Abstract:Abstract：The Qinghai-Tibet Plateau is the highest, largest and youngest plateau in the world, known as the best natural laboratory for understanding continental geodynamics. The formation and evolution of the Tethys and the uplift of the plateau constitute two major themes in the study of the Qinghai-Tibet Plateau. Of many scientific problems, eight have been reviewed in this paper, namely, the formation and evolution of the Tethys; Indo-Asia continental collision; the structure and composition of the crust/mantle of the Qinghai-Tibet Plateau; the origin of the extremely thick crust in the plateau; lateral deep crustal and asthenospheric mantle；mantle plumes; uplift and growth of the plateau；mineralization.

Abstract:Abstract：The Qinling Orogen in central China has been a long-term geologicalyl studied focus for its unique tectonic location, complicated geological history and abundant mineral resources. In previous studies geologists have clarified its tectonic framework, outlined its geological evolution, and reached a consensus that the final transition from marine basin to intracontinental mountains occurred in Indosinian (Triassic：251~199.6 Ma). However, the details of basin-to-mountain transition process, the age of final oceanic closure, the nature of Triassic tectonic setting, and the associated magmatism and mineralization in the area have been poorly constrained and hotly debated. Based on a comprehensive re-assessment of results from geological, geophysical, geochemical and ore deposit studies, the author compares the Triassic Qinling with present Mediterranean Sea, which contemporaneously accommodates oceanic slab subduction and intercontinental collision as well as gradual transition from oceanic subduction to intercontinental collision. The Qinling paleo-Tethys finally closed in a westward zipper-like way during the period of 230~200 Ma, and instantly followed by intercontinental collision between the Yangtze block and Qinling-North China united continents. Therefore, the Triassic tectonic setting in Qinling was neither a simple intercontinental collision, nor a post-orogenic or post-collisional regime. Indosinian magmatism was intensive in Qinling, forming igneous rocks including at least the adakites, calc-alkaline granitoids, high-K calc-alkaline granitoids, alkaline intrusions, Rapakivi-like granites, and carbonatites. These rocks show zoning spatial distribution, namely, northward from the Mian-Lue suture, the Yangshan-Yanzhiba peraluminous S-type granite belt, southern Qinling high-Mg and adakitic calc-alkaline granite belt, northern Qinling high-K calc-alkaline granite belt, and the carbonatite-alkaline intrusion belt at the southern margin of North China craton. Such Indosinian magmatites with distinctive petrologic complexity, lithologic diversity, spatial zonation and compositional polarity cannot be formed in syn- and/or post-collisional tectonic settings, but could have resulted from a northward paleo-Tethysan slab subduction along the Mian-Lue geosuture. Although the Indosinan mineralization has been ignored for a long time, a great number of Triassic ore deposits of economic significance have been recently discovered, including Molybdenum-containing carbonatite dykes, porphyries and orogenic-type quartz veins; orogenic-type, porphyry-/breccia pipe-type, and Carlin-type and Carlin-like gold deposits; and orogenic-type silver-dominant poly-metal deposits. This shows that mineralization of various genetic types strongly occurred in the transition regime from oceanic slab subduction to intercontinental collision, and that the Indosinian ore deposits are of exploration potential in Qinling Orogen.

Abstract:Abstract：This paper systematically deals with the process of geodynamic evolution in Central Asia and its adjacent areas as well as the regional geology and metallogenic characteristics conditioned by such action, and presents new cognitions and opinions as follows: ① The original Paleo-Asian Ocean zone between Siberian landmass and Sino Korean-Tarim landmass is the special zone of “double-direction accretion” which includes both double-direction side accretion and vertical accretion developed in the same time in the history of geology. ② The “clustered continents of Paleo-China” are independent paleocontinents between Laurasia and Gondwanan. Due to their special location, they form the watershed between Paleo-Asian Ocean and Paleo-Terhys. ③ In the final analysis, the “inter-power” of geodynamics comes from two sources: the first source is the centrifugal force (tension) and extrusion force formed by the rotation and revolution of the earth, constituting the basis of geodynamics. The second source is the eternal “high heat energy bank” in the earth’s interior. The present earthquakes and volcanic activities all result from geological events of the instantaneous change from heat to powerful kinetic energy when the ultrasaturated high heat energy is released from the earth’s surface. ④ These fracture systems with different characteristics caused by the geodynamic system are good ore-controlling and ore deposition space. Hence the “mineral prediction method with fracture system” is one of the simple and effective methods. On such a basis, four test and verification zones of mineral prediction are advanced.

