Qinling fold belt is located at the junction of the North China plate and the Yangtze plate, and its portion in Henan Province is a part of the East Qinling Mountains(EQM). The East Qinling Mountains can be subdivided into the northern and southern parts, which are separated by the Shangnan-Zhenping suture. Six stages of the Paleozoic biopalaeogeographical evolution can be recognized in the East Qinling Mountains. From the Cambrian to the early Middle Ordovician, the Cambrian radiolaria and the Early Ordovician conodonts of the Erlangping trough in the northern part of EQM, and the Cambrian trilobites and Early Ordovician conodonts as well as cephalopods of the northern Xichuan shelf in the southern part of EQM belonged to the South China Province, while the Cambrian trilobites and the Early Ordovician conodonts of the southern Xichuan shelf belonged to the South China Province with some elements of the North China Province. From the late Middle Ordovician to the end of Ordovican, the cephalopods, gastropods and corals in the Erlangping trough, and the conodonts, coral, brachiopods, cephalopods as well as trilobites in the Xichuan shelf were from the North China Province. During the Early Silurian, the corals of the Erlangping trough and the graptolites of the Xichuan shelf belonged to the South China Province. From the Middle Silurian to the Early Devonian, no fossils were found in EQM, which probably was a land and connected with the North China block. From the Middle Devonian to the Early Carboniferous, the spores of the Shishuyuan trough in the northern part of EQM and those of the Nanwan trough in the southern part of EQM belonged to the South China Province, and the Late Devonian corals, brachiopods, plants , and the Early Carboniferous fusulinids of the Xichuan shelf were from the South China Province. From the Late Carboniferous to the end of Permian, the spores of the Shishuyuan trough were from the North China Province, and the marine sediments were absent in the southern part of EQM. During the Paleozoic times, six evolutionary stages in EQM are from the South China Province to North China Province, then to South China Province to North China paleoland and finally to South China Province to North China Province ,which constitute three evolutionary cycles. In conclusion, the biopalaeogeography of the northern and southern parts of EQM indicates an obvious unity of the evolutionary directions and a similarity of the evolutionary times.
The Euloma changshanense Lu, which is collected from the Lower Ordovician in Jiangshan，Zhejiang, is a part of old shield of exuviations. It is an imprint of librigenal doublure. We analyze its process of exuviations through observing the deuterogenous remnants shield and consider that two librigenal cheeks link up in the middle of foreside of cephala. During the exuviations，the body of the trilobite climbed up，separated itself from the foreside of cephala， but the librigenal cheeks were still on the new shield. Then，they were propped up by the new trilobite，the imprint of librigenal doublure in the foreside of cephala was preserved only. It reflects that there was a period of break when the trilobites were exuviating. During the exuviations，there was a time out. Furthermore the new trilobites usually carried or hauled the librigenal cheeks and hypostoma on the old cephala，which made the old shield leave behind the carapace. The status of exuviations happened instantly，and it belonged to autochthonous remains，indicating that trilobite was in the status of sedentary water with abundant sediment supplying. The sediments would bury the trilobite during the exuviations or exuviations shortly. The Yinzhufu Formation at Jiangshan is fairly thick. It is overlain by the Azygograptus suecicus Zone which is at the lower part of the Dawanian stage. In contrast，at Yushan (in Jiangxi Province)，not far away from Jiangshan, the Yinzhufu Formation is overlain by the Tetragraptus approximates Zone which is at the lower part of the Yushanian stage. This indicates that the Yinzhufu Formation is diachronous. However the Euloma changshanensis Lu is always found at the uppermost part of the Yinzhufu Formation on both places， indicating that these trilobites belong to the Lower Ordovician，but they thrived over a long period of time from the late-Tremadoc to the end of Yushanion Stage. It also indicates that the Yinzhufu Formation is relatively thick，but the sedimentary environment did not change much and，even the genus and species such as trilobites，Euloma changshanense and so on changed little. Such a formation is a good stratigraphical interral to study the exuviations of trilobite and the evolutionary progress of the ecological replacement.
