Abstract:The project for compilation of Regional Geology of China has been implemented for eight years, and the work has been carried out at the provincial and regional level, covering twenty-four provinces and two autonomous regions. During this period, the compilation work for eleven provinces was completed and has passed the check acceptance, and the results are to be published soon. The compilation is a huge comprehensive and integrated work for these regions or even for whole China. Some innovative achievements have been gained: Precambrian geology research has got major breakthrough; some regional and national stratigraphic systems have been reclassified; the spatial-temporal distribution of magmatic rocks has been analyzed and summarized; the tectonic units have been divided and, as a result, the understanding of the geological structure of China has been deepened; the typical oceanic-basin stratigraphic systems have been detected; the three-dimensional geological map has been successfully compiled. The completion of the project for compilation of Regional Geology of China will provide a series of basic geological monographs which are expected to exert tremendous influence on China's geological work as well as on national economy and social development.

Abstract:The problem"When did plate tectonics begin?"is one of highly controversial issues at present. In this paper, the different ideas concerning this problem are described on the basis of advanced involving supercontinent,geological criteria of plate tectonics and numerical models. The authors hold that plate tectonicis is not an independent event in the globe in a special period, i.e., it is not a major isochronic thermo-tectonic event. Meanwhile, subduction caused by plate tectonics with lateral movement have occurred since Neoarchean. Few high pressure and ultru-high pressure metamorphic rocks, however, in deep subduction belt occurred at the early stage of plate movement because of a higher mantle temperature. The authors agree with the opinion that the transitional period from proto-style to modern style plate tectonic roughly occurred around the Neoproterozoic.

Abstract:In this paper, the authors describe the rock assemblage series and geochemical characteristics of the intra-oceanic arc and initial arc during the ocean-continent transition, and propose that the magmatic arc was formed together with the ocean-continent transition and the underplating crust-mantle transition. The former arc environment was the place where the primary continent was formed by the ocean-continent transition, which constituted diagnostic basalts of former arc of intra-oceanic arc similar to the midoceanic ridge. The formation process of the continent is as follows: the oceanic crust grew from the mantle, and the immature arccontinent crust grew from the ocean-continent transition in the oceanic crust: at last, the mature continent crust grew from the curstmantle transition of underplating arc-continent crust. Therefore, the growth and formation of the earth's crust was mainly realized by the accretion of magma.

Abstract:LA- ICP-MS zircon U- Pb dating was carried out for Dongshan metamorphic rocks in Fujian Province. Their ages obtained are 176.8 Ma, 203 Ma, 230 Ma,1320 Ma and 1810 Ma respectively, Among them, the 176.8 Ma is the age of magmatic zircon in volcanic-sedimentary rocks, representing the formation age of the sedimentary rock; 203 Ma and 230 Ma represent Late Triassic granitoids; 1320 Ma and 1810 Ma represent the metamorphic basement age of metamorphic rocks. The geochemical data indicate that these metamorphic rocks have poor Si and high Al, Fe, K and are characterized by low Co,Ni,V content and high Ba, Rb, Zr, Hf, U, Th, La values,exhibiting crust source features; relatively high REE content, slight enrichment of LREE, indistinct fractionation between LREE and HREE, and weak negative Eu anomaly all indicate that sources of the metamorphic rocks might have been mantle-crust and granitoids of I series. The Qingyingshan Formation seems to have been the early Jurassic product of the marine-terrigenous facies at the rifting stage, accompanied by volcanism.

Abstract:Based on integrated studies of petrography, geochemical and geochronology of the porphyritic monzogranite and monzogranite from the middle segment of the Qaidam Mountain composite granite, the authors hold that the porphyritic monzogranite is a K-rich peraluminous S-type granite formed by the biotite partial melting of greywacke under the condition of higher pressure (0.8-0.9 Gpa) and temperature (about 820℃), and resulted from continent-continent collision in (456.2±3) Ma; The monzogranite is a K- rich metaluminous S- type granite, which was formed by the muscovite partial melting of meta politicarenaceous sedimentary rocks under the condition of lower pressure (<0.8 Gpa) and temperature (about 750℃), and was formed in an extension geological setting in (437.2 ± 1.5) Ma. Combined with the results of previous studies, the authors consider that the Qaidam Mountain composite granite was formed in a complex plate tectonic system which transformed from contraction to extension.