Abstract:Abstract：Based on an analysis of gravity data and regional geological structure in combination with the achievements made by previous researchers, the authors summarized the 3D lithospheric tectonic macroscopic characteristics of China’s land and seas detected by the geological-geophysical map compilation group and other researchers, and applied the Block Tectonics Theory to interpret the tectonic macroscopic framework of China’s land and seas. On such a basis, the authors divided the study regions into three tectonic domains or more than 20 blocks, analyzed the characteristics of the three tectonic domains and block units, and indicated that Indosinian movement resulted in the fundamental change of the lithospheric stress field and created the conditions for the formation of present tectonic macroscopic framework.

Abstract:Abstract：Recent researches on the northern margin of the North China Craton (NCC) and its adjacent areas have been mainly focused on the main pre-Yanshanian tectonic framework and the late Mesozoic tectonomagmatic evolution and lithosphere destruction. This paper gives a brief review on the previous research progress and future prospect in this aspect. The northern NCC has undergone multiple magmatic processes after its cratonization during ~1.8 Ga. Large volumes of 1.35-1.30 Ga mafic sill (dyke) swarms in northern NCC are related to the breakup of the NCC from the Columbia supercontinent and might indicate that the NCC was probably a member of Nena including the Laurentia (North America and Greenland), Siberia and Baltica cratons in the supercontinent. The evolution of the northern continental margin of the NCC was probably initiated at 1.35 Ga. During the Early Paleozoic, the Bainaimiao island arc belt was located to the south of the NCC. At the end of Early Paleozoic, the island arc was accreted to the NCC probably by arc-continental collision. Early-Middle alkaline complexes with emplacement ages ranging from 410-380 Ma in northern NCC are probably related to the extension after arc-continental collision between the NCC and the Bainaimiao arc terrane. From the Late Carboniferous (~320 Ma), the northern margin of the NCC became an Andean-style continental arc due to the southward subduction of the Paleo-Asian oceanic plate beneath the NCC. The southward subduction of the Paleo-Asian oceanic plate also occurred in the Xing-Meng orogenic belt during this period, which resulted in the formation of the Baolidao island arc. Final closure of the Paleo-Asian Ocean and collision between the Mongolian arc terrane and the NCC occurred during the latest Permian~earliest Triassic period with post-collison magmatism from ~250 Ma. During the Late Triassic~Early Jurassic period, the northern NCC is characterized by strong thrusting. In the early Jurassic, the Archean-Paleoproterozoic basement metamorphic rocks were widely exposed. The tectonic framework of the northern margin of the NCC and its adjacent areas was preliminarily established prior to the Yanshanian tectonism and magmatism.

Abstract:Abstract：A comparative study of geotectonic cycles and evolution characteristics of the tectonic domain from the Atlantic Ocean to Paleo-Asia Ocean on the global scale is beneficial to understanding the regional tectonic evolution of the giant tectonic domain. The establishment of the concept of “dynamic behaviors” of the attributes of paleocontinents tectonic units and the correlation analysis of the composite orogenic area and its neighboring tectonic units have revealed that the formation and development of the North China foreland basin were closely related to the tectonic evolutionary process of the neighboring composite orogenic area. In North China and its northward areas, Late Paleozoic-Early Mesozoic tectonic framework has the following features：1）In the Mongolian-Da Hinggan composite orogenic area, Paleozoic fold belts were interwoven with intermediate massifs, leading to the development of the epicontinental sea basin and the aulacogen and superposed basins during the Carboniferous-Permian period and the inter-mountainous basin during the Triassic period, based on the fold belt of the earlier stage. 2）The foreland basin in North China was developed synchronically with the tectonic evolution process of the northern composite orogenic area and formed the marine facies, marine-continental interaction sediments on the old land during the Carboniferous period and the continental facies sediments during the Permian-Middle Triassic period, characterized by red bed and gypsum salt in local areas. 3）The “tectono-magmatic activation belt” on the North China continental margin in the Late Paleozoic?Early Mesozoic period was the southernmost tectonic unit of the Mongolian-Da Hinggan composite orogenic area.

Abstract:Abstract：Since the Yanshanian movement, enormous tectonic transformation has taken place in eastern North China. The tectonic pattern transformed from the conjunction-enlargement between North China platform and Yangtze platform in the end of Indosinian movement to the evolution of mantle plume and regional extensional faulting. In the process of North China mantle plume uplifting, the plume was blocked by the bottom of the lithosphere and mushroomed outwards. With the thinning and faulting of the lithosphere, detached plastic mantle rocks were cut by the ductile shearing zone in the surrounding areas of the basin, which resulted in anatectic magmatism. The anatectic magmatism drove the uplifting of country rocks and formed a series of secondary uplifts (mantle branches). Then the landform in eastern North China transformed from high plateau into a coupling pattern of one basin with multiple mountains——a spatial pattern of heat thinning fault basin on the top of the mantle plume with a series of surrounding mantle branches. The faulting basin in eastern North China is coupled westward with Taihang orogenic belt, northward with Yanshan orogenic belt, eastward with Korean peninsula, and southward with Dabieshan orogenic belt (central fault basin with surrounding mantle branches).

