Abstract:Abstract：Study of helium isotrope of UHP rocks in the Dabie area shows that minerals of UHP rocks such as eclogite in the Dabie area were not derived from the mantle but formed at top of the lithospheric mantle (LID). According to the deep geophysical data, the authors propose a new model for the formation of UHP minerals at the lithospheric mantle lid, i.e. when supracrustal rocks were subducted to the LID, UHP metamorphic rocks were formed at strong pressures caused by convergence of plates and high temperatures produced by the mushroom cloud mantle, and then were exposed at the surface due to doming and erosion of the crust. The available literature indicates that when visco-plastic continental plates collided and were subducted the deformation of the LID was much more complex than the deformation due to subduction of a rigid plate. The direction of subduction was mostly vertically downward, and the subducted plate and retro-side wedged each other like fried dough twist and the subducting direction might change at depth. When the LID partially melted, subducted materials would spread in the locally molten layer and formed UHP metamorphic rocks at high pressures and temperatures. The global distribution of main UHP metamorphic rocks is associated with the distribution of the Paleo-Tethys Ocean. However, it is not certain whether both of them were soft collision between visco-plastic continental plates and whether there were high-temperature regions at the LID near the collision zone.

Abstract:Abstract：Based on an analysis of the characteristics of the rock association and geochemistry of volcanic rocks of the Wusushan Group, combined with a comparative study of the regional geological setting of the neighboring regions, the authors discuss the environment and tectonic affinity and implications of the Wusushan Group in the southwest of Lanzhou in the Qilian orogen. The Wusushan Group is a rock association consisting mainly of intermediate and intermediate-basic volcanic rocks and dacite with small amounts of pyroclastic rocks and ordinary sedimentary rocks, which formed in the Mid-Late Ordovician and underwent low greenschist facies metamorphism. Geochemical characteristics of different types of volcanic rocks show that the rocks formed in an island arc or forearc tectonic setting. By analyzing the characteristics of the rock association and geochemistry of volcanic rocks of the Wusushan Group and comparing these characteristics with those of the Lajishan tectonic belt and North Qilian orogen, it is preliminarily thought that the Wusushan Group is probably not the eastward extension of the Lajishan tectonic belt but the structural remnants of the extension of the island arc belt at the southern margin of the North Qilian Mountains southwest of Lanzhou. The redefinition of the tectonic affinity of the Wusushan Group is of great significance for solving the eastward extension of the Qilian orogen, understanding the intersection relation between the Qilian orogen and Qinling orogen and establishing the tectonic framework of the east-central segment of the Qilian orogen.

Abstract:Abstract：The rock- and ore-forming ages of the Zijinshan pluton were precisely redefined based on SHRIMP zircon dating. CL images of zircons in the Zijinshan biotite granite show that there are three zircon morphologies. The results of dating indicate that the three types of zircon have different ages and different geological implications. The first type of zircon crystal is perfect and has core-rim structure. The core is rounded. This type of zircon is considered inherited zircons dated at ~1000 Ma. The second type of zircon has well-developed but incomplete crystal morphology. It is half-baked with indistinct growth zoning or no growth zoning, showing the features of magmatic zircons. The age of the zircons is 168±4 Ma, which represents the crystallization age of the pluton, indicating an Early Mesozoic Middle Jurassic age. The third type of zircon is perfect and has clear growth zoning. It has undergone late-stage reworking. Its age is 119±15 Ma, suggesting an Early Cretaceous age. There is no report of large-scale mineralization at 168±4 Ma in the study area; so the main part of the Zijinshan pluton is not a mineralized pluton, only showing weak tin mineralization. The third group of SHRIMP U-Pb ages is considered as the record of large-scale Cu-Au mineralization. It is possibly just this stage of hydrothermal processes that commenced the prologue to the large-scale, long-continued, multistage magmatic hydrothermal processes and thus laid a foundation for the copper-gold mineralization in the area.

Abstract:Abstract：In the geologic record, the strontium isotopic composition of marine carbonate reflects the evolution of the global strontium balance between reservoirs. This balance is thus inherently related to changes in sea level through time. Late Cretaceous-early Paleogene strata in the Gamba area, Tibet, are well developed. Strontium isotope analysis was performed on 26 unaltered oceanic carbonate samples from sections in Zongshan and Zongpu and the evolutionary curve drawn by the data obtained is well correlated with the global oceanic strontium isotope record. The negative extreme values of the curves are nearly consistent with the negative extremes of the stratigraphic boundaries. The negative peak value (0.707612) of the curve of the Zongshan section corresponds to that of the Upper/Lower Cretaceous boundary, and the negative extreme value (0.707761) of the curve of the Zongpu section corresponds to that of the Paleocene/Eocene boundary. The Late Cretaceous-Paleogene strontium isotope curve also agrees with the known sea level change. In addition, the cause for the change in strontium isotope values in the Gamba area is discussed.