Abstract:The garnet monzonitic granite in the Liangcheng area of Inner Mongolia was classified as Early Archean intrusive rocks (γ₁¹⁽²⁾)by the 1:200000 regional geological survey in the early 1970s. The rock was named porphyroid medium-coarse granite and called Manhanshan pluton. 1:250000 regional geological survey divided it into weakly-gneissic garnet monzonitic granite, weaklygneissic porphyroblastic biotite-garnet monzonitic granite and other different geological units. To further study the formation age of the garnet-granite, the authors conducted zircon LA-MC-ICP-MS U-Pb dating of weakly-gneissic porphyritic biotite-garnet monzonitic granite, and the results yielded an age of (1933.3±9.8) Ma, which represents the magmatic crystallization ages of the garnet monzonitic granites. Geochemical analyses show that the garnet monzonitic granites resulted from partial melting of the Neoarchean khondalite series, with the features of strongly peraluminous S- type granites. Combined with existing age data, it is held that the North China Craton occurred in large- scale tectono- magmatic thermal events during 1 900- 2 000 Ma (Middle Paleoproterozoic).

Abstract:This paper presents the zircon LA-ICP-MS U-Pb age, petrology, geochemistry and TTG intrusive rock combination of the Early Paleozoic granite from southeast edge of Dayao Mountain on the southwestern margin of Qinzhou-Hangzhou collision belt. The series of intrusive rock occurs as stocks or dikes with different sizes, which aligns in NE direction as an arc-like belt. According to the distribution of time and space, the intrusive rocks can be divided into two tectonic-magmatic belts: i.e., Gulong- Xiacheng Middle-late Ordovician gabbro diorite + TTG intrusive rock combination (445-475 Ma) and Luoping-Gupao Early Silurian granodiorite-granite rock combination (432-436 Ma). The intrusion with wide range of SiO₂ (51.56%-73.12%) is mainly characterized by low K₂O, high CaO and relative enrichment of Na (Na₂O>K₂O) and is dominated by meta-aluminum and weak peraluminum (A/CNK value ≈ 1), which exhibits evolution trends form low-K, cale-alkaline to high-K calc-alkaline series. Furthermore, the rocks have low total REE (ΣREE=67.82×10^-6-214.81×10^-6), showing chondrite-normalized REE patterns with weak-middle negative Eu anomalies and enrichment of light REE. In addition, the MORB normalized multi-element variation diagram clearly displays intensive enrichment of large ion lithophile elements such as Rb, Th, U and LREE and obvious depletion of Ta, Nb. These petro-geochemical characteristics indicate that the intrusive rocks belong to active continental margin granite rock combination. Combined with regional geological characteristics, the authors hold that the granite series, dominated by I-type granite with crust-mantel mixing source, is the product of typical continental margin, which recorded Early Paleozoic ocean-continent subduction-collsion event at the southeast edge of Dayao Mountain area. The polarity of the TTG intrusive rock combination and granodiorite-granite combination shows that, together with the Cathaysia Yunkai continental margin (subducting from northwest to southeast) adjacent to the east of Dayao Mountain, the oceanic subducation basalt slab, subducting from southeast to northwest, constitutes a bi-directional subduction-collision geodynamic mechanism.

Abstract:The ophiolite in central East Kunlun tectonic mélange belt along the east section of East Kunlun Mountains is mainly composed of serpentines, gabbro, diabase, basalt and peat siliceous rock. The LA-ICP-MS zircon U-Pb dating of the gabbro in ophiolite shows that the age is (537.2 ± 3.5) Ma, which indicates that the ophiolite was formed in the Early Cambrian. Detailed petrogeochemical studies show that the protolith of serpentines is peridotite and the rare earth element distribution curve has wide U-type characteristics. The gabbro displays obvious accumulate texture with varying degrees of Eu anomalies. The light rare earth is relatively high but the total rare earth is low. The light rare earth of basalt is relatively higher than heavy rare earth. And it shows systematic enrichment of LILE, no differences of HFSE and slight depletion of Nb and it also has double features of E-MORB and IAB. The ophiolite originated in back-arc basin which had been formed by the subduction of Proto-Tethys Ocean in Buqingshan- Anyemaqen before the Early Cambrian and then eventually formed a basin in East Kunlun region after extension.

