The Northwest China in this paper refers to the broad region bounded by the Helan Mountains and Liupan Mountains to the east, and by the Kunlun Mountains to the south. Based on the study of stratigraphy and petrology of outcrop and well sections, according to the single factor analysis and comprehensive mapping method, the various single factor maps of the Lower, Middle and Upper Cambrian and lithofacies palaeogeography maps of the Early, Middle and Late Cambrian in Northwest China were compiled. These lithofacies palaeogeography maps possess three characteristics, i.e. quantification, multirank and multitype. Quantification means that the determination of each palaeogeographic unit is based on quantitative single factor data and maps. This makes palaeogeography developed into the quantitative stage. Multirank means that palaeogeographic units are classified into three or more than three ranks. For instance, lands and seas are the first rank. In the seas, the platforms, basins and slopes are defined as the second rank. In platforms, the banks, tidal flats, and lakes are further drawn out as the third rank. Multitype means that palaeogeographic units, especially the second and third rank units, can be further divided into different types on the basis of their rock types. For instance, platforms can be divided into carbonate platforms, clastic platforms, etc.；basins can be divided into siliceous basins, clastic basins, limestone basins, flysch basins, etc.；and banks can be divided into sparry grain banks (penebanks, embryonic banks),etc, limemud grain banks (penebanks, embryonic banks), mixed banks (penebanks, embryonic banks) . The framework of lithofacies palaeogeography of the Cambrian in Northwest China can be summerized as following. There were both lands and seas. In seas there were platforms and basins distributed alternatively. In platforms there were scattered banks, flats and lakes. Between platforms and basins there were slopes. The features of lithofacies palaeogeography of the Xinjiang and Beishan Area and that of the West Kunlun, Gansu and Qinghai Area are different；however the framework and evolution stage of lithofacies palaeogeography and the transgression process of the whole Northwest China are just the same.
A systematic research on the late Early Carboniferous to Early Permian Brachiopods in the North China Platform shows that the evolution of the Brachiopod faunas have consistent regional characteristics. A total of 5 evolution stages and 8 assemblage zones have been identified. Five stages include the Tianshifu stage (C13～C21), the Benxi stage(C22), the Early Taiyuan stage (C23), the Late Taiyuan stage (P11) and the Shanxi stage (P12), which consist of the 1st, the 2nd, the 3rd, the 4th7th, and the 8th assemblage zones, respectively. All of these assemblage zones in the North China Platform have been compared with contemporaneous faunas in other parts of the world. Besides, the Brachiopod biogeography of the late Late Carboniferous to Early Permian in the research area has also been expounded. A new Brachiopod subprovince, the TianshanLiaoji (LiaoningJilin) Brachiopod biogeographical subprovince, has been established to represent the distribution of the Tianshifu Brachiopods in the northeastern part of the North China Platform.
The reservoir rock facies, with its principal indicators, has recorded aspects of sedimentary facies, diagenetic change and oilgas indication. These indicators include ① petrological characteristics such as sedimentary facies and vitrinite reflectance; ② physical characteristics such as the pore/pore throat diameter ratio and the coordination number of pore throat connecting pore; and ③ organic geochemical parameters such as those photochemical parameters of individual organic inclusions. Based on these quantitative indicators, the defined reservoir rock facies not only can be used for evaluation of itself, but also can be put into facies columns or palaeogeographic maps to be used to predict and trace oilgas reservoirs. All these parameters can be determined with Microscopic photometry, micro FTIR and Laser Raman methods. The uncovered polished thin sections are commonly used for these analyses. For the convenience of studying pore throat structures, some duplicate core samples need to be soaked in the rose colour fluorescence liquid and then cut into three dimentional thin sections which are parallel and perpendicular to beddings.
There are many depositional characteristics of storm deposits in the Lower Sinian Jiayunn Formation around Xuzhou area, including scouringfilling structures, hummocky crossstratifications, storm flowgenerated intraclastic limestones, graded bedding and convolute bedding. Through detailed field observation and laboratory study, a total of six types of storm deposits have been recognized.Type I is represented by the thin bedded silty micrites formed by distal stormturbidity currents below storm wave base. Type II is characterized by the limestones with gutter cast and HCS, which were deposited at the place between storm and fine weather wave base. Type III consists of intraclastic limestones with the debris flow introclasts, HCS, and scouring base, which was formed in the vicinity of the fair weather wave base. Type IV is characterized by the intraclastic limestones with scouring surface, HCS and convolute bedding, which was formed in the upper ramp environment. Type V is characterized by oolitic rudaceous limestones intercalated within the lagoonfacies thinbedded limestones, which wasdeposited at shoal side of the lagoon. Type VI is represented by lagoonfaciesstorm deposits with scouring surface, thinbedded intraclastic limestones, HCSand fair weather deposits. These types of storm deposits tend to superimpose each other vertically to form an upward shallowing sequence.
