班公湖带多不杂超大型富金斑岩铜矿床的成岩成矿年代学、岩石学及高氧化岩浆¬流体-成矿作用

Duobuza copper deposit, newly discovered typical gold-rich porphyry copper deposit with superlarge potential, is located in the Tiegelong Mesozoic tectonic -magmatic arc of the southern edge of Qiangtang block and the northern margin of Bangonghu-Nujiang suture. Quartz diorite porphyrite and grandiorite porphyry, occurred in stock, are the main ore-bearing porphyries. As the emplacement of porphyry stock, a wide range of hydrothermal alteration has developed. Within the framework of the ore district, abundant hydrothermal magnetite developed, and the relationship between precipitation of copper and gold and hydrothermal magnetite seems much close. Correspondingly, a series of veinlets and network veinlets occurred in all alteration zones. Therefore, systematic research on such a superlarge high-grade Duobuza gold-rich porphyry copper deposit can fully revealed the metallogenic characteristics of gold-rich porphyry copper deposits in this region, establish metallogenetic model and prospecting criteria, and has important practical significance on the promotion of regional exploration. In addition, this research on it can enrich metallogenic theory of strong oxidation magma-fluid to gold-rich porphyry copper deposit, and will be helpful to understand the metallogenic characteristics in early of subduction of Gangdese arc stages and its entire evolution history of the Qinghai-Tibet Plateau, the temporal and spatial distribution of ore deposits and their geodynamics settings. Northern ore body of Duobuza copper deposit have been controlled with width (north-south) about 100 ~ 400 m, length (east-west) about 1400 m, dip of 200 °, angle of dip 65 °~ 80 °. And controlled resource amount is of 2.7 million tons Cu with grade 0.94% and 13 tons Au with 0.21g/tAu. Overall features of ore body are large scale, higher grade copper, gold-rich. Ore occurred in the body of granodiotite porphyry and quartz diorite porphyrite and its contact zone with wall rock. Through the detailed mapping and field work studies, some typies of alteration are identificated as follows: albitization, biotititation, sericitization, silication, epidotization, chloritization, carbonatization, illitization, kaolinization and so on. The range of alteration is more than 10km2. Wall alteration zone can be divided into potassic alteration, moderate argillization alteration, argillization, illite-hydromuscovite or propylitization from ore-bearing porphyry center outwards, but phyllic alteration has not well developed and only sericite-quartz veins occurred in local area. Moreover, micro-fracture is development in ore district , and correspondingly a series of veinlets are development as follows: biotite vein (EB type), K-feldspar-biotite-chalcopyrite-quartz vein, magnetite-antinolite-K-feldspar vein, quartz-chalcopyrite-magnetite veins (A-type), quartz-magnetite-biotite-K-feldspar vein, chalcopyrite veinlets in potassic alteration zone; (2) chalcopyrite occurring in the center vein–quartz vein (B type), chalcopyrite veinlets, chalcopyrite-gypsum vein in intermediate argillization alteration; (3) chalcopyrite- pyrite-quartz vein, pyrite-quartz vein, chalcopyrite-gypsum veins, quartz-gypsum- molybdenite-chalcopyrite vein in argillization alteration; (4) gypsum veins, quartz-(molybdenite)-chalcopyrite vein, quartz-pyrite vein, gypsum- chalcopyrite vein, potassium feldspar veinlets, Carbonate veins, quartz-magnetite veins in the wall rock. In short, various veins are very abundant within the framework of the ore district. The results of electronic probe microscopy analysis (EMPA) indicate that Albite (Ab 91.5~99.7%) occurred along the rim of plagioclase phenocryst and fracture, and respresents the earliest stages of alteration. K-feldspar (Or 75.1~96.9%) altered plagioclase phenocryst and matrix or formed secondary potassium feldspar veinlets. Secondary biotite occurred mainly in phenocryst, matrix and veinlets, belong to magnesium-rich biotite formed under the conditions of high-oxidation magma- hydrothermal. Chloritization developed in all alteration zones and alterd iron- magnesium minerals such as biotite and hornblende and then formed chlorite veinlets. As the temperature rises, Si in the tetrahedral site of chlorite decreased, and chlorite component evolved from diabantite to ripiolite. The consistent 280℃~360℃ of formation temperature hinted that chlorite formed on the same temperature range in all alteration zones. However, formation temperature range of chlorite from the gypsum-carbonate-chlorite vein was 190℃~220℃, and it may be the product of the latest stage of hydrothermal activity. The closely relationship between biotite and rutile indicate that most of rutiles are precipitated in the process of biotite alteration and recrystallization. In addition, the V2O3 concentration of rutile from ore body in Duobuza gold-rich porphyry copper deposit is >0.4％, indicate that V concentration in rutile has important significance on marking main ore body of porphyry copper deposit. Apatites from Duobuza deposit all are F-rich. And apatite in the wall rock contained low MnO content and relatively high FeO content, which may due to the basaltic composition of the wall rocks. The MnO in apatite from altered porphyry show a strong positive correlation with FeO. In addition, Cl/F ratio of apatite from wall rock was highest, followed by the potassic alteration zone and potassic alteration zone overprinted by moderate argillization alteration was the lowest. SO2 in Apatite are in the scope of 0 to 0.66%, biotite in the apatite has the highest SO2, followed by the potassic alteration zone, potassic alteration zone overprinted by moderate argillization alteration, and the lowest in the surrounding rocks, which may be caused by the decrease of oxygen fugacity of hydrothermal fluid and S exhaust by sulfide precipitation in potassic alteration. Magnetite in the wall rock have higher Cr2O3 and lower Al2O3 features compared with altered porphyry, this may be due to basalt wall rock generally has high Cr content. And magnetites have higher TiO2 content in potassic alteration than moderate argillization alteration overprinted by potassic alteration, argillization and wall rock, suggested that its formation temperature in potassic alteration was the highest among them. The ore minerals mainly are chalcopyrite and bornite, and Au contents of chalcopyrite, bornite, and pyrite are similar with chalcopyrite slightly higher. The Eu* negative anomaly of disseminated chalcopyrite was relatively lower than chalcopyrite in veinlets. Within a drill hole, the Eu* negative anomaly of disseminated chalcopyrite was gradually larger from bottom to top. Magnetite has the same distribution model, with obvious negative Eu* abnormal, and ΣREE in great changes. The gypsum has the highest ΣREE content and the obvious negative anomaly, and biotite obviously has the Eu* abnormal. Based on the petrographic and geochemical characteristics, five series of magmatic rocks can be broadly classified; they are volcanic rocks of the normal island arc, high-Nb basaltic rocks, adakites, altered porphyry and diorite. The Sr, Nd, Hf isotopes and geochemistry of various series of magmatic rock show that they may be the result of mixing between basic magma and various degrees of acid magma coming from lower crust melted by high temperature basic underplating from partial melting of the subduction sediment melt metasomatic mantle wedge. Furthermore S isotope and Pb isotope of the sulfide, ore-bearing porphyries and volcanic rocks indicated ore-forming source is the mantle wedge metasomatied by subduction sediment melt. Oxygen fugacity of magma estimated by Fe2O3/FeO of whole rock and zircon Ce4+/Ce3+ indicated that the oxidation of basalt-andesitic rocks is higher than ore-forming porphyry, and might imply high-oxidation characteristics of underplated basic magma. Its high oxidative mechanism is likely mantle sources metasomatied by subduction sediment magma, including water and Fe3+. And such high oxidation of basaltic magma is conducive to the mantle of sulfides in the effective access to melt. And the An component of dark part within plagioclase phenocryst zoning belong to bytownite (An 74%), and its may be a result of magma composition changes refreshment by basaltic magma injection. SHRIMP zircon U-Pb and LA-ICP-MS zircon U-Pb geochronology study showed that the intrusions and volcanic rocks from Duobuza porphyry copper deposit belong to early Cretaceous magma series (126~105Ma). The magma evolution series are as follows: the earliest diorite and diorite porphyrite → ore-bearing porphyry and barren grandiorite porphyry →basaltic andesite → diorite porphyrite → andesite → basaltic andesite, and magma component shows a evolution trend from intermediate to intermediate-acid to basic. Based on the field evidences, the formation age of high-Nb basalt may be the latest. The Ar-Ar geochronology of altered secondary biotite, K-feldspar and sericite shows that the main mineralization lasting a interval of about 4 Ma, the duration limit of whole magma-hydrothermal evolution of about 6 Ma, and possibly such a long duration limit may result in the formation of Duobuza super-large copper deposit. Moreover, tectonic diagram and trace element geochemistry of volcanic rocks and diorite from Duobuza porphyry copper deposit confirm that it formed in a continental margin arc environment. Zircon U-Pb age of volcanic rocks and porphyry fall in the range of 105~121Ma, and Duobuza porphyry copper deposit locating in the north of the Bangonghu- Nujiang suture zone, suggested that Neo-Tethys ocean still subducted northward at least early Cretaceous, and its closure time should be later than 105 Ma. Three major inclusion types and ten subtypes are distinguished from quartz phenocrysts and various quartz veins. Vapor generally coexisting with brine inclusions, suggest that fluid boiling may be the main ore-forming mechanism. Raman spectrums of fluid inclusions display that the content of vapor and liquid inclusion mainly contain water, and vapor occasionally contain a little CO2. In addition, the component of liquid inclusions mainly include Cl-, SO42-, Na+, K+, a small amount of Ca2+, F-; and Cl- and Na+ show good correlation. Vapor mainly contains water, a small amount of CO2, CH4 and C2H6 and so on. The daughter minerals identified by Laman spectroscopy and SEM include gypsum, chalcopyrite, halite, sylvite, rutile, potassium feldspar, Fe-Mn-chloride and other minerals, and ore-forming fluid belong to a complex hydrothermal system containing H2O-NaCl-KClFeCl2CaCl2. H and O isotopic analysis of quartz phenocryst, vein quartz, magnetite, chlorite and gypsum from all alteration zones show that the ore-forming fluid of Duobuza gold-rich porphyry copper deposit consisted mainly of magmatic water, without addition of meteric water. Duobuza gold-rich porphyry copper deposit formed by the primary magmatic fluid (600-950C), which has high oxidation, ultra-high salinity and metallogenic element-rich, exsolution direct from the magma, and it is representative of the typical orthomagmatic end member of the porphyry continuum. Moreover, the fluid evolution model of Duobuza gold-rich porphyry copper deposit has been established. Furthermore, two key factors for formation of large Au-rich porphyry copper deposit have been summed up, which are ore-forming fluids earlier separated from magma and high oxidation magma-mineralization fluid system.

