14 resultados para Geoenvironmental zoning
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
The stability of a soil slope is usually analyzed by limit equilibrium methods, in which the identification of the critical slip surface is of principal importance. In this study the spline curve in conjunction with a genetic algorithm is used to search the critical slip surface, and Spencer's method is employed to calculate the factor of safety. Three examples are presented to illustrate the reliability and efficiency of the method. Slip surfaces defined by a series of straight lines are compared with those defined by spline curves, and the results indicate that use of spline curves renders better results for a given number of slip surface nodal points comparing with the approximation using straight line segments.
Resumo:
Surveys on migratory waterbirds and their habitats at Lashihai Lake, China, were conducted from October 1999 to April 2000. Five fixed points, representing different degrees of habitat disturbance and quality, were selected around the lake. We used counts (n = 30) to compare diversity and abundance of waterbirds at each point and evaluate the effects of habitat disturbance. The distribution of waterbirds was affected by disturbance, with snore than one-third of the total species and nearly half of the total individuals occurring at the least disturbed point. Species richness was weakly and abundance was strongly correlated to habitat disturbance, but not to habitat quality. Habitat destruction and use of canoes were prominent at the lake. Naxi ethnic fishermen (n = 37) were interviewed. They caught 570 waterbirds between October 1999 and March 2000 in fishing nets. An estimation of the total number of waterbirds been trapped on the lake is 6164. Diving species were most susceptible. Conservation measures that should implement immediately include the cessation of habitat destruction, better plan for the development of tourism, a reduction in the number of canoes and zoning of the non-fishing area. (C) 2002 Elsevier Science Ltd. All rights reserved.
Resumo:
中国拥有92466 Km2的各类高原湿地,具有湿地退化、过度放牧等相似特征,保护与利用矛盾突出。高寒湿地保护区尽管在制度上以核心区、缓冲区来约束当地的放牧等外来干扰行为,但在实际管理中却不能起到应有的作用。 本研究以四川若尔盖湿地国家级自然保护区为例,应用3S技术,建立保护区多功能动态分区工作流模型,通过不同植被类型的识别和空间特征分析、不同动物类群在上述植被生境中的时空分布特征分析、保护区主要干扰因素的时空分布特征分析,突出对保护区主要保护对象(湿地生态系统)的保护,对保护区进行管理分区,依据野生动物利用特征和植被生长特征对核心区进行年周期动态利用,缓解保护与发展的矛盾,促进保护区的优化管理。 应用归一化植被指数(NDVI)与植被盖度的相关性,将归一化植被指数(NDVI)转化为植被盖度指数(MDVI),结合保护区牧场划分和时空利用特征专家经验,结果表明,MDVI值在1-139之间主要代表着水体、裸地、沙地等;MDVI140-256为草地和高山灌丛;MDVI210是当地夏牧场和秋冬牧场的划分区间值。 合理的区划需要资金、技术和政策的支持,为保证保护区多核心动态分区的实施,本研究提出了生态工程、牧业发展方式转变、湿地特色产业发展、湿地政策、社区参与和科技支撑等六大保障措施。 In China, 92466 Km2 highland or frigid wetlands are (were) facing major management problems, such as wetland degradation and overgazing. Conflict between conservation and utilization on those wetlands can be found anywhere today. Although many nature reserves have been setup for protection of frigid wetland, and core and buffer zone has been declared to forbid any kinds of disturbance, local farmers still use these areas for grazing. As an example by Sichuan Roige Wetlands National Nature Reserve(SRWNRR), we set up a 3S flow model to analyze the character of year-round distribution patters of vegetation, wildlife, and grazing. Combined and overlapped these characters together, we select multi-core zone and buffer zone, then define a dynamic management period in different zone to optimize protection wetland in the reserve. Normalized Difference Vegetation Index(NDVI)is highly related with coverage of vegetation. When convert NDVI to MDVI (coverage index, 1-256), index 139 and 210 can be as inflexion to distinguish among water/sand/bared land, summer pasture, and autumn / winter pasture. We use these to select different layers and analyze grazing pattern. To be more realistic, we put forward some strategies to support our multi-core and dynamic management of wetland in Roige, including ecological restoration engineering, changing of stock raising industry, changing of wetland policy, community based management and technology renovation supports.
