Abstract:Abstract：Based on the results of deep geophysical exploration, combined with geological and geochemical data, this paper analyzes the Oligocene tectono-magmatic settings of deep-seated mineralization in the Andean porphyry copper belt in the South America stable ocean-continent subduction regime, the Gangdise porphyry copper belt in the southern Tibet unstable continent-continent collision regime and the Jamda porphyry copper belt in the Sanjiang area in the unstable continental island-continent collision regime. Six basic conditions for mineralization have been summarized：(1) there was a good supply of upper mantle-derived high-temperature magmatic hydrothermal fluids; (2) a regional source for copper extraction was available; (3) there were a partial melting layer of the upper crust or magma chamber for circulation and deposition of copper-bearing hydrothermal fluids; (4) there were tensile faults in the upper crustal tectonic system for emplacement of magmatic hydrothermal fluids; (5) the chemical properties of the country rocks were important for the precipitation of ore materials; and (6) the relatively stable tectonic stage created conditions for the precipitation of ore materials. In the case of an unstable regime, it is necessary to look for a relatively stable time interval in the regime. The main differences in mineralization between the continent-continent collision regime and ocean-continent subduction regime lie in the long tectonically unstable stage, continental crustal thickening and tectonic complication, as well as the mechanism of crack and break of the mantle lithosphere. The author proposes new ore prospect areas in the Gangdise belt.

Abstract:Abstract：With economic and social development and scientific and technological progress, as well as unprecedented expansion of the area of geological services, geological maps, as the concentrated manifestations of the results of geological work and a main tool for its services to the economic and social development, have gained great attention of governments of various governments and international organizations and shown some distinctive features and development trends, which are mainly marked by developments from specialized geological maps to more practical maps, from monodisciplinary geological maps to multidisciplinary maps, from regional and national maps to international and global maps and from surface geological maps to those that reflect the deep crustal architecture and structure. In addition, many revisions have been made in map surface structure and form of expression, which enables more geological information to be incorporated in the maps

Abstract:Abstract：Southern Northeast Asia covers the area where the West Pacific tectonic belt, North America or Okhotsk Plate, Central Asia orogenic belt, the Sino-Korea and the Yangtze blocks meet together. In the course of Pangaea and supercontinent assembling and disintegration this belt has experienced multple tectonic events since the Mesozoic and has acquired a rather complicated structure. The tectonic affiliation of many middle-scaled and small scaled blocks, including that of the Korea Peninsula, have long been disputed. Based on recent obtained SHRIMP geochronologic data and palaeobiogeographic and tectonic evidences, the authores in this paper deem that the Korea Peninsula and the Hida-Oki belt of Japan might have been affiliated to the Sino-Korea Plate during the Paleozoic, Sakhalin-Hokkaido massifs, to the North America Plate, and the Bureya-Jiamusi-Khanka massifs, to Siberia Plate. Since the 80's of last century most authors have regarded the discussed area as connected with the westward subduction of the West Pacific oceanic crust under Northeast Asia since the Mesozoic. But recently more and more scholars prefer to interpret the geodynamics of crust-lithospheric thinning of Eastern Asia from continent collision and extrusion. The southern Northeast Asia belt has experienced two stages of tectonic development: consumption of the Palaeo-Asian Ocean during the late Hercynian-Indosinian epoch and convergence-collision between the southern and the northern continents during the late Yanshanian epoch (late Jurassic to early Cretaceous). It was these processes that resulted in the extension of the Central Asia orogenic belt to the Yinshan-Yanshan region at the northern edge of the Sino-Korea plate and the formation of a plateau morphology caused by crustal thickening similar to the Qinghai-Tibet Plateau today. In the late Cretaceous to Palaeogene, the crust-lithosphere thinning of this area caused the appearance of large scale extension type Basin-Range structure. In the meantime, the northward section of the Tanlu faults system underwent sinistral displacement. Along the East Asia continental margin occurred accretion, and the rotation of the Pacific plate caused compressional deformation and extensive peneplanation. Many heavy metal and noble metal placeres in the fault basins bordering Palaogene uplifts in Heilongjiang and Jinin were formed in this period. In the Neogene the crust-lithosphere further thinned and the continental rifts developed into the East Asia-Pacific rift belt and the NNE-trending Basin-Range structure came to appear. The Sea of Japan opened, the Western Pacific island arcs appeared. The recent topographic steps of China was initiated at the end of the Early Pleistocene. But the present geomorphic frame that controls the nowadays climate and river system was not formed until post-late Pleistocene time.