Based on the investigations of 46 species of fossil spores and pollen belonging to 28 genera which were found from the Yongping Formation and Wayaopu Formation of Upper Triassic in Tongchuan region of Shaanxi Province, the early to late Late Triassic palynoflora in the region was established. According to the characters of the palynoflora, the Late Triassic palaeoecological, palaeoclimatic and palaeogeographic characters as well as the sedimentary environments in the region were discussed. The results indicate that during the early Late Triassic, the palaeoclimatic conditions and the sedimentary environments were favorable for the formation of petroleum, and during the late Late Triassic ,the palaeoclimatic conditions and the sedimentary environments were favorable for the formation of coal and natural gas.
Through an intensive study on pollen and spores from the cores of Hm, Dh1 and G2 in eastern part of Shanghai, five palynological assemblages and three sub-assemblages have been distinguished. The five stages about the evolution of palaeovegetation and palaeoclimate which are reconstructed in the Holocene in this area are as follows: the mixed forest of conifers and broad-leave trees—grassland, reflecting a temperate and little moist climate(sub-arctic period); the mixed forest of conifers and broad-leave trees with a few kinds of evergreen broad-leave trees, reflecting a temperate and slightly dry climate(Boreal period); the evergreen broad-leave forest being mainly composed of Quercus(evergreen) and Castanopsis, indicating a hot and moist climate(Atlantic period);the mixed forest of conifers and broad-leave trees, taking Quercus, Pinus and Gramineae as the main elements in palynological assemblages, reflecting a warm and little dry climate (Sub-Boreal period); the mixed forest of deciduous broad-leaves, evergreen broad –leaves and conifers-grassland, with Quercus (deciduous, evergreen) and pines being the main components, reflecting a warm and moist climate (Sub-Atlantic period). The study provides reliable evidences for the division and correlation of the ages of the sediments in this region and also provides important palynological information for the reconstruction of palaeovegetation, palaeoclimate and palaeoenvironment of the Holocene in this area.
The Qinshui Basin in southeastern Shanxi Province is an important base for coalbed methane exploration and production in China. The methane reservoirs in this area are mainly the Carboniferous and Permian coals and their thickneses are strongly controlled by the depositional environments and palaeogeography. In this paper, petrological and sedimentary facies researches are conducted on the outcrops and drill cores of the Taiyuan and Shanxi formations in the Qinshui Basin and the basin-wide lithofacies palaeogeographic maps for these two formations have been reconstructed. The Taiyuan Fomation is composed of limestones, aluminous mudstones, siltstones, silty mudstones, sandstones, and mineable coal seams, with a total thickness varying from 44.9 m to 193.48 m. The coal seams have a thickness ranging between 0 and 16.89 m, averaging 7.19 m. During the deposition of the Taiyuan Formation, the northern part of the study area was dominated by the lower deltaic sedimentary system, the central and southern parts were dominated by the lagoon environment, the southeastern corner was occupied by the carbonate platform setting. Coal is relatively thick in the northern part and the southeastern corner. The Shanxi Formation consists of sandstones, siltstones, mudstones and coals, with the limestones being locally developed. The thickness of the Shanxi Formation is from 18.6 m to 213.25 m, with the thickneses of coal seams being from 0 to 10 m and averaging 4.2 m. During the deposition of the Shanxi Formation, the northern part of the Qinshui Basin was mainly dominated by lower deltaic plain distributary channel environment, the central and southern parts were mainly the inter-distributary bay environment, and the southeastern part was occupied by the delta front mouth bar environment. The thick coals are distributed in the central and southern parts where the inter-distributary bay dominated. It is evident that the distribution of thick coal zones of the Taiyuan Formation is consistent with the distribution of sand-rich belts, mainly located in the areas of northern lower deltaic plain and southeastern barrier bar environments, while the distribution of the thick coal zones of the Shanxi Formation coincides with the distribution of mudstone-rich belts, located in the areas of the central and southern inter-distributary bay environments.
