489 resultados para Yunnan.


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稀矿山式铜矿是指赋存在昆阳群因民组地层中的铜铁矿床,其大地构造背景属于元古代裂谷带,大陆裂谷是超大型铜等多金属矿形成和分布的有利环境,在裂谷下部常发育异常地慢和岩浆源,裂谷空间上的多层次性使矿床具有明显垂向分带特征,其演化时间的长期性、脉动性和继承性便于多期成矿作用相互叠加、矿质的高度聚集。稀矿山式铜矿以落雪矿区稀矿山矿段最为典型,主要分布在因民落雪大乔地一稀矿山、滥山、磨子山,滥泥坪6-4巷、白锡腊和拖布卡地区。该类矿床广布于康滇地轴南段东川、武定一罗茨、元江、易门狮子山、金沙江南岸的花生坪、红门厂等地,已知中型铜矿床1处(稀矿山)、中型铁矿床2处(鹅头厂、笔架山)、小型铜(铁)矿床多处,上世纪90年代易门狮子山该类矿床的发现,表明该类矿床在东川-易门具找矿潜在远景。本文通过对东川矿区稀矿山式铜矿的常量元素、微量元素、包裹体、同位素及同位素定年等地球化学研究,获得以下认识:1.东川矿区地层(包括其下覆基底)和晋宁期碱基性岩中Cu等成矿元素背景值较高,且在蚀变过程中均能析出Cu等成矿元素。矿床中Cu等成矿物质来源复杂,以深源为主,部分来源于地层(因民组紫色层和落雪组白云岩)及基底地层:矿区内的退色蚀变作用可能是混合流体碱质交代改造作用的结果,对铜矿形成影响明显,是铜矿化的标志;2.该类矿床成矿流体属于中高温、中高盐度、高密度Na,(K+)Ca2+-SO42-(Cl-)型,以深部岩浆水为主,混有大量海水和变质水。矿床中发现了富NZ包裹体,可能是矿床形成时,深大断裂活动、碱基性岩浆带来地球深部(上地慢和下地壳)物质并形成的成矿流体,在氧化一去挥发分作用过程中所形成;3.铁矿体被铜矿体包围,铁矿石被铜矿细脉穿插,说明铜矿化的形成晚于铁矿化。黄铜矿单矿物的Re-05同位素年龄研究表明其成矿年龄为826士230Ma,接近矿区碱基性岩年龄,与昆阳裂谷内其它类型铜矿成矿时代相当,均属于晋宁-澄江期;4.东川矿区晋宁一澄江期碱基性岩侵入活动明显,常作为因民组复杂角砾岩胶结物和岩脉(体)产出,多分布于深大断裂及其派生的次级构造附近,明显受南北向小江深大断裂走滑运动引起的右行旋扭及其派生构造控制,与“落因破碎带”和“铜矿分布”较吻合,均为“Z”字形。表明东川矿区铜矿形成与深大断裂及其派生次级构造和,宁-澄江期碱基性岩侵入活动关系密切;5.昆阳裂谷内的多数铜矿同位素成矿年龄多集中在9.0亿-6.5亿年之间,属于晋宁-澄江期,与Redina大陆裂解时限相当。表明裂谷内铜矿床的形成可能与Rodinia大陆裂解有关。因此,总结东川稀矿山式铜矿成矿模式为沉积(Fe、Cu)-热液叠加(Cu)改造:晋宁-澄江期,小江深大断裂发生走滑运动,在东川矿区造成右行旋扭及其派生构造,形成“Z”,字形落因破碎带,同时来自深源(下地壳或上地慢)碱基性岩浆侵入,不仅带来了大量Cu等成矿物质,更重要的是提供了热源,促使地层水(落雪组白云岩和因民组紫色层)循环,与富碱(Na和K)岩浆水混合,形成富碱中高温高盐度流体。因民组紫色层与其底部角砾岩接触带,具有较高的空隙度和渗透率,有利于成矿流体的运移和成矿。在这种混合流体作用下,地层中Cu等成矿物质析出,叠加改造了初始铜矿化最终形成稀矿山式铜矿。

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本论文在前人数据资料和研究成果的基础上,以北衙金矿床及其相关的富碱侵入岩作为主要研究对象,以探讨滇西新生代富碱火成岩成岩过程及富碱岩浆上升演化过程中的流体分异,北衙金矿床的成因,最终揭示北衙金矿床与相关的富碱侵入岩之间的关系为主要研究目的,通过主、微量(包括稀土)元素地球化学,Pb、Sr、Nd、C、O、S及He-Ar等同位素地球化学,以及流体包裹体地球化学等方面的研究获得以下主要认识:-1.滇西新生代富碱火成岩来源于EM-II型富集地慢,源区的交代富集过程与古特提斯洋壳的俯冲有关,俯冲板片的含水流体对上覆上慢楔的交代是滇西富碱侵入岩(相当于A型花岗岩)含水的原因,这次富碱岩浆活动是一次滞后的弧岩浆活动;富碱中、酸性岩浆由碱性玄武质岩浆混染约20%的主要来自变质基底的地壳物质演化而来;滇西新生代富碱岩浆具备岛弧岩浆的氧化条件(即fogfo2>FMQ+2,FMQ代表铁橄榄石一磁铁矿一石英氧缓冲),并在其上升演化过程中分异出大量的流体相,具有较大的An、Cu成矿潜力。2.北衙金矿的矿化时代33.0±1.5Ma与相关的富碱侵入岩的成岩时代(32-34Ma)一致。3,成矿早期流体或初始流体具有富碱岩浆在变质基底内分异的流体的Nd和sr同位素组成(Isr≈0.722390,ε Nd(t)≈-2.8)、矿区及外围富碱斑岩的平均Pb同位素组成(206Pb/204Pb=18.590,207Pb/204Pb=15.606,208Pb/204Pb=38.770)、与相关富碱斑岩一致的稀土配分模式、岩浆热液的C、O同位素组成(δ13C≈-5%0,61、尧11%0)、以及壳一慢混合He-Ar同位素组成(3He尸He;1 .80-1.94 Ra,3He/3 6Ar=1 .19 * 10-3-3.93火10·3)并显示明显的He-Ar分异(4oAr*/He=0.34-0.75),且以高温、高压、高盐度、富c02为特征,说明初始流体主要在变质基底内由富碱岩浆分异而来;初始流体在上升过程中由于温度、压力降低发生富co2相和盐水相的分离,成矿元素优先分配进入富COZ相,逐步演化为成矿阶段流体;成矿阶段流体在去气或与大气降水混合过程中释放出其中的成矿元素。4.约80%的成矿金属来自富碱岩浆,其余部分主要通过岩浆流体从变质基底摄取。结论:北衙金矿与相关的富碱侵入岩具有密切的成因关系。

