胶东地区金矿床成矿时代及其成矿地球动力学背景-兼论壳幔相互作用与成岩成矿

Jiaodong Peninsula is the largest repository of gold in China. Varieties of studies have been involved in the mechanism of metallogenesis. This thesis is a part of the project "Study of basic geology related to the prespecting of the supra-large deposits" which supported by National Climbing Program of China to Prof. Zhou. One of the key scientific problems is to study the age and metallogenic dynamics of ore deposit and to understand how interaction between mantle and crust constrains on metallogenesis and lithogenesis. As Jiaodong Peninsula to be study area, the Rb-Sr, Sm-Nd and Pb isotopic systematics of pyrite and altered rocks are measured to define the age and origin of gold. The elemental and Sr-Nd-Pb isotopic compositions of dikes and granites was studied to implicate the source and lithogenesis of the dike and granite and removal of lithosphere and the interaction between mantle and crust in the Jiaodong Peninsula. Considering the tectonic of Jiaodong Peninsula, basic on the time and space, this thesis gives a metallogenic dynamics of gold mineralization and discusses the constraints of the interaction between mantle and crust on the metallogenesis and lithogenesis. This thesis reports the first direct Rb-Sr dating of pyrites and ores using sub-sampling from lode gold deposit in Linglong, Jiaodong Peninsula and the results demonstrate this as a useful geochronological technique for gold mineralization with poor age constraint. The Rb-Sr data of pyrites yields an isochron age of (121.6-122.7) Ma, whereas, those of ore and ore-pyrite spread in two ranges from 120.0 to 121.8 Ma and 110.0-111.7 Ma. Studies of characteristic of gold deposit, microscopy of pyrite and quartz indicate that the apparent ages of ore and ore-pyrite are not isochron ages, it was only mixed by two end members, i.e., the primitive hydrothermal fluids and wall rocks. However, the isochron age of pyrite samples constrains the age of gold mineralization, i.e., early Cretaceous, which is in good consistence with the published U-Pb ages of zircon by using the SHRIMP technique. The whole rock Rb-Sr isochron age of altered rocks indicates that the age of gold mineralizing in the Xincheng gold deposit is 116.6 ± 5.3 Ma. The Sr, Nd and Pb isotopic compositions of pyrite and altered rocks indicate that the gold and relevant elements were derived from multi-sources, i.e. dikes derived from enriched lithospheric mantle and granites, granodiorites and metamorphic rocks outcropped on the crust. It also shows that the hydrothermal fluids derived from mantle magma degassing had play an important role in the gold mineralizing. The major and trace elements, Sr-Nd-Pb isotopic data of granites and granodiorites suggest that the Linglong Granite and Kunyushan Granite were derived from partial melting of basement rocks in the Jiaodong Peninsula at post-collision of North China Craton with South China Craton. Guojialing Granodiorite was considered to be derived from a mixture source, that is, mixed by magmas derived from an enriched lithospheric mantle and crust during the delamination of lithosphere induced by the subduction of Izanagi Plate and the movement of Tancheng-Lujiang Fault. There are kinds of dikes occurred in the Jiaodong Peninsula, which are accompanying with gold mineralization in time and space. The dikes include gabrro, diabase, pyroxene diorite, gabrrophyre, granite-porphyry, and aplite. The whole rock K-Ar ages give two age intervals: 120-124 Ma for the dikes that erupted at the gold mineralizing stage, and <120 Ma of the dikes that intruded after gold mineralizing. According to the age and the relationship between the dikes and gold mineralizing, the dikes could be divided into two groups: Group I (t = 120-124 Ma) and Group II (t < 120Ma). Group I dikes show the high Mg and K, low Ti contents, negative Nb anomalies and positive Eu anomalies, high ~(87)Sr/~(86)Sr and negative εNd(t) values and an enrichment in light rare earth elements, large ion lithosphile elements and a depletion in high field strength elements. Thus the elemental and isotopic characteristics of the Group I dikes indicate that they were derived from an enriched lithospheric mantle perhaps formed by metasomatism of the melt derived from the recycled crustal materials during the deep subduction of continent. In contrast, the Group II dikes have high Ti, Mg and K contents, no negative Nb anomalies, high ~(87)Sr/~(86)Sr and positive or little negative εNd(t) values, which indicate the derivation from a source like OIB-source. The geochemical features also give the tectonic constraints of dikes, which show that Group I dikes were formed at continental arc setting, whereas Group II dikes were formed within plate background. Considering the tectonic setting of Jiaodong Peninsula during the period of gold mineralizing, the metallogenic dynamics was related to the subduction of Izanagi Plate, movement of Tancheng-Lujiang Fault and removal of lithopheric mantle during Late Mesozoic Era.

