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.

塔里木地块奥陶纪古地磁新结果及其构造意义

The Tarim Block is located between the Tianshan Mountains in the north and the Qinghai-Tibet Plateau in the south and is one of three major Precambrian cratonic blocks of China. Obviously, the Paleozoic paleogeographic position and tectonic evolution for the Tarim Block are very important not only for the study of the formation and evolution of the Altaids, but also for the investigation of the distributions of Paleozoic marine oil and gas in the Tarim Basin. According to the distributions of Paleozoic strata and suface outcrops in the Tarim Block, the Aksu-Keping-Bachu area in the northwestern part of the Tarim Block were selected for Ordovician paleomagnetic studies. A total of 432 drill-core samples form 44 sampling sites were collected and the samples comprise mainly limestones, argillaceous limestones and argillaceous sandstones Based on systematic study of rock magnetism and paleomagnetism, all the samples could be divided into two types: the predominant magnetic minerals of the first type are hematite and subordinate magnetite. For the specimens from this type, characteristic remanent magnetization (ChRM) could generally be isolated by demagnetization temperatures larger than 600℃; we assigned this ChRM as component A; whilst magnetite is the predominant magnetic mineral of the second type; progressive demagnetization yielded another ChRM (component B) with unblocking temperatures of 550-570℃. The component A obtained from the majority of Ordovician specimens has dual polarity and a negative fold test result; we interpreted it as a remagnetization component acquired during the Cenozoic period. The component B can only be isolated from some Middle-Late Ordovician specimens with unique normal polarity, and has a positive fold test result at 95% confidence. The corresponding paleomagnetic pole of this characteristic component is at 40.7°S, 183.3°E with dp/dm = 4.8°/6.9° and is in great difference with the available post-Late Paleozoic paleopoles for the Tarim Block, indicating that the characteristic component B could be primary magnetization acquired in the formation of the rocks. The new Ordovician paleomagnetic result shows that the Tarim Block was located in the low- to intermediate- latitude regions of the Southern Hemisphere during the Middle-Late Ordovician period, and is very likely to situate, together with the South China Block, in the western margin of the Australian-Antarctic continents of East Gondwana. However, it may have experienced a large northward drift and clockwise rotation after the Middle-Late Ordovician period, which resulted in the separation of the Tarim Block from the East Gondwanaland and subsequent crossing of the paleo-equator; by the Late Carboniferous period the Tarim Block may have accreted to the southern margin of the Altaids.

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.

龙滩工程左岸边坡监测资料分析与稳定性评价研究

On the basis of the geological analysis and rock mass toppling deformation and failure mechanism analysis of Longtan engineering left bank slope, the synthetic space-time analysis and influence factors analysis on the surface monitoring data and deep rock mass monitoring data of B-zone of left bank slope are carried on. At the same time, based on the monitoring data analysis in conjunction with the predecessor's mechanics analysis results, the deformation state of B-zone of the left bank slope is discussed and its stability is synthetically evaluated. The detailed research contents and results are as following: According to the monitoring drill histogram analysis of Longtan engineering left bank slope, numerical simulation analysis and model experimentation analysis of bedded counter-inclined steep slope, a new type of toppling deformation and failure mode is proposed, that is "up-slope warping". Then the deformation and failure mode of bedded counter-inclined steep slope is summarized as "down-slope toppling" type, "up-slope warping" type and "complex fold" type. On the basis of synthetic space-time analysis to surface monitoring data and deep rock mass deformation monitoring data of B-zone of Longtan left bank slope;, we can get the conclusion that there exists potential instability rock mass over 520m altitude, especially over 560m altitude of slope B, and the rock mass of around strong-weathering line or creep rock mass breaking band controls the deformation of the whole slope. 1. According to the synthetic space-time analysis and influence factors analysis to the surface monitoring data of B-zone of Longtan left bank slope, a dynamical index, accumulative total acceleration index, which is used to analyze the influence factors of slope surface deformation, is raised. The principle and method of accumulative acceleration index are explained, and the index can be used for the influence factors analysis of the similar slope. 2. Summarize the results of geologic analysis, monitoring analysis and mechanics analysis, the following conclusion can be gotten: the stability of B-zone of the slope is basically good. However, on the condition of drainage and slope toe loading engineering, there is still some creep deformation in the rock mass over 520m altitude, especially over 560m altitude. So, better measures of the monitoring and timely maintenance of the drainage system are suggested in the paper.