Abstract:This paper reports the discovery of a special kind of metabasic-volcanics combination in Chenccai accretion complex of Zhejiang Province. It is mainly composed of amphibolite and hornblendite. Geochemical characteristics of the rocks are low Ti and high Mg. Their protoliths are tholeiite and calcalkali basalts. The rocks have low values of REE, and the average REE is 25.46×10^-6. The ratios of LREE to HREE and La_N toYb_N are lower, and the average of the ratios are respectively 1.87 and 1.30. The average of δ (Eu)is 0.97. The REE distribution model is similar to N-MORB and T-MORB. Trace elements show enrichment of incompatible elements Cr, Ni and LILE such as K, Rb, Ba and U and depleted in HFSE such as Nb, Zr, P and Ti. The geochemical characteristics are very similar to those of boninites. The ratios and discrimination diagrams of trace elements indicate that the metabasic-volcanics were formed in an intra oceanic arc. The discovery of the intra oceanic arc type metabasic- volcanics shows that Chencai Group resulted most probably from the subducted accretionary complex which contained ancient fragments of oceanic crust from the middle Neoproterozoic to early Paleozoic rather than the Cathaysia Block basement.

Abstract:The Jining Group is concealed low-grade metamorphosed strata in western Shandong Province. Based on isotopic ages and micropaleoplants analysis, combined with regional stratigraphic correlation and iron formations correlation, this paper discusses formation age of Jining Group. Results of isotopic age determination show that the genesis of zircon grains in dacite is complex, the upper intercept age of 7 points from 16 zircon analyzed points is 2522±7 Ma and the youngest age is 2487±7 Ma. In 30 pieces of rock samples, 11 samples were found to contain the microplants, which are mainly lower diversity simple spherical acritarchs, such as Leiosphaeridia, Trachysphaeridium and Stictosphaeridium. After comparison, it is considered that stratigraphic characteristics and metamorphic grade of Jining Group are similar to features of Proterozoic and Mesoproterozoic strata in North China, and are different from things of Neoarchean strata. Characteristics of seam of iron ore in Jining Group are unlike Neoarchean BIF in western Shandong Province and North China Craton; nevertheless, they are very similar to features of Yuanjiacun BIF in Shanxi Province. Synthetic analysis shows that Jining Group was formed in the transitional period from Archaean to Proterozoic. The thorough study is helpful to understanding the evolution of the regional geological environment in Archaean-Proterozoic period.

Abstract:The Jiangnan orogen is located between the Cathaysian and Yangtze blocks, where numerous Neoproterozoic igneous rocks have been identified, which provide a chance to study the mantle-crust interaction and plate tectonics of the earth's earlier history. The tectonic evolution of the eastern segment of the Jiangnan orogen seems to be clear, but the tectonic evolution of its southwestern segment remains controversial mainly due to absence of field relationship-consistent geochronologic framework. The Fanjingshan area is located in the northern portion of the southwestern segment of the Jiangnan orogen. 1:50000 geological mapping of that area revealed detail field relationship between different geological units, thus it is an ideal area to construct a reasonable geochronologic framework. This paper reports four in- situ zircon U/Pb dating results of mafic to ultramafic plutons which intruded the Neoproterozoic Fanjingshan Group. (deposition time 850- 830 Ma). The new data obtained by the authors demonstrate that the three gabbroic plutons crystallized at 813 Ma, 804 Ma, and 748 Ma, respectively. Combined with previously published geochronologic data, the authors hold that the magmatism that occurred in the southwestern segment of the Jiangnan orogen consisted of two stages: the Jinning-I stage (850 to 825 Ma) and the Jinning-II stage (820 to 750 Ma), which correspond to the sedimentation time of Fanjingshan and Xiajiang Groups, respectively. Between them is an angular unconformity. Such a magmatic geochronological framework is consistent with that of the sedimentary rocks. The tectonic setting of the Neoproterozoic tectonostratigraphy is not very clear due to the fact that regional tectonic setting remains unclear.