Abstract:Abstract：The Altyn Tagh fault belt has a very important position in the study of continental geodynamics, but there is still a dispute over the trend of its westward extension after it passes Gozha Co. The Gozha Co fault is an ENE-trending linear structural zone and has undergone multi-stage activities. In the macrostructural to microstructural contexts, this article discusses in details its geometry and kinematics, and on that basis, combined with the data of the dynamic metamorphism, sedimentary basin, rock and stratigraphic distribution and deformation chronology, the Gozha Co fault is divided into four phases: the ductile left-lateral strike-slip fault (J3-K1), ductile-brittle normal-strike-slip fault (E1- N1), ductile-brittle reverse-strike-slip fault (N2) and brittle left-lateral slip fault (Q). Integrated analysis of the data of geological survey and geophysical field as well as features of satellite images shows that the Gozha Co fault and Altyn Tagh fault belt are correlative linear structures which have similar kinematic and dynamic characteristics and formed in the same dynamic system, thus belonging to the same fault system. Therefore, the Altyn Tagh fault belt neither stops at Lazhulong in the west, nor turns from north of Gozha Co to the northwest but continues to extend to the southwest via Gozha Co and enters into Kashmir from the Kongka Pass after passing Lungmu Co and the Qiangchengmo River.

Abstract:Abstract：The prototype basin of the Jiaolai basin at different stages of its Cretaceous evolution and its tectonic origin have been reconstructed and determined based on the field observations of typical outcrop sections, interpretations of seismic profiles and borehole logging data and analysis of sedimentary and subsidence history of the Jiaolai basin and by following the principles and analytic methods for the study of modified and superimposed basins. The results show that the Jiaolai basin experienced three distinctive stages of sedimentation and subsidence during the Cretaceous. During the deposition of the Early Cretaceous Laiyang Group the prototype basin was mainly manifested by two NE-NNE-trending aulacogens: one developed along the Juxian-Zhucheng fault depression, and the other along the Mou-Ji fault zone. Their depocenters were controlled by the northern frontal fault zone of the Sulu orogenic belt and the Mou-Ji fault zone respectively. The deposition-subsidence rates during the stage underwent marked spatial differentiation. The maximum subsidence rates occurred along the axial zones of the aulacogens, reaching 200-350 m/Ma, and they decreased to ~60 m/Ma toward the slope zones on both sides. The Early Cretaceous Qingshan Group corresponds to a suite of intermediate-mafic to intermediate-acid volcanic rocks with a sequence of fluvio-lacustrine deposits of the Dasheng Group accumulated along the Yishu rift basin. This period was a stage of the typical continental rifting. The Jiaolai basin evolved to a volcanic basin, with a mean subsidence rate of 35-70 m/Ma. The prototype of the Late Cretaceous basin consisted of three half-grabens (i.e. the Laiyang, Gaomi and Zhucheng subbasins), whose subsidence was controlled by W-E-trending normal faults. These grabens were tectonically dextral pull-apart basins bounded on the west by the Tanlu fault and on the east by the Mou-Ji fault. During the stage the subsidence rates were relatively constant, being 63-73 m/Ma. Finally, the paper discusses the possible dynamic mechanisms in different stages of extension of this Cretaceous basin.