柴达木盆地北缘地区油气成藏过程模拟与含油气系统评价

As an important part of petroleum exploration areas in the west of China, the north part of Qaidam basin is very promising in making great progress for petroleum discovery. But there are still many obstacles to overcome in understanding the process of petroleum formation and evaluation of oil & gas potential because of the complexity of geological evolution in the study area. Based upon the petroleum system theory, the process of petroleum formation is analyzed and the potential of oil & gas is evaluated in different petroleum systems by means of the modeling approach. The geological background for the formation of petroleum systems and the consisting elements of petroleum systems are described in detail. The thickness of strata eroded is estimated by means of vitrinite reflectance modeling, compaction parameter calculating and thickness extrapolating. The buried histories are reconstructed using the transient compaction model, which combines of forward and reverse modeling. The geo-history evolution consists of four stages - sedimentation in different rates with different areas and slow subsidence during Jurassic, uplifting and erosion during Cretaceous, fast subsidence during the early and middle periods of Tertiary, subsidence and uplifting in alternation during the late period of Tertiary and Quaternary. The thermal gradients in the study area are from 2.0 ℃/100m to 2.6 ℃/100m, and the average of heat flow is 50.6 mW/m~2. From the vitrinite reflectance and apatite fission track data, a new approach based up Adaptive Genetic Algorithms for thermal history reconstruction is presented and used to estimate the plaeo-heat flow. The results of modeling show that the heat flow decreased and the basin got cooler from Jurassic to now. Oil generation from kerogens, gas generation from kerogens and gas cracked from oil are modeled by kinetic models. The kinetic parameters are calculated from the data obtained from laboratory experiments. The evolution of source rock maturation is modeled by means of Easy %Ro method. With the reconstruction of geo-histories and thermal histories and hydrocarbon generation, the oil and gas generation intensities for lower and middle Jurassic source rocks in different time are calculated. The results suggest that the source rocks got into maturation during the time of Xiaganchaigou sedimentation. The oil & gas generation centers for lower Jurassic source rocks locate in Yikeyawuru sag, Kunteyi sag and Eboliang area. The centers of generation for middle Jurassic source rocks locate in Saishenteng faulted sag and Yuka faulted sag. With the evidence of bio-markers and isotopes of carbonates, the oil or gas in Lenghusihao, Lenghuwuhao, Nanbaxian and Mahai oilfields is from lower Jurassic source rocks, and the oil or gas in Yuka is from middle Jurassic source rocks. Based up the results of the modeling, the distribution of source rocks and occurrence of oil and gas, there should be two petroleum systems in the study area. The key moments for these two petroleum, J_1-R(!) and J_2-J_3, are at the stages of Xiaganchaigou-Shangyoushashan sedimentation and Xiayoushashan-Shizigou sedimentation. With the kinetic midels for oil generated from kerogen, gas generated from kerogen and oil cracked to gas, the amount of oil and gas generated at different time in the two petroleum systems is calculated. The cumulative amount of oil generated from kerogen, gas generated from kerogen and gas cracked from oil is 409.78 * 10~8t, 360518.40 * 10~8m~3, and 186.50 * 10~8t in J_1-R(!). The amount of oil and gas generated for accumulation is 223.28 * 10~8t and 606692.99 * 10~8m~3 in J_1-R(!). The cumulative amount of oil generated from kerogen, gas generated from kerogen and gas cracked from oil is 29.05 * 10~8t, 23025.29 * 10~8m~3 and 14.42 * 10~8t in J_2-J_3 (!). The amount of oil and gas generated for accumulation is 14.63 * 10~8t and 42055.44 * 10~8m~3 in J_2-J_3 (!). The total oil and gas potential is 9.52 * 10~8t and 1946.25 * 10~8m~3.