Abstract:Formation age, sedimentary environment and source rock characteristics of the Kunyang Group are problems of considerable controversy. In order to identify the provenance and tectonic setting of the Kunyang Group in central Yunnan, the authors analyzed the sedimentary assemblage and sedimentary facies of the Kunyang Group, and conducted LA-ICP-MS detrital zircon U-Pb dating of 3 metamorphic sandstone samples from the Kunyang Group, which yielded different youngest concordant ages for Huangcaoling Formation, Heishantou Formation and Meidang Formation, being 984.0 Ma, 945.0 Ma and 954.0 Ma respectively. Age spectrum of these detrital zircons reveals a wide age range from Archean to Neoproterozoic with prominent peak at ~1.0 Ga, ~1.35 Ga and ~1.73 Ga and the second peak at ~2.44 Ga, mainly concentrated on ~1.35 Ga and ~1.73 Ga. It is inferred that the Kunyang Group source area mainly experienced 1, 1.35 and 1.73-2.44 Ga tectonic thermal events, and the age of the Dahongshan Group in southwest Yangtze Block is about 1.7Ga. The period of tectonic thermal event in Greenvillian is from 1.0 Ga to 1.3Ga. The authors also analyzed the geochemical characteristics of 20 extremely low-grade metamorphic rocks from Kunyang Group. The result shows that source rocks of Kunyang Group are quartzose cyclic sediments, felsic rocks and some mafic rocks formed in active continental margin or continental island arc. It is concluded that, from late Mesoproterozoic to early Neoproterozoic (0.95-1.0 Ga), the Kunyang Group was formed in the foreland basin with its provenance mainly from the Dahongshan Group in southwestern Yangtze block and Grenville-aged island arc.

Abstract:Systematical geological section has not been established in Beijing plain area. Western Hills of Beijing were divided into 3 systems by R. Pumpelly in 1867 and 12 layers by F. V. Richthofen in 1871. The Sinian strata were limited to pre-Cambrian by A. W. Grabau in 1922. The Nankou geological section was divided into 7 formations by Tian Qi-juan in 1923. The Sinian strata were divided into 3 groups which were Nankou Group, Jixian Group and Qingbaikou Group by Gao Zhen-xi in 1934. The Qingbaikou Group was divided into 3 formations of Xiamaling Formation, Longshan Formation and Jingeryu Frmation by Qiao Xiu-fu in 1976. The Ming Tombs geological section was divided into 4 systems and 12 formations by Wang Chang- qing in 1980. In 1991, ‘Regional Geology of Beijing Municipality'divided Ming Tombs into 3 systems and 12 formations. This paper established a stratigraphic table in Beijing plain area and detailed Archean gneiss and Proterozoic strata. The Archean gneiss was discovered in Yufa"Xingre-1 Well"and Anding"Xingre-2 Well". The Jixian system from Jingre-70 Well, Jingre-59 Well, Jingre-71 Well and Jingre- 75 Well was cataloged. The Xiamaling Formation to be established and Longshan Formation and Jingeryu Formation of Qingbaikou system were also cataloged at Yizhuang Primary School of South Beijing.

Abstract:Archean metamorphic strata are widely distributed in Miyun and Huairou District in the northern mountainous area of Beijing. This area has experienced multi-stage geological tectonism and produced abundant mineral resources, and thus aroused much interest among geological experts both in China and abroad. This paper puts forward a new classification scheme of the metamorphic strata and the supracrustal rock on the basis of deeply and systematically studying Archean metamorphic formation, metamorphic conditions, deformation and metamorphism, isotope chronology and some other aspects, thus raising the research level of metamorphic rocks to a new height.

Abstract:A set of Neoproterozoic(820-635 Ma)sedimentary strata are developed in Hunan, Guizhou and Guangxi, which occur above the Wuling Movement and below the Zhendan System, serving as the formation of lift basin with the well developed succession and clear sedimentary boundary. The stratigraphic system, according to the stratigraphical division and correlation of the regional rock and strata in combination with the recent results of chronology, shows a completed distribution and evolution, successive strata, and a clear division mark; it therefore can be completely divided and contrasted. On the basis of the stratigraphic division and correlation, the authors formulated a stratigraphic framework, which presents a set of detailed and accurate data for studying the stratigraphic division and correlation of the Neoproterozoic ( 820- 635 Ma) sedimentary strata in the Yangtze Paleocontinent, and also offers the new resultant data for studying the Precambrian including the Neoproterozoic in China.