荣成基底片麻岩原岩岩石成因及其构造意义

Extensive high to ultrahigh pressure metamorphic rocks are outcropped in the the Dabie-Sulu UHP orogenic belt. Disputes still exist about for protolith nature of metamorphic rocks, petrogenesis, tectonic setting, and influence on upper mantle during the Triassic deep subduction. In this study, a combined study of petrology, geochemistry, isotope geochemistry and zircon chronology was accomplished for high-grade gneisses in the basement of the ultrahigh-pressure metamorphic Rongcheng terrane to reveal protolith nature and petrogenesis of the gneisses and to disucss the magmatic succession along the northern margin of the Yangtze block in Neoproterozoic. Gneisses in the Rongcheng terrane are characterized by negative Nb, Ta, P and Ti anomalies, relatively low Sr/Y ratios and relatively high Ba/La, Ba/Nb and Ba/Zr ratios, mostly displaying geochemical affinity to Phanerozoic volcanic arc. Neoproterozoic protolith ages (0.7 ~ 0.8 Ga) and Paleoproterozoic average crustal residence time (1.92 ~ 2.21 Ga) favour a Yangtze affinity. The gneisses mostly display characteristics of enrichment of LREE, flat heavy rare earth elements (REE) patterns, moderately fractionation between LREE and HREE and slight negative or positive Eu anomalies, probably reflecting that melting took place in the middle to low crust (26 ~ 33 km), where amphibole fractionated from the melts and/or inherited from source material as major mineral phases in the source area. Sr-Nd isotopic composition of the gneisses supports this conclusion. According to εNd(t) and εHf(t) values, the gneisses can be divided into three groups. Gneisses of group I have the highest εNd(t) and εHf(t) values, corresponding to the range of -6 ~ -3 and -2.9 ~ 13.4, respectively. This suggests obvious influx of depleted mantle or juvenile crust in the formation of protoliths. Gneisses of group II have medium εNd(t) (-9 ~ -7) and εHf(t) values (-15.8 ~ -1.4), corresponding to relatively high TDM2(Nd) (1.99 ~ 2.31 Ga) and TDM2(Hf) (1.76 ~ 2.67 Ga) , respectively. This suggests these gneisses were formed by partial melting of Paleoproterozoic crust. Gneisses of group III have the lowest εNd(t) (-15 ~ -10) and εHf(t) values (-15.8 ~ -1.4), corresponding to the largest TDM2(Nd) (1.99 ~ 2.31 Ga) and TDM2(Hf) ( 1.76 ~ 2.67 Ga), respectively. This indicates that gneisses of group III were formed by remelting of Archean crustal material and further demonstrates existence of an Archean basement probably of the Yangtze affinity beneath the Rongcheng terrane. Gneisses of three groups have also certain different geochemical characteristics. Contents of REEs and trace elements reduce gradually from group I to group III. Zirconium saturation temperatures also show similar tendency. Compared to gneisses of group II and group III, gneisses of group I display geochemical feature similar to extensional tectonic setting, having relatively little influence by the source area. Therefore, geochemical characteristics for gneisses of group I can indictate that the protoliths of the Rongcheng gneisses formed in an extensional rifting tectonic setting. This conclusion is supported by the results of eclogites and gabbros previously reported in the Dabie-Sulu orogenic belt. Statistical results of the protolith ages of the Rongcheng gneisses show two age peaks around ~728 Ma and ~783 Ma with an about 50 Ma gap. Extensive magatism in abou 750 Ma along the northern margin of the Yangtze block can hardly be observed in the Rongcheng terrane. This phenomenon likely suggests discontinuous Neoproterozoic magmatism along the northern margin of the Yangtze block.