鄂尔多斯盆地西缘中生代构造与地层分析及盆地演化研究

Through the detailed analyses of Mesozoic tectono-stratigraphy and basin formation dynamic mechanism and the styles of different units in the western margin of Ordos Basin(Abbreviated to "the western margin"), while some issues of the pre-Mesozoic in the western margin and central part of Ordos Basin also be discussed, the main views and conclusion as follows: 1. There are three types of depositional systems which are related with syndepositional tectonic actions and different tectonic prototype basins, including: alluvial fan systems, river system (braided river system and sinuosity river system), lacustrine-river delta system and fan delta system. They have complex constitutions of genetic facies. For the tectonic sequence VI, the fan sediments finning upper in the north-western margin and coarse upper in the south-western margin respectively. 2. In order to light the relationship between basin basement subsidence rate and sediment supply and the superposed styles, five categories of depositional systems tracts in different prototype basins were defined: aggrading and transgressive systems tracts during early subsidence stage, regressive and aggrading systems tracts during rapid subsidence, upper transgessive systems tracts during later subsidence stage. Different filling characteristics and related tectonic actions in different stages in Mesozoic period were discussed. 3. In order to determined the tectonic events of the provenance zones and provenance strata corresponding to basins sediments, according the clastics dispersal style and chemical analyses results of sediments in different areas, the provenance characteristics have been described. The collision stage between the "Mongolia block" and the north-China block may be the late permian; The sediments of Mesozoic strata in the north-western margin is mainly from the Alex blocks and north-Qilian Paleozoic orogeny, while the south-western margin from Qinling orogeny. The volcanic debris in the Yan'an Formation may be from the arc of the north margin of north-China block, although more study needed for the origin of the debris. The provenance of the Cretaceous may be from the early orogeny and the metamorphic basement of Longshan group. 4. The subsidence curve and subsidence rate and sedimentary rate in different units have been analyzed. For different prototype basin, the form of the subsidence curves are different. The subsidence of the basins are related with the orogeny of the basins.The beginning age of the foreland basin may be the middle Triassic. The change of basement subsidence show the migration of the foredeep and forebulge into the basin. The present appearance of the Ordos basin may be formed at the late stage of Cretaceous, not formed at the late Jurassic. 5. The structure mode of the west margin is very complex. Structure transfer in different fold-thrust units has been divided into three types: transfer faults, transition structures and intersected form. The theoretic explanations also have been given for the origin and the forming mechanism. The unique structure form of Hengshanpu is vergent west different from the east vergence of most thrust faults, the mechanism of which has been explained. 6. In Triassic period, the He1anshan basin is extensional basin while the Hengshanbu is "forland", and the possible mechanism of the seemingly incompatible structures has been explained. First time, the thesis integrate the Jurassic—early Cretaceous basins of west margin with the Hexi corridor basins and explain the unitive forming mechanism. The model thinks the lateral extrusion is the main mechanism of the Hexi corridor and west margin basins, meanwhile, the deep elements and basement characters of the basins. Also, for the first time, we determine the age of the basalt in Helanshan area as the Cretaceous period, the age matching with the forming of the Cretaceous basins and as the main factor of the coal metamorphism in the Helanshan area. 7. The Neoprotterozoic aulacogen is not the continuation of the Mesozoic aulacogen, while it is another new rift stage. In the Paleozoic, the Liupanshan—southern Helanshan area is part of the back-arc basins of north Qilian ocean. 8. The Helanshan "alacogen" is connected with the north margin of north China block, not end at the north of Zhouzishan area like "appendices". Also, I think the upper Devonian basin as the beginning stage of the extensional early Carboniferous basins, not as a part of the foreland basins of Silurian period, not the collision rift. 9. The controlling factor of the difference of the deformation styles of the north-west margin and the south-west margin is the difference of the basements and adjacent tectonic units of the two parts.

塔里木盆地塔中地区寒武-奥陶系烃源岩古地温及成烃演化史研究

The present maturity of Cambrian and Ordovician source rocks in Tazhong area, Tarim basin, is studied using several organic petrology methods and conodont CAI method. The highest palaeotemperature that the Cambrian-Ordovician undergone is revealed by Laser Roman Microprobe (LRM) analysis and by simulating experiment of the kerogen chemical kinetics. In according to all above study, the thermal history of Cambrian and Ordovician is reconstructed based on numerical simulating approaches. The characteristics of secondary hydrocarbon generating are studied by inclusions analysis. The reflectances of the samples in the drills located in Tazhong area show that the maturities of Cambrian source rocks are in the stages of condense oil-dry gas, and that of Ordovician source rocks range from peak of oil generating to wet gas stage. The palaeotemperature data of Cambrian-Orovician source rocks from well Tacan 1, based on LRM analysis, are in coincidence with that from other methods. Also are the palaeotemperature data of Cambrian-Orovician source rocks in well Tacan 1 based on the simulating experiments of kerogen pyrolysis, similar to the homogenization temperatures of inclusions in the source rocks. Aaccording to the vitrinite inflectance data of the TZ12 well and Tacan 1 well, the paleotemperature gradients are analysized and reconstructed. These data show that the paleotemperature gradient in Tazhong area was the highest during Cambrian-Ordovician period, it was up to 3.5°C/100m. Following, the temperature gradient descended gradually and it reached to the lowest at present (2.2°C/100m). The histories of maturation and hydrocarbon generation of Cambrian and Ordovician source rocks in Tazhong area are researched systematically and quantitatively, the results show that periods of oil generation from Cambrian and Ordovician source rocks lasted for a long time from Ordovician to Carbonferious periods because the central Cambrian stratum in the north slope of Tazhong area is buried differently in depth. The top of the Cambrian entered into the peak of oil generation in middle-late Ordovician, and most area of the north slope of Tazhong area entered into the peak of oil generation in Carbonferious period, and on the uplift belt some of source rocks entered into the peak of oil generation in Permian period. In early Devonian, the central of the Lower Ordovician source rocks near the Manjiaer depression reached the peak of oil generation and near the top of the Tazhong uplift did not reached the peak of oil generation until early Cretaceous. The middle-upper Ordovician entered into the peak of oil generation in early-middle Jurassic. The time of the middle-upper Ordovician in the top of the uplift belt entering into the peak of oil generation was delayed, because the source rock was buried shallowly, and it did not reached the peak of oil generation until middle Cretaceous. Middle-upper Ordovician in the top of the north slope has been in the peak of oil generation now, it is consistent with the maturity (1.0-1.2%Ro) of the source rocks. The characteristics of the inclusions formed by kerogens are different from that by crystal-enclosed organic matters(OM) during secondary hydrocarbon generation of Cambrian and Ordovician source rocks. The secondary hydrocarbon generation mainly occurred in Mesozoic-Cenozoic period, in an area of about 9000km2 in the north slope. The intensity of the secondary hydrocarbon generation of Cambrian and Ordovician is up to 21kg/torg and 36kg/torg) respectively. Using the staged gas chromatography, the high-over maturated carbonate source rocks are analysized to release the adsorbed OM, inclusions OM and crystal-enclosed OM, respectively, and to evaluate their relative contributions to secondary hydrocarbon generation. The three periods of oil and gas migration and petroleum pools formation in Tazhong area are determined according to organic inclusions and solid bitumen.