Abstract:The third revolution of stratigraphy was that of sequence stratigraphy, which uniquely focused on analyzing changes in facies and characteristics of strata. Lutonggou section in Hebei Province, characterized by sequential strata, evident and special sequence boundary and an ocean of sedimentary phenomena, is favorable for the sequence-stratigraphic division of the Cambrian in the North China Platform. Lithofacies in this section principally consist of micrite,oolitic limestone and dolomite, and sedimentary facies include tidal-flat facies, beach facies, ramp facies and shelf facies. The Cambrian strata in Lutonggou section can be divided into 9 third-order sequences according to the characteristics of sedimentary facies stacking patterns and long-periodic cycle change under the new chronostratigraphic system. Cambrian depositional succession, that was bounded by the third-order sequence"TST+CS+HST"formed by Series 3 Xuzhuang Formation, changed from the mixed tidal flat to the ramp carbonate deposits. At the same time, the sequence type changed from the succession dominated by the"TST+HST"to the drowning unconformity dominated by the"CS+HST". Furthermore, abundant stromatolite bioherms suggest a special depositional phenomenon that the skeleton- poor stormy sea in the late Cambrian was marked by the increase of microbial carbonate together with the radiation of metazoan. The sequence stratigraphy research on the Lutonggou section of Cambrian strata based on the characteristics of facies superposition and cycling will give a typical example for the sequence stratigraphy division of widespread Cambrian strata in the northeast of North China Platform, and also provide more ideas for the widespread tracking and correlation.

Abstract:Ordovician strata in central- southern Hunan consist of"finer clastic-chert- bearing series-coarser clastic rock", and their thickness varies regularly. Spatially, the thickness contours are distributed northeastwards nd meanwhile, the thickest tends to move southeastwards. In the study area, chert samples of Yanxi Formation in Lingkou section show high SiO₂ values (89.08 %- 94.32%) and Al/(Al+Fe+Mn) ratios (0.52-0.79), and are characterized by slight enrichment of LREE and no obvious cerium and europium anomalies. Samples of equivalent formation in Daqiao section shows high SiO₂ values (91.74 %-95.14%), and the Al/(Al+ Fe+Mn) ratios range from 0.34 to 0.56, with characteristics of LREE enrichment, intermittently negative cerium anomaly and no europium anomaly, and low Y/Ho ratios (20.65±1.63). Geochemical characteristics and discrimination diagrams of middle-upper Ordovician cherts in central-southern Hunan indicate that these rocks were bio-genetic and formed in an open continental margin. A correlation with equivalent formation in adjacent areas shows that these cherts have similar origins and sedimentary environments, which indicates that they formed in the same basin. Combined with the analysis of the iso-thickness diagram, it could be suggested that the basin in central-southern Hunan experienced the change from passive margin to foreland basin during Ordovician, and the cherts probably resulted from this transition. In addition, there is no obvious hydrothermal activity, suggesting the geodynamics that caused the uplift of Cathaysian block might have been located to the further southern or southeastern extension range of the cherts series in central-southern Hunan.

Abstract:The Youjiang Basin in western Guangxi is a late Paleozoic-Mesozoic compound rift basin on the southwestern margin of Yangtze landmass. Under the regional extensional system, there appears the structural framework of extension-dominated alternate basin- platform and horst- graben style fault block structure. Structural- sedimentary event layers such as Permian sponge reefs, synsedimentary breccias belt and turbidite series are well developed, suggesting a marginal platform slope environment. In the interior or on the margin of the platform, there are parallel, micro- angle or overlap unconformities dominantly between upper Devonian and lower Carboniferous, between upper Carboniferous—lower Permian and middle Permian, between upper Permian and middle Permian, and between lower Triassic and middle Triassic strata, which respectively reflect four unconformable structural events of Liujiang orogeny, Qiangui epiorogenic event, Dongwu revolution, and Guixi movement. Based on the summarization of Late Paleozoic-Triassic extensive structural features of the Youjiang Basin, this study aims at providing useful reference for the investigation of the dynamics background and evolution mechanism of the Youjiang Basin, western Guangxi.