Abstract:Abstract：Field observations suggest that the Wanyangshan granite batholith is a complex batholith composed of different intrusive units that were sourced from multiple magmatism during the Caledonian. The types of granite in the batholith include biotite granodiorite, biotite monzogranite, and biotite-muscovite monzogranite. There are many very fine-grained mafic xenoliths in biotite granodiorite and biotite monzogranite. U-Pb analyses of zircons show that the Wanyangshan granite batholith formed in the Silurian, at ca 441-462 Ma. Geochemical analyses showed that：the Wanyangshan granite has a SiO2 content of 66.99 to 73.04%, an average K2O content of 3.91% and an average Al2O3 content of 13.74%, with Na2O+K2O=6.26 to 7.39% and K2O/Na2O=1.45 on the average. The Wanyangshan granite has a higher total REE concentration (264.43 g/g). Chondrite-normalized REE patterns show a significant differentiation between LREE and HREE and a remarkable enrichment in LREE. Eu values (Eu=0.53) indicate that the primitive magma was basic and enriched in plagioclase most likely. The Wanyangshan granite is significantly depleted in HFSE (Ta, Nb, Sr, P, and Ti), which indicates that these granite samples are strongly related with subduction. For isotopic compositions, the Wanyangshan granite has a range of initial strontium from 0.71223 to 0.71376, and a range of epsilon strontium (εSr(t)) from 109.8 to 131.5. Epsilon neodymium (εNd(t)) ranges from -7.1 to -8.3, with the depleted mantle model age of 1.74-1.86 Ga. In general, geochemical and isotopic analyses indicate that the Wanyangshan granite is ferruginous, peraluminous, high-K, calc-alkaline S-type granite, with higher concentrations of aluminium and potassium. Its primitive magma could be mainly sourced from melting of the crust, and is most likely to have been contaminated by the mantle in the early stage of magmatism evolution. The Wanyangshan granite formed under the conditions of post-orogenic extension after the collision between the Cathaysian and Yangtze blocks in the Caledonian.

Abstract:Abstract：On the basis of regional geological survey and integrated research, the authors conducted detailed studies of the petrology, contact relationships, isotope ages and geochemistry of the original Baihua intrusion in the southeastern part of Tianshui, West Qinling, and through the studies they separated the Xiongshangou intrusion from the Baihua intrusion and gained a preliminary knowledge of the characteristics of magmatic activity of this separated intrusion. The rock type of the early-stage Xiongshangou intrusion is plagiogranite, which is petrochemically characterized by a low K2O content with K2O∕Na2O=0.33-0.42 and A∕CNK=1.01-1.05；the rock type formed in the late stage is monzogranite, which is enriched in K2O with K2O∕Na2O=1.01-1.43 and A∕CNK=0.86-1.07, and the rock belongs to the tholeiite-calc-alkaline series. Furthermore, the intrusion shows characteristics of enrichment in the trace elements Th, Hf, Nb and Zr and in LREE and no or unpronounced Eu negative anomalies, with δEu=0.58-0.87 and low δ18O (δ18O=＋3.32‰). The rock has the features of “I”-type granite and the magma was derived from materials of the lower crust and the intrusion formed in a continental arc tectonic environment.

Abstract:Abstract：Based on geologic mapping and integrated study in the Baihaba-Chonghuer district, northwestern Altay, Xinjiang, Lower Devonian fossils were collected from the strata that were originally assigned to the Ordovician or Sinian-Cambrian, and Caledonian and Hercynian isotopic geologic ages were acquired in some distinct plutons. Subzones with quartzite-like and thorn-like textures were distinguished in low-grade metamorphic rocks and kyanite, sillimanite, almandine and staurolite zones were recognized from regional dynamic heat-flow metamorphic rocks. The new evidence indicates that the Caledonian and Hercynian phases of regional low-temperature dynamic metamorphism occurred in the Baihaba district of the study area and that two phases of regional dynamic heat-flow metamorphism occurred in the southeastern part of the study area: the Caledonian phase in Hailiutan and the Hercynian phase in Chonghuer, which are superposed along the Kugen fault. This division gives a new answer to the dispute about the metamorphic types and generations in the area that lasted for nearly half century.