论大型拆离滑覆构造的特征、形成机制及其与油气成藏关系—以渤海湾盆地冀中坳陷饶阳凹陷为例

The studies of this paper is an important part of the "ninth five" science&technology-tackling project of CNPC -The oil and gas distribution regulation and the aims of explortion in jizhong depression. Basing on the former research results, with the materials of regional structural setting, major tectonic movements, bi-and tri-dimension seismic sections, oil well sections and reservoir sections, this paper involves studies of tectonic evolution, sedimentarv evolution, magma movement and reservoir prediction. The existence of huge stripping and gliding nappe is proved in the RaoYang Sag for the frist time. The properties, development, evolution and the relationship with reservoir of the stripping and gliding nappe are discussed in details in this paper. It is also talked about the affects of stripping and nappes to oil and gas exploration theoretically and practically in the paper. The marking attributes of the stripping and gliding nappe includes stripping and gliding plane, two deformation systems, stratigraphic repeat and hiatus close to the stripping and gliding plane, and the deformation attributes in the front and back of stripping and gliding nappe. The RaoYang stripping and gliding nappes can be divided into different belts in north-south direction and different zones in east-west direction. RaoYang Stripping and gliging nappes took place in the late Paleogene period and before the sedimentation of Neogene period. The sliding direction is NWW. The sliding distance is about 6km. The geothermal gradient in the separating slump area is low and stable. The formation of the stripping and gliding nappes is due to the regional structural setting, the sediments of Paleogene system, the soft roof and the uneven rising movement of structure units. The evolution of the stripping and gliding nappes can be divided into the following stages: regional differential elevation and subsidence, unstable gravity and gravitational sliding, the frist wholly stripping faults and sliding stage, and the following second and third stripping faults and sliding stages. The identification of RaoNan stripping and gliding nappes has an important role on the research of regional structure and oil and gas exploration. Basing on the properties of stripping and gliding nappes, we can identtify the gliding fractures, ductile compressional folds, the front and back structures of gliding nappes and gliding plane covered structures. Combination with different reservoir forming conditions, these structures can lead to different categories of reservoirs.