Resumo:
小麦(Triticum aestivum L.)是世界上种植面积最大,总产量最高,食物加工种类最丰富的粮食作物,占世界人口35 %-40 %的人们以此为主要食物。因此小麦产量的高低和品质的优劣直接影响人们对食物需求的安全和满意程度,也影响着人类的营养平衡以及面粉和食品加工业的发展。随着生活水平的提高,人们对于小麦的品质越来越重视。培育优质专用小麦新品种,制定优质专用小麦品种品质生态区划,从而在不同程度上实现小麦的区域化种植和产业化经营具有重要的意义。 影响小麦品质的因素主要是遗传因素和环境因素,其中环境因素又包括各种自然生态因素和人为因素。研究表明,小麦品质的环境间的差异大于品种间的差异,气候条件是影响小麦品质的最重要的因子,小麦品质的地域间的差异反映出了小麦的品质区域分布规律。为了满足市场对不同品质小麦的需求,对小麦进行区域化研究具有重要的理论和现实意义。本研究结合四川的地理、气候特点,研究不同品质类型与生态环境的关系,为在复杂的生态环境内进行品质区划提供依据。 本研究首先根据四川省小麦种植区域的生态特点,在四川省多个典型生态区:川南丘陵的荣县、川西南高原的西昌、川西平原的双流布点种植,采用的小麦试验材料为不同品质类型:中筋小麦川育12、川育14、川育16由本所提供;弱筋小麦川麦32和强筋小麦川麦36由四川省农科院作物所提供。通过研究品质性状与品种及各个生态因子包括地点、土壤土质差异等的关系,明确不同生态环境中适宜种植的小麦品种类型,强筋小麦、中筋小麦更适合于在荣县、双流地区种植,弱筋小麦更适合于在西昌地区种植,为品种品质区划奠定基础。 其次,选择了本课题组育成的稳定中间品系,对其品质性状SDS沉降值进行了多年测定。分析了品质性状SDS沉降值与多种气候因子的相关性,结果表明SDS沉降值与日均温、日照时数成正相关,与降水量成负相关,为品质育种提供了理论依据。 此外,以中筋小麦新品种小麦川育14为材料,应用三元二次正交旋转回归模型设计试验,研究主要栽培因子播期、密度和施肥量对产量的影响,并建立函数模型。经计算机模拟寻优,筛选出了高产高效栽培组合措施,并确定了置信域。结合四川省不同的地理情况,在平原和丘陵地区分别进行实验,并各自建立了高产高效栽培组合措施,为川育14品种的推广提供了理论指导。 Wheat is one of the most important crops in the world. About 35%-40% people all over the world, take the wheat as their most important food. So the quality, as well as the quantity of the wheat makes a direct effect on people’s demands of food and their satisfaction. It also effects on human’s healthy, and the development of the Food processing industry. With the development of the living standard, people pay more attention to the quality of wheat. So, we set a special ecology zoning for wheat. It is significant to carry out planting the wheat in special zoning in varying degrees. The main factors affecting wheat quality are heredity and environment including many ecological factors and the factors in cultivation. As to the quality,the difference between ecology and cultivation is more important than the difference between special wheat. In so many factors, climate is the most important one. From the difference in quality between different zones,we can conclude the rule of distribution abort quality of wheat. Finding out the intersection of numerous wheat not only can meet the demand of food production,but also has important signification in theory and realism。In our research, according to the complex geography in Sichuan province, we study the relationship between numerous kinds of quality characters in wheat and the ecology. So, we can set a foundation for more research. In this research, firstly, we plant wheat in some typical ecological regions of SICHUAN province: RONGXIAN(south of SC)、XICHANG(south of SC), SHUANGLIU(west of SC). The materials of the experiments: ChuanYu12, ChuanYu14, ChuanYu16(from our institute), Chuanmai32, Chuanmai36 (from the Chinese academy of agriculture sciences of Sichuan. Through the research on the relationship between the quality of wheat and those ecology factors, we can make a definition that which area is perfect matched with which kind of wheat. And it can satisfy the demand of people. Secondly, select many sorts of wheat from our research group. All of them are selected and bred more than 3 years(2003-2005). And we make every-year determination as well. We’ve gotten SDS value from those 9, and various data on factors of climate. We also got to know the relation ship between those numbers. Thirdly, use Chuanyu14 as material, the mathematical model of the relation between the production of wheat and main agricultural measures such as date, density and fertilizer. The model was established by association of three elements two return, rotate and regression. We set a suitable model and get a suitable method which can make high harvest. Based on various kinds of geographical regions in Sichuan province, we set different models which can be used in plain and hill. So, we can plant Chuan Yu 14 in Sichuan province under the result in research.
