Abstract:Abstract：Detailed field observations have revealed that the Damiao iron ore field obviously has excellent potential and is likely to become the largest base area of iron resources in China. New evidence supports neither the opinion that all the component igneous units in the Damiao anorthosite complex were evolutionary products of a unique primary magma nor the hypothesis that ore magma was responsible for the formation of the Damiao-type iron deposit. The anorthosite underwent at least two more times of deformation than the norite, suggesting that the norite was emplaced after the consolidation and cooling of the anorthosite. The generation of the Damiao-type iron deposit is closely related to the noritic magma. Nevertheless, the ore-forming materials were derived from the concurrently emplaced transmagmatic fluids instead of from the noritic magma differentiation. The degassing process of the ore magma-fluid mixed materials in the deep crust led to the concentration of the ore-forming materials in the norite and the differentiation characteristics of the mineral veins, i.e., the apatite was concentrated in the shallow place, while the titanomagnetite became rich in the deeper part. The main ore bodies are buried in the norite substrate beneath the anorthosite cover. Therefore, the Damiao iron ore field is a very promising area instead of a crisis mine.

Abstract:Abstract：Major and trace element geochemistry of rocks and ores from the Platreef deposit of the Bushveld Complex was systemically studied in this paper by using new ICP-MS analytic method for the purpose of making a comparison with geochemistry of the Jinchuan Cu-Ni-PGE sulfide deposit and probing into the genesis of this type of deposits so as to guide their prospecting work. It is concluded that ∑REE values of the Platreef rocks are close to values of lherzolite from the Jinchuan Cu-Ni-PGE sulfide deposit, with very similar REE patterns. Chondrite-normalized REE patterns of the ore-bearing rocks from both deposits assuming right-inclined fractionation, with enrichment of LREE and smoothness of HREE; nevertheless, Platreef rocks have a positive Eu anomaly，whereas Eu negative anomalies are evident for most lherzolite and ores from the Jinchuan deposit. This might be a reflection of insignificantly varying plagioclase/orthopyroxene ratios during the crystallisation of the rocks. it is evident that, relative to the Jinchuan deposit, the Platreef deposit has higher contents of strongly fractionated incompatible elements but shows a trough-shaped profile with pronounced depletion of Nb and Ta，suggesting a model of crustal contamination during mantle plume magma emplacement, evolution and ore formation that resulted in the geochemical features of trace elements similar to arc picrite. Jinchuan ore-bearing magma is enriched in Fe, Ti and highly incompatible lithophile elements, exhibiting geochemical features of Ferropicrites trace elements; and hence it is thought to have been derived from conrrespondingly enriched mantle ( EMI) sources even if there probably also existed some crustal substance contamination during the rock-forming and ore-forming process. The primitive mantle-normalized PGE patterns of platreef rocks are arch-shaped with the enrichment of Pt, Pd and Ru relative to Os, Ir and Rh, and incompatible elements Cs, Rb, Th, U and LREE as well as chalcophile elements Cu and Ni, suggesting that the residual mantle peridotite from which the Bushveld Complex derived has undergone infiltration and contamination-mantle metasomatism by external mineral-enriched fluids containing highly incompatible elements, which may be responsible for the fractionation of PGE from mantale-derived magma.

Abstract:Abstract：Ophiolites occur as lenses or slices within the Late Triassic metamophic sedimentary rocks in southern Qinghai Province, where no research work has been done before. The gabbro exposed in the Chaggur area is a unit of the ophiolite and belongs to the low-K tholeiitic series. The SHRIMP U- Pb age of zircons from gabrro is (239.8±3.1)Ma, suggesting that the re-spreading time of the Bayanhar ocean was most likely at the early stage of Middle Triassic. The gabrro is characterized by high MgO, Al2O3 and low K2O, TiO2. All rock samples have low REE abundances and show similar REE distribution patterns characterized by slight LREE enrichment with very distinct positive Eu anomalies. (La/Yb)N ratios are 1.10~ 4.40, whereas δEu values are 1.50~ 2.41. The samples are enriched in large ion lithophile elements (LILE) and depleted in Nb, Zr and Ti in the trace spider diagram, implying that the magma source was affected by input of some components from the subduction zone. It is thus considered that lithogeochemistry of the Chaggur gabrro was characterized by intraplate and arc volcanic rocks, and hence the gabrro was formed in a back-arc basin setting and should belong to the western segment of the Garzê-Litang ophiolite mélange.