Abstract:The lithospheric evolution of Hebei- Beijing- Tianjin region constitutes a complete tectonic evolution cycle. The lithosphere experienced multi- stage evolution, comprising tension cracking (non- orogenic) at the early stage of Late Triassic, stable transition at the late stage of Late Triassic (pre-orogenic), squeeze intraplate orogeny between the Early Jurassic and middle stage of Early Cretaceous (sym- orogenic), and stable transition during Cretaceous- Paleocene (post- orogenic). During the intraplate orogenic process of Yanshan tectonic cycle, the original cratonic lithosphere was strongly transformed and rebuilt, and formed a new orogenic lithosphere, which seems to have been the most important content of the Yanshan tectonic cycle and the substantive result of intraplate orogeny.

Abstract:As the first named location of the Ordovician Zhongbao Group, Shihuigou area in Yongdeng County of North Qilian Mountain is an ideal place for the study of the Ordovician tectonic evolution of North Qilian orogenic belt. On the basis of the measured stratigraphic section, the Zhongbao Group in Shihuigou area can be divided into upper and lower part respectively: the lower part mainly consists of mafic-intermediate volcanic rocks and pyroclastic rocks, whereas the characteristics of the upper part is the existence of carbonate, cherts and siltstone interbedded with intermediate-basic pyroclastic rocks. Field investigation shows that there are many layers of cherts and strong deformation in the upper part of the Ordovician Zhongbao Group. According to the study of the rock assemblage, stratigraphic sequence, sedimentary facies, volcanic eruption facies, deformation features and spatial combination relationship, this set of special sedimentary strata are considered to be the typical olistostromes. Considering its internal structure and volcanic-sedimentary succession, the authors hold that the olistostromes should be deposited in the deep-water basin near the island arc, which belonged to a tectonic background of archipelagic ocean. The discovery of olistostromes in the Zhongbao Group provides reliable evidence for recovering and establishing the Ordovician sedimentary environment and paleogeographic evolution of the North Qilian orogenic belt. It also offers important sedimentologic evidence for further studying the trench-arcbasin system spatial pattern of the North Qilian orogenic belt.

Abstract:This paper describes the geological results of 1:50000 geological survey conducted in the West Kunlun Mountains area in Xinjiang. The data were obtained by using profiling and regional geological mapping methods on the Devonian strata of the Karakorum Mountains stratigraphic region. New data concerning lithology and lithofacies, rock association characteristics, contact relationship, biological fossil and the basic sequence were collected. Multiple stratigraphic division and correlation were studied. The Devonian strata were divided in upward succession into Dawangding Formation (Middle- Lower Devonian), Huangyangtan Formation (Middle Devonian), Luoshigou Formation (Middle Devonian) and Tianshendaban (Upper Devonian) Formation, exhibiting comfortable contact relationships. Abundant fossils were found in the Devonian strata except Tianshendaban Formation. Two new formations (Dawangding and Huangyangtan) and six new biostratigraphic units (comprising 3 brachiopoda units, 1 coral unit, 1 ammonite unit, and 1 trilobita unit) were established. Huangyangtan Formation is the major regional ore-bearing bed with gypsum. The lithostratigraphic sequence, biostratigraphic sequence and chronostratigraphic sequence of the Devonian strata in the working area were newly redefined and improved systematically. The study has not only improved the research degree of the Devonian strata in the Karakorum Mountains area but also offered necessary geological history data for the analysis of the geotectonic evolution and the metallogenic regularity in the working area.

Abstract:The Amushan Formation has been widely used since its founding. It was once synonymous with the Upper Carboniferous of Inner Mongolia geosyncline zone in the last century. With the improvement of geological research, the subdivision of tectonic units, stratigraphic regionalization and other changes have also occurred. Based on a comprehensive study of regional data, the authors hold that the Amushan Formation is the deposition production of the northern Late Paleozoic continental margin of North China plate, and the outcropped areas are restricted to south of Solon- Siramulen River fault. It was formed during the upper Carboniferous-Lower Permian period (C2-P1), and its limestone layer is rich in fusulinids, corals and other fossils. The Amushan Formation and the Sanmianjing Formation are products of different stratigraphic subdivisions in the same stratigraphic region.