Based on the analysis of drilling data and core, the sedimentary facies of the Shanxi formation to Member 8 of Xiashihezi formation of Permian in Suligemiao oil and gas-bearing area, north Ordos basin, are divided into braided river, meandering river, delta and lake. By the theory of sequence stratigraphy, the Shanxi formation and Member 8 of Xiashihezi formation are divided into 5 sequences, and the sequence stratigraphic framework is set up. The lithofacies paleogeography map is drawn according to system tract. The feature and evolution of the lithofacies paleogeography are discussed in the sequence stratigraphic framework. During the sedimentary period of Shanxi formation, the paleogeography situation was meandering river-delta deposit, which has sedimentary differentiation from north to south. During the sedimentary period of Member 8 of the Xiashihezi formation, the alluvial system removed into the south of study area widely and formed river-delta deposit, in which the braided river is dominant. The channel sand body is high quality reservoir in Suligemiao oil and gas-bearing area, and its development is relative to lowstand system tract. By the palaeogeography mapping in the unit of system tract, the distribution and transferred direction of sedimentary microfacies are shown distinctly. It is an effective method to prospect the high quality reservoir.
The origin of Molar Tooth carbonate rocks has been studied more than 100 years, and many scholars have put forward different hypotheses about it. Up to now, a consensus still has not been reached. This study cites all kinds of origin hypotheses for Molar Tooth carbonate rocks at present, points out all the problems and controdictions in these origin hypotheses and advances the possibility of biologic origin for Molar Tooth carbonate rocks. The biological evolution regularity of the Proterrozoic illustrates the formation, blooming and withering periods of Molar Tooth carbonate rocks corresponded to the appearing and blooming time boundary of the Eucaryotes and appearing time boundary of the Metazoans. The evidences that prove the possibility of biologic origin for Molar Tooth carbonate rocks include: the structure features, chemical components(especially the shape of pyrite and aboundance of SnO2), the distribution regularity of carbon and oxygen isotopes and the diversity of biomarkers. It is emphasized that there is a negative correlation between the growth and blooming of the Proterozoic stromotolites and Molar Tooth carbonate rocks development. Difficulties in explaining the biologic origin are also set forth. Finally, this study points out that future research should be focus on the sedimentary environments and lithofacies for the formation of Molar Tooth carbonate rocks, especially their early diagenesis and relavent geochemistry characters. The change of chemical features of ancient oceans in the Proterozoic will be the fundamental means to probe the origin for Molar Tooth carbonate rocks.
The Shuangyang Formation reservoir of Paleogene is the important oil-gas abounding formation. Based on the lithological feature, diagenesis of Shuangyang Formation are revealed by thin section observation, Scanning El ectron Microscope observation, clay minerals X-diffraction analysis and other methods. It is revealed that there are compaction, cemetation, metasomatism and dissolution .It shows a typical feature that montmorillonite translate to illite of Shuangyang Formation reservoir, and it undergoes montmorillonite graduation zone, the first rapid translation zone and second rapid translation zone. Corresponding the diagenesic stage is divided into early diagenesic B stage , late digenesic A1 and diagenesic A2. stage 。The order of diagenesis of Shuangyang Formation is builted. The types and intensities are different in the vertical, which causes the reservoir property zonal.
Two large-scale circular slump structures are well developed on the middle-rear Luokou point bar of the downstream of Yellow River. The smaller one is 42.54 m long, 31.55 m wide and 0.63m high and the larger one is 58.30 m long, 46.24 m wide and 0.76 m high. These structures can be divided into three parts: the main body belt, the transitional belt and the vanishing belt according to the geometrical characters and the kinematical elements. Some larger collapsed blocks, which are 20～30 cm wide, 2～3 m long and 40～60 cm high and with the shape of arc-slice, dominate in the main body belt whose length is 8～15 m，what is more, the collapsed slots are open or filled with the silt in the main body of this structures.The 10～20 m long transitional belt, with the character of moderate collapsed blocks whose dimensions are 5～20cm wide, 0.5～2m long and 20～40cm high has the same shape of arc-slice as the main body belt, but the slots are somehow different because some are half-open and edothers are stuffed with the silt. It is important that the relative movement directions of the collapsed blocks have a change here, i.e. from the sere one-way movement to the relative movement. The relative glides with the circle center of a big radial cavum, which are formed by the associate erosive grooves’ gathering, contribute to this kind of ring-like collapsed and slippery structures. The 15～30 m long vanishing belt which is located beyond the area of the transitional belt, is characterized by the decreasing of the block’s dimension as well as the displacement space of the slide of blocks.The structures studied here are developed in a horizontal surface with the collapse gradient of 0.745 degree, and they are developed and accomplished in a “domino”manner. Some factors such as the liability to liquefaction of the fine sediments made up of silts and muddy-silts, the supersaturated pore water due to sudden and sharp rising or falling level of the Yellow River and the seepage water formed by the the special configurations of the Luokou point bar, all contributed to the development of the collapsed structures.