大兴安岭南段中生代火山-侵入杂岩带的双层叠置构造体制兼论滇中武定、易门碳酸质火山岩年代、来源及矿库与找矿研究

These are two parts included in this report. In the first part, the zonation of the complexes in its series, lithofacies, the depth of magma source and chambers is discussed in detailed for the first time based on the new data of petrol-chemistry, isotopes, tectono-magma activity of Mesozoic volcano-plutonic complexes in the southern Great Hinggan Mts. Then, the genetic model of the zonality, double overlapped layer system, is proposed. The main conclusions are presented as follows: The Mesozoic volcanic-plutonic complexes in the southern Great Hinggan were formed by four stages of magma activity on the base of the subduction system formed in late Paleozoic. The Mesozoic magmatic activity began in Meso-Jurassic Epoch, flourished in late Jurassic Epoch, and declined in early Cretaceous Epoch. The complexes consist dominantly of acidic rocks with substantial intermediate rocks and a few mefic ones include the series of calc alkaline, high potassium calc alkaline, shoshonite, and a few alkaline. Most of those rocks are characterized by high potassium. The volcano-plutonic complexes is characterized by zonality, and can be divided mainly into there zones. The west zone, located in northwestern side of gneiss zone in Great Xinggan mountains, are dominated of high potassium basalts and basaltic andesite. The middle zone lies on the southeast side of the Proterozoic gneiss zone, and its southeast margin is along Huangganliang, Wushijiazi, and Baitazi. It composed of dominatly calc-alkaline, high potassium calc-alkaline rocks, deep granite and extrusive rhyolite. The east zone, occurring along Kesheketong Qi-Balinyou Qi-Balinzuo Qi, is dominated of shoshonite. In generally, southeastward from the Proterozoic gneiss zone, the Mesozoic plutons show the zones-mica granitites zone, hornblende-mica granitite zone, mica-hornblende granitite zone; the volcanic rocks also display the zones of calc alkaline-high potassium calc alkaline and shoshonites. In the same space, the late Paleozoic plutons also display the same zonality, which zones are combined of binary granite, granodiorite, quartz diorite and diorite southeast wards from the gneiss. Meso-Jurassic Epoch granite plutons almost distribute in the middle zone on the whole. Whereas late Jurassic Epoch volcanic rocks distribute in the west and east zone. This distribution of the volcano-plutonic complexes reveals that the middle zone was uplifted more intensively then the other zones in Meso-Jurassic and late Jurassic Epoches. Whole rock Rb-Sr isochron ages of the high potassium calc-alkaline volcanic rocks in the west zone, the calc-alkaline and high potassium calc-alkaline granite the middle zone, shoshonite in the east zone are 136Ma, 175Ma and 154Ma, respectively. The alkaline rocks close to the shoshonite zone is 143Ma and 126Ma. The isochron ages are comparable well with the K-Ar ages of the rocks obtained previously by other researchers. The compositions of Sr ans Nd isotopes suggest that the source of Mesozoic volcanic-plutonic complexes in Great Hinggan Mts. is mostly Paleo-Asia oceanic volcanic-sedimentary rocks, which probably was mixed by antiquated gneiss. The tectonic setting for Mesozoic magmatism was subductive continental margin. But this it was not directly formed by present west Pacific subduction. It actully was the re-working of the Paleozoic subduction system( which was formed during the Paleo-Asia ocean shortening) controlled by west Pacific subduction. For this reason, Although Great Hinggan Mts. is far away from west Pacific subduction zone, its volcanic arc still occurred echoing to the volcanic activities of east China, it, but the variation trend of potassium content in volcano-plutonic complexes of Great Hinggan is just reverse to ones of west Pacific. The primitive magmas occurred in the southern Great Hinggan Mts. Include high-potassium calc-alkaline basalt, high potassium calc-alkaline rhyolite, high potassium rhyolite, non-Eu negative anomaly trachy-rhyolite et al. Therefore, all of primitive magmas are either mafic or acid, and most of intermediate rocks occurring in the area are the products of Mesozoic acid magma contaminated by the Paleozoic volcanic- sedimentary rocks. The depth of those primitive magma sources and chambers gradually increase from northwest to southeast. This suggests that Paleozoic subduction still controlled the Mesozoic magmatism. In summary, the lithosphere tectonic system of the southern Great Hinggan Mts. controlling Mesozoic magmatism is a double overlapped layer system developing from Paleozoic subduction system. For this reason, the depth of crust of the southern Great Hinggan Mts. is thicker than that of its two sides, and consequently it causes regional negative gravity abnormity. The second part of this report shows the prolongation of the research work carried on in my doctor's period. Author presents new data about Rb-Sr and Sm-Nd isotopic compositions and ages, geochamical features, genesis mineralogy and ore deposit geology of the volcanic rocks in Kunyang rift. On the base of the substantial work, author presents a prospect of copper bearing magnetite ore deposit. The most important conclusions are as follows: 1. It is proved that all of these carbonatites controlled by a ringing structure system in Wuding-Lufeng basin in the central Yunnan were formed in the Mesoproterozoic period. Two stages could be identified as follows: in the first stage, carbonatitic volcanic rocks, such as lavas(Sm-Nd, 1685Ma), basaltic porphyrite dykes(Sm-Nd, 1645Ma), pyroclastic rocks and volcaniclastic sedimentary rocks, formed in the outer ring; in the second stage, carbonatitic breccias and dykes(Rb-Sr, 1048 Ma) did in the middle ring. The metamorphic age of the carbonatitic lavas (Rb-Sr, 893 Ma) in the outer ring was determined. The magma of carbonatitic volcanic rocks derived mainly form enriched mantle whose basement is depleted mantle that had been metasomated by mantle fluid and contaminated by Archaean lower crust. Carbonatitic spheres were discovered in ore bearing layers in Lishi copper mining in Yimen recently, which formed in calcite carbonatitic magma extrusion. This discovery indicates that the formation of copper ore deposit genesis relates to carbonatitic volcanic activity. The iron and copper ore deposits occurring in carbonatitic volcanic- sedimentary rocks in Kunyang rift results from carbonatitic magmatism. Author calls this kind of ore deposits as subaqueous carbonatitic iron-copper deposit. The magnetic anomaly area in the north of Lishi copper mining in Yimen was a depression more lower than its circumference. Iron and copper ores occurrig on the margin of the magnetic anomaly are volcanic hydrothermal deposit. The magnetic body causing the magnetic anomaly must be magnetite ore. Because the anomaly area is wide, it can be sure that there is a large insidious ore deposit embedding there.