Abstract:Abstract：The marble rock group is the top one of three rock groups of the khondalite series in the Daqing Mountains area, Inner Mongolia. It, as a suite of Mg-rich marble, is characterized by development of very thick and extensive dolomitic marble, with small amount of clastic rocks at the bottom. Besides dolomite，the mineral composition also commonly includes one or several Mg-rich silicate minerals such as serpentinized olivine, diopside and phlogopite. The rocks are rich in CaO, MgO and LOI, reflecting the geochemical characteristics of carbonate rocks. The CaO＋MgO content is more than 44.96％ and the CaO/MgO ratio is relatively low, being 1.37-10.94; so the protolith should be dolostone that has a very low content of fragments and mainly formed by chemical deposition. The sedimentary environment of the protoliths graded from the paralic deltaic facies at the initial stage through the littoral-neritic faces to the enclosed sea basin facies which was separated by barrier islands under dry climatic conditions. The tectonic environment also passed from the metastable to stable one. This suggests that the protoliths of the suite of metamorphosed sedimentary strata may have formed on the passive continental margins, but were more likely to be similar to intracratonic aulacogen or rift deposits such as the Mesoproterozoic Changchengian System and Jixianian System.

Abstract:Abstract：Based on the urban bedrock geological mapping and research on the section, the Middle-Lower Ordovician Nanshanshang section in Banqiao Township, Lin'an City, was chosen as the candidate stratotype. According to the stratigraphic sequence, lithologic association and boundary markers, combined with the general characteristics of regional changes, four formation-rank lithostratigraphic units were redefined and distinguished. The stratigraphic age of the section was determined to be Early-Middle Ordovician according to the stratigraphic and fossil correlation of the Jingshan Range and Banqiao sections. This redefinition is of great significance for the reconstruction of the stratotype section, protection of geoheritages, lithostratigraphic mapping and exploitation and utilization of Ordovician limestone resources.

Abstract:Abstract：Recently the authors have carried out field geological survey and measured sections in the Pinglu area, Shanxi. According to the survey and section they have made a detailed study and classification of the Paleogene strata distributed in the study area, redefined Paleogene lithostratigraphic units in the area, established the biostratigraphic and chronostratigraphic sequences and provided new ESR dating data. The fluvio-lacustrine strata have been divided from younger to older into the Oligocene Liulinhe Formation (E23l) and Xiaoan Formation (E13x), Eocene Xitan Formation (E42x), Zhaojialing Formation (E32z), Podi Formation (E22p) and Menli Formation (E12m) and Paleocene Batou Formation (E1b). This study provides an important basis for the study, division and correlation of the Paleogene of North China and even the whole country.

Abstract:Abstract：The grain-size analysis and magnetic property measurements of late Cenozoic sediments of borehole SG7 in the Yangtze delta plain have revealed the evolution of dominant magnetic minerals with time and coupling effects of neotectonic movement, climate and sea level changes on the sediment provenance and depositional environment. Results demonstrate that strong and weak magnetic properties alternated with the highest signal of the whole profile during the Pliocene. Dominant magnetic minerals are magnetite, maghemite, goethite, and pyrite indicating a warm/humid climate and an intermontane lacustrine environment in the area and that the sediments were mainly derived from the weathering product of the Bailonggang basalt in the surrounding areas. During the early part of the early Pleistocene, magnetic signals were weakest of the borehole, with magnetite predominating. This implies that the material sources changed due to tectonic subsidence, i.e. the material sources were mainly iron-poor intermediate-acid hypabyssal rocks and extrusive rocks. Meanwhile, channel deposits formed during glaciation are mainly preserved, reflecting an intermontane fluvial or alluvial fan environment. During the late part of the early Pleistocene to the end of the late Pleistocene, magnetic signals increased markedly and fluctuated with the grain size of sediments. Coarse-grained magnetite derived from metamorphic rocks dominates magnetic minerals in coarse-grained sediments, while goethite, hematite and pyrite are found in fine-grained sediments, which suggests that the paleogeographic environment gradually evolved to the alluvial plain and coastal plain. Fine-grained maghemite and magnetite appeared again during the late part of the late Pleistocene, indicating the input of the material sources from the upper Yangtze catchments. Magnetic susceptibility of Holocene sediments is obviously higher than that of Pleistocene fine-grained sediments, indicating Yangtze estuary/delta environments.