Abstract:Abstract：Northeast China area consists of several micro-continental blocks, such as Jiamusi Block in the southeast, Xing’an-Songliao Block in the middle, and Erguna blocks in the northwest. Studies of the suture zones between the blocks indicate that the amalgamation of these blocks ended before Late Paleozoic and formed a big continental block, i.e., Jia-Meng Block. From Late Paleozoic the cover sequences started to develop and formed a Late Paleozoic continental margin cover sequence.The tectonic setting of the southern margin of the Jia-Meng Block was an active continental margin during early Paleozoic. The Paleo-Asian ocean plate broke down during the northward subduction around 320 Ma, and formed a volcanic arc. Meanwhile the Hegenshan back-arc basin ocean was opened. The continuous northward subduction resulted in the arc-continent collision, and the Hegenshan Ocean was closed at 280 Ma. The tectonic setting changed from active margin to passive margin. Finally the Paleo-Asian ocean was closed at the end of Late Permian, and the whole area became an intracontinental terrestrial setting.

Abstract:Abstract：In this study, seismicity background, stress fields, seismogenic tectonics and dynamics for the 2008 Wenchuan M8 Earthquake were investigated employing earthquake focal mechanisms, source fault parameters and coseismic displacements from GPS. The results suggest that the 2008 Wenchuan M8 event occurred under the tectonical motion in and around the Qinghai-Tibet plateau during a seismically active period since 2001. The Wenchuan M8 event with the 300 km long earthquake fault occurred on the eastern edge of the Qinghai-Tibet plateau, which filled the seismicity gap zone lacking M8 event from 1990. The eastward extensional motions of the Tibetan plateau and the counter action constitute the main tectonic property. The M8 Wenchuan event and its strong aftershocks occurred under a seismogenic stress field where P-axes align stably in NWW-SEE direction. It implies that the seismogenic stress field for the Wenchuan M8 event is mainly attributable to the actions of the stress fields lying on the southern segment of NSSB, the Shichuan basin and the South China block. The results from the source fault parameters and coseismic displacements from GPS suggest that the tectonic movement of the up-eastward slip of the Qinghai-Tibet plateau on the western side of the Longmen Mountain and the relative down-westward slip of the Sichuan basin might have been the causative mechanism of the 2008 Wenchuan M8 event.

Abstract:Abstract：Zhanggongshan area is located in the junction zone between Anhui Province and Jiangxi Province. The flysch formation, consisting mainly of continental margin epimetamorphic fine clastic rocks and subordinately of volcanic rocks, is widely distributed in the area. A mass of high precise isotopic dating shows that the epimetamorphic strata might have been formed in Neoproterozoic between 820 Ma and 840 Ma. On the basis of a systematic field investigation, 5 stages of fold deformation were recognized through the analysis of the strata. F1 is the outcrop scale rootless intrafolial fold shaped in tight congruous fold and recumbent fold with original bedding (S0) as he deformation face; F2 is nearly EW-trending open inclined fold and congruous fold with early structural foliation as the deformation face; F3 is the tight congruous fold or inclined fold related to large scale thrust nappe; F4 belongs to penetrative asymmetrical tight shear fold group related to heat uplift of Yanshanian granitic magmas; F5 is a plunging vertical fold distributed near the regional brittle shear strike-slip faults zone. These folds correspond to different tectonic cycles respectively. This paper emphatically describes the geometry, superposition pattern, deformation order and kinematic characteristics of fold deformation, and analyzes the deformation mechanism and geocontinental dynamics.

Abstract:Abstract：Bouguer gravity anomaly data from Qinghai-Tibet plateau were processed by the match-filter method. According to he first order vertical derivative radial average logarithmic energy spectrum curves, the Bouguer gravity anomaly in Qinghai-Tibet Plateau can be divided into three layers．The Longmuco-Shuanghu tectonic zone is always discerned in the middle and deep gravity anomaly field, whereas the Geji-Gaze-Cuoqen-Shenza concealed fault is always existent in the shallow and middle gravity anomaly field. There is a huge and smooth low gravity anomaly contour line encirclement in Qiangtang terrane of northern Tibet，and there exist a series of WE-trending gravity anomaly blocks in southern Tibet.