Abstract:Abstract：The formation ages of the early Precambrian metamorphic series in the Alxa area, Inner Mongolia, have preliminarily been determined using the zircon SHRIMP U-Pb and single-zircon stepwise evaporation methods. The Yiken Us Formation-complex in the lower part of the Debusige Group-complex formed ~2700 Ma ago and underwent two phases of metamorphism in the late Neoarchean and at the end of the Paleoproterozoic. The oldest (3.5 Ga) detrital zircons in the area have been found in the formation-complex, suggesting that older crustal material probably exists in the area. The Bayan Ul Formation-complex formed in the period of 2500-2264 Ma and is considered to be of Paleoproterozoic age. SHRIMP ages of 1367 and 1617 Ma have been obtained for detrital zircons in the Alxa Group-complex, which means that the possibility that the Alxa Group-complex might belong to the Mesoproterozoic cannot be ruled out. Isotope chronological studies indicate that the Precambrian metamorphic series in the area consists of several metamorphic series of different ages and geneses, which have their own compositional characteristics, so they should be subdivided into the Neoarchean Debusige Group-complex, Paleoproterozoic Bayan Ul Formation-complex and Paleo- and Mesoproterozoic Alxa Group-complex.

Abstract:Abstract：Several metagabbro dikes are found on the southwestern margin of the Tarim plate. They are characterized by lower total REE contents, enrichment in LREE and LILE and depletion in HREE and HFSE. SHRIMP U-Pb zircon dating shows that: the 207Pb/206Pb weighted mean age for six spots is 2 675±12 Ma (MSWD=0.20); the discordia upper and lower intercept ages for nine spots are 2 671±13 Ma and 287±16 Ma (MSWD=0.91) respectively. The weighted mean age of 2 675 or the discordia upper intercept age of 2 671 represents the crystallization age of metagabbro, and the lower intercept age of 287±16 Ma represents the metamorphism age of metagabbro. The discovery of the Neoarchean metagabbro dikes on the southwestern margin of the Tarim plate proves the existence of an Archean old continental nucleus on the southwestern margin of Tarim, provides the record of magmatic activity of the breakup of the Neoarchean old continental nucleus in the North China craton and furnishes important information for the stratigraphic division and correlation in this region and tectonic evolution of the old continental nucleus in the early stage.

Abstract:Abstract：The Kumdaban rock mass swarm distributed in an uplift of medium- and low-grade metamorphic rocks on the northern margin of the Azhong block is a large-scale composite rock mass, in which the contact relationships between different rock types are very clear. From early to late, their emplacement order is fine-grained biotitic monzogranite→medium-grained biotite monzogranite containing phenocrysts. The geochemical data of the rocks testify that the rock mass swarm is similar to the continental island-arc granite (CAG) and displays the features of crust-derived granite. The single-zircon U-Pb age of 449.7±5.8 Ma obtained from the rock mass swarm indicates a Late Ordovician age for the emplacement of the rock mass swarm. The formation of the rock mass may be related to the southward subduction of the Early Paleozoic oceanic crust in Hongliugou-Lapeiquan.

Abstract:Abstract：Based on a comparison in petrological features, diagenesis and reservoir characteristics between gas and non-gas reservoirs, the difference in their diagenetic facies is analyzed. Gas reservoirs are mainly developed in solution pore diagenetic facies of coarse-grained lithic quartzose sandstone and mud-bearing coarse lithic quartzose sandstone, whereas non-gas reservoirs mainly occur in compact diagenetic facies of mud-bearing medium-fine lithic quartzose sandstone and residual intergranular pore diagenetic facies of mud-bearing medium-coarse lithic quartzose sandstone. The mechanism of secondary pore formation was studied through fluid-rock interaction physical and mathematic modeling. The results show the following mechanism: during stage A of the middle diagenetic evolution phase, substantial organic acid was expulsed from source rocks and dissolved more soluble components such as tuff and feldspar in reservoirs of the Sulige gas field, thus forming secondary pores. The medium- and coarse-grained sediments and fine-grained sediments experienced different diagenetic evolution paths because of different energy intensities of their water bodies and their diagenesis. Medium- and coarse-grained sediments are easy to form gas reservoirs because their secondary pores are well developed, there are certain residual primary pores and the total porosity is high. However, fine sediments are not easy to form gas reservoirs because all their primary pores disappear, secondary pores are scarce and the total porosity is very low.