Abstract:Abstract：Based on geological survey and measured profiles, the authors carried out a detailed study and classification of the Neogene strata distributed in the Yushe area of Shanxi Province. ESR dating combined with biostratigraphic and Paleomagnetic dating of the Neogene strata in the study area revealed the stratigraphic sequence as follows (in descending order): Upper Pliocene Mazegou Formation, Lower Pliocene Gaozhuang Formation and Miocene Mahui Formation. Based on the measured section, the authors divided the fluvio-lacustrine facies sediments of the three formations into 37 layers, with the total thickness being 446.5m. It is obvious from the ESR dating that the Mazegou Formation (2.50～3.04Ma), the Gaozhuang Formation (3.25～5.25Ma) and the Mahui Formation (5.30～13.10Ma) should belong respectively to Late Pliocene, Early Pliocene and Late Miocene.

Abstract:Abstract：The North Tarim Uplift is one of the most important oil and gas-bearing areas in the Tarim Basin. Seismic section and balanced section were used to reveal its structural styles and evolution. The structural styles in the North Tarim Uplift are remarkably different in its different parts. Yingmaili in the west of the North Tarim Uplift mainly has decollement folds and faults and 'y'-style transpressure faults, while the east of the North Tarim Uplift has well-developed basement-involved faults, fault-propagated-folds and recoil faults. There are two mechanisms responsible for the difference. First, during the Sinian-Early Ordovician period, the east part developed normal faults, which were inverted later and formed the basement-involved structure. Second, salt was deposited in Yingmaili during Middle Cambrian, which was favorable for the development of the decollment structure. The evolution is also different in different parts. During the Sinian-Early Ordovician period, the east part developed huge normal faults, while the Yingmaili was a stable carbonatite platform. During the Late Ordovician-Devonian period,the east part was inverted and uplifted, whereas Yingmaili was only the slope of the uplift. During Carboniferous and Permian, all parts of the North Tarim Uplift underwent serious deformation.

Abstract:Abstract：Cenozoic nappe structures in the Kalpin fault uplift constitute a part of southern South Tianshan marginal thrust system. The number of nappe sheets is different from place to place, and the corresponding relationship of the nappe sheets in different parts is not clear because of the disturbance of the dip faults, which forms an unique orocline. The Cenozoic orogenic movement of southern South Tianshan is largely characterized by the deformation of the nappe sheets. By means of TM image interpretation and field geological investigation, the structural features at the intersects between the dip faults and the nappe sheets and the minor structures which can show the formation information of the nappe sheets were studied in detail. On the basis of the study, the disturbed nappe sheets in different parts of the uplift were connected successfully and the number of the nappe sheets was identified as well. A tectonic model has been suggested, which holds that the disturbed nappe sheets resulted from folding and fault slipping in the striking direction of the nappe sheets when they thrusted southeast under the NW-striking maximum principal compression stress, and the dip faults originated from the minor faults that occurred in the wings of the folded nappe sheets.

Abstract:Abstract：The depositional facies of Lower Triassic Jialingjiang Formation in Chishui area of Guizhou belongs to continental-marine carbonate platform deposition. Based on field outcrop in combination with drill core, this paper divided the sedimentary facies into several types and pointed out that beach subfacies and dolomite-flat microfacies are depositional faices zones in favor of the development of T1j21－T1j1 and T1j51 reservoirs in this area and, using the “single factor analysis and multifactor integration graphing method”,obtained compositional thickness percentage distribution trend of different petrographic categories in the T1j21layer. On such a basis, the depositional facies of T1j21－T1j1 and T1j51favorable segments were also analyzed. It is thus concluded that, except for the southeast part of the Baoyuan structure, the Wunan structure, the Tai-9 well field and the Xue-1 well field, the T1j21－T1j1 layers mostly have quite favorable dolomite-flat microfacies,with the development of beach subfacies at the top of T1j1 layer in certain places. The development of T1j51 layer dolomite-flat microfacies is better in the southeast than in the northwest,with the central southern part of the Baoyuan structure being the best, the Wanglong structure possessing the second place,the Xuebaiping structure probably fairly good, and Taihe and Wunan structures being the worst. The deposition of the platform inner bar is localized around Wang12 and Wang 6 well area of the Wanglong structure.