Abstract:Abstract：The newly marked Precambrian stratigraphic column of China was discussed by the Subcommission on Precambrian of National Commission on Stratigraphy of China on November 24, 2009. According to the common understanding reached at this meeting, Changcheng System comprising Changzhougou, Chuanlinggou, Tuanshanzi and Dahongyu Formations is limited in 1.8-1.6 Ga, whereas the Jixian System consisting of Gaoyuzhuang, Yangzhuang, Wumishan, Hongshuizhuang and Tieling Formations is limited in 1.6-1.4 Ga. The unnamed system (1.4-1.0 Ga) only includes Xiamaling Formation in the Jixian section. The Qingbaikou System composed of Luotuoling and Jing’eryu Formations is limited in 1.0-0.78 Ga. The Nanhua System is between 780-635 Ma and the Sinian System is between 635-542 Ma in age. According to a series of SHRIMP U-Pb dating data from late Precambrian in Jiannan orogenic belt, the strata should be assigned to the upper part of the Qingbaikou System. Moreover, new zircon U-Pb dating data obtained in North China Platform reveals the existence and distribution of the volcanic province. In dealing with the basic global geodynamics, it is useful to set up a basic late Precambrian section with unified and high-precision chronological dating.

Abstract:Abstract：Located on the northern side of the eastern section of Jangnan orogen, Lushan area has outcropped metamorphic rocks of Pre-Sinian Xingzi Group and Shuangqiaoshan Group. Recently, the authors found a suite of spilite-ceratophyre with pillow structure in strata of Shuangqiaoshan Group. An analysis of element geochemistry reveals that the spilite-ceratophyre and the concomitant dacite have the characteristics of oceanic-island basalt, hence their formation environment should have been a back-arc small oceanic basin upside continental crust. The authors thus hold that the suture of southern Jiangxi (Shexian County) had an approximately EW strike, and extended straightforward to Lushan area of northern Jiangxi, whereas the Jiangnan orogen remained not closed from 830 Ma to 850 Ma. It is also held that the Shuangqiaoshan Group is a component part of the basement of “poly-basement with one cover” in the middle-lower Yangtze block.

Abstract:Abstract：A study of Re-Os isotopic chronology of molybdenite suggests that the metallogenic age of the Anqiantan tungsten ore deposit in south Jiangxi area within eastern Nanling region is about 156 Ma and that of the Yuanlingzhai molybdenum ore deposit is about 160Ma. Statistics indicate that there occurred 3 epochs comprising 6 stages of mineralization during Mesozoic in the eastern and central parts of the Nanling metallogenic belt. These stages are about 225 Ma and 195 Ma of Indo-Chinese period, 170-160 Ma, 160-150 Ma and 150-145Ma of Early Yanshanian period, and about 135 Ma and 100 Ma of Late Yanshanian period. The mineralization during Early Yanshanian period is the strongest one, so that Early Yanshanian is the major metallogenic period for tungsten and tin ore deposits in the eastern and central parts of the Nanling metallogenic belt. There exist independent W-Sn polymetallic ore deposits, Sn ore deposits, Cu-Pb-Zn polymetallic ore deposits and Mo ore deposits. Combined with an analysis of metallogenic chronology, the authors hold that there might exist undiscovered or neglected mineral resources in the horizontal direction as well as metallogenic potential at the depth of the known ore deposits in the vertical direction. This study has provided theoretic basis for geological prospecting in the second space of the eastern and central parts of the Nanling metallogenic belt.

Abstract:Abstract：Qiangtang basin located in northern Tibetan plateau is a key area in studying the evolution of the Paleo-Tethys Ocean and the boundary of Gondwana and Eurasia, and the age and properties of its basement directly determine the tectonic attribute of southern Qiangtang plate and the range of Gondwana. In this paper, LA-ICP-MS U-Pb dating was carried out for zircons from granitic gneiss inclusions (xenoliths) in Wugong Mountain area, central Qiangtang. The dating results show that granitic gneiss inclusions were formed in late Triassic (209.1±2.8Ma). This age is consistent with the existing research results of the convergence events of Gondwana and Eurasia in central Qiangtang, so the granitic gneiss inclusions are material records of the convergence events of Gondwana and Eurasia. Moreover, the dating results also indicate that granitic gneiss inclusions contain a age record of the end of Pan-African period (464.5±4.8Ma), which is the first age of Pan-African movement found in Qiangtang area, and this age can be compared with ages of large amounts of early Paleozoic granitic rocks in Nujiang area and Baoshan area in western Yunnan, internal Indian plate and Himalayan orogenic belt, suggesting that southern Qiangtang plate has good affinity to Indian plate. All the results obtained by the authors can provide fresh evidence for the study of the properties of Qiangtang basement and the age of the convergence events of Gondwana and Eurasia.

Abstract:Abstract：Quartz-diorite intrusion is spatially and temporally associated with the REE-Sc mineralization in the Yijiang REE-Sc deposit, Rucheng County, Hunan Province. To constrain the age of the quartz-dioritic pluton related to REE-Sc mineralization, the authors conducted U-Pb analysis of zircon. Hafnium isotope data were also acquired through laser-ablation multi-collector ICPMS analysis of the zircon, with the aim of gaining an insight into the age and nature of the source region of the pluton. The yielded age (424±3 Ma) confirms that this quartz-diorite intrusion belongs to the Caledonian period. Hafnium analysis shows that the Caledonian quartz-diorite has negative and variable εHf values (-1.9 to -7.6) and Palaeo-Mesoproterozoic (1.5 to1.9 Ga) depleted-mantle model ages, which is interpreted to reflect derivation from an isotopically heterogeneous mantle-crust mixed source. The source region of these magmas might have been correlated at least with Palaeo-Mesoproterozoic materials of the South China Block, which has been held to underlie Hunan Province; however, further work is necessary to demonstrate this suggestion.