北山及邻区古生代-早中生代增生与碰撞大地构造格局

The Beishan orogenic collage locates at the triple-joint among Xinjiang, Gansu, and Inner Mongolia Provinces, at which the Siberian, Tarim and North China plates join together. It also occupies the central segment of the southern Central Asian Orogenic Belt (CAOB). The main study area in the present suty focused on the southwest part of the Beishan Mountain, which can be subdivided into four units southernward, the Mazhongshan continental block, Huaniushan Arc, Liuyuan suture zone and Shibanshan-Daqishan Arc. 1. The Huaniushan Arc was formed by northernward dipping subduction from the Orcovician to Permian, in which volcanic rocks ranging from basic to acidic with island arc affinity were widely developed. The granitiod intrusions become smaller and younger southward, whichs indicates a southward rollback of slab. The granitiod intrusions are mainly composed of I type granites, and their geochemical compositions suggest that they have affinities of island arc settings. In the early Paleozoic（440Ma-390Ma）. The Shibanshan-Daqishan Arc, however, were produced in the southernward dipping subduction system from Carboniferous to Permian. Volcanic rocks from basic to acidic rocks are typical calcic-alkaline rocks. The granitiod intrusions become smaller and younger northernward, indicating subdution with a northernward rollback. The granitiod intrusions mainly consist of I-type granites, of which geochemical data support they belong to island arc granite. 2. Two series of adakite intrusions and eruptive rocks have been discovered in the southern margin of the Huaniushan Island Arc. The older series formed during Silurian (441.7±2.5Ma) are gneiss granitoid. These adakite granites intruded the early Paleozoic Liuyuan accretionary complex, and have the same age as most of the granite intrusions in the Huanniushan Arc. Their geochemical compostions demonstrate that they were derived from partial melting of the subudcted oceanic slab. These characteristics indicate a young oceanic crust subduction in the early Paleozoic. The late stage adakites with compositons of dacites associate with Nb-enriched basalts, and island arc basalts and dacites. Their geochemistries demonstrate that the adakites are the products of subducted slab melts, whereas the Nb-enriched basalt is products of the mantle wedge which have metasomatized by adakite melts. Such a association indicates the existences of a young ocean slab subduction. 3. The Liuyuan suture zone is composed of late Paleozoic ophiolites and two series of accretionary complexes with age of early Paleozoic. The early Paleozoic accretionary complex extensively intruded by early Palozioc granites is composed of metamorphic clastics, marble, flysch, various metamorphic igneous rocks (ultramafic, mafic and dacite), and eclogite blocks, which are connected by faults. The original compositions of the rocks in this complex are highly varied, including MORB, E-MORB, arc rocks. Geochronological study indicates that they were formed during the Silurian (420.9±2.5Ma and 421.1±4.3Ma). Large-scale granitiods intruded in the accretionary complex suggest a fast growth effect at the south margin of the Huaniushan arc. During late Paleozoic, island arc were developed on this accretionary complex. The late Paleozoic ophiolite has an age of early Permian (285.7±2.2Ma), in which the rock assemblage includes ultra-mafic, gabbros, gabbros veins, massive basalts, pillow basalt, basaltic clastic breccias, and thin layer tuff, with chert on the top.These igneous rocks have both arc and MORB affinities, indicating their belonging to SSZ type ophiolite. Therefore, oceanic basins area were still existed in the Liuyuan area in the early Permian. 4. The mafic-ultramafic complexes are distributed along major faults, and composed of zoned cumulate rocks, in which peridotites are surrounded by pyroxenite, hornblendites, gabbros norite and diorite outward. They have island-arc affinities and are consistent with typical Alaska-type mafic-ultramafic complexes. The geochronological results indicate that they were formed in the early Permian. 5. The Liuyuan A-type granite were formed under post-collisional settings during the late Triassic (230.9±2.5Ma), indicating the persistence of orogenic process till the late Triassic in the study area. Geochronological results suggested that A-type granites become younger southward from the Wulungu A-type granite belt to Liuyuan A-type granite belt, which is in good agreement with the accretionary direction of the CAOB in this area, which indicate that the Liuyuan suture is the final sture of the Paleo-Asin Ocean. 6. Structural geological evidence demonstrate the W-E spreading of main tectonic terrenes. These terrenes had mainly underwent through S-N direction contraction and NE strike-faulting. The study area had experienced a S-N direction compression after the Permian, indicating a collisional event after the Permian. Based on the evidene from sedimentary geology, paleontology, and geomagnetism, our studies indicate that the orogenic process can be subdivided into five stages: (1) the pre-orogenic stage occurred before the Ordovicain; (2) the subduction orogenic stage occurred from the Orcovician to the Permian; (3) the collisional orogenic stage occurred from the late Permian to the late Triassic; (4) the post-collision stage occurred after the Triassic. The Liuyuan areas have a long and complex tectonic evolutional history, and the Liuyuan suture zone is one of the most important sutures. It is the finally suture zone of the paleo-Asian ocean in the Beishan area.

高温实验中重金属钼在硅酸盐熔体中的含量研究

This dissertation discusses current status of high temperature and high pressure and focuses on analyzing systematically the solubility of heavy metals in the silicate magma in HTHP experiments. The high temperature study on the content of heavy metal molybdenum in the silicate melts in this dissertation, which is granted, based on the geology mineralization model and the theory of HTHP experiments and combined with mineralization grade and geochemical nature of Mo, discusses the difference of mineralization between mantle plume and aqueous fluids and comes to the conclusions, which are as follows: (1) The content of Mo in the silicate melts is much greater than Mo mineralization grade. The molybdenum ore has the exploitation value when the industrial grade is higher than 0.06%. Mo content in different silicate melts varies because of the concentration of SiO2, that is, Mo content in the granodiorite is greater. (2) The content of Mo, which varies with reaction time, arises first and drops down in the alkali basalt melts, while variation is not too obvious in the granodiorite melts on the whole. (3) According to the picture of sample, the conclusion is not reached very well on some issues, such as the volatility and characteristic of molybdenum oxide and dependence on the geology environment.