Resumo:
针对原子力显微镜(AFM)纳米成像中存在的失真问题,研究了通过探针建模实现AFM扫描图像重构方法.目前探针盲建模算法在重构AFM图像时存在较大误差,因此提出基于探针模型预估计的AFM扫描图像重构方法.该方法采用分区探针针尖建模,并通过基于该探针模型的反卷积运算实现AFM扫描图像重构,获得比较接近真实形貌的AFM扫描图像.文中介绍了算法的具体步骤,通过仿真和实验结果证明,该方法能够有效降低AFM图像重构时引入的误差,得到的图像更能反映样品表面真实的形貌。
Resumo:
The occurrence of Late Cretaceous mafic dykes and their entrained peridotite and granulite xenoliths as well as clinopyroxene xenocrysts in the Qingdao region provide us a precious opportunity to unveil the nature and characteristics of the Late Mesozoic lithospheric mantle and lower crust beneath the Jiaodong region, and the change of the magma sources. These studies are of important and significant for understanding the lithospheric evolution in the eastern North China Craton. There were two periods of magma activities in Late Mesozoic in Qingdao Laoshan region, one was around 107Ma in the Early Cretaceous and the other around 86Ma in the Late Cretaceous according to the whole rock K-Ar age determination. The Early Cretaceous mafic dykes and the Late Cretaceous mafic dyke (i.e. Pishikou mafic dike) have completely different geochemical characteristics. The Early Cretaceous mafic dykes are enriched in LILE, strongly depleted in HFSE (Nb, Ta, Zr, Hf) and characterized by the highly radiogenic Sr and Nd isotopic compositions. These geochemical features indicate that the Early Cretaceous mafic dykes were derived from an enriched lithospheric mantle. In contrast, the Late Cretaceous mafic dyke is enriched in LILE, without HFSE depletion (Nb, Ta, Zr, Hf) and has less radiogenic Nd and Sr isotopic compositions. These geochemical features indicate that the Late Cretaceous mafic dyke was derived from the asthenosphere modified by subducted pelagic sediment contamination. The intrusive age of the Late Cretaceous mafic dyke provides further information for the termination of the lithosphere thinning for the eastern North China Crtaon. Pishikou Late Cretaceous mafic dyke contains abundant peridotitic xenoliths, granulite xenoliths and clinopyroxene xenocrysts. The peridotitic xenoliths can be divided into two types: high Mg# peridotites and low Mg# peridotites, according to their textural and mineral features. The high-Mg# peridotites have high Fo (up to 92.2) olivines and high Cr# (up to 55) spinels. The clinopyroxenes in the high# peridotites are rich in Cr2O3 and poor in Al2O3. The low-Mg# peridotites are typified by low Mg# (Fo <90) in olivines and low Cr# (Cr# <0.14) in spinels. The clinopyroxenes in the low-Mg# peridotites are rich in Al2O3 and Na2O and poor in Cr2O3. These two type peridotites have similar equilibrated temperatures of 950C-1100C. The Clinopyroxenes in the high-Mg# peridotites generally have high and variable REE contents (REE = 5.6-84 ppm) and LREE-enriched chondrite-normalized patterns ((La/Yb)N>1). In contrast, the clinopyroxenes in the low-Mg# peridotites have low REE contents (REE = 12 ppm) and LREE-depleted patterns ((La/Yb)N<1). The textural, mineral and elemental features of the low-Mg# peridotites are similar to those of the low-Mg peridotites from the Junan, representing the newly-accreted lithospheric mantle. However, the mineralogical and petrological features of the high-Mg# peridotites are similar to those of the high-Mg# peridotites from the Junan region, representing samples from the old refractory lithospheric mantle that was strongly and multiply affected by melts of different origins Late Cretaceous