Abstract:Abstract：The Shahejie Formation in Raoyang Sag mainly comprises a set of terrigenous clastics such as conglomerate, conglomeratic sandstone, sandstone, siltstone and mudstone. A study of sedimentary characteristics led to the recognition of typical braided river delta deposition, whose characteristics are distinct and significantly different from other types of deltas resulting from river tractive current sedimentation which are generally controlled by torrential flood and seem to be seasonal sediments. The most notable feature of the braided river delta deposition in this area is the existence of a three-layer structure, which is composed from bottom to top of pre-braided river delta subfacies, braided river delta front subfacies and braided river delta plain subfacies, showing an obvious progradational sequence. There are several main microfacies, such as braided distributary channel, flood plain, subaqueous distributary channel, subaqueous inter-distributary channel, mouth bar and sheet bar. According to lithologic characteristics, sedimentary structure, grain size and sedimentary sequence of the braided river delta, a sedimentary model for the braided river delta was established. From lithologic characteristics of deposition, it is thought that the thickly-bedded conglomerate and conglomeratic sandstone developed in the braided river delta are widely distributed and constitute favorable oil and gas reservoirs. The sand bodies of the subaqueous distributary channel and mouth bar make up the most beneficial reservoirs and can form useful lithologic reservoirs. These places deserve much attention in future exploration.

Abstract:Abstract：Based on core logging and sample analysis of Qiangzi Well-2 petroleum shallow drilling hole in southern Qiangtang basin, the authors hold that the southern Qiangtang basin was in the evolution stage of passive margins in Middle Jurassic Bajocian and Aalenian period, and formed an upward coarsening and shoaling delta facies prograding sequence of Sewa Formation. On the cumulative curve in the grain size arithmetic probability graph, characteristics of saltation mass and suspension are obvious. The C-M diagram of grain sizes is characterized by typical braided river delta deposition. Pollen analysis also indicates a dry and hot climate of tropical and subtropical zones. In Middle Jurassic Bajocian period, the basin developed a comparatively stable stage of depression basin and formed carbonate platform shoaling sedimentary sequence of Buqu Formation, comprising mainly abundant oolitic, rudaceous and bioclastic limestone. The entire southern Qiangtang basin developed a regular transgressive-regressive cyclic succession from Aalenian period to Bajocian period in Middle Jurassic, forming in upward succession delta subfacies, delta frontal subfacies, platform-frontal slope subfacies, open platform subfacies and limited platform subfacies.

Abstract:Abstract：The Neogene Zhujiang Formation and Hanjiang Formation of Panyu low uplift in the Zhujiang River mouth basin were divided into seven sequences on the basis of an analysis of outcrops, cores, logs, 3D seismic information and palaeobiologic characteristics. Some were assigned to obvious truncation or obvious overlapping and unconformity, and the others to gentle truncation or overlapping unconformity and conformity. Every third-order sequence was divided into system tracts and fourth-order sequences whose boundaries seem to be main flooding surfaces. Combined with the seismic attributes, the distribution and development of the depositional systems in the fourth-order sequences were revealed. Under paleogeomorphologic conditions and relative sea-level change control, the deltaic sand bodies in the lowstand tract system were distributed in the uplift-gentle slope-break zone. In the highland system tracts, however, they were distributed in or west of the uplift zone. This paper has divided the stratigraphic traps into four types with a prediction of their distribution. The lowstand sand bodies in the southeastern syndepositional fault slope-break zone and in the east have good hydrocarbon pool-forming conditions, which are hence considered to be favorable for the formation of structural-lithologic traps or lithologic traps.