Abstract:The Coqen Basin has recently become one of the important areas of mineral exploration in Tibet, and the Chuanba area in northern Coqen Basin is the prospective area for coal resources. The lower Cretaceous strata in Chuanba area consist in upward succession of Zelong Group, Duoni Formation and Langshan Formation. On the basis of the outcrop section sedimentary facies analysis and the lithofacies type summarization in combination with regional data analysis, the lower Cretaceous strata can be divided into 7 sedimentary facies, i.e., neritic muddy shelf, carbonate platform, mixed platform, tidal flat, braided river delta, fan delta and braided river. Zelong Group, composed of pyroclastic rocks, fine conglomerate, pebbly sandstone and sandstone, develops fan delta sedimentary facies. Duoni Formation, composed of fine conglomerate, sandstone, siltstone, mudstone, limestone, carbon mudstone and coal, develops neritic muddy shelf, mixed platform, braided river delta and braided river facies. Langshan Formation, composed of limestone, mudstone, siltstone and fine stone, develops tidal flat, mixed platform and carbonate platform sedimentary facies. The study of coal accumulating process based on an analysis of sedimentary environment showed that the interdistributary bay of braided river delta plain in Duoni Formation was the main coal-forming environment. The Agesang-Chuanba area and its eastward extensional area are the main zones of coal accumulation in the study area.

Abstract:Quaternary geology and geomorphology map is one of the series of maps in the second edition of the National Regional Geology Annals, with special attention paid to the close integration with ecological environment and geological disasters. The map includes such important geological contents as Quaternary geological epoch, genetic type, combination type of lithology and geomorphology genesis, active faults and transgression range with the attachment of the typical profiles of Quaternary geologygeomorphology and important landscape attractions. The map has the following characteristics: (1) Digital elevation model (DEM) grayscale image is for the first time used as background for the geographic base map. (2) Quaternary geology features and geomorphologic genetic types are compiled on the same map. (3) The colors of Quaternary geological bodies are indicated by the colors of genetic types. (4) Geomorphologic part is divided into different levels of morphological types and geneses of distinctive micro-topography attractions. In short, the map is a brand new one with three-dimensional drawing, obvious terrain elevation, fine arrangement, bright color, and availability for disaster prevention and control and geological tourism applications.

Abstract:The Holocene strata of central Inner Mongolia were investigated using sedimentological features and 14C\OSL dating data. The authors present two Holocene profiles that illustrate different sediments from a sand dune in Haoluku, and a lake in Huitengxile. Holocene stratigraphic boundaries are defined by lithological indicators and dating results. The Holocene sequences can be divided into three units. In Huitengxile Lake, the beginning (11.4 ka) of the Holocene was associated with a lake level rise, which led to lithological succession from fluvial clastic sedimentation to lacustrine organic deposition. Sand dune was formed during this period (about 12.5 ka). During the middle Holocene, typical limnological facies (8.2 to 4.5 ka) appeared in Huitengxile Lake, and the climate turned to be warmer and more humid with the occurrence of thick palaeosoil layers (7.0-2.3 ka) in the dune. Evolution of lacustrine environment followed by nearshore environment was evident from 4.5 ka in late Holocene in Huitengxile Lake, and the period (2.3 ka~) of sand dune reactivation during the drought stage was recorded.

Abstract:The Quaternary stratigraphy of twenty basins in Qilianshan Mountain and adjacent areas includes Guide Basin, Xunhua- Hualong Basin, Tongren Basin, Xining Basin, Menyuan Basin,Linxia Baisin, Lanzhou Basin, Dingxi Basin, Tianshui Basin,Subei Basin, Jiuquan Basin, Yumen Basin, Zhangye Basin, Wuwei Basin, Har Lake Basin, Suli Basin, Muli Basin, Minhe Basin, Gonghe Basin, Qinghai Lake Basin and Qaidam (N) Basin. The authors studied these basins based on the previous data and field investigations. Characteristics of Quaternary tectonic landform evolution, sedimentary sequence of basins, palaeontology and paleoclimate were used as the basis to make stratigraghic division and also to unify the name of parts of sequences. The general characteristics of Quaternary sedimentation of the study areas are as follows: Loess is widely distributed in the east (central Gansu Province) with the thickest loess in the world. Alluvial fan and aeolian deposits are distributed in the north (Gansu Corridor). Pluvial-alluvial and lacustrine deposits are distributed in the south (north Qaidam Basin), followed by aeolian sand and loess of late Pleistocene. The transition from lake to alluvial and aeolian deposits happened at the Gonghe Basin. Qinghai Lake has lasted for a long time. Moraines, pro-glacial and river terrace are distributed in the high mountains in the middle and west. According to the above characteristics and principles, the sedimentary sequences of Qilian Mountain and adjacent areas are divided into the following realms: Lanzhou- Xining stratigraphic realm, Guide stratigraphic realm, Jiuquan- Zhanagye stratigraphic realm, North Qaidam Basin stratigraphic realm, Gonghe stratigraphic realm, Qinghai Lake stratigraphic realm and Subei-Menyuan stratigraphic realm.