库车坳陷第三纪磁性地层和磁组构的研究

The Tertiary Kuche depression, also known as one of the most economically important oil and gas prospecting regions in the Tarim Basin, is a foreland basin formed by flexural subsidence resulting from the southward thrusting of the southern Tianshan. Detailed geological and geophysical studies on the Tertiary sequence of the Kuche region would provide constraints not only on the Mesozoic and Cenozoic deformation patterns, and its controlling on the formation and distribution of oil and gas of the Kuche depression, but also on the India-Asia postcollisional uplift and continental deformation of the Tianshan regions. In this thesis, the Tertiary sequence of the Kuche depression, which is composed of the upper Kumukeliemu Formation, Suweiyi Formation, Jidike Formation, Kangcun Formation, and Kuche Formation, was selected for magnetostratigraphic and anisotropy of magnetic susceptibility (AMS) study. Among a total of 697 collected sites, 688 sites gave magnetic fabric results and 686 sites yielded reliable paleomagnetic results, building up magenetostratigraphy for the Tertiary sequence of the Kuche depression. By correlating with international geomagnetic polarity timescale, the followings were concluded: 1) the time interval of the sampling sections is some 31-8.1 Ma; 2) the boundaries for Kangcun/Jidike Formations, Jidike/Suweiyi Formations, and Suweiyi/Kumukeliemu Formations are at about 13.5 Ma, 26 Ma and 29 Ma respectively; 3) the Jidike Formation might be formed in an interval between the late Upper Oligocene and middle Miocene, whereas the Suweiyi Formation was formed in the Upper Oligocene, in turn, the Paleogene/Neogene boundary is most likely to be at the bottom of the Jidike Formation in the Kuche depression; 4) the dramatic transition from the marine/lacustrine to fluvial/alluvial facies in the Suweiyi Formation and the lower Jidike Formation of the Kuche depression, which may indicate the initiation of Cenozoic thrusting in the Kuche depression, is probably occurred in the late Oligocene, i.e. at about 28-25 Ma. On the other hand, systematic differences of the AMS parameters, such as the corrected anisotropy of magnetic susceptibility, shape parameter of ellipsoids, q factors, angles between the intermediate and minimum magnetic susceptibility directions and bedding, indicate that a dramatic transition of tectonic strain is most likely to occur at about 16 Ma (middle Miocene) in the Kuche depression. Taking into account the initiation o f C enozoic thrusting in the Kuche d epression i s at about 2 8-25 M a, we argue that the intensive Cenozoic thrusting in the Kuche depression is mainly happened during a period between the late Oligocene to middle Miocene.

辽河坳陷构造活动与油气运聚

The relation between tectonic activity and oil and gas migration and accumulation is one of the major subjects studied in petroleum geology and oil and gas exploration process. Oil and gas exploration practice and understandings thus obtained over a long term have indicated that tectonic activities within hydrocarbon bearing basins had important controlling effect on oil and gas migration and accumulation, but the influence of different hydrocarbon basins and tectonic activities on migration, accumulation and distribution of oil and gas differs to certain degree. Liaohe Depression is located in the northeast strip of Baohai Gulf Basin. The two major faults, Tanlu and Yilan-Yitong fault of Tanlu fault system, which played a significant controlling role on the forming and evolution of Cenozoic hydrocarbon basins in eastern China, pass along the east and west side of the Depression. The special structural location had made Liaohe Depression different from other depressions in the Basin in terms of tectonic evolution, depositional evolution, organic evolution, oil and gas migration and accumulation, and reservoir distribution. Major reasons resulting in these differences are tectonic activities and stress effect. Through analytical study of tectonic evolution history, .depositional history, hydrocarbon evolution history, and oil and gas accumulation history in Liaohe Depression, this paper systematically discusses the controlling effect of regional right-hand rotation strike-slip tectonic activity and stress effect on forming of major hydrocarbon bearing structures, major period of hydrocarbon expulsion from source rock, major direction of secondary oil and gas migration, and distribution of oil and gas accumulations since mid-late period of Oliocene, Paleogene. It has been concluded that major oil and gas bearing anticline structures within the Depression are reversal anticlines formed by right-hand rotation strike-slip shear compressional stress, main hydrocarbon expulsion period happened in the moving period of major right-hand rotation strike-slip tectonic activity, the direction of right-hand rotation strike-slip shear compressional stress was the main direction of secondary oil and gas migration, and the discharging zone of right-hand rotation strike-slip shear compressional stress was major accumulation zone of oil and gas.

库车坳陷-南天山盆山系统第三纪脆性构造研究

Study on the structural coupling relationship between basin and range is not only helpful to recognize the basin formation and evolution systematically, but also to guide petroleum exploration in the basin. As a late Paleozoic Orogen, the South Tianshan Mountains reactivated and uplifted rapidly during the Cenozoic, and led to the Mesozoic-Cenozoic considerable thick deposits in the Kuqa Depression. The researches of the dissertation were carried out in the Kuqa depression-South Tianshan M ountain s ystem, a nd t he b rittle m icrotectonics w. ere c hosen as t he m ost important object. Based on observations and measurements of the field, we made detailed investigations on the geometry and kinematics of this area, and analyzed the abutting and cutting relationships and relative sequence of many brittle structures, such as joint, shear fractures, faults and some small-scale structures related to them closely. According to those brittle fractures' relationships with stress, the nature and variation of regional palaeostress field during the Cenozoic were studied through inversion of fault slip data and inferring stress state from joint sequences. And the deformation time was estimated primarily via ESR dating of faulting. Results show that the stress field varies as well in times as in space. The maximal principal stress direction shifted from the vertical to the horizontal, and stress regime from weak extension to strong compression from the Paleogene to the Neogene regionally. During the late Neogene, the structural deformation of the South Tianshan and the basin-range boundary was dominated by near N-S extension, while near N-S compressive deformation in the interior of the Kuqa Depression. There exits obvious differential stress state from the north to the south. ESR dating of the faulting during the Cenozoic indicates that, the normal faulting in the north edge of the Kuqa Depression have been active all along from the Miocene to the early Pleistocene, but the thrusting and reverse faulting in the interior only been active from the Pliocene to the early Pleistocene. On the base of those geological data and some geophysical information and theoretical calculation results, we infer that, the different stress regime the basin-range system is ascribed to the vertical uplift of the Tianshan Mountain. It was the vertical uplift that lead to the gravity-driven gliding of thick layers lying on the faulted basement from the South Tianshan Mountain to the Kuqa depression, and to folding and thrusting in the interior and frontal of the Kuqa depression. Combining the structural evolution with petroleum geological conditions of the Kuqa Depression, we think that the strong compressive deformation of the Kuqa Depression during rapid uplifting of the Tianshan Mountains from the Pliocene to the early Pleistocene play crucial role in the structural trap formation and proliferous gas accumulation.