Abstract:Abstract：Based on a comprehensive analysis of lithostratigraphy, chronostratigraphy, spore-pollen zones and foraminiferal assemblages of the Quaternary bore core from the northern bank of the Qiantang River, the author holds that the Holocene sedimentation began from the depth of 35.7 m (about 10.4 ka B.P.), and the strata from this level to the depth of 71.1 m should belong to Late Pleistocene. The author also divides the paleoenvironmental evolution of this hole since 31.2 ka B.P. into five development stages, with a systematic description made in such aspects as paleovegetation, paleoclimate and paleogeography of each stage. It is pointed out that the second stage (20.1～10.4 ka B.P.) was within the low sea level period, during which the climate was cool, cold and dry, that the early period of the second stage may correspond to the glacial maximum of last glaciation, and that the fourth stage (7.5～2.5 ka B.P.) was within the high sea level period, when the climate was warm, hot and damp, corresponding to the Holocene climate optimum that was in line with the global change. The climate change of the last 30,000 years since Late Quaternary in this area exhibits a good comparability with that of the Shenzhen Bay area in southern China.

Abstract:Abstract：As a result of changes in the strength of tectonic activity, the sand bodies of Upper Triassic Xu 4 Member in central Sichuan basin had different accommodation space /sedimentary supply values in the process of sedimentation. The Xu 4 Member sand bodies consist from bottom to top of three vertical superimposed types, namely regression, aggradation and transgression． The regressive sand body mainly includes high energy truncation style channel,truncation style mouth bar and far-bar sand groups. The aggradation sand body mainly comprises erosion style channel and high energy truncation style channel, and the transgressive sand body is mainly composed of low-energy channel, low-energy truncation channel,complete mouth bar and lower breached mouth bar． Different sand body combinations have different styles of sand bodies, particles are of different sizes, and strong and weak hydrodynamic activities have different features. Hence sand bodies of different geneses formed different diagenetic facies and reservoir facies. The aggradation sand body is of corrosion facies and lining chlorite facies with high porosity, so it constitutes a good reservoir; the transgressive sand body is of compaction and binder facies with unsatisfactory physical properties; and the transgressive sand body is of corosion and binder facies with relatively good physical properties, so it serves as a medium-sized reservoir. Of these sand groups of three different geneses,the aggradation sand body has developed the high energy truncation style channel and formed widely distributed high-energy water channels in the plane,the sand body is thick, the extension is long with the development of favorable diagenetic facies,the physical properties are relatively good, and hence it can provide sufficient space for oil-gas enrichment． In addition, the sedimentary contact between the channel model and the regressive model is unconformable and shows a mosaic relation, so it can act as the channel way for gas migration．The transgressive sand body reservoir at the top tends to become tight and form a favorable cap rock, thus constituting a favorable position for oil and gas enrichment in central Sichuan basin．

Abstract:Abstract：This paper deals with the contents of such elements as B, V, Ni, Sr, Ba, Th and U by using the ICP-MS (Inductively Coupled Plasma-Ms Spectrometer) technique for 28 samples collected from Sinian-Silurian strata in Chuandongnan-Qianzhong region and its periphery areas. The contents of major and trace elements were determined by means of GB/T14506.28-93 and X-Ray Fluorescence Spectrometry. The corresponding relationships between the Sr/Ba, V/Ni, V/(V+Ni), Sr/Ca, Ca/Mg and Th/U values and the sedimentary environments were studied. The results show that the main sedimentary environments are bathyal, deep-sea or shallow sea stagnant environments. The difference in spatial distribution of elements reflects regional variation of the sedimentary environment.

Abstract:Abstract：Basic geological conditions for the migration and accumulation model of the deep marine basin are similar to those of the shallow-water continental shelf; nevertheless, the deeper the sag and fractures, the bigger the dimensions of the deposits and infillings, and hence the dimensions of the source rocks in the deep marine basin are larger and can lay an abundant source foundation for deep water oil and gas. In view of insufficient well logging data and shortage of geological information for the deep water area, the authors placed the emphasis on the early-stage prediction and evaluation of source rocks in the deep basin and analyzed the oil and gas resource potential by taking into account geological and geochemical characteristics of the source rocks in the shallow water and the evaluation parameters in combination with the interpretation of the sequence stratigraphic data across the deep water and the integrated research on petroleum and gas.