Abstract:Abstract：Integrated methods, including thin section identification, cast thin section examination, mercury penetration, scanning electron microscopy (SEM), X-ray diffraction (XRD) and fluid inclusion analysis, were used to reveal the controls of sandstone diagenesis in the Majiashan-Xiaojianzi oilfield on reservoirs. Study indicates that the diagenesis of sandstone of the Chang 61 and Chang 4+5 members in the Yanchang Formation has reached stage A of the middle diagenetic phase. The distribution of diagenetic facies exhibits a distinctive regularity: dissolution pore facies, chlorite cement facies, carbonate cement facies and compact matrix facies occur in succession from the sand bodies of subaqueous distributary channels and center of river mouth sandbars to margins and down to the subaqueous distributive bay. The physical properties of sandstone become poor successively. The favorable reservoirs are dissolution pore facies and chlorite cement facies in the sand bodies of subaqueous distributary channels and center of river mouth sandbars.

Abstract:Abstract：Three-stage magma mixing occurred in the Weiya vanadium-bearing titianomagnetite ore district, East Tianshan, Xinjiang. The first stage was mixing of gabbroic and granitic magmas, which formed dioritic rock; the second stage was mixing of dioritic and granitic magmas, which formed quartz monzonitic rock; the third stage was mixing of quartz monzonitic and dioritic magmas. The data points of the rocks produced during the third stage of magma mixing show a linear relation in the Hake diagrams of main oxides vs. SiO2. The rocks formed in three stages of magma mixing show similar geochemical characteristics in terms of REE and trace elements and their distribution patterns are also similar, and the transitional rocks-hybrid rocks formed during magma mixing have inheriting relations with their respective end-member rocks. The inheriting relations of the three stages of magma mixing are as follows: the first stage gave rise to hybrid rock with a composition equivalent to that of diorite, which belongs to the same type of rock as the basic end-member rock of the second stage and displays similar geochemical characteristics to those of various types of rock formed in the second stage; and the quartz monzodiorite formed in the second stage can be completely correlated with the end-member rock—quartz monzonite-porphyry—of the third stage. The three stages of magma mixing in the Weiya area might suggest that magma mixing can occur in multiple stages and that the primary parent magma of igneous rocks in the area was derived from continental crustal acid sialic magma and mantle-derived mafic magma, and magma mixing reflects the essence of crust-mantle interaction in this area.

Abstract:Abstract：Volcanic rocks are widespread in the Mesoproterozoic Xiong'er Group in western Henan and have undergone repeated structural activities, magmatic intrusion and erosion. On the basis of the remaining primary structures of rocks, paleo-faults and petrological and petrographic indicators, attitude of strata and geomorphologic features, a series of paleovolcanic craters, such as the Gaoshuiquan, Guanjia, Caoliba, Shibapan and Shuangyuangou paleovolcanic craters, have been identified in the Ruyang area. The early-stage paleovolcanism was marked by NEE-trending fissure-type outpouring, the middle-stage paleovolcanism evolved into central eruption, accompanied by fissure eruption, and the late-stage paleovolcanism was manifested by central eruption. Regional volcanism occurred throughout the Xiong'er period and from NE to SW with time. The paleovolcanic craters and the subvolcanic rocks controlled by the paleovolcanic edifices provide regional ore search information.