Abstract:Abstract：Some zircon dating data of the tuffaceous bed are reported for the first time from the Sibao and Xiajia groups in Guanxi and Guizhou. In combination with the SHRIMP U-Pb dating of the granite that intruded into the Sibao Group, the Xiajia Group is determined to be of Late Neoproterozoic. These isotopic data are very important for us to redefine the age of the Sibao Group and to conduct regional correlation of strata in the corresponding period and tectonic evolution. The Sibao Group (the same as the Fanjingshan, Lengjiaxi and Shuangqiaoshan groups) and the Danzhou Group (the same as the Xiajiang, Banxi and Heshangzheng groups), which are subsequent metamorphosed rocks well developed in the Jiangnan Orogen, formed a metamorphosed basement of the Jiangnan Continent. In the past, the Sibao Group, which constituted the main part of the Sibao Movement, was designed to Mesoproterozoic, and the determined age still affects the stratigraphic subdivision and correlation of the metamorphosed rocks in whole Jiangnan Continent and restricts the determination of the geological background and metallogenic conditions of the Jiangnan Orogen. Based on studying zircon from bentonite in the Sibao Group and overlying strata, the authors accurately dated the zircon at (814.0±6.3) Ma in the Jialu Formation, and (773.6±7.9) Ma in the Qingshuijiang Formation. The series of zircon dating data have solved the problem of the Neoproterozoic ages and also provided a new marker for the Jiangnan Orogen.

Abstract:Abstract：A large number of directional microgranular dioritic enclaves occur in Yangtianhu adamellite of Qitianling composite body. Microgranular dioritic enclaves，which commonly show cloudleted and sub-rounded shapes, display igneous textures and are from meter to centimeter in size. These enclaves are darker in color and finer in granularity than their hosting adamellite. Based on an analysis of the inner structural CL images of zircons, this paper discusses U-Pb ages and Hf isotopes of zircons from the host adamellite and mafic microgranular enclaves by using in situ zircon analysis of LA-ICP-MS and MC-ICP-MS. The ages of （157.2±3.7）Ma from host adamellite and （168.6±3.5） Ma from enclaves were obtained, respectively. The Yangtianhu adamellite intrusion was formed by the mingling between the partial melting products from the crustal materials and the magma derived from the mantle.

Abstract:Abstract：Many scholars at home and abroad believe that lithospheric evolution was related to the subduction of the Pacific plate to the Eurasian plate in eastern China in early Mesozoic. In recent years, the authors examined lithosphere evolution in eastern China from the lithosphere –asthenosphere deep geological process and found that early Mesozoic lithospheric evolution and the subduction of the Pacific plate to the Eurasia plate had no direct relationship, and they might have been the results of the joint action, i.e., the subduction of some oceanic basins of the East Asian seas that originated in China’s eastern periphery to the eastern China continental and collisional orogenic belt and the asthenosphere upwelling caused by such actions. From the beginning to the end, upwelling asthenosphere controlled the layer ringed detachment between the lithosphere and the asthenosphere and between the crust and the mantle, the underplating, and the lithospheric deformation, shortening and extension as well as magmatic activities.

Abstract:Abstract：The component evolution of ancient lithospheric mantle was constrained by three deep-seated geological processes, i.e., ① melt extraction, ② lithospheric mantle metasomatism of melt/fluid from different sources, and ③ interaction between lithosphere and asthenosphere /asthenospheric melt. Two stage enstatites (Py1 and Py2) were discovered in a sample of peridotite xenolith from Mengyin kimberlite. The enstatites of the early stage are residual minerals in the early peridotites with coarse-grained texture. However, the enstatites of the late stage were formed under the plastic rheological condition. A comparison of major and trace elements between the two kinds of peridotites from Mingyin, Fuxian and South Africa shows that the coarse-grained peridotites have higher Mg’ (0.902~0.93) and lower Al2O3 (0.22%~2.32%) values, whereas the peridotites with shear texture have lower Mg’ and higher Al2O3(1.69%~2.75%) values, suggesting that the late stage peridotites have lower refractory degree than the early stage peridotites. This phenomenon finds expression in the mantle component evolution process not only controlled by melt extraction but also by the interaction between lithosphere and asthenosphere / asthenospheric melt. The action caused the evolution of mantle composition from refractory back to fertile, and such an evolution trend is called “inverse evolution”. At least two magma extraction events and two “inverse evolution” processes occurred in ancient lithospueric mantle of North China Craton approximately during the 3 Ga geological period. Compared with the action ③ in Phanerozoic, it was characterized by smaller scale, lower strength and more obvious heterogeneity.