mafic dike in the Qingdao region also contains two types of granulite xenoliths according to the mineral constituents: the pyroxene-rich granulites and the plagioclase-rich granulites. Equilibrated temperatures calculated from the cpx-opx geothermometers are in a range of 861C - 910C for the pyroxene-rich granulites and of 847C - 890C for the plagioclase-rich granulites. The equilibrated pressure for the plagioclase-rich granulites is in a range of 9.9-11.7 kbar. Combined with the results of the peridotitic xenoliths, a 40C temperature gap exists between the peridotite and the granulite. The petrological Moho was 33~36 km at depths, broadly consistent with the seismic Moho estimated from the geophysical data. This indicates that there was no obvious crust-mantle transition zone in the Qingdao region in the Late Mesozoic. Pishikou Late Cretaceous mafic dyke entrained lots of clinopyroxene xenocrysts which are characterized by the chemical zoning. According to the zoning features, two types of clinopyroxene xenoliths can be classified, the normal zoning and the revise zoning. The normally-zoned clinopyroxene xenocrysts have LREE-depleted REE patterns in the cores. In contrast, the revisely-zoned clinopyroxenes have LREE-enriched REE patterns in the cores. According to the rim and core compositions of xenocrysts, all the rims are balanced with the host magma. Meanwhile, the origins of the cores were complicated, in which the normally-zoned clinopyroxenes were derived form the lithospheric mantle and some of the reversely-zoned clinopyroxnes were originated from the lower crust. Other revisely-zoned clinopyroxenes had experienced complex geological evolution and need to be further investigated. According to the above results, a simplified lithospheric profile has been established beneath the Qingdao region and a constraint on the nature and characteristics of the lithospheric mantle and lower crust has been made.
Resumo:
Abstract With the Development of the West Regions, the contradiction between economy and geological hazards was once again brought to our face in the Loess Plateau where was ,and is liable to geological hazards for the unique conditions of geology, hydrogeology, geography and meteorology. The goal to realize harmonious development between human and the earth was always there, and landslide hazard zoning provided us an effective way against geological hazards and damage. In the background of the construction of 750KV transformer substation in TianShui, we summarized some theories, methods and development of landslide hazard zoning and discussed the application of information value model in landslide hazard zoning. A called “judgement matrix” like in AHP was introduced to the information value model to solve the key point of landslide hazard zoning — choice of factors and weight of each factor. GIS was applied in the landslide hazard zoning, with its comprehensive function on data management, spatial analysis and mapping. A zonation map of landslide hazard was worked out on MAPGIS aimed to have something of reference and instruction on the construction of the transformer substation. Key words: landslide; hazard zoning; information value model; GIS; judgement matrix
Resumo:
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-KClFeCl2CaCl2. 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 (600-950C), 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.