Abstract:Abstract：The stratigraphic age and sedimentary environment of the laterite bed in the Xihe basin have been studied in detail in the contexts of lithology, sporo-pollen assemblages and stratigraphic correlation and the geological evolution process during that time has been traced. The sporo-pollen assemblage in this area is the veld whose dominant elements are herbaceous Artemisia and subordinate elements are Pinus, Juglans and Graminae, of which Juglans and Ulmus are typical Paleogene-Neogene genera and species. Based on a comprehensive analysis of the lithologic and biological features, the authors think that the "laterite" bed in the Xihe basin belongs to the Pliocene Baogedawula Formation (N2b). In a plan view, the stratigraphic sequence type shows changes of the sedimentary environment from the river, alluvial fan and delta at the basin edge to the deep lake in the center of the basin.

Abstract:Abstract：The Xinbei Oilfield, located in the northern part of the Kendong buried-hill drape tectonic zone, Bohai Gulf basin. Its exploration and development are still in the primary phase. In order to know the reservoir characteristics and accumulation rule of the oilfield, based on the exploration and development practice, the stratigraphic characteristics, sedimentary characteristics and reservoir characteristics were studied. The sedimentary system of the oilfield consists in ascending order of Paleogene lacustrine facies and Neogene fluvial facies (including braided stream sediments, meandering river sediments and anastomosing river sediments). Braided stream sediments can be subdivided into two subfacies: diara (channel sand bars) and channel floor lag；meandering river sediments can be subdivided into three subfacies: channel, bank, and flood plain；and anastomosing river sediments can be subdivided into two subfacies: channel and flood plain. The main reservoir of the Xinbei oilfield is meandering river sediments, and the point bar and diara subfacies have the best physical properties for hydrocarbons accumulation. The above research results show strong controlling effects of the sedimentary characteristics on hydrocarbon accumulation. The main reservoir type is the lithologic reservoir.

Abstract:Abstract：Using the data of drill hole 86-46 in Dashiqiao, Hulin City, the high-resolution sequence stratigraphic division of the Hulin Formation in the Dunmi downfaulted basin, eastern Heilongjiang, was made, and three medium-term datum plane cycles were recognized. The three cycles are all made up of broadly symmetric structure consisting of two half-cycles of rising and falling, and they may be subdivided into tow basic types, namely, the rising half-cycle thicker than the falling half-cycle and the rising half-cycle less thick than the falling half-cycle. They represent three marked lake transgression-regression in the Dunmi downfaulted basin. On that basis, the authors discuss the relation between the medium-term datum plane cycles of the high-resolution sequences and coal-accumulation processes. Of the cycles, the falling half-cycles of the medium-term datum plane cycles shows the best coal-accumulating processes and are favorable horizons of important coal beds of commercial value, while the rising half-cycle of the cycle shows poor-poorer coal-accumulating processes. This study shows the falling half-cycles of the first and second medium-term datum plane cycles in the Hulin Formation are best and are our first selected horizons for coal mining and coal prospect expansion.

Abstract:Abstract：The Longshang tin-polymetallic deposit, located in the Xitian area, eastern Hunan, is a large one of the Xitian tin orefield. Its orebodies occur in the contact zones between the Xintian composite granite and carbonate rocks of the Middle Devonian Qiziqiao Formation. In this study, 40Ar/39Ar isotopic dating of muscovite was carried out in order to determine accurately the mineralization age of the deposit. The results show that the 40Ar/39Ar plateau ages of two muscovite samples from the deposit are 155.6±1.3 Ma and 157.2±1.4 Ma respectively and their isochron ages are 155.4±1.7 Ma (MSWD=0.74) and 156.5±1.7 Ma (MSWD=1.4) respectively, which agree within the error limits with mineralization age (150 Ma) of the Heshuxia tin-polymetallic deposit reported previously in the same ore field and are also in accordance with the early intrusive stage of the Xitian composite granite (151-165 Ma). Based on these age data, this paper suggests that the mineralization age of the tin-polymetallic deposit in the Xitian ore field is 150-160 Ma and that their mineralization is closely related to the Xitian composite granite. Both are products during a peak stage of large-scale rock- and ore-forming processes in the early Yanshanian in South China.

Abstract:Abstract：The Dajing Cu-Sn polymetallic deposit is characterized by its large size, many associated elements, narrow and dense ore veins and high grades. However, no Yanshanian intrusions were found within the limits of the ore field, so the genesis of the deposit is in controversy. From a viewpoint of mantle branch tectonics, the deposit is situated at the core of the Da Hinggan Mountains mantle branch, and the multiple evolution of the mantle hot plume linked up the deep hydrothermal ore fluids. The ore fluids extracted some ore materials on the way, which concentrated in favorable structural fractures and formed the deposit. The orientation of ore-controlling fractures is closely related with the regional structural stress field during mineralization. The zoning of the ore-forming elements Sn, Cu, Au, Ag, Pb and Zn within the deposit should be related to mineralization and crystallization temperatures of ore materials. The mineralizations of the elements such as Sn, Cu and Au, which crystallized under higher P-T conditions, are in the center of the ore field; whereas the mineralizations of the elements such as Ag, Pb and Zn, which crystallized under lower P-T conditions, were mostly localized in the surroundings of the deposit.

