LakeThe Yellow River poured intoit twice during the second shifting stage,among which once shifted and flowed across Dayeze Lake,and the water transgressed northwards and formed the LiangshanpoLakeDuring the third shifting stage,the Yellow River crevassed and poured intoit three times,shifted and flowed across the Liangshanpo Lake twice which led to the further expansion of the lake and finally formed socalled the “Babaili Liangshanpo Lake”.After that the Yellow River poured intoit several times,the sources shortened and the lake shrankThe Yellow River did not flow through theLiangshanpo Lake during its fourth shifting stage,with the lake shrank furtherThe Yellow River poured into the Liangshanpo Lake twice during its fifth shifting stage and the lake expandedThen the source of the Yellow River was cut off  and the lake was separated into northern five lakes including Anshan Lake,while the Liangshanpo Lake became land because of the filling of sediments for a long whileThe source of the Yellow River was cut off during its sixth shifting stage,with the northern five lakes migrating to the north and gradually shrinking and disappearingOnlythe Anshan Lake experienced the pouring of the Yellow River once and was filled to form the Dongping LakeThe lake was dried up when the source of the Yellow River was cut off and the water of the Yellow River once flooded back into it during the flooding periods

According to the notes recorded by Liu Yueshen in the Yuan Dynasty，Jiangxi Province was exposed to severe cold climate，indicated by heavy snow，thefrozen rivers，and cold summer from 1328 to 1330 AD  It snowed in regions as south as the Nanling Mountains in 1328 and 1329 AD  In 1329 AD，the rivers in the Jishui County at the latitude of around 27°N were frozen The summer in the southern part of Jiangxi Province was described similar to that in the Inner Mongolia Plateau in 1330 AD The cold climate of these three years was like that of the extreme cold years from the 17th to 19thcenturies  It is one of  the rare extremely cold events in the past 2000 years

A series of saturated hydrocarbons,including nalkanes,terpanes and steranes,have been identified in inhalable particulates (PM10) samples collected in northwestern urban district in Beijing by means of the GC and GCMS The parameters of the saturated hydrocarbons,such as major peak carbon number,carbon preference index (CPI) and hopane 22S/(22S+22R) ratios,have been calculated,which can beused to reflect the sources of the extractable organic matters in PM10 The nalkanes in PM10 samples from Beijing air have the major peak carbon numbersranging from 23 to 27 and the CPI values between 1 and 3,suggesting that the saturated hydrocarbons may be derived from both modern higher plants and incomplete combustion of fossil fuels (coal and petroleum )The results also show that the saturated hydrocarbons in the spring and summer PM10 samples are mainly from biomass such as higher plants,pollen and microbes,while the saturated hydrocarbons in the autumn and winter PM10samples are mainly from incomplete combustion offossil fuels  Many terpanes presented in PM10similarly indicate a source of incomplete combustion of fossil fuels such as petroleum Steranes detected in PM10imply that parts of saturated hydrocarbons may come from engine oil released by vehicles

Reservoir properties and their controlling factors in different tectonic settings,sedimentary environments and burial depth are studied by analyzing a large amount of data of reservoir properties，combined with thinsection petrography and scanning electron microscopic(SEM)analysisThere are many types of clastic reservoir rocks in the Paleogene of Dongying Sag，mostly formed in different sedimentary environments，such as alluvial fan，river，fan delta，nearshore subaqueous fan,deepwater turbidite fan，deltafront slump turbidite fan，shoreshallow lake bar and so onClastic reservoir rocks consist of conglomerate，pebbly sandstone，mediumcoarse sandstone，fine sandstone and siltstone，of which medium sandstone and fine sandstone are thebest reservoir rocksReservoir properties of rocks in different sedimentary facies and areas are differentReservoir rocks in fluvial，[BF](fan)[BFQ]deltafront subaqueous distributary channel and mouth bar,have the most effective reservoir propertiesCentral uplift zone has better reservoir properties than north steepslope zone and south slope zone at the same burial depthIn addition，reservoir properties are getting worse and worse with increasing burial depth(influence of secondary pores are not taken into account).Based on the analysis of reservoir properties and diagenetic，the reservoir properties of clastic rocks in Dongying Sag are dominated by four factors，namely compaction,carbonate dissolution，cementation，and sedimentary conditionsAmong them，compaction and diagenetic degree(the relative degree of dissolution and cementation)are main factorsThe effect of sedimentary conditions on reservoir properties manifests the development of primary pore，and its control on dissolution and cementation

The Bonan Oilfield is located in the Bonan Sag ofJiyang Depression, and is a deeply buried low permeability faulted lithologic reservoirwith the largest oil reserves in Shengli Oilfield of Shandong Province The main oil bearing strata are in the Member 2 and Member 3 of Shahejie Formation of Paleogene with a low to middle porosity and a low permeability The low permeability reservoir is characterized by its complex genetic mechanism By employing the concept of diagenetic reservoir facies, the evaluation of reservoir quality in the third area of Bonan complex oilfield was made in order to predict the distribution of effective reservoir and its storage capacity more accurately The research on sedimentary facies and diagenesis of the reservoir combined  withanalyses of diagenesis effect of low permeability reservoir on the reservoir property and with the division of diagenesis stages indicates that the geneticmechanism of the low permeability reservoir in this area is the filling and cementation of autogenetic mineral during diagenesis Using seven chosen parameters including flow zone index, porosity, permeability, median grain size, mud content, median pore throat radius and variance coefficient, and applying cluster and discriminant methods, four kinds of diagenetic reservoir facies were classified Combined with the analyses of their characteristics and sedimentary facies, the timespace distribution is also givenOur result provides a guide to the development of low permeability oilfield[WTHZ]