Resumo:
Based on a viewpoint of an intricate system demanding high, this thesis advances a new concept that urban sustainable development stratagem is a high harmony and amalgamation among urban economy, geo-environment and tech-capital, and the optimum field of which lies in their mutual matching part, which quantitatively demarcates the optimum value field of urban sustainable development and establishes the academic foundation to describe and analyze sustainable development stratagem. And establishes a series of cause-effect model, a analysissitus model, flux model as well as its recognizing mode for urban system are established by the approach of System Dynamics, which can distinguish urban states by its polarity of entropy flows. At the same time, the matter flow, energy flow and information flow which exist in the course of urban development are analyzed based on the input/output (I/O) relationships of urban economy. And a new type of I/O relationships, namely new resources-environment account, are established, in which both resource and environment factors are considered. All above that settles a theoretic foundation for resource economy and environment economy as well as quantitative relationships of inter-function between urban development and geoenvironment, and gives a new approach to analyze natinal economy and urban sustainable development. Based on an analysis of the connection between resource-environmental construct of geoenvironment and urban economy development, the Geoenvironmental Carrying Capability (GeCC) is analyzed. Further more, a series of definitions and formula about the Gross Carrying Capability (GCC), Structure Carrying Capability (SCC) and Impulse Carrying Capability (ICC) is achieved, which can be applied to evaluate both the quality and capacity of geoenvironment and thereunder to determine the scale and velocity for urban development. A demonstrative study of the above is applied to Beihai city (Guangxi province, PRC), and the numerical value laws between the urban development and its geoenvironment is studied by the I/O relationship in the urban economy as following: · the relationships between the urban economic development and land use as well as consumption of underground water, metal mineral, mineral energy source, metalloid mineral and other geologic resources. · the relationships between urban economy and waste output such as industrial "3 waste", dust, rubbish and living polluted water as well as the restricting impact of both resource-environmental factors and tech-capital on the urban grow. · Optimization and control analysis on the reciprocity between urban economy and its geoenvironment are discussed, and sensitive factors and its order of the urban geoenvironmental resources, wastes and economic sections are fixed, which can be applied to determine the urban industrial structure, scale, grow rate matching with its geoenvironment and tech-capital. · a sustainable development stratagem for the city is suggested.
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The research on mechanical effects of water-rock and soil interaction on deformation and failure of rocks and soils involves three aspects of mechanics, physics and chemistry. It is the cross between geochemistry and rock mechanics and soil mechanics. To sum up, the mechanical effects of water-rock and soil interaction is related to many complex processes. Research in this respect has been being an important forward field and has broad prospects. In connection with the mechanism of the effects of the chemical action of water-rock on deformation and failure of rocks and soils, the research significance, the present state, the developments in this research domain are summarized. Author prospects the future of this research. The research of the subject should be possessed of important position in studying engineering geology and will lead directly to a new understand on geological hazard and control research. In order to investigation the macroscopic mechanics effects of chemical kinetics of water-rock interaction on the deformation and failure, calcic rock, red sandstone and grey granite reacting chemically with different aqueous solution at atmospheric temperature and atmospheric pressure are uniaxially compressed. The quantitative results concerning the changes of uniaxially compressive strength and elastic modulus under different conditions are obtained. It is found that the mechanical effects of water on rock is closely related to the chemical action of water-rock or the chemical damage in rock, and the intensity of chemical damage is direct ratio to the intensity of chemical action in water-rock system. It is also found that the hydrochemical action on rock is time-dependent through the test. The mechanism of permeation and hydrochemical action resulting in failure of loaded rock mass or propagation of fractures in rocks would be a key question in rock fracture mechanics. In this paper, the fracture mechanical effects of chemical action of water-rock and their time- and chemical environment-dependent behavior in grey granite, green granite, grey sandstone and red sandstone are analyzed by testing K_(IC) and COD of rock under different conditions. It