Abstract:Abstract：This paper discusses two igneous rock types (HMA and MA) related to oceanic subduction based on a brief review of the experimental petrological data. On such a basis, some suggestions are put forward as follows： (1) The utilization of both the MgO % and FeO/MgO (% ratio) at given SiO2 as the diagnostic parameters is emphasized in recognition of HMA and MAl. (2) On the basis of the LF-CA (Low-Fe calc-alkaline) characteristics, HMA and MA may be distinguished from each other by using the SiO2%-MgO % parameter system. (3) Either of the two methods, i.e., the diagram approach (Fig.2&3) or the numeric approach (Table 1,2&3), may be used for the nomenclature of HMA and MA.

Abstract:Abstract：Based on 39 SHRIMP and LA-ICP-MS Zircon U-Pb ages, 192 petrochemical data, and two representative age frameworks, this paper suggests a preliminary scheme of the age framework for the early Precambrian granites in western Shandong Province, i.e., three stages of （1）early-middle Neoarchean（2741～2612 Ma）,（2）Late Neoarchean（2563～2500 Ma）, and（3）early Paleoproterozoic（2494～2435 Ma）, which correspond to three rock assemblages and the evolutional trends of （1）T1T2G1 with trondhjemitic trend,（2）T1T2G1G2QM with both trondhjemitic and calc-alkaline trends,（3）G2QM with calc-alkaline trend. On the basis of both SiO2-MgO and SiO2-FeO/MgO relations, most of T1T2G1 having the magnesian andesitic rock (MA) characteristics is considered to have been formed in the oceanic subduction setting. It is thought that three stages of granitic rock assemblages might have been formed in island-arc, continental marginal arc, and continental collisional settings, respectively, and probably represented the compositions of immature, semi-mature, and mature continental crust, respectively. Thus, the granitic rocks have recorded the process of the formation of the continental crust.

Abstract:Abstract：It is emphasized in this paper that, so far as the principle and method for compilation of metallogenic map are concerned, mineralization itself should be more preferentially taken into consideration, though tectonic setting is the basis. Mineralization itself is the first important factor in delineation of a metallogenic unit and its boundary. The authors still use the term metallogenic province here. Nonetheless, different from previous usage, the term metallogenic province here has not only space attribute, but, what is more important, time attribute. The metallogenic province used here means an area where mineral deposits are distributed and formed due to the same or related mineralization in the same or nearly the same epoch and geological settings on a certain tectonic basis. Metallogenic regions (zones), metallogenic potential and prospective regions are thus delineated. A metallogenic region (zone) is an area delineated on the basis of distribution of mineral deposits and favorable geological settings. A metallogenic potential region is delineated on the basis of favorable geological settings with or without known occurrences of mineralization therein. A prospective region is predicted or speculated in consideration of favorable geological settings for mineralization concerned. Following this consideration, the authors suggest a principal framework and steps to divide metallogenic units on the tectonic basis. Metallogenic units in cratonic areas are divided into metallogenic provinces of basement stage, cover stage and post-cratonic stage. Metallogenic units in orogenic areas are divided into metallogenic provinces of early stage, late stage and post-orogenic stage. Metallogenic units of mineralizations related to mafic and ultramafic rocks are delineated according to the fractures, rifts or ophiolite zones concerned. Boundaries of metallogenic units developed in late stages of craton or orogen, especially in post-cratonic or post-orogenic stages, may be discordant with or even traverse tectonic boundaries.The authors have primarily delineated some metallogenic units in consideration of the circumstance of China, for example, the Jiao (Shandong)-Liao (Liaoning) magnesite talc-graphite metallogenic province in the eastern end of the North China Craton, the Yan (Hebei)-Liao (Liaoning) iron-gold metallogenic province in the northern margin of the North China Craton, the West Qinling lead-zinc metallogenic province in the West Qinling Variscan Orogen and the Da Hinggan Ling polymetal-iron metallogenic province in the Da Hinggan Ling Variscan Orogen as well as metallogenic potential and prospective regions therein. This division, in fact, has implied and predicted prospecting areas.

Abstract:Abstract：Chromite is an essential component of stainless steel, and China is the largest consumer of stainless steel in the world. However, only a few chromite deposits have been discovered in China, so China must rely almost entirely on imports for this strategic metal. Chromite forms two types of deposits, namely layered and podiform deposits. Chromite deposits in China are all of the podiform type and occur mainly in Tibet, Xinjiang and Inner Mongolia, where they are hosted in mantle peridotites and cumulates sequences in ophiolites. Deep mantle minerals have recently been discovered in-situ in chromite deposits in Tibet and the Polar Urals, which strongly suggests that chromite was formed in the deep mantle rather than in shallow mantle peridotite as suggested by previous researchers. It is held that large chromite deposits can be formed deep in the mantle and be hosted even in small bodies of mantle peridotite. It is thus necessary to reevaluate the current models for chromite formation and to undertake a new investigation into the ophiolite peridotites and chromite deposits in China.