Abstract:Abstract：The No. 6 coal seam lies in the upper part of Taiyuan Formation within the Hada Gol Ga-bearing coal deposit of northeastern Ordos Basin. This coal seam is a low sulfidation type of bituminous coal with low coalification. Due to the special geological background and paleosedimentary environment,the bauxitic clay stone and the coal seam are extremely enriched in boehmite,Ga and REE. The average content of Ga is 44.8μg/g, and the ∑REE values vary from 110.82μg/g to 467.21 μg/g in seven coal segments, suggesting that Al, Ga and REE have similar geochemical behaviors and coexistence features. It is considered that Al, Ga and REE were derived from the same sources：① the erosion area of paleobasement, where there existed igneous rocks and metamorphic rocks with high K and Al；② clay stone and bauxite in Upper Carboniferous Benxi Formation overlying Middle Ordovician might have been an important provenance of Ga；③ clayey glutenite in coal measure strata is characterized by volcanic crystal fragments and volcanic ash,implying that they partly provided dissolvable Al and Ga materials； ④ Lower Permian Taiyuan Formation comprises such continental-marine interactive deposits as offshore coastal deposit, lagoonal deposit, delta deposit, barrier island deposit and lake-marsh sedimentary system. Such lithofacies paleogeography served as an advantage sedimentary environment of coal seams and bauxite strata for the accumulation of Ga. It is thus known that the origin of Ga in coal is characterized by multi-sources, inheritance, multiple periods and certain steps, suggesting that the accumulation process of Ga was very complicated.

Abstract:Abstract：Crisis mines and old mines possess great mineral resource potentials in their deep and marginal parts, but the search for resources in the depth is frequently confronted with enormous difficulties and risks. Old mines have usually experienced high degrees of exploration and exploitation, resource prognosis and prospecting goals have to be transferred to the three-dimensional space in the depth, and geophysical and geochemical anomaly information is strongly interfered by mining activities. Therefore, the adoption of new prognostic and appraisal methods for crisis mine prospecting seems to be an important means for making breakthrough in the appraisal and prospecting work in the deep and marginal parts of old mines. Aimed at solving the problems of evaluating and prospecting for replaceable resources in crisis mines, this paper established a core workflow for the stereoscopic quantitative prediction of concealed ore bodies, i.e., the flow chart of "geological data integration→quantitative mineralization information extraction→three-dimensional quantitative prediction", by using a data-driven and knowledge-driven combination method. From the viewpoint of the field analysis, the ore-controlling field models of magmatites, faults, strata, lithology and folds and the mineralization distribution filed model were constructed, with their solutions reached by transferring continuous models into discrete models. By means of statistical analysis and nonlinear programming, the correlation between geological ore-controlling fields and mineralization indexes was analyzed, and then the quantitative location parameters which describe the control of geological factors over mineralization were extracted. Thus the quantitative index set of geological ore-controlling factors was obtained. The stereoscopic quantitative prediction models composed of mineralization mathematical models and ore potential estimation models were built on the basis of the relationship between the mineralization indexes and the geological ore-controlling factor indexes. With the prediction models, the three-dimensional localization and quantitative prediction of concealed ore bodies were carried out in the deep and marginal parts of the Dachang mine, and the prediction database was created, based on which the unit prediction maps were drawn according to elevation levels. A three-dimensional visualization software system for displaying and querying the prediction results was developed. Deep prospecting drill holes were designed and put in practice following the prediction results and new ore bodied were thus found in the depth of the Changpo section and the Tongkeng section within the Dachang mine, which shows that the prediction models and results are effective.

Abstract:Abstract：Nanling region has favorable geological conditions for mineralization and hence serves as the main tin producing area in China. In recent years new breakthrough has been made in geological prospecting. Beginning with an analysis of ore-forming geological background and the classification of ore deposit types, the authors chose some study areas where ore-forming geological conditions are favorable, tin resource are abundant, ore deposit types are complex and working extent is relatively high. Adopting the “three step” resource estimation method in combination with other multi-source geological synthetic prediction means such as the Chinese geological analogy method and the integrative geological method, the authors utilized the resources extent evaluation system to predict the tin resource potential.

Abstract:Abstract： Based on data obtained from the Regional Geochemistry-National Reconnaissance Project (RGNR) of Hebei Province and using 2.4 ng/g as the threshold of geochemical anomaly, the authors delineated three Au geochemical blocks distributed in the northern part of Hebei Province. Statistics of these two geochemical blocks and a regional geochemical anomaly show that the gold mineralization coefficient is 0.45%. Calculation of gold resource potential based on this gold mineralization coefficient reveals that there are still 1836.3 ton (given 1000 m thickness of every rock mass) gold resources in geochemical anomalies within the province. The exploration extent of No.2 Au geochemical block is relatively low, but its estimated potential resources account for 3.8% of itself, and hence this block seems to be the most promising area in further exploration.