Abstract:Beijing plain, located in the piedmont alluvial fan area, has lots of lakes and rivers in its administrative area. Because of the variability of sedimentary environment, the three-dimensional structure is very complex. Due to the complexity of the threedimensional structure of the Quaternary strata, the Quaternary stratigraphic division is relatively difficult to some extent. Some researcher have established the lithostratigraphic units such as Nihewan Group, Zhoukoudian Group and Malan Group based on some geological data from different sources. These stratigraphic units are mainly based on fossil pollen, foraminifera, and Ostracoda in sedimentary sag drill holes, and a small amount of paleomagnetic data, and are actually the chronostratigraphic units. Because the units are not uniform and the identification mark is not clear, it is difficult to get a broad consensus. In the past 10 years, the increase of the accumulation of data, the understanding of the three-dimensional structure of the Quaternary, and especially the popularity of the ancient magnetic prospecting technology have laid the foundation for the division of the Quaternary strata in Beijing plain. Based on paleomagnetic data from more than 40 drill holes, the authors initially established the bottom boundaries of lower, middle and upper Pleistocene series. According to the engineering geological prospecting, hydrogeological drilling, archaeological excavations and peat investigation materials, the authors compiled a Holocene isopach map for Beijing Plain.

Abstract:In this paper, a magnetostratigraphic sequence of drill hole was established on the basis of analyzing the deep drill hole data from the northern districts of Beijing plain, such as Changpin, Shunyi and Chaoyang, especially on analyzing magnetostratigraphy and pollen in Houshayu region. In combination with the research onthe activity of Nankou-Sunhe fault, Shunyi fault and Huangzhuang-Gaoliying fault, the authors determined Quaternary stratigraphic framework of Houshayu sag. The results shows that the bottom boundaries of lower Pleistocene, middle Pleistocene and upper Pleistocene of G3 drill hole are 511.7 m, 175.5 m, and 31.6 m respectively in Houshayu sag. In the late Yanshanian period, Houshayu sag was formed by the combined action of NE-trending Sunhe fault, NW-trending Nankou-sunhe fault and Huangzhuang-Gaoliying fault which controlled the western boundary of Beijing sag.In the Quaternary, the variability of the rate objectively reflects the characteristics of rise or fall of the blocks. Housahyu sag located in the hanging wall of the Huangzhuang-Gaoliying fault and the footwall of Shunyi fault were formed by the mutual movement between fracturesduring the Quaternary sedimentation, with the deposition rate of the sag in the early, middle and late Pleistocene being respectively 0.198mm/a, 0.255mm/a, and 0.243mm/a.

Abstract:The tectonic pattern of Beijing area in Tertiary was"two uplifts and one depression". Due to the strong activity of the north part of Sunhe fault since the Quaternary period, new Quaternary depression basin, i.e., Shahe depression, was separated from the above pattern. The authors conducted research on Quaternary magnetic stratigraphy of drill hole ZK3 in Shahe depression. In combination with the 14C isotopic dating results, the authors obtained the depth of the bottom of the strata in early Pleistocene, Middle Pleistocene, late Pleistocene and Holocene, being 439.8 m, 157.4 m, 87.7 m and 7.2 m respectively. On such a basis, the authors established the Quaternary stratigraphic sequence of drill hole profile. The Quaternary deposition rates were 0.19 mm/a, 0.11 mm/a, 0.70 mm/a and 0.63 mm/a. A comparative analysis of the activity regularity of the basin- controlling fault, i.e., Nankou- Sunhe fault, and characteristics of Beijing Xishan (Western Hills) uplift shows that since the Quaternary period, influenced by Beijing Xishan uplift, the contemporaneous faults that controlled Shahe depression, i.e., Nankou Sunhe faults, activated strongly, and controlled the evolution of Shahe depression. The variation rule of average deposition rate of the strata in the drill hole, the mountain uplift rate and the fault activity rate have a good response relationship.