is found that: ①the fracture mechanical effect of chemical action of water-rock is outstanding and time-dependent, and high differences exist in the influence of different aqueous solution, different rocks, different immersion ways and different velocity of cycle flow on the fracture mechanical effects in rock. ②the mechanical effects of water-rock interaction on propagation of fractures is consistent with the mechanical effects on the peak strength of rock. ③the intensity of the mechanical fracture effects increases as the intensity of chemical action of water-rock increases. ④iron and calcium ion bearing mineral or cement in rock are some key ion or chemical composition, and especially iron ion-bearing mineral resulting in chemical action of water-rock to be provided with both positive and negative mechanical effects on rock. Through the above two tests, we suggest that primary factors influencing chemical damage in rock consist of the chemical property of rock and aqueous solution, the structure or homogeneity of rocks, the flow velocity of aqueous solution passing through rock, and cause of formation or evolution of rock. The paper explores the mechanism on the mechanical effects of water-rock interaction on rock by using the theory of chemistry and rock fracture mechanics with chemical damage proposed by author, the modeling method and the energy point of view. In this paper, the concept of absorbed suction between soil grains caused by capillary response is given and expounded, and the relation and basic distinction among this absorbed suction, surface tension and capillary pressure of the soil are analyzed and established. The law of absorbed suction change and the primary factors affecting it are approached. We hold that the structure suction are changeable along with the change of the saturation state in unsaturated soils. In view of this, the concept of intrinsic structure suction and variable structure suction are given and expounded, and this paper points out: What we should study is variable structure suction when studying the effective stress. By IIIy κHH's theory of structure strength of soils, the computer method for variable structure suction is analyzed, the measure method for variable structure suction is discussed, and it reach the conclusions: ①Besides saturation state, variable structure suction is affected by grain composition and packing patter of grains. ②The internal relations are present between structure parameter N in computing structure suction and structure parameter D in computing absorbed suction. We think that some problems exit in available principle of effective stress and shear strength theory for unsaturated soil. Based on the variable structure suction and absorbed suction, the classification of saturation in soil and a principle of narrow sense effective stress are proposed for unsaturated soils. Based on generalized suction, the generalized effective stress formula and a principle of generalized effective stress are proposed for unsaturated soils. The experience parameter χ in Bishop's effective stress formula is defined, and the principal factors influencing effective stress or χ. The primary factor affecting the effective stress in unsaturated soils, and the principle classifying unsaturated soils and its mechanics methods analyzing unsaturated soils are discussed, and this paper points out: The theory on studying unsaturated soil mechanics should adopt the micromechanics method, then raise it to macromechanics and to applying. Researching the mechanical effects of chemical action of water-soil on soil is of great importance to geoenvironmental hazard control. The texture of soil and the fabric of soil mass are set forth. The tests on physical and mechanical property are performed to investigate the mechanism of the positive and negative mechanical effects of different chemical property of aqueous solution. The test results make clear that the plastic limit, liquid limit and plasticity index are changed, and there exists both positive and negative effects on specimens in this test. Based on analyzing the mechanism of the mechanical effects of water-soil interaction on soil, author thinks that hydrochemical actions being provided with mechanical effects on soil comprise three kinds of dissolution, sedimentation or crystallization. The significance of these tests lie in which it is recognized for us that we may improve, adjust and control the quality of soils, and may achieve the goal geological hazard control and prevention.The present and the significance of the research on environmental effects of water-rock and soil interaction. Various living example on geoenvironmental hazard in this field are enumerated. Following above thinking, we have approached such ideals that: ①changing the intensity and distribution of source and sink in groundwater flow system can be used to control the water-rock and soil interaction. ②the chemical action of water-rock and soil can be used to ameliorate the physical and mechanical property of rocks and soils. Lastly, the research thinking and the research methods on mechanical effects and environmental effects of water-rock and soil interaction are put forward and detailed.