Abstract:Abstract：Located in Xiongershan metamorphic core complex of Henan Province, the Lizigou gold deposit has such mineralization types as Au, Ag and Pb (Ag) and shows considerable exploration potential. An analysis of fluid inclusions has revealed that there exist different types and combinations of inclusions at different ore-forming stages. At the early ore-forming stage (Ⅰ), the fluids were characterized by high temperature and high salinity, suggesting that they might have come from the depth; at the main ore-forming stage (Ⅱ), the temperature of the fluids dropped, and the salinity was relatively low but varied in a wide range (from 18.14 to 0.59 wt%); at the late ore-forming stage (Ⅲ), the ore-forming fluids further evolved, and the temperature and salinity decreased. Hydrogen and oxygen isotope data show that δD values of the ore-forming fluids at the early ore-forming stage varied in the range of -77.85 ‰- -70.43 ‰, implying that they were derived from hydrothermal and magmatic hydrothermal solutions; at Stage II and Stage III, the fluids obviously deviated from magma water and drifted towards atmospheric water in composition.

Abstract:Abstract：Based on an analysis of 166 heavy mineral samples from the 3rd Member of Ziniquanzi Formation (E1-2z3) in the central southern margin of the Junggar Basin and taking into account such factors as regional structure, climate and sediment characteristics, the authors have reached the following conclusions: the palaeogeographic conditions for the deposition of the 3rd Member of Ziniquanzi Formation were dry, with the development of multi-channel and intermittent braided rivers in the same direction characterized by shallowness, multiple sources and gentle slopes. A number of parallel rivers were developed, moved and extended vertical to the shoreline. Nevertheless, various kinds of sedimentary facies with a fairly great width were spread parallel to the shoreline.

Abstract:Abstract：In this paper, the contents and chemical speciation of Pb, Hg, Cr, Cd, As, Cu and Zn in farmland surface soils along three sections in sewage irrigation areas of Shijiazhuang City were investigated, and the heavy metal pollution was evaluated. The results show that heavy metals (with the exception of As) of surface soils along three sections in sewage irrigation areas of Shijiazhuang City have been concentrated in varying degrees： the contents of Hg and Cd are high, and the average contents of heavy metals in the downriver surface soils exceed their contents in the upriver and middle reach areas. Geoaccumulation indexes indicate that As in the surface soils has not caused pollution, and Hg and Cd in the surface soils have caused mild-moderate degrees of pollution in the surface soils, as evidenced by the arithmetic means of natural soils of Hebei Province. Chemical speciation of Pb, Hg, Cr, As, Cu and Zn in surface soils is mainly in the residual form, and Cd is mainly existent in exchangeable fractions and carbonate state. Cd has a certain degree of bioavailability and potential ecological harmfulness.

Abstract:Abstract：Different kinds of surface sediments are distributed in main roads of each urban area of Harbin, which include road bare soils, river alluvial deposits, soils, building soils and so on. These surface sediments were sampled on the basis of an analysis of their grain sizes and chemical composition. The results show that there exist plenty of coarse-grained components (>63μm) in riverbed alluvial deposits but less fine-grained components of silt and clay, and hence the latter have exerted relatively insignificant influence on the sand-dust weather of Harbin. Although there exist certain amounts of fine-grained materials in soils, they fail to participate in the sand-dust weather under the action of wind power because of the vegetation cover and the cohesion between soil particles. The road bare soils and building soils with large amounts of fine-grained materials that are liable to be transported for a long distance have similar chemical composition and chemical weathering features to sand-dust deposits in Harbin. Characteristics of grain sizes and chemical composition indicate that road naked soil and building soil constitute important material sources for sand-dust weather in Harbin in that they can supply sand-dust weather with a large amount of silt-dust materials. It is considered that it is the city building soil and road naked soil with large amounts of fine particles that exert a remarkable influence on the dust-sand weather in Harbin, and that the control of the loose earth surface naked soil is the key to the prevention of the dust-sand weather in Harbin.