Abstract:Abstract：The Ulan Uzhur copper deposit, situated on the western margin of the Qaidam basin is a porphyry copper deposit controlled by granite porphyry dikes. The major element, rare earth element (REE) and trace element characteristics indicate that ore-controlling granite porphyry and its wall rock plagiogranite (porphyritic) belong to the calc-alkaline series characterized by enrichment of LREE, pronounced negative Eu anomalies and depletion of Sr, Ba and Ca. They formed in a syncollisional orogenic environment and are related to the subduction-collision and closing of the late Variscan-Indosinian Songpan-Garzê Paleo-Tethys ocean. The ore-controlling granite porphyry and its wall rocks underwent strong hydrothermal alteration and show apparent alteration zoning. The main hydrothermal alteration includes potassic, phyllic and porphyritic alteration. The core of the granite porphyry is usually marked by a zone of potassic and silicic alteration superimposed by phyllic alteration, and the wall rocks adjacent to the granite porphyry are phyllic zones, and those distal to the granite porphyry are propylitic zones. The intensity of mineralization is apparently positively correlated to the intensity of alteration. The spatial distribution, attitude and size of the copper orebodies are also controlled by granite porphyry. The mineral assemblage, hydrothermal alteration, sulfur and oxygen isotopic compositions and results of microthermometric measurements of fluid inclusions—all suggest that the Ulan Uzhur copper deposit formed at high to medium temperatures and that the ore-forming fluids and materials were derived from magma. So the deposit is a porphyry copper deposit related to hypo- and mesothermal processes.

Abstract:Abstract：This research was based on the study of the data of phosphate deposits of northern China, which was a part of the “Project of Atlas Compilation by Five Countries' Geologists (China, Russia, Kazakhstan, Mongolia, and the Republic of Korea)”. Phosphate deposits in northern China may be divided into the sedimentary type, metamorphosed sedimentary type and magmatic type. Sedimentary phosphate deposits mainly formed in the late Sinian Doushantuoan period and Early and Middle Cambrian, and phosphate is mainly of marine organic origin. Metamorphosed sedimentary phosphate deposits mainly occurred in the Mesoproterozoic, and phosphate is mainly volcanic phosphate, possibly also mixed with organic phosphate. Both sedimentary and metamorphosed sedimentary types contain phosphate transported into the basin due to terrestrial weathering. Magmatic phosphate deposits are mainly related to Hercynian and Caledonian ultramafic magmatic rocks, and they form a mineralogenetic series together with iron vanadium and titanium. Attention should be paid to looking for sedimentary phosphate deposits in Sinian and Lower Cambrian strata on the southern margin of the North China platform and in Lower Cambrian strata on the northern margin of the Tarim block, while metamorphosed sedimentary phosphate deposits are promising on the northern margin of North China. For magmatic phosphate deposits it is necessary to carry out exploration in Caledonian and Hercynian ultramafic rocks.

Abstract:Abstract：The Gangdise porphyry copper metallogenic zone belongs to the Himalaya-Tethyan metallogenic domain—one of the three porphyry copper metallogenic belts in the world, where a major breakthrough has been made in mineral exploration in recent years. The Gangdise zone is also a porphyry metallogenic zone where a major breakthrough has been made in copper exploration in China. The discovery and evaluation of a number of large and superlarge porphyry copper deposits such as the Qulong deposit signifies the primary formation of a new base of exploration and exploitation of over ten million tons of porphyry copper ores. The paper mainly introduces the latest achievements and experience in exploration of the Qulong, Zhunuo, Chongjiang and Jiru porphyry copper deposits in the Gangdise belt, and on that basis, it summarizes the main results of theoretical research on the rock- and ore-controlling structures, features of ore-bearing porphyries and their source regions, metallogenic characteristics, metallogenic series and mineralizing ages in this belt and at last presents some thoughts and suggestions on the disadvantages and future direction in the copper exploration and theoretical research.

Abstract:Abstract：Analysis of the compositions of gas and liquid phases in quartz inclusions suggests that the ore-forming fluids in the Shihu gold deposit are a K+-Na+-Ca2+-SO2－4-NO－3-Cl－system rich in organic volatiles such as CO2, H2O and CH4 and C2H6. Analysis of sulfur and carbon isotopes shows that sulfur and carbon are derived from the mantle, and hydrogen and oxygen isotope analysis shows that the ore-forming fluids are a mixture of magmatic hydrothermal fluids and meteoric water. The average of six homogenization temperature data is 310℃, indicating mesothermal mineralization, and 53 data of decrepitation temperatures mainly cluster at two ranges, namely, 320-350℃ and 360-380℃, which reveals that approximately two mineralization occurred. The ore-forming pressure was 20.3 MPa and the ore-forming depth was 0.75 km, with lgfo2=39.95, Eh=-0.42 to -0.64V and pH=5.94 to 6.44-all these suggest that the deposit was emplaced in a near-surface, relatively oxidized and weakly alkaline ore-forming environment. The vertical isothermal diagram of quartz inclusions at different levels in orebody 101-4 suggests that the ore-forming fluids moved from south to north and from deep to shallow, with the direction of the fluid movement coinciding with the pitch direction of the orebody, implying that there are very good ore prospects at depths of the southern end of the mining area.