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The Dabie Mountains is a collisional orogenic belt between the North China and Yantze Continental plates. It is the eastern elongation of the Tongbai and Qingling orogen, and is truncated at its east end by the Tan-Lu fault. Jadeite-quartzite belt occurs in the eastern margin of UHPMB from the Dabie Mountains. Geochemical features indicate that the protoliths of the jadeite-quartzite and associated eclogite to be supracrustal rocks. The occurrence of micro-inclusions of coesite in jadeite and garnet confirmed that the continental crust can be subducted to great depth (8 0-100km) and then exhumed rapidly with its UHP mineral signature fairly preserved. Therefore, study of UHP jadeite-quartzite provides important information on subduction of continental crustal rocks and their exhumation histories, as well as the dynamics of plate tectonic processes at convergent margins. The purpose of this paper is to investigate the presence of hydrous component in the jadeite-quartzite belt, significant natural variations in the hydrous component content of UHP minerals and to discuss the role of water in petrology, geochemistry and micro-tectonic. On the basis of our previous studies, some new geological evidences have been found in the jadeite-quartzite belt by researches on petrography, mineralogy, micro-tectonic, hydrous component content of UHP minerals and combined with the study on rheology of materials using microprob, ER, TEM. By research and analysis of these phenomenona, the results obtained are as follows: 1. The existence of fluid during ultra-high pressure metamorphic process. Jadeites, omphacite, garnet, rutile, coesite and quartz from the jadeite-quartzite belt have been investigated by Fourier transform infrared spectrometer and TEM. Results show that all of these minerals contain trace amount of water which occur as hydroxyl and free-water in these minerals. The two-type hydrous components in UHP minerals are indicated stable in the mantle-depth. The results demonstrated that these ultra-high pressure metamorphic minerals, which were derived from continental crust protoliths, they could bring water into the mantle depth during the ultra-high pressure metamorphism. The clusters of water molecules within garnet are very important evidence of the existence of fluid during ultra-high pressure metamorphic process. It indicated that the metamorphic system was not "dry"during the ultra-high pressure stage. 2.The distribution of hydrous component in UHP minerals of jadeite-quartzite. The systematic distribution of hydrous components in UHP minerals are a strong indication that water in these minerals, are controlled by some factors and that the observed variations are not of a random nature. The distribution and concentration of hydrous component is not only correlated with composition of minerals, but also a function of geological environment. Therefore, the hydrous component in the minerals can not only take important part in the UHP metamorphic fluid during subduction of continental crustal rocks, but also their hydroxyl transported water molecules with decreasing pressure during their exhumation. And these water molecules can not only promote the deformation of jadeite through hydrolytic weakening, but also may be the part of the retrograde metamorphic fluid. 3.The role of water in the deformed UHP minerals. The jadeite, omphacite, garnet are strong elongated deformation in the jadeite-quartzite from the Dabie Mountains. They are (1) they are developed strong plastic deformation; (2) developed dislocation loop, dislocation wall; (3) the existence of clusters of water molecular in the garnet; and (4) the evolution of micero-tectonic from clusters of water molecular-dislocation loop in omphacite. That indicated that the water weakening controlled the mechanism of deformed minerals. Because the data presented here are not only the existence of clusters of water molecular in the garnet, but also developed strong elongation, high density of dislocation and high aspect ratios, adding microprobe data demonstrate the studied garnet crystals no compositional zoning. Therefore, this indicates that the diffusion process of the grain boundary mobility did not take place in these garnets. On the basis of above features, we consider that it can only be explained by plastic deformation of the garnets. The clusters of water molecules present in garnet was directly associated with mechanical weakening and inducing in plastic deformation of garnet by glissile dislocations. Investigate of LPO, strain analysis, TEM indicated that these clinopyroxenes developed strong elongation, high aspect ratios, and developed dislocation loop, dislocation wall and free dislocations. These indicated that the deformation mechanism of the clinopyroxenes plastically from the Dabie Mountains is dominant dislocation creep under the condition of the UHP metamorphic conditions. There are some bubbles with dislocation loops attached to them in the omphacite crystal. The bubbles attached to the dislocation loops sometimes form a string of bubble beads and some loops are often connected to one another via a common bubble. The water present in omphacite was directly associated with hydrolitic weakening and inducing in plastic deformation of omphacite by dislocations. The role of water in brittle deformation. Using microscopy, deformation has been identified as plastic deformation and brittle deformation in UHP minerals from the Dabie Mountains. The study of micro-tectonic on these minerals shows that the brittle deformation within UHP minerals was related to local stresses. The brittle deformation is interpreted as being caused by an