Abstract:Abstract：The Mengxi porphyry copper-molybdenum deposit is located in the Beitashan- Qiongheba copper, nickel, gold and iron ore district of the Junggar-Southern Mongolia metallogenic belt within the Paleo-Asian oceanic metallogenic domain. Based on an analysis of the geological background as well as geological and geochemical features of this region, the authors hold that the ore-bearing porphyry consists mainly of Middle-Late Silurian intermediate-acid rocks, with the wall rocks being Middle-Upper Ordovician Huangcaopo Group (O2-3hcq), and the ore deposit is an Early Paleozoic porphyry copper deposit instead of a Late Paleozoic porphyry copper deposit considered by previous researchers. The ore-forming process can be divided into three stages, i.e., the pyrite-quartz stage, the chalcopyrite-pyrite-quartz stage, and the carbonate rock-quartz stage. Metallic mineral ores include more than 70% pyrite, 15% chalcopyrite, and a small amount of magnetite and molybdenite. Secondary minerals are malachite, limonite, and blue copper ore. The mineral assemblages are mainly of medium-low temperature. Element geochemical features show that rocks of the copper-molybdenum deposit are Al-high, Na-high calc-alkaline granite relatively enriched in ion lithophile elements Sr, K, Rb, Ba, Th and depleted in high-field strength elements Nb, Ta, Hf, Ti. The discrimination diagrams of (Yb + Nb)-Rb and Y-Nb show that the rocks were formed in a volcanic arc. The (R1-R2) structural diagram suggests syn-collisional granite. It is thus concluded that the main intrusive rocks in the region resulted from the participation of volcanic arc crustal collision in the tectonic setting, and that the structure in the Mengxi porphyry copper-molybdenum deposit is a syn-collisional continental island arc.

Abstract:Abstract：Mineralizations in Central Asia and adjacent areas were dominated by C, B, P, Mg, Au, Fe and Cu in the early stage (in Precambrian) of evolution of the earth, and by Al, Pb, Zn, W, Sn, Mo, Hg and Sb in the late stage (in late Phaneozoic). 　　Carbon (graphite) dominated in Precambrian might have been related to the low oxygen fugacity in the crust and the atmosphere in the early stage of the earth; in that case carbon was not easy to be oxidized. B and P are volatile elements, hence their enrichment in Precambrian may imply that the crust was relatively enriched with B and P in the early stage of the earth. Mg, Fe and Au compositions indicate that the crust was rich in these elements at that time. Cu mineralization took place repeatedly in Proterozoic, Paleozoic and Mesozoic. Economically important Al deposits, i.e., bauxite deposits, presented peak mineralization in Carboniferous and Permian, as can be seen in China. Pb, Zn, W, Sn, Mo deposits were formed in Mesozoic. Hg and Sb, though primarily deposited in Paleozoic, were mainly formed in Mesozoic, even later than Pb, Zn, W, Sn, Mo mineralizations. In the Periodic Table, C, B，P, Mg and Al belong to Periods 2-3. The mineralizations of these elements mainly took place in Precambrian; Fe, Au, Cu, Pb, Zn, W, Sn, Mo, Hg and Sb belong to Periods 4-6. Mineralizations of these elements mainly took place in the late stage of the evolution of the earth. Uranium (U) belongs to Period 7. The U mineralization in China almost all appeared after mineralizations of W, Sn, Mo, Bi, Fe, Cu, Zn, Nb, Ta and REE. In other words, in the evolutionary history of the earth, the atomic structures of ore-forming elements become more and more complex, while the outer electronic layers increase from 2 or 3 layers (C, B, P, etc.) up to 7 layers (U).In ore-prospecting, therefore, to look for mineral deposits of the elements in the upper part of the Periodic Table, we should conduct relevant prospecting work in old crustal regions (Precambrian regions); to look for those in the middle part of the Period Table, we should take into account both old and young crustal regions; to look for those in the lower part of the Periodic Table, we should carry out relevant work in the regions where young geological, tectonic, magmatic and hydrothermal activities are developed.Since Phanerozoic, especially since Late Paleozoic and Mesozoic, further developments of the hydrosphere, atmosphere and biosphere have made the evolutionary tendency further complicated; the formation of sedimentary deposits，especially the recycles of C, H and O, have resulted in the generation of large amounts of coal, petroleum and natural gas.