板北断块油藏储层均质特征与剩余油分布研究

With the growing development and perfection of reservoir describing technology, its research achievements have played an increasingly important role in old oilfields in recent years. Reservoir description quantitatively describes, characterizes and predicts every kind of reservoir characters in 3D space. The paper takes Banbei block reservoir as an object, studies the reservoir characters and residual oil distributing characteristics of gravity flow genetic reservoir, and definitudes potential adjustment direction of reservoir development. Main achievements are gained as follows. Through fine correlation of strati graphic sequence, the classification of layers and single sands of main payzones in Banbei block is ascertained, the classifying methods of sedimentary unit in gravity flow reservoir characterized with picked cyclical marker bed are formed. On the basis of comprehensive logging evaluation, depositional characters of Banbei block are studied, and classifying methods of sedimentary microfacies in gravity flow reservoir are described. The sedimentary background of main oil layers in Banbei block is open lake with shallow water, and belongs to lacustrine underwater gravity flow- lacustrine phase depositional system. Main microfacies types are underwater water course^ water course side-wing, underwater floodplain, between two water courses, and lacustrine mud, etc. Reservoir sands mainly are underwater water course sands. Influenced by distributing characters of gravity flow underwater water course, sand shapes in plane mainly are stripe, finger-shape, tongue-shape. Sand distribution shows obvious split property. Sands overlap each other. According to comprehensive analysis of lithologic data, logging parameters, and dynamic production data, the researching threads and methods of reservoir heterogeneous characters are perfected. The depositional characters of gravity flow underwater water course in Banbei block determine its high reservoir heterogeneity. Macroscopic heterogeneity is studied in many aspects such as the scale of layers, the scale of single sands, in-situ scale, the distribution of interlayer types, the interlayer scale, and heterogeneity in plane. Thus, heterogeneous characters of reservoir are thoroughly analyzed. Through microscopic research of reservoir, the types of porous structure and related parameters are determined. According to the analysis of dynamic production data, the reaction and inner influential factors of reservoir heterogeneity in waterflood development are further revealed. Started with the concept and classifying methods of flow unit, clustering classification which can better meet the requirements of production is formed. The flow unit of Banbei block can be classified into four types. According to comprehensive evaluation, the first and second type of flow unit have better percolating capability and reserving capability. Research thread of 3D model-building and reservoir numerical simulation combined as an integral is adopted. The types and characters of residual oil distribution are determined. Residual oil of Banbei block mainly distributes in the boundary of sands, near the faults, areas with non-perfect injection-production well pattern , undeveloped sands, vertically poor developed layers. On the basis of comprehensive reservoir study, the threads and methods of improving development effect towards reservoir with high water cut, high recovery percent, serious heterogeneity are ascertained. The whole waterflood development effect of Banbei block reservoir is good. Although its water cut and recovery percent is relatively high, there is still some potential to develop. According to depositional characters of gravity flow and actual production situation? effective means of further improving development level are as follows. We should drill new wells in every kind of areas abounding with residual oil, implement comprehensive measures such as increasing liquid discharge, cyclic waterflood, changing fluid direction when injection-production well pattern is perfected, improve water quality, enhance displacement efficiency in flooding.

商都盆地二氧化碳气成藏条件研究

The bedding sequences, based on the results from others, have been constructed by geological researches. Furthermore, the reservoir, gas-bearing characteristics and reservoir-blanket association have been increasingly understudied by the geological and seismic studies as well as the log data. The deep dynamics for the formation and development of Shangdu basin resulted from complicated fault system and its continued action have been obtained. The studies on the reservoir condition reveal that the mantle-derived magmatism provided the materials for the CO_2 gas reservoir after Paleogene Period and the huge regional fault not only control the evolution of basin and sedimentary but also pay a role as a passage of the CO_2. The sandstone of river course formed in Paleogene System, with very good reservoir condition, are widely developed in the study area. The blanket with good condition is composed by the basalt in Hannuoba Formation and lake facies shale of Shangdou Formation. Local structures and good encirclement are resulted from the different sedimentary environment and later differential sagging. All statements above demonstrate that there is a very good pool-forming condition for the CO_2. In addition, the high abundance of H_2 recognized during drill exploration are also of significance.More than 30 inorganic CO_2 gas reservoirs have been determined during the exploration for the oil-bearing basins in the eastern China, which are developed along the two sides of Tanlu Fault or within it. In which the CO_2 gas reservoir in Shangdou basin is an inorganic gas reservoir far away from Tanlu Fault. Thus the determination of the CO_2 gas reservoir in Shangdou basin is significant for sciences due to the first exploration for the inorganic CO_2 gas reservoir in our country. The geophysical exploration carried on the CO_2 gas reservoir is benefited for the research of prospecting techniques of CO_2 reservoir.

工程地质三维可视化技术及其工程应用研究

Study of 3D visualization technology of engineering geology and its application to engineering is a cross subject which includes geosciences, computer, software and information technology. Being an important part of the secondary theme of National Basic Research Program of China (973 Program) whose name is Study of Multi-Scale Structure and Occurrence Environment of Complicated Geological Engineering Mass(No.2002CB412701), the dissertation involves the studies of key problems of 3D geological modeling, integrated applications of multi-format geological data, effective modeling methods of complex approximately layered geological mass as well as applications of 3D virtual reality information management technology.The main research findings are listed below:Integrated application method of multi-format geological data is proposed,which has solved the integrated application of drill holes, engineering geology plandrawings, sectional drawings and cutting drawings as well as exploratory trenchsketch. Its application can provide as more as possible fundamental data for 3Dgeological modeling.A 3D surface construction method combined Laplace interpolation points withoriginal points is proposed, so the deformation of 3D model and the crossing error ofupper and lower surface of model resulted from lack of data when constructing alaminated stratum can be eliminated.3D modeling method of approximately layered geological mass is proposed,which has solved the problems of general modeling method based on the sections or points and faces when constructing terrain and concordant strata.The 3D geological model of VII dam site of Xiangjiaba hydropower stationhas been constructed. The applications of 3D geological model to the auto-plotting ofsectional drawing and the converting of numerical analysis model are also discussed.3D virtual reality information integrated platform is developed, whose mostimportant character is that it is a software platform having the functions of 3D virtualreality flying and multi-format data management simultaneously. Therefore, theplatform can load different 3D model so as to satisfy the different engineeringdemands.The relics of Aigong Cave of Longyou Stone Caves are recovered. Thereinforcement plans of 1# and 2# cave in phoenix hill also be expressed. The intuitiveexpression provided decision makers and designers a very good environment.The basic framework and specific functions of 3D geological informationsystem are proposed.The main research findings in the dissertation have been successfully applied to some important engineering such as Xiangjiaba hydropower station, a military airport and Longyou Stone Caves etc.