大别（超）包产到户铁岩和阜新火山岩铂族元素斌存规律研究

The platinum-group elements (PGE), including Os, Ir, Ru, Rh, Pt and Pd, axe strongly siderophile and chalcophile. On the basis of melting temperature, the PGE may be divided into two groups: the Ir group (IPGE, >2000°C) consisting of Os, Ir and Ru, and the Pd group (PPGE, <20GO°C) consisting of Rh, Pt and Pd. Because of their unique geochemical properties, PGE provide critical information on global-scale differentiation processes, such as core-mantle segregation, late accretionary history, and core-mantle exchange. In addition, they may be used to identify magma source regions and unravel complex petrogenetic processes including partial melting, melt percolation and metasomatism in the mantle, magma mixing and crustal contamination in magma chambers and melt crystallization.Compared with other rocks, (ultra)mafic rocks have lower REE content but higher PGE content, so PGE have advantages in studying the petrogeneses and evolution of them. In this study, we selected (ultra)mafic rocks collected in Dabie Orogen and volcanic rocks from Fuxin Region. Based on the distribution and behaviour of platinum-group elements, combined with other elements, we speculate the magma evolution and source mantle of these (ultra)mafic rocks and volcanic rocks.Many (ultra)mafic rocks are widely distributed in Dabie Region. According to their deformation and metamorphism, we classed them into three types. One is intrusive (ultra)mafic rocks, which are generally undeformed and show no or little sign of metamorphism, such as (ultra)mafic intrusions in Shacun, zhujiapu, Banzhufan, qingshan, Xiaohekou, Jiaoziyan, Renjiawan and Daoshichong. The other one is ultrahigh pressure metamorphic (ultra)mafic rocks, some of them appeared as eelogites, such as complex in Bixiling and adjacent Maowu. Another one is intense deformed and metamorphic, termed as tectonic slice, alpine-type (ultra)mafic rocks. The most representative is Raobazhai and Dahuapin. However, there are many controversies about the formation of those (ultra)mafic rocks. Here, we select typical rocks of the three types. The PGE were determined by inductively coupled plasma mass spectrometry (ICP-MS) ater NiS fire-assay and tellurium co-precipitation.The PGE tracing shows that three components are needed in the source of the cretaceous (uitra)mafic intrusions. They could be old enriched sub-continental lithospheric mantle, lower crust and depleted asthenospheric mantle. The pattern of PGE also shows the primitive magma of these intrusions underwent S saturation. According to palladium, we can conclude that the mantle enrich in PGE. Distribution of PGE in Bixiiing and Maowu (ultra)mafic rocks display they are products of magmas fractional crystallization. The (ultra)mafic rocks in Bixiiing and Maowu are controlled by various magmatic processes and the source mantle is depleted in PGE. Of interest is that the mantle produced UHP (ultra)mafic rocks are PGE-depleted, whereas the mantle of cretaceous (ultra)mafic intrusions are enrich in PGE. This couldindicate that the mantle change from PGE-enriched to PGE-depleted during120-OOMa, which in accord with the time of tectonic system change in the East China. At the same time, (ultra)mafic intrusions in cretaceous took information of deep mantle, which means the processes in deep mantle arose structural movement in the crust The character of PGE in alpine-type (ultra)mafic rocks declared that the rocks had experienced two types of metasomatic processes - hydrous melt derived from slab and silicate melt. In addition, we analyze the platinum-group elements in volcanic rocks on the northern margin of the North China Craton, Fuxin. The volcanic rocks characterized by negative anomalies of platinum. This indicates that platinum alloys, which may host some Pt resided in the mantle. The PGE patterns also show that Jianguo alkali basalts derived from asthenospheric mantle source, but wulahada high-Mg andesites derived from lithospheric mantle.