Modern investigations of sea floor illustrate that various bed forms of bottomcurrents origin are welldeveloped on sea floor. Different bed forms including contour drifts and sediment waves associate with each other orderly. The exact formation mechanism of these associations, especially to the sediment waves of upslope migration, is not fully understood by predecessors. Through detailed study of these bedform associations, this article reached several conclusions as follows: ① according to the theory of internal waves, the formation of different units which make up the sediment waves can be explained. The internal waves of seaward propagation can create sediment waves migrating upslope. ② The contour currents colliding with the overlapped lowdensity normal seawater can create internal waves of large scale at the interface of the thermohaline. ③ Using the coeffect of contour currents and internal waves, this article interprets the formation mechanism of those bedform associations developed on seafloor. ④ The examples of deposits associations of contour currentinternal wave coeffect origin are developed in the stratigraphic record as well as on modern sea floor. Based on these conclusions, this article proposed the concept contour currentinternal wave deposits associations for the first time. A synthetic model of deepwater traction deposits in the statigraphic record is also proposed.
The south Shangdian fault block is located in the Shangdian region of Shandong Province. The sequence stratigraphy of the Dongying Formation in this block has been thoroughly studied. The Dongying Formation is well defined by unconformity surface or discontinuity surface both at its top and bottom, hence it is believed to be a welldeveloped sequence. Within this Formation, some superb retrograded lacustrine delta deposits have been developed due to lacustrine transgression. According to analyses of lithology, cyclicity, and the preservation state of the Dongying Formation, three systems tracts, lowstand, transgressive, and highstand, have been differentiated and a total of 9 parasequences and 32 rhymes are further subdivided. In addition, more than 100 boreholes and related seismic profiles have been studied, sequence stratigraphic correlations along 14 cross sections have been made, and finally the precise, flow unit grade, and stereoscopic sequence stratigraphic framework of the Dongying Formation has been reconstructed in the south Shangdian fault block. As a result of this analysis, a set of scientific data is provided for production of the oilfield, some benefits have been gained and the method has been proved to be efficient.
The postglacial sedimentary strata developed in north Jiangsu Coastal Plain mainly include littoral facies, offshoreneritic facies and tidal flat facies from the lower part to the upper part. Element geochemical study shows that the Changjiang and the Huanghe Rivers have a great influence on development of north Jiangsu Coastal Plain in postglacial period. During the early stage, the Changjiang's influence exceeded the Huanghe's, especially in the southern and middle part of north Jiangsu area, whereas the Huanghe River only transported small amount of matter and mainly influenced the northern part. After the postglacial transgression maximum, the Huanghe's influence was stronger than the Changjiang's, and only a narrow tributary of the Changjiang River transported limited amount of matter to Qianggang and Sancang area. The mainstream of the Changjiang River did not enter to sea via north Jiangsu area, so it did not carry much matter to form the tidal sand bodies either. During the last two thousand years, sediments of this area were mainly from the Huanghe River. Study also shows that element geochemical method is useful in provenance discrimination, because it can effectively avoid the influence of hydraulic sorting.
In this paper, the changes of the Asian monsoon system at about 2.6 Ma ago are discussed based on atmospheric simulations and analysis of the geological records. The results show that the Asian monsoon system reorganized at about 2.6 Ma ago. At that time, both winter and summer monsoons being strengthened obviously and the direction of the winter monsoon in North China changed from NorthWestWest to NorthWestNorth. In China, the area influenced by the East Asian monsoon increased, but the area influenced by Indian monsoon decreased. This is attributed to the uplifting of the Qinghai—Xizang Plateau and the southwestward migration of the center of the Asian Low. At some time of the Pliocene, the Tropical Southwest Monsoon had spreaded onto the Qinghai—Xizang region and has influenced areas over the North China and Northwest China. However, after 2.6 Ma BP, the effects of the Tropical Southwest Monsoon on Northwest China and the Northern part of the Qinghai—Xizang Plateau has decreased again. All these suggest that the Qinghai—Xizang Plateau perhaps reached about 2000 meter elevation above sea level at about 2.6 Ma BP.
Sedimentological analyses of core sections of the Angulinao and Bojianghaizi Lakes show that the climates of these lakes have experienced several stages during the Megathermal of Holocene:warming during 8.4～7.3 ka BP, stable during 7.3～6.2 ka BP, fluctuation during 5.5～5.0 ka BP, sub stable humid during 5.0～3.0 ka BP and cooling down from 3.0 ka BP to present. The climatic changes in this region coincide with those in other regions of China. In 270 a BP, the climates turned to humid slightly, but since 1950 A.D., the climate becomes drying. Compared with sealevel fluctuation, the sediments in inland closed lakes have more advantages in studying climate change.
Study on formation and evolution of the DatongYangyuan basin reveals that the earliest basin appeared in the region was the Jiangjunmiao basin, then the Datong basin, and the Yangyuan basin. The ancient DatongYangyuan lake did not appear until the end of the Tertiary and the beginning of the Early Pleistocene. This lake lasted about two millions years and vanished in the Late Pleistocene. Since the Cenozoic this region has experienced frequent volcanism and active tectonism. Several times of stronger earthquake have happened in recent decades.