Abstract:Abstract：The Dayangshugou molybdenum deposit is located at the junction between the Liaoxi (western Liaoning) platform subsidence and Shanhaiguan platform rise in the Yanshan platform fold zone on the northern margin of the North China platform, in the western segment of the Bajiazi-Yangjiazhangzi polymetallic ore belt. It is a large rich molybdenum deposit found during check verification of geochemical anomalies of stream sediments. Orebodies are all hosted in Yanshanian fine granite. There are close temporal-spatial and genetic relations between the deposit and the granite. The orebodies occur as veins and blind orebodies increase toward the depth, forming dense orebody bundles. The exploration work comprised three stages: additional stream sediment geochemical survey, soil geochemical survey, geological survey and engineering check verification. The discovery of the molybdenum deposit shows that there is still great potential for undiscovered mineral resources in eastern China where the degree of exploration is very high. The regional geochemical anomalies play a guiding role in mineral exploration. In the new round of mineral exploration we should firstly exploit and screen the geochemical anomalies in the ore belt the second time, then gradually improve the quality of anomaly check verification and finally carry out exploration, which is an efficient method for mineral exploration.

Abstract:Abstract：Selenium is an important trace element that has important influence on human health and its natural distribution is very uneven in topsoils in different areas in most cases. Recently, the development of natural Se-rich food according to the clues to local Se-rich soils is an important direction for the study of the agro-geological environment. Multi-target 1∶250000 regional soil geochemical survey in the Jiangsu Province shows that there exist relatively extensive Se-rich topsoils in some low mountains and hills in the Liyang-Yixing area, southern Jiangsu though selenium in topsoils is not rich in most areas of Jiangsu. According to the clue natural Se-rich tea has been discovered in the Liyang-Yixing low mountain-hill area. Preliminary study indicates that the formation of local Se-rich topsoils is related to some particular geological setting and that the soil environment producing natural Se-rich tea is relatively advantageous.

Abstract:Abstract：Geochemical indices and the method of integral values in the hierarchical cluster model are used and 16 indices such as N, P and K2O are chosen to carry out a preliminary classification of the agricultural eco-environmental quality of topsoils in Fuzhou. Five ranks of agricultural eco-environment districts are distinguished. Among them, the general eco-environmental district is largest, accounting for 58% of the total area. The excellent and good eco-environmental districts are relatively small and the area of the two districts is equivalent to the very poor eco-environmental district, accounting for~3%. Most eco-environmental districts are rich in potassium and poor in trace elements and minor elements. According to the characteristic of various eco-environmental districts, the authors put forward suggestions of the overall agricultural planning and layout in Fuzhou.

Abstract:Abstract：The construction of the geological map spatial databases has great significance for the fast renewing of basic geological maps, sharing of information resources and study of basic geoscience. The 1∶1 million geological map database (2005 edition) was constructed on the basis of the 1∶500,000 geological map database. The 1∶1 million Geological Map Spatial Database of China was built with the softwares such as MapGIS, ArcGIS and Access and by absorbing fully the latest information and outcomes of 1∶250,000 and 1∶50,000 geological surveys and using the most advanced geoscience theories, modern information technology and advanced cartographic theories. The databases include the geographical map database, geological map database, metadata base and rock/strata database, with a data quantity of 1.6 GB. The spatial database management system possesses strong functions of map retrieval and inquiry, automatic map making and automatic legend drawing.