Abstract:Abstract：The Baishaziling tin deposit is hosted in the Dayishan composite granite body. Two types of tin deposit, altered granite type and greisen vein type, are distinguished, and they occur in association with each other in space. The paper discusses the genesis and ore-forming processes of the deposit according to the geological setting and geological characteristics of the deposit and the results of isotope and inclusion analyses. Pb isotope study shows that ore-forming materials of tin were derived from the mixed source of mantle and crust. Hydrogen and oxygen isotope features indicate that ore-forming fluids were mainly boiling magmatic water. Coupling of altered granite-type and greisen vein-type tin ore veins and consistency of their fluid inclusion and sulfur and lead isotope features show that the combined effect of tectonism and magmatic evolution was the main controlling factor for mineralization. With temperatures of 180-425℃, a salinity of 1.40-11.22% and pressures of (67-537)×105 Pa, the Baishaziling tin deposit is a mesothermal-hypothermal deposit.

Abstract:Abstract：The Huachanggou gold deposit is a hydrothermal alteration-type deposit controlled by a ductile shear belt. The paper summarizes the application of the organic hydrocarbon gas method in gold exploration in the Huachanggou gold deposit. Analysis of the composition of quartz inclusions in ore and comparison of the content features of hydrocarbon components in different types of rock in several levels show that a certain amount of organic matter had participated in the process of gold mineralizing in this gold deposit. Organic hydrocarbon gas is its important associated gas component and there is a close relationship between hydrocarbon gas anomalies and gold mineralization in space. Therefore, the application of the organic hydrocarbon gas method has great significance for looking for deep blind ore deposits.

Abstract:Abstract：This paper introduces the application of the pyrite thermoelectric property measurements in gold exploration of the Shihu gold deposit. Pyrite is the main gold-carrying mineral. Four gold mineralization stages may be distinguished. The thermoelectric type assemblage of pyrite is PN?圯P≤N from mineralization stages Ⅰ to Ⅳ. In the mineralization area, from the top downward when (P and P% decrease, (N and N% increase, which in the main coincides with the results of mineralogical mapping by using the distribution of pyrite type (P%) and the mean of the thermoelectric coefficient (P. Some typomorphic information such as formation temperatures of pyrite, relative burial depths of orebodies, characteristics of orebodies and prospects of the deep part may be obtained according to thermoelectric properties of pyrite.

Abstract:Abstract：The Muluo REE deposits is genetically closely related to carbonatite-alkaline complexes. Carbonatite is mainly composed of calcite (>90%) with a CaO/(CaO+MgO+FeO+Fe2O3+MnO) ratio of 95.7-99.6%, so it is calcite carbonatite. The carbonatite is characterized by relative enrichment in the LILE Ba, Sr and LREE, relative depletion in the HFSE Nb, Ta, Ti, Zr and P, higher ratios of Zr/Hf and La/Nb and lower ratios of Sm/Nd and Rb/Sr, implying that the rock was derived from the enriched mantle (EMI). Geochemical study shows that the Muluo carbonatite is the product of reactivation of the mantle remnants of the Emeishan mantle plume caused by the Himalayan orogenic movement；however, the carbonatitic molten magma was contaminated with crustal material during its ascent. The molten magma of carbonatite-alkaline rocks brought substantial REE to extensional sites resulting from orogeny in the Himalayan orogenic phase and formed REE deposits.

Abstract:Abstract：The fussy logic space decision model does not use binary maps to divide the study area into the area advantageous to mineralization and the area disadvantageous to mineralization but uses continuously changing fuzzy membership values based on the regularity of geological data, thus avoiding the loss of useful geological information effectively. In this paper the geological, geochemical and geophysical data are analyzed and processed using the Arc-SDM extension based on the GIS platform and the close relationship between ore deposition and evidence themes is analyzed using the method of weights of evidence. On that basis, different fuzzy membership values are given to original geological variables using the tabulation method. The results of fuzzy logic prediction show that 85% of the known mineral deposits (occurrences) appear within the target limits that only make up 13.2% of the study area, which are highly coincident with the known mineral deposits (occurrences). The prediction results are ideal and may be used to guide further mineral prospecting.