东准噶尔和尔赛斑岩铜矿特征及其形成的构造背景

Hersai porphyry copper deposit(PCD) of eastern junggar, newly discovered copper deposit, is located at the eastern segment of the Xiemisitai-Kulankazigan-Zhifang-Qiongheba Paleozoic island arc, Eastern Junggar. The Hersai PCD is developed in a intrusive complex, characterized by intensive and multiform hydrothermal alteration, including potassic alteration, silification, chloritization，sericitization，kaolinitization and carbonatization. Granodiorite, grandiorite porphyry, granite and concealed explosion breccia are hosts of the ore bodies containing veinlet and disseminated ore. Ore-bearing granite (ZK107-1-9), granodiorite (ZK107-1-9) and Ore-barren granodiorite (HES2-1) are selected to date zircon U-Pb age by SHRIMP method, and have an age of 429.4±6.4Ma ,413.0±3.4Ma and 411.1±4.8Ma, respectively, showing that they were emplaced from Late Silurian to Early Devonian. In addition, sample ZK107-1-9 has some hydrothermal zircons with a weighted mean 206Pb/238U age of 404.9±3.7Ma which is interpreted to be related to the granodiorite porphyry. Re-Os dating of five molybdenite samples yielded a weighted average model age of 408.0±2.9Ma, indicating the metallogenic epoch of the Hersai PCD. The ore-forming age is close to the petrogenic time of garnodiorite (411-413Ma), this suggests the ore-forming porphyry is most possiblely granodiorite porphyry. Systematic major - trace elements and Rb-Sr-Sm-Nd-Pb-Hf isotopic characteristics were studied. Analysis results show that these intrusives have some interesting and special characteristics, as following:1) containing both calc-alkaline rocks and high potassium calc-alkaline rocks ; 2) have some characteristics of adakite, but not totally, such as much lower La/Yb ratios and no Eu anomaly or just faint Eu anomaly; 3) have an initial 87Sr/86Sr ratios(0.703852-0.704565) similar to that of BSE, positive εNd(t) values between 6.1 and 7.4, the initial 206Pb/204Pb values (17.576-17.912), 207Pb/204Pb values (15.400-15.453) , 208Pb/204Pb values (37.252-37.466) , and high εHf(t) values (10.2-15.4) close to the value of depleted mantle. These geochemical features suggest that these igneous rocks in the Hersai area not only have some characteristics of island arc, but also some characteristics that only appear in the continental margin arc. It is suggested that Hersai PCD is formed in the subduction setting by the partial melting of young crust. These works and advancements mentioned in the paper are helpful to understand the deposit geology, geochemistry and metallogenesis of Hersai PCD. It is also significant to understand mineralization and tectonic setting in the Qiongheba area.

东营凹陷幔源流体对原油生物标志化合物的影响研究

A large number of mantle-derived fluid activities occurred in the Dongying Sag. On the basis of the studies on the geochemical characteristics of these fluids in this sag, the spatial distribution of biomarkers in petroleum and their relationships with the parameters of mantle-derived fluids were studied, to reveal the influence of mantle-derived fluids on the biomarkers and to evaluate the reliability of these biomarkers when applied to oil-source correlation and maturity analysis. Most biomarkers used in oil correlation kept the characteristics of their sources during burial thermal evolution. Even some of them were not influenced by mantle derived fluids, such as the relative content of C27-C29 steroid（ααα20R）and C21/C23 tricyclic terpane. However, Pr/Ph and C35/C34 hopanes were sensitive to both heat energy and materiel input by the mantle-derived fluids. γ-waxnae/C30hopanes and C24 tetracyclic terpanes /C26 tricyclic terpanes responded only to thermal influence by mantle-derived fluids. They did not chemically reacted with the mantle-derived fluids. Fluorene series compounds reacted with hydrogen and / or carbon dioxide from the mantle. Mantle-derived fluids affected most maturity index. The huge thermal energy with mantle-devied fluids weakened the relationship between the maturity parameters and depth. Among them, pregnane/C27-29 steroid and Ts/(Ts+Tm) were more sensitive to the heat of the fluids. ααα20S/(20S+20R) took the second place. αββ/(ααα+αββ) and 22S/(22S+22R) were not thermally influenced by the mantle-derived fluid. Besides, the substance of mantle-derived fluids reacted with fragrants, hopanes or moretanoids and thus altered the values of MPI1, MPI2, MPR, C30 hopanes/(C30 hopanes + moretanoids) and alkyl-diben zothiophene/diben zothiophene. The thermal alernation of phenanthrene series and their spatial distribution show that the heat energy carried by mantle-derived fluids was not fierce but spread widely in Dongying Sag, which is favorable to hydrocarbon generation with little destroy. In sum, mantle-derived fluids affected biomarkers through thermal energy and chemical reactions and changed the values of oil-source correlation and maturity parameters in the deep-seated fault belts. Therefore, in the deep-seated fault belts, oil-source correlation should be restudied and the new parameters need to be explored.

内蒙古中部道郎和都格铜多金属矿的地质特征矿床类型及找矿模式研究

Daolangheduge copper polymetallic deposit is located on east edge of Ondor Sum-Bainaimiao metallogenic belt, which is a prospective area of porphyry copper deposit, in Xianghuangqi of central Inner Mongolia. Geotectonically, it occurred in the continental margin accretion belt along the north margin of North China Plate, south of the suture zone between North China Plate and Siberian Plate. The intrusive rocks in this area mainly consist of intermediate-acid magmatic rocks, and the quartz veins, tourmaline veins and the transitional phase are comparatively developed. According to our research, the ore-bearing rock body is mainly quartz diorite while the surrounding rock is mainly biotite granite. Besides, the wall rock alteration are mainly propylitization, pyritization and silicification, which consist of epidotization, actinolitization, chloritzation and so on. The metallic minerals are mainly chalcopyrite and pyrite. In addition, the primary ore is mainly of quartz-chalcopyrite-pyrite type. Above all, Daolangheduge copper polymetallic deposit is suggested to be categorized in the porphyry copper type. With isotopic dating and geochemical research on quartz diorite of ore-bearing rock body, the zircon LA-ICP-MS U-Pb dating of two samples yields an age of 266±2 Ma, falling into the range of late Permian Epoch. It is the first accurate age data in Xianghuangqi area, so it should play a key role in the research of deposit and magmatic rocks in this area. With the major elements and trace elements analysis of 14 samples, the quartz diorite should be among the calc-alkaline series, the geochemical characteristics show higher large-ion lithophile elements of Rb, Sr and LREE, low high-field strength elements of Nb, Ta and high transition elements of Cu, Cr . Also, the REE patterns have negative Eu anomalies. With the same analysis of 4 sample for the biotite granite, the geochemical characteristics show higher Rb, Th,, Zr, Hf and LREE, low Nb, Sm and HREE and Eu has no anomaly. It should be among the calc-alkaline series, over aluminum quality and has characteristics of Adakites. According to isotopic dating and geochemical characteristics of ore-bearing rock body, it is suggested that its materials mainly derived from upper mantle that had fractional crystallization and its magma source region may be affected by fluid metasomatism of paleo-asian ocean. It should be an extensional process of post-orogeny according to regional tectonic evolution. Consequently, because of the decrease of temperature and pressure, the ore forming fluid was raised to surface and mineralized accompanied by magmatic activity which might occur in south of the suture zone. By geological survey, further geophysical and geochemical work is needed. In this area, we have accomplished high precision magnetic prospecting, high density electrical survey, gravity prospecting, soil geochemical prospecting, X-ray fluorescence analyzer prospecting and so on. According to geophysical and geochemical abnormal and surface occurrence, 11 drills are arranged to verification. The type of ores are mainly quartz-chalcopyrite-pyrite ores within 3 drills by drill core logging. Although the grade as well as the scale of already-found Cu deposits are insufficient for industrial exploitation, the mineralization prospect in this region is supposed to be great and the potential in mineral exploration at depth is excellent.