Hainan Island and the mainland have the history of being connected, disconnected, reconnected and redisconnected, which makes the biota of the island and its ecological environment have some correlation and some differences with South China Mainland. The diversity of modern biology in Hainan Island is directly inherited and developed from that of the Cenozoic, especially, the biological community in the Early Holocene of the Quarternary, whose components is basically identical with the modern ones. Since Hainan Island is located at the low latitude zone, and got few influences from Ice Age of the Quaternary, which led to the preservation of its old flora and animals. In the Early Holocene the global climate turned warm, the palaeobiogeographical division in the island were prosperous. San Ya Luobi Cave is the earliest site of human cultural activities up to now, and the earliest inhabitants-----San Ya Human-----is a branch of Archaian Yue nationality. Their ingoing and multiply and later immigrants greatly changed the biology and environment in the island.
According to the comprehensive research achievements of stratigraphy such as biostratigraphy, magnetostratigraphy (ESR dating method), seismic stratigraphy and sequence stratigraphy and by means of the recognition of regional isochronous sequence boundaries, the analysis on boundary orders and the correlation of boundary properties in the faulted basin, a regional isochronous sequence framework of the Paleogene in Jiyang Depression is established on the basic unit of third-order sequences. Then the analysis on the comparison of all second-order sequences and major subtle reservoirs which were developed in the third-order sequences in the four sub-depressions of the Jiyang Depression shows that the second-order sequences are directly controlled by tectonic episodes, therefore, they are similar in characteristics. The cyclicity of major third-order sequence stratigraphic framework coincides to each other among the four sub-depressions, with the marker sediments developed in the same or similar cycle positions. However, the third-order sequence boundary properties of T2, T4, and T6 are apparently different among different sub-depressions. According to the sequence genesis dynamics, the consistency of cycle properties and the difference of boundary properties indicate respectively that the sedimentary environments control the sediment types in the same sequence stratigraphic framework and the migration of tectonic depocenters and sedimentary centers in the Bohai Bay Basin controls the sequence boundary properties.
An ancient diary named “Weng Tonghe Diary” written in the late Qing Dynasty by Weng Tonghe and edited by Chen Yijie was dug out in this paper. First of all, every sand dust record was extracted from this diary. Based on the records of full months, the general status and evolvement character of sand dust weather in Beijing during 1860~1898A.D. were analyzed statistically. It is found that, (1) The average sand dust days of Beijing during 1860~1898 A.D. are 10.4 days which are more than average frequency of 1990’s even ignoring the difference in the standard on sand dust. (2) Sand dust weather mainly arose in spring weight of which reaches 70%, in which the weight of April and May is over 50%; and winter is the second high frequent season weight of which is 20%. (3) Comparing with 1961~2000 A.D., sand dust process during 1860~1898A.D. was more highly concentrated in spring. (4) The trend of annual total number of sand dust days decreased from 1860 A.D. to 1898 A.D., so as to the number of dust days in spring. (5) During 1860~1898 A.D., there were 23 sand dust weather processes that were lasting longer than one day, of which the longest one lasted 4 days. These finds may be helpful to study the impact of climate change on sand dust weather and to analyze evolvement regulation of sand dust weather in Beijing.
The estuary runoff of the Yellow River decrea sed during the late 20th century and its lower course became dry many times.Besi des its obvious effect on ecology development and especially on agriculture prod uction,speoial attention should be paid to the fact that the amount of transpo ttd sediments also decreased obviously along with the runoff decreasing thus led ding to the sharp reduction of continentbuilding area of the estuary since the 1990s.The continentbuilding stopped and marine transgre ssion occurred during 1996 and 1997.Among a series of ecological environmental problems resultmg from the decreasing of estuary runoff and amount of transpor ted s ediments of the Yellow River,the decreasing of continentbuilding area and the transgression of ocean water may be related with the future of the Yellow River Delta and may endanger the safety of the Shengli Oilfield at present.thus a great attention should be paid.Checking the changes of ecological environments by geophysical logging techniques is also discussed in the paper.