interaction of high fluid pressure, volume changes. The hydroxyl within UHP minerals transported water molecules with decreasing pressure due to their exhumation. However, under eclogite facies conditions, the litho-static pressure is extreme, but a high fluid pressure will reduce the effective stress and make brittle deformation possible. The role of water in prograde metamorphism. Geochemical research on jadeite-quartzite and associated eclogite show that the protoliths of these rocks are supracrustal rocks. With increasing of temperature and pressure, the chlorite, biotite, muscovite was dehydrous reaction and released hydrous component during the subduction of continental lithosphere. The supracrustal rocks were transformed UHP rocks and formed UHP facies assemblage promotely by water introduction, and was retained in UHP minerals as hydrous component. The water within UHP minerals may be one of the retrograde metamorphic fluids. Petrological research on UHP rocks of jadeite-quartzite belt shows that there was existence of local fluids during early retrograde metamorphism. That are: (1) coronal textures and symplectite around relict UHP minerls crystals formed from UHP minerls by hydration reactions; (2) coronal textures of albite around ruitle; and (3) micro-fractures in jadeite or garnet were filled symplectite of Amp + PI + Mt. That indicated that the reactions of early retrograde metamorphism dependent on fluid introduction. These fluids not only promoted retrograde reaction of UHP minerals, but also were facilitate to diffuse intergranular and promote growth in minerals. Therefore, the hydrous component in the UHP minerals can not only take important part in the UHP metamorphic fluid during subduction of continental crustal rocks, but also their hydroxyl transport water molecules with decreasing pressure and may take part in the retrograde metamorphic fluid during their exhumation. 7. The role of water in geochemistry of UHP jadeite-quartzite. Geochemical research show that there are major, trace and rare earth element geochemical variations in the jadeite-quartzite from the Changpu district of Dabie Mountains, during retrograde metamorphic processes from the jadeite-quartzite--gneiss. The elements such as SiO_2、FeO、Ba、Zr、Ga、La、Ce、PTN Nd% Sm and Eu increase gradually from the jadeite-quartzite to retrograded jadeite-quartzite and to gneiss, whilst TiO_2. Na_2CK Fe2O_3、Rb、Y、Nb、Gd、Tb、Dy、Ho、Er、Tm、Yb decrease gradually. And its fO_2 keep nearly unchanged during early retrograde metamorphism, but decreased obviously during later retrograde metamorphism. These indicate that such changes are not only controlled by element transformation between mineralogical phases, but also closely relative to fluid-rock interaction in the decompression retrograde metamorphic processes.
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Seepage control in karstic rock masses is one of the most important problems in domestic hydroelectric engineering and mining engineering as well as traffic engineering. At present permeability assessment and leakage analysis of multi-layer karstic rock masses are mainly qualitative, while seldom quantitative. Quantitative analyses of the permeability coefficient and seepage amount are conducted in this report, which will provide a theoretical basis for the study of seepage law and seepage control treatment of karstic rocks. Based on the field measurements in the horizontal grouting galleries of seepage control curtains on the left bank of the Shuibuya Hydropower Project on the Qingjiang river, a hydraulic model is established in this report, and the computation results will provide a scientific basis for optimization of grouting curtain engineering. Following issues are addressed in the report. (1) Based on the in-situ measurements of fissures and karstic cavities in grouting galleries, the characteristics of karstic rock mass is analyzed, and a stochastic structural model of karstic rock masses is set up, which will provide the basis for calculation of the permeability and leakage amount of karstic rock mass. (2) According to the distribution of the measured joints in the grouting galleries and the stochastic results obtained from the stochastic structural model of karstic rock mass between grouting galleries, a formula for computation of permeability tensor of fracturing system is set up, and a computation program is made with Visual Basic language. The computation results will be helpful for zoning of fissured rock masses and calculation of seepage amount as well as optimization of seepage control curtains. (3) Fractal theory is used to describe quantitatively the roughness of conduit walls of karstic systems and the sinuosity of karstic conduits. It is proposed that the roughness coefficient of kastic caves can be expressed by both fractal dimension Ds and Dr that represent respectively the extension sinuosity of karstic caves and the roughness of the conduit walls. The existing formula for calculating the seepage amount of karstic conduits is revised and programmed. The seepage amount of rock masses in the measured grouting galleries is estimated under the condition that no seepage control measures are taken before reservoir impoundment, and the results will be helpful for design and construction optimization of seepage curtains of the Shuibuya hydropower project. This report is one part of the subject "Karstic hydrogeology and the structural model and seepage hydraulics of karstic rock masses", a sub-program of "Study on seepage hydraulics of multi-layer karstic rock masses and its application in seepage control curtain engineering", which is financially supported by the Hubei Provincial key science and technology programme.