碎屑锆石年龄和Nd-Hf同位素组成对扬子基底演化的制约

The South China craton was formed by the collision of the Yangtze and Cathaysia blocks during the Neoproterozoic Jiangnan orogeny (also termed as the Jingnin or Sibao orogeny in Chinese literature). Basement rocks within the Yangtze block consist mainly of Proterozoic sediments of the Lengjiaxi and Banxi Groups. U-Pb ages of detrital zircons obtained by the LA-ICP-MS dating technique imply that the deposition of the Lengjiaxi Group continued until the Neoproterozoic. The youngest detrital zircons suggest a maximum deposition age of ~830 Ma for the Lengjiaxi Group, consistent with the initiation time of the deposition of the overlying Banxi Group, likely indicating continuous deposition of these two groups and a short temporal hiatus (~10 Ma) between the Neoproterozoic sedimentary rocks distributed in the South China craton. Detrital zircons from both the Lengjiaxi and Banxi Groups have a wide range of εHf(t) values from -12 to 14.2 and a continuous Nd and Hf model age spectrum from ~820 Ma to 2200 Ma. Some grains have model ages ranging up to ca. 2.9-3.5 Ga, indicating that both juvenile mantle material and ancient crust provided sedimentary detritus. This is also consistent with the Nd isotopic signature of sedimentary rocks recorded in the Lengjiaxi Group, suggesting a back-arc tectonic setting. The Banxi Group has slightly enriched Nd isotopic signatures relative to the Lengjiaxi Group, implying a higher percentage of old continental material in the sedimentary source. Combined with previously published data, new results can help us to reconstruct the Neoproterozoic tectonic evolution of the South China craton. The age spectrum of detrital zircons and Nd-Hf isotopic composition suggests a two-stage collision: Between 1000 Ma to 870 Ma, a continental magmatic arc was build up along the eastern margin of the Yangtze block. Convergence led to continent-based back-arc extension, subsidence and formation of a back-arc basin. Detritus originating from arc-related magmatic and old basement rocks was transported into this back-arc basin resulting in formation of the Lengjiaxi Group and its equivalents. At around 870 Ma, a second (oceanic) arc was formed by extension of an inter-arc basin, subduction subsequently led to the first collision and the emplacement of the blueschist mélange. Accretion of the magmatic arc lasted until the closure of an oceanic basin between the Yangtze and Cathaysia blocks at about 830 Ma. Shortly after the collision, subsequent uplift, further extension of the former back-arc basin and post-collisional granitoid magmatism caused a tilting of the Lengjiaxi sediments. Between 830 Ma and 820 Ma, subsequent closure of the oceanic back-arc basin and formation of the Jiangnan orogen took place, leaving a regional unconformity above the Lengjiaxi Group. Above this unconformity the Banxi Group was immediately deposited during the post-tectonic stage.

人工源宽角地震资料中的广角效应及其对地壳速度成像的影响

The seismic wide-angle reflection/refraction method is the one of the most effective method for probing the crustal and upper mantle structure. It mainly uses the wide-angle reflection information from the boundary in the crust and the top boundary of the upper mantle to rebuild the crust and upper mantle structure. Through analyzing the reflection and transmission coefficients of various incident waves on the interface, we think relative to the pre-critical angle reflection information the post critical angle reflection information that received by wide-angle seismic data exists a time-shift effect with the offset variation, and then it must cause the error for velocity analysis and structure image. The feature of the wide-angle seismic wave field of the fourteen representative crust columns tell us that the wide-angle effects in the different representative tectonic units for the interface depth and the interval velocity in crust. We studied the features of the wide-angle seismic wave field through building the crust model and inverse its travel time by GA method to know the wide-angle influence on crustal velocity image. At last we finished the data processing of the Tunxi-Wenzhou wide-angle seismic profile. The results are as following: (1) Through building crust model, we labeled the travel time for all the phases by ray tracing method and remove wide-angle effects method, it revealed the wide-angle effect exists in the seismic data. (2) The travel time inversion by GA method can tell us that the depth by traditional ray tracing method is shallower than the result by remove wide-angle effects method, the latter can recover the crust structure model in effect. (3) We applied the two method mentioned before to the fourteen representative crust columns in China. It indicates that the removed wide-angle effect method in travel time inversion is reasonable and effective. (4) The real data processing from Tunxi-Wenzhou wide-angle seismic profile give us the basic structure through the two ways. The main influence exhibits in the difference of the interval velocity of the curst, and the wide-angle effects in shallow interface are stronger than the deep interface.

中国大陆地区远震体波接收函数与岩石圈厚度的研究

Movements of separation and convergence between the continental plates, as well as the interaction beween the lithosphere and asthenosphere is the dominant factor in plate evolution. Moreover, those phenomena, the formation, enrichment and storage of energy and mineral strorage, as well as intraplate earthquakes are all relate to plate movement and evolution. Therefore, the study of continental lithosphere, is not only helpful to analysing the dynamic model between lithosphere and asthenoshere as well as different plates, but also important to the nation's economy and the people's livelihood. And the lithospheric thickness or Lithosphere-Asthenosphere Boundary (LAB) is one of the most important parameters in study of continental lithospheric formation and evolution. Chinese continent composed by many small plates, possesses diverse type of lithospheric structure. But our knowledge ahout Chinese continental lithosphere, especially the regional research, is almost based on the low-resolution results of surface wave dispersion analysis and seismic wave tomography. Howere, recently a technique employing S-to-P converted body waves (the S receiver function technique) has been developed that can be used to identify the LAB with a higher resolution. This thesis has collected waveform data of 232 broadband seismic stations that are located in China and neighboring regions. Using teleseismic S-wave and P-wave receiver functions have studied the Chinese continental lithospheric structure. The results of this study indicate that, the thickness of Chinese continental lithosphere become thinner from west to east, and obvious difference exists between different blocks. Four types of lithosphere have been detected: (1) Convergence thicking lithosphere in Tibetan Plateau; (2) Stable lithosphere in Tarim basin and upper Yangtze craton; (4) Active lithosphere in Orogenic belts; (4) Break-up thinning lithosphere in east China craton