亚洲地形和海陆分布变化对东亚环境格局形成演化的作用：数值模拟与地质记录对比

Earlier studies on the distribution of geological environmental indicators in China revealed drastic changes from a zonal climate pattern (planetary-wave-dominant pattern) in the Paleogene to a monsoon-dominant one in the Neogene, which suggested an inception of the initial East-Asian summer monsoon. However, there are different views about the time and causes of the changes.Here, we attempt to compile a series of paleoenvironmental maps based on newly collected climate indicators from the literatures and chronologically constrained evidence of geological maps in order to re-examine the temporal and spatial evolution of climate belts in China during the Cenozoic with special emphasis on the changes of the arid belt. These indicators include mammalian fauna, coal, carbonate concretions, jarosite, salt, gypsum deposits and pollen assemblages etc, with chronological controls that we believe reliable. Pollen assemblages and mammalian fauna have been classified into three categories (arid, semi-arid/sub-humid, humid) to reflect the intensity of aridity/humidity. Salt, jarosite and gypsum deposits are classified as the arid indicators. Carbonate concretions and coal are classified into the semi-arid/sub-humid and humid one respectively. Paleoenvironmental maps at 8 time slices have been reconstructed. They are the Paleocene, Eocene, Oligocene, Miocene, Early Miocene, Middle Miocene, Late Miocene and Pliocene.And furthermore, we attempt to use IAP^AGCM to simulate the evolution of climate belts in emphasizing on the changes of the rain band, and compare the results with the paleoenvironmental maps in order to examine the causes of the drastic paleoenvironmental changes near the Oligocene/Miocene boundary. 36 sensitive numerical experiments are carried out using the IAP__AGCM to analyze the impacts of the uplift of the Himalayan-Tibetan complex, shrinkage of the Paratethys Sea, expansion of the South China Sea and the development of the polar ice sheets on rain band in China.The main conclusions are as follows:The obtained results essentially confirm the earlier conclusions about a zonal climate pattern in the Paleogene and a different pattern in the Neogene, and illustrate that a monsoon-dominant environmental pattern with inland aridity formed by the Early Miocene, which is temporally consist with the onset of eolian deposits in China.Cenozoic cooling and the formation of polar ice sheets are unlikely the main causes to the changes of environmental patterns mentioned above in China. But northern hemispheric cooling and the ice-sheets can intensify the Siberian High Pressure, and strengthen the winter monsoon circulations and enhance the aridity in the west part of China. These results support the earlier studies.Shrinkage of the Paratethys Sea and uplift of the Himalayan-Tibetan complex played important roles in strengthening the East Asian monsoon and induceing the above changes of environmental pattern, which is consistent with the earlier studies. Furthermore, "the monsoon-dominant pattern" appears when the Himalayan-Tibetan complex reaches to about 1000-2000 meters high and the Paratethys Sea retreats to the Turan Plate.4) Expansion of the South China Sea is another significant factor that drives the evolution of environmental patterns. We believe that the above three factors co-act and drive the change of the environmental patterns from a planetary-wave-dominant one to a monsoon-dominant one. However, the impacts of each factor vary by regions. The uplift mainly increases the humidity in Southwestern China and the aridity in northwestern country. The shrinkage mainly increases the humidity in Northern China and also enhances the aridity in the northwestern country. The expansion greatly increases the humidity in the south part of China.

A Quantitative Study on Paleo—River Environment During Late Jurassic on yaojie Region,Minhe Basin

Fluvial Sedimentation of alluvial facies prevailed during the Late Jrassic in the Minhe Basin.On the basis of the study of sedimentary facies of the Upper Jurassic series.this paper focuses on the river types suing the "Architecture Element" analysis method proposed by Miall,and calculated all the quantitative parameters to reflect the characteristics of the stream channel geometry and hydrodynamic conditions of paleo-rivers with the equations of ethrideg,schumm et al.Finally,we discussed the characteristics of environmental evolution of palsorivers on the quantitative basis.Our conclusion indicates that the evolution of paleo-rivers during the Late Jurassic,from early to late,shows such a tendency as alluvial fan river→ braid river→alluvial fan river→mid-sinuoisty river→ high-sinuosity river.

Mantle-derived gaseous components in ore-forming fluids of the Xiangshan uranium

The Xiangshan U deposit, the largest hydrothermal U deposit in China, is hosted in late Jurassic felsic volcanic rocks although the U mineralization post dates the volcanics by at least 20 Ma. The mineralization coincides with intrusion of local mantle-derived mafic dykes formed during Cretaceous crustal extension in South China. Ore-forming fluids are rich in CO2, and U in the fluid is thought to have been dissolved in the form of UO2 (CO3)22− and UO2 (CO3) 34− complexes. This paper provides He and Ar isotope data of fluid inclusions in pyrites and C isotope data of calcites associated with U mineralization (pitchblende) in the Xiangshan U deposit. He isotopic compositions range between 0.1 and 2.0Ra (where Ra is the 3He/4He ratio of air=1.39×10−6) and correlates with 40Ar/36Ar; although there is potential for significant 3He production via 6Li(n,α)3H(β)3He reactions in a U deposit (due to abundant neutrons), nucleogenic production cannot account for either the 3He concentration in these fluids, nor the correlations between He and Ar isotopic compositions. It is more likely that the high 3He/4He ratios represent trapped mantle-derived gases. A mantle origin for the volatiles of Xiangshan is consistent with the δ13C values of calcites, which vary from −3.5‰ to −7.7‰, overlapping the range of mantle CO2. The He, Ar and CO2 characteristics of the ore-forming fluids responsible for the deposit are consistent with mixing between 3He- and CO2-rich mantle-derived fluids and CO2-poor meteoric fluids. These fluids were likely produced during Cretaceous extension and dyke intrusion which permitted mantle-derived CO2 to migrate upward and remobilize U from the acid volcanic source rocks, resulting in the formation of the U deposit. Subsequent decay of U within the fluid inclusions has reduced the 3He/4He ratio, and variations in U/3He result in the range in 3He/4He observed with U/3He ratios in the range 5–17×103 likely corresponding to U concentrations in the fluids b0.2 ppm.