Abstract:Abstract：Central Asia and its adjacent regions are located along a huge tectonic active belt between old blocks of Asian continent. Basins of various types are developed in this area. In the aspect of formation and evolution mechanism, single type basins like rift basins, foreland basins, and craton basins as well as their superimposed basins are developed. In formation ages, Precambrian, Palaeozoic and Mesozoic-Cenozoic sedimentary basins are developed. Sedimentary basins of different types and ages are developed in different geotectonic backgrounds. The properties of their basements, basin formations, subsidence features, and structural and petroliferous characteristics show remarkable differences. The types and formation ages of the sedimentary basins are closely related to hydrocarbon distribution regularity and petroleum prospects. Rift valley sedimentary basins seem to have great potential of petroleum resources, whereas craton rift and depression basins have certain potential of petroleum resources.

Abstract:Abstract：Based on an investigation of the sedimentary characteristics of the Nanhuan diamictite (tillite) by means of grain size analysis and provenance discrimination of sandstone, the authors tentatively established the Nanhuan-Sinian sedimentary sequences in the southwestern margin of Tarim Basin. It is concluded that the Nanhuan diamictite (tillite) and the interglacial stage sediments were derived from recyclic orogenic zone, dissected island arc and transitional island arc. However, the sedimentary provenance discrimination of sandstone composition has made the authors believe that the Nanhuan-Sinian sediments in the southwestern margin of Tarim Basin have properties of the recyclic orogenic zone. This understanding is very important for restoring the prototype of the Tarim Basin.

Abstract:Abstract：This paper has proposed for the first time that tempestites were developed in the Middle Sha 3 Member of Shahejie Formation in Gunan Subsag. Based on core observation and analyses, the authors found two places of tempestites which were developed respectively in sediments of shallow lake and those of delta front. Some sedimentary structures were developed in this zone which were co-existent to serve as facies marks： Surface structures include gutter cast, truncated structure, surface of scour due to storms, whereas bedding structures include massive bedding, hummocky cross stratification, swale cross stratification, wavy bedding and wave-ripple bedding; in addition, life-escaping structures and contemporaneous deformation were also developed. The ideal vertical sequence of the tempestites in this zone is a Bouma-like sequence, and consists from bottom to top of five segments, namely SA, graded bedding; SB, parallel bedding; SC, storm wave oscillating effect; SD, wavy bedding; SE, mudstone segment. The discovery of tempestites is helpful to defining the shore-shallow lacustrine boundary, adds some new sedimentary facies types to this area, provides the new basis for lithostratigraphic division, and also supplies new space to the prospecting for ideal oil and gas reservoirs and source rocks.

Abstract:Abstract：Geological hazards often cause grave damages to people's lives and property, and hence the study of the meteorological early-warning for geological hazards has practical significance. With Lingtai County of Gansu Province as an example, this paper elaborates the research on meteorological early-warning based on GIS and the good results obtained. Starting with the intrinsic and extrinsic factors that cause the loess geological hazards, the authors carried out the study of geological hazards liability zoning in Lingtai County (intrinsic factors), and then, with a full consideration of the impact of rainfall on geological hazards (external factors), conducted the geological hazards meteorological early-warning zoning study. The authors employed the critical-day synthesized effective process of the rainfall criteria precipitation method in the key and secondary warning zones of Lingtai County. Good prediction results were obtained, which indicate that, being practical and effective, this method can provide a scientific basis for the further study of geological hazards meteorological early-warning in the loess region.

Abstract:Abstract：This paper systematically describes the basic situation of the computer mapping of Atlas of 1∶2 500 000 Geological Maps of Central Asia and Adjacent Areas, which is conducted by the cooperation of experts from China, Russia, Mongolia, Kazakhstan and South Korea. The geographic overview of the mapping region, the drawing of the basic geographical map, the mapping process of the geological map series, the naming rules of each layer, and all parts of the map publication are dealt with in detail. The 1∶2 500 000 basic geographical map is the base of the Atlas of Geological Maps of Central Asia and Adjacent Areas, and its mapping process is similar to that of the Geological Map and Metallogenic Regularity and Mineral Energy Resource Prognosis Map. This paper fully summarizes the principles and methods for computer mapping of Atlas of 1∶2 500 000 Geological Maps of Central Asia and Adjacent Areas from the design and preparation to the publication.

Abstract:Abstract：The spatial database of 1：1M geological map of China has just been established in China, which includes ?2.0G abundant data of 64 geographical maps and 64 geological maps. The management system for this database has been designed on the basis of the MapGIS format, which integrates for the first time spatial database of 1：1M geological map with strata database. This management system is characterized by simplicity, flexibility, convenience and practicability. The major functions of the management system include the search of spatial scope, the retrieval of geographical and geological features, the display of various properties, the automatic creation of legends, and the inquiry of metadata. Using this new database management system, we can easily set up an operation platform for visualization of database applications, on which various visual figures, dynamic cartographies and special maps will be quickly created.