南海张裂大陆边缘数值模拟研究

The South China Sea (SCS) is one of the largest marginal seas in the western Pacific, which is located at the junction of Eurasian plate, Pacific plate and Indian-Australian plate. It was formed by continent breakup and sea-floor spreading in Cenozoic. The complicated interaction among the three major plates made tectonic movement complex and geological phenomena very rich in this area. The SCS is an ideal place to study the formation and evolution of rifted continental margin and sea-floor spreading since it is old enough to have experienced the major stages of the basin evolution but still young enough to have preserved its original nature. As the demand for energy grows day by day in our country, the deep water region of the northern continental margin in the SCS has become a focus of oil and gas exploration because of its huge hydrocarbon potential. Therefore, to study the rifted continental margin of the SCS not only can improve our understanding of the formation and evolution processes of rifted continental margin, but also can provide theoretical support for hydrocarbon exploration in rifted continental margin. This dissertation mainly includes five topics as follows: (1) Various classic lithosphere stretching models are reviewed, and the continuous non-uniform stretching model is modified to make it suitable for the case where the extension of lithopheric mantle exceeds that of the crust. Then simple/pure shear flexural cantilever model is applied to model the basement geometries of SO49-18 profile in the northern continental margin of the SCS. By fitting the basements obtained by using 2DMove software with modeling results, it is found that the reasonable effective elastic thickness is less than 5km in this region. According to this result, it is assumed that there is weak lower crust in the northern continental margin in the SCS. (2) We research on the methods for stretching factor estimation based on various lithosphere stretching models, and apply the method based on multiple finite rifting model to estimate the stretching factors of several wells and profiles in the northern continental margin of the SCS. (3) We improve one-dimension strain rate inversion method with conjugate gradient method, and apply it to invert the strain rate of several wells in the northern continental margin of the SCS. Two-dimension strain rate forward modeling is carried out, and the modeling results show that effective elastic thickness is a key parameter to control basin’s geometry. (4) We simulate divergent upwelling mantle flow model using finite difference method, and apply this newly developed model to examine the formation mechanism of the northwest and central sub-basin in the SCS. (5) We inverse plate thickness and basal temperature of oceanic lithosphere using sea-floor ages and bathymetries of the North Pacific and the North Atlantic based on varied-parameters plate model, in which the heat conductivity, heat capacity and coefficient of thermal expansion depend on temperature or depth. A new empirical formula is put forward based the inversed parameters, which depicts the relation among sea-floor age, bathymetry and heat flow. Then various similar empirical formulae, including the newly developed one, are applied to examine the sea-floor spread issue in the SCS based on the heat flow and bathymetry data of the abyssal sub-basin.

东天山镁铁-超镁铁岩铜镍硫化物矿床通道式成矿机制与岩体含矿性评价研究

A mafic-ultramafic complex belt well developed in Eastern Tianshan, Xinjiang, NW China, which contains a series of Cu-Ni sulfide deposits. This area is the important production basis for Cu-Ni deposits, including Tulargen deposit, Hulu deposit, Huangshan-Huangshandong deposit, Hulu deposit, Xiangshan deposit, Tianyu deposit, Chuanzhu deposit. In China, especially Eastern Tianshan, it is prevalent that large Cu-Ni deposits occurred in small intrusions, typically including Jinchuan, Kalatongke, et al., so the ore-forming mechanism and evaluation rule for those small intrusions are very meaningful and of universal significance. On the basis of the research to typical Cu-Ni deposits, ore-forming conditions and processes are summarized through which to evaluate the ore-bearing potential for barren intrusions and unexplored mafic-ultramafic intrusions. By the contrast, metallogenic rule and mechanism of ore genesis are concluded, and evaluation system is preliminarily set up on the basis of these conclusions. Quantitatively simulation for the composition of olivine is introduced for the first time in China to discuss the interaction between magma and sulfide, and a new method to calculate the Mg-Fe composition of primitive magma is developed. Interaction between magma and sulfide liquid is used to get the Ni content in sulfide liquid. Sulfur isotopic characteristics in sulfide minerals in country rocks and ores are used to judge crustal sulfur introduction, which is applied for the first time in China. Re-Os isotopic characteristics are related to the ore-forming process, to interpret the process of enrichment of chalcophile elements. On the basis of the evaluation system, Mati, Chuanzhu, Luodong, Xiadong, those intrusions are evaluated to their ore-bearing potential. According to the studies to typical Cu-Ni deposits, conduit-type ore-forming model is set up, and the characteristics of the model are concluded systematically. The evaluation system and conduit-type ore-forming model can be helpful to the evaluation of mafic-ultramafic intrusions in this and similar mafic-ultramafic intrusion belts. The studied typical deposits and mafic-ultramafic intrusion include Tulargen deposit, Hulu deposit, Huangshandong deposit, Chuanzhu deposit, Mati intrusion，Luodong intrusion, Xiadong intrusion, and others. Through studies, there are similar characteristics for Tulargen and Hulu deposits in magma origin, composition of primitive magma（MgO=12.5%, FeO=12% and MgO=11%, FeO=10.5% respectively）, magma evolution, mechanism of sulfide segregation and conduit-type ore-forming process. By Re-Os isotopic system, the ore forming date of Tulargen deposit is 265.6±9.2Ma, which is consistent to regional metallogenic event, but little younger. The Mg-Fe composition of primitive magma of Baishiquan, Huangshandong area, Kalatongke is lower than that of Tulargen and Hulu deposit, showing common basalt composition. The Mg# value（Mg#=(Mg/Mg+Fe）increases gradually from Kalatongke to Baishiquan to Huangshan-Huangshandong East. Baishiquan intrusions show relatively higher crustal contamination by evidence of trace element, which indicates the lower magma original source, from depleted mantle to crust. One break is the discovery of komatiitic intrusion, Xiadong intrusion, which shows characteristics of highly magnesium (Max Fo=96). The primitive magma is calculated of MgO=28%，FeO=9%, belonging to komatiitic magma. Tectonic evolution of Eastern Tianshan is discussed. By the statistics of ore-forming data of porphyry copper deposits, magmatic sulfide Cu-Ni deposits, orogenic hydrothermal gold deposits, we believe that those deposits are the successive products of oceanic subduction, are and back-arc basin collision and post-orogenic extention. And Cu-Ni sulfide deposits and orogenic gold deposits occurred in the stage of post-orogenic extention. According to the conclusions, the conduit-type ore-forming mechanism of magmatic sulfide deposit is set up, and its characteristics and conditions are concluded as well. The conduit-type ore-forming system includes magma generation, sulfide segregation, enrichment of chalcophile elements, interaction of sulfide and magma, sulfide collection in limited space in magma conduit and bottom of the chamber, which make a whole ore-forming system.The ore-forming process of Cu-Ni sulfide deposits is concluded as three steps: 1. mantle derived magma rises upward to the middle-upper crust; 2. magma suffers crustal contamination of different degrees and assimilates crustal sulfur, which leads to sulfur saturation and sulfide segregation. Sulfide liquid interacts with magma and concentrates chalcophile elements; 3. enriched sulfide located in the conduit(Tulargen) or bottom of the chamber (Hulu). Depleted magma rises upward continuously to form barren complexes. For the practical cases, Tulargen deposit represents the feeding conduit, and Hulu deposit represents the bottom of the staging magma chamber. So the deeper of west of Tulargen and southwest of Hulu are the favorite locate for ore location. The evaluation for ore potential can be summarized as follows: (1) Olivine can be served as indicator for magma evolution and events of sulfide segregation; (2) Sulfur isotopic characteristics is an efficient method to judge sulfur origin for magmatic sulfide deposit; (3) Re-Os content of the ores can indicate interaction between sulfide and silicate magma and crustal contamination; (4) PGE mineralization is effected by degree of partial melting of mantle; (5) Cu/Zr is efficient parameter to judge sulfide segregation; (6) The effects of multiple magma fractionation and emplacement are important, for inverse order shows the destruction to previous solid lithofacies and orebodies. Mati, Chuanzhu, Xiadong, Luodong, mafic-ultramafic intrusions are evaluated using evaluation system above. Remarkable Ni depletion is found in olivine of Mati, and southwest of the intrusion can be hopeful location for ore location. Chuanzhu intrusion has remarkable evidence of sulfide segregation, but the intrusion represents the narrow feeder conduit, so the wide part of the conduit maybe the favorite location for sulfide to deposit. The ore potential of Luodong and Xiadong is not good. Both the intrusions show no Ni depletion in olivine, and there is no sulfide in country rocks, so no crustal sulfur is added into the magmatic system. For Sidingheishan, a very large intrusion, the phenomenon of sulfide segregation is found, but there are no favorite places for sulfide to deposit. So the Cu-Ni ore potential maybe not good, but PGE mineralization should be evaluated further.

东喜马拉雅构造结新生代碰撞变形与岩石圈演化

The Eastern Himalayan Syntaxis (EHS) is one of the strongest deformation area along the Himalayan belt resulted from the collision between Indian plate and the Eurasian Plate since the 50～60Ma, and has sensitivity tracked and preserved the whole collisional processes. It should depend on the detail geological investigations to establish the deformational accommodate mode, and the uplift history, to elucidate the deep structure and the crust-mantle interaction of the Tibet Plateau of the EHS. The deep-seated (Main Mantle Thrusts) structures were exhumed in the EHS. The MMT juxtapose the Gangdese metamorphic basement and some relic of Gangdese mantle on the high Himalayan crystalline series. The Namjagbawa group which is 1200～1500Ma dated by U/Pb age of zircon and the Namla group which is 550Ma dated by U/Pb age of zircon is belong to High Himalayan crystalline series and Gangdese basement respectively. There is some ophiolitic relic along the MMT, such as metamorphic ocean mantle peridotite and metamorphic tholeiite of the upper part of ocean-crust. The metamorphic ocean mantle peridotites (spinel-orthopyroxene peridotite) show U type REE patterns. The ~(87)Sr/~(86)Sr ratios were, 0.709314～0.720788, and the ~(143)Nd/~(144)Nd ratios were 0.512073～0.512395, plotting in the forth quadrant on the ~(87)Sr/~(86)Sr-~(143)Nd/~(144)Nd isotope diagram. Some metamorphic basalt (garnet amphibolite) enclosures have been found in the HP garnet-kynite granulite. The garnet amphibolites can be divided two groups, the first group is deplete of LREE, and the second group is flat or rich LREE, and their ~(87)Sr/~(86)Sr, ~(143)Nd/~(144)Nd ratios were 0.70563～0.705381 and 0.512468～0.51263 respectively. Trace element and isotopic characteristics of the garnet amphibolites display that they formed in the E-MORB environment. Some phlogolite amphibole harzburgites, which exhibit extensive replacement by Phl, Amp, Tc and Dol etc, were exhumed along the MMT. The Phl-Amp harzburgites are rich in LREE and LILE, such as Rb, K etc, and depletes Eu (Eu~* = 0.36 ～ 0.68) and HFSE, such as Nb, Ta, Zr, Hf, P, Ti etc. The trace element indicate that the Phl-Amp harzburgites have island arc signature. Their ~(87)Sr/~(86)Sr are varied from 0.708912 to 0.879839, ~(143)Nd/~(144)Nd from 0.511993 to 0.512164, ε Nd from- 9.2 to - 12.6. Rb/Sr isochrone age of the phlogolite amphibole harzburgite shows the metasomatism took place at 41Ma, and the Amp ~(40)Ar/~(39)Ar cooling age indcate the Phl-Amp harzburgite raising at 16Ma. There is an intense crust shortening resulted from the thrust faults and folds in the Cayu block which is shortened more 120km than that of the Lasha block in 35～90Ma. With the NE corner of the India plate squash into the Gangdese arc, the sinistral Pai shear fault and the dextral Aniqiao shear fault on the both sides of the Great bent of Yalun Zangbu river come into active in 21～26Ma. On the other hand, the right-lateral Gongrigabu strike-slip faults come into activity at the same period, a lower age bound for the Gongrigabu strike-slip fault is estimated to be 23～24Ma from zircon of ion-probe U/Pb thermochronology. The Gongrigabu strike-slip faults connect with the Lhari strike-slip fault in the northwestern direction and with the Saganing strike-slip at the southeastern direction. Another important structure in the EHS is the Gangdese detachment fault system (GDS) which occurs between the sedimental cover and the metamorphic basement. The lower age of the GDS is to be 16Ma from the preliminary 40Ar/39Ar thermochronology of white mica. The GDS is thought to be related to the reverse of the subducted Indian crust and the fast uplift of the EHS. Structural and thermochronology investigation of the EHS suggest that the eastern Tibet and the western Yunnan rotated clockwise around the EHS in the period of 35～60Ma. Later, the large-scale strike-slip faults (RRD, Gaoligong and Saganing fault) prolongate into the EHS, and connect with the Guyu fault and Gongrigabu fault, which suggest that the Indianchia block escape along these faults. Two kind of magmatic rocks in the EHS have been investigated, one is the mantle-derived amphibole gabbro, dioposide diorite and amphibole diorite, another is crust origin biotit-garnet adamellite, biotit-garnet granodiorite and garnet-amphibole-biotite granite. The amphibole gabbro dioposite diorite and amphibole diorite are rich in LREE, and LILE, such as Ba, Rb, Th, K, Sr etc, depleted in HFSE, such as Nb, Ta, Zr, Hf, Ti etc. The ratio of ~(87)Sr/~(86)Sr are from 0.7044 to 0.7048, ~(143)Nd/~(144)Nd are from 0.5126 to 0.5127. The age of the mantle origin magamatic rocks, which result from the partial melt of the raising and decompression anthenosphere, is 8Ma by ~(40)Ar/~(39)Ar dating of amphibole from the diorite. The later crust origin biotite-garnet adamellite, biotite-garnet granodiorite and garnet-amphibole-biotite granite are characterized by aboudance in LREE, and strong depletion of Eu. The ratios of ~(87)Sr-~(86)Sr are from 0.795035 to 0.812028, ~(143)Nd/~(144)Nd from 0.51187 to 0.511901. The ~(40)Ar/~(39)Ar plateau age of the amphibole from the garnet-amphibole-biotite granite is 17.5±0.3Ma, and the isochrone age is 16.8±0.6Ma. Their geochemical characteristics show that the crust-derived magmatic rocks formed from partial melting of the lower curst in the post-collisional environment. A group of high-pressure kaynite-garnet granulites and enclave of high-pressure garnet-clinopyroxene grnulites and calc-silicate grnulites are outcroped along the MMT. The peak metamorphic condition of the high-pressure granulites yields T=800～960 ℃, P=1.4～1.8Gpa, corresponding the condition of 60km depth. The retrograde assemblages of the high-pressure grnulites occur at the condition of T=772.3～803.3 ℃, P=0.63～0.64Gpa. The age of the peak metamorphic assemblages are 45 ～ 69Ma indicated by the zircon U/Pb ion-plobe thermochronology, and the retrograde assemblage ages are 13～26Ma by U/Pb, ~(40)Ar/~(39)Ar thermochronology. The ITD paths of the high-pressure granulites show that they were generated during the tectonic thickening and more rapid tectonic exhumation caused by the subducting of the Indian plate and subsequent break-off of the subducted slab. A great deal of apatite, zircon and sphene fission-track ages, isotopic thermochronology of the rocks in the EHS show that its rapid raising processes of the EHS can be divided into three main periods. There are 35～60Ma, 13～25Ma, 0～3Ma. 3Ma is a turn in the course of raising in the EHS which is characterized by abruptly acceleration of uplifting. The uplift ratios are lower than 1mm .a~(-1) before 3Ma, and higher than 1mm .a~(-1) with a maximum ratio of 30mm .a~(-1) since 3Ma. The bottom (knick point) of the partial anneal belt is 3.8km above sea level in the EHS, and correspond to age of 3Ma determined by fission-track age of apatite. The average uplift ratio is about 1.4 mm .a~(-1) below the knick point. The EHS has raised 4.3km from the surface of 2.36km above sea level since 3Ma estimated by the fossil partial anneal belt of the EHS. We propose a two-stage subduction model (B+A model) basing on Structural, thermochronological, magmatical, metamorphic and geophysical investigations of the EHS. The first stage is the subduction of the Indian continental margin following after the subduction of the Tethys Ocean crust and subsequent collision with the Gangdese arc, and the second stage is the Indian crust injecting into the lower crust and upper mantle of the Tibet plateau. Slab break-off seems to be occurred between these two stages.

五台山区义兴寨岩体、车厂－北台岩体地球化学和变质作用及其大地构造意义

There are many Archean TTG grey suites in the Wutaishan area, northern Shanxi Province, China. In the past one hundred years, many geologists have done excellent research work in the Wutaishan and its adjacent regions. However, the TTG suites were almost neglected. Located in the northern slope of Mt. Hengshan-namely the Archean Hengshan Island Arc, intruded the Zhujiafang supercrustal rocks at almost 2.5Ga, the Yixingzhai TTG Suite is originated from partial melting of the ancient lower crust upper mantle by REE and trace elements, and the emplacement occurred in an Archean island arc. The rocks are mainly of tonalitic, I type, and calc-alkaline trends are found in the magmatic evolution. At almost 1.8 Ga, the suite was transformed to be dome-like schists in an arc-arc collision event, and the rocks were metamorphosed to an extent of amphibolitic to granulitic facies. The peak metamorphic condition is of 710-760 ℃/0.68-0.72GPa, and the subsequent cooling history is recorded as 560-620 ℃/0.46-0.60GPa. In the center of the Mt. Wutaishan-known as the Archean Wutaishan Island Arc, intruded the Archean Chechang-Beitai TTG Suite, which is of 2.5Ga old and of trondhjemitic and tonalitic, with coexisting I- and S-types and a trondhjemitic magmatic evolution trend. Through REE and trace elements, the suite is believed to be from the partial melting of the ancient lower crust or upper mantle. The 1.8 Ga collision event also made the suite gneissic and the it was metamorphosed to be amphibolitic facies, whose peak condition is approximately of 680 (±50) ℃/0.7Gpa, and the subsequent cooling process is recorded as 680 (±50) ℃、550(±50) ℃、420(±10) ℃. Crustal growth is fulfilled through magmatic intrusion as well as eruption at about 2.5Ga, arc-arc collision at about 1.8 Ga in the Wutaishan area and its environs. Additionally, the biotite-muscovite and muscovite-plagioclase geothermometers are refined, and the biotite-hornblende geothermometer is developed in this dissertation.

南海北部大陆边缘盆地深部地热特征用地球动力学演化

This report is a conclusion of the major research outcome during my post-doctoral residence of research and work. Its content covers the researches of the deep thermal characteristic and dynamics evolution beneath the northern margin basin of South China Sea. In this report, the each other action and effect between lithosphere ad mantle convection were regarded by the combine of deep and shallow study, subdivision from whole to part, and pay equal attention to determine the nature and fixed quantity. The investigative method we used in this report is geothermal and gravity methods. By the help of geological model and geophysics modeling, we calculated lithosphere thermal structure, rheology structure and mantle convection. Firstly, the report introduces concisely the purpose and the previous achievement to this research. Then, it analyzed the characteristic of heat flow on South China Sea. The structure of deep temperature and thermal has been calculated in some models of heat generation and conduction. The rock rheology structure also was computed by the relationship between temperature and viscosity. All these calculations were finished under the guidelines of combine with geology and geophysics. Meanwhile, the fields both deep mantle convection and small scale upper mantle convection are computed. Beside, the density and temperature disorder resulted by mantle convection were also computed with the convection field. After these, the report bring the contribution of local field of mantle convection, thermal construct and effective viscosity beneath the northern margin basin of South China Sea. And, base on the tectonic background and evolution feature, this report discussion the evolution mechanism of south China Sea and its northern margin basin. The end of this report, the main conclusion of this research was summarized and brings out.