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铊是一种低温元素,可形成富铊矿床。主要呈独立矿物红铊矿、斜硫砷系铊矿、Imhofite等形式存在。在卡林型金矿中Aa-Tl关系密切。流体包裹体、稳定同位素稀土元素地球化学,成矿模拟实验研究表明:富铊矿床的成矿流体主要来自大气降水和地层中的热卤水,成矿物质主要来源于地层,部分可能来自深部。从而建立了富(含)铊矿床形成的三阶段成矿模式。铊的环境地球化学研究表明,富铊矿床的开发利用是导致环境铊污染和地方性锭中毒的原因。

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The cultivation of rubber trees in Xishuangbanna Prefecture in China’s Yunnan Province has triggered an unprecedented economic development but it is also associated with severe environmental problems. Rubber plantations are encroaching the indigenous rainforests at a large scale and a high speed in Xishuangbanna. Many rare plant and animal species are endangered by this development, the natural water management is disturbed and even the microclimate in this region has changed over the past years. The present study aims at an assessment of the environmental benefits accruing from a reforestation project partly reversing the deforestation that has taken place over the past years. To this end a Contingent Valuation survey has been conducted in Xishuangbanna to elicit local residents’ willingness to pay for this reforestation program that converts existing rubber plantations back into forest. It is shown that local people's awareness of the environmental problems caused by increasing rubber plantation is quite high and that in spite of the economic advantages of rubber plantation there is a positive willingness among the local population to contribute financially to a reduction of existing rubber plantations for the sake of a partial restoration of the local rainforest. These results could be used for the practical implementation of a PES (Payments for Eco-System Services) system for reforestation in Xishuangbanna.

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L’histoire de la médicalisation de la maternité en Chine reste encore mal connue et ce mémoire constitue une amorce pour tenter de défricher ce riche et vaste terrain. Il examine dans quel cadre et dans quelle mesure la prise en charge de la maternité des femmes chinoises a évolué au sein des postes médicaux consulaires français du sud de la Chine (Guangdong, Guangxi, Yunnan), de l’arrivée des premiers médecins en 1898, jusqu’à la veille de la Seconde Guerre mondiale en 1938. Il démontre comment a pu se traduire l’œuvre médicale française en matière de prise en charge de la grossesse, de l’accouchement et des soins à donner au nouveau-né dans les établissements de santé consulaires, et tente de voir jusqu’à quel point, pourquoi et dans quels domaines précisément l’offre de soins à l’occidentale proposée par les Français dans ces régions a pu atteindre les futures et nouvelles mères chinoises.

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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

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El presente trabajo investigativo constituye una herramienta de consulta para las personas y organizaciones interesadas en conocer el panorama actual de la situación comercial entre China y Colombia en busca de toma de decisiones acertadas en materia de negocios entre ambas naciones. En él se analizan en detalle cada una de las veintidós provincias de la República Popular China; en cuanto a panorama general; logística aérea, terrestre y marítima; partidas arancelarias y Top 10 de los productos importados por cada una de ellas desde Colombia. Este trabajo está enfocado en el estudio del comercio desde Colombia hacia China, actualizado al año 2012 y busca enseñar los productos líderes de importación, al igual que aquellos productos potenciales; de acuerdo a la información de su valor en dólares, su porcentaje de participación en el total importado y su comportamiento histórico en los últimos tres años. Así mismo se analizan los principales países proveedores de cada provincia y las diferentes partidas arancelarias a profundidad. Finalmente, se espera que el presente trabajo abra las puertas a un nuevo panorama acerca de oportunidades de negocio y alternativas comerciales a productos colombianos en China.

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Hundreds of tropical plant species house ant colonies in specialized chambers called domatia. When, in 1873, Richard Spruce likened plant-ants to fleas and asserted that domatia are ant-created galls, he incited a debate that lasted almost a century. Although we now know that domatia are not galls and that most ant-plant interactions are mutualisms and not parasitisms, we revisit Spruce`s suggestion that ants can gall in light of our observations of the plant-ant Myrmelachista schumanni, which creates clearings in the Amazonian rain forest called ""supay-chakras,"" or ""devil`s gardens."" We observed swollen scars on the trunks of nonmyrmecophytic canopy trees surrounding supay-chakras, and within these swellings, we found networks of cavities inhabited by M. schumanni. Here, we summarize the evidence supporting the hypothesis that M. schumanni ants make these galls, and we hypothesize that the adaptive benefit of galling is to increase the amount of nesting space available to M. schumanni colonies.

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Mapping ecosystem services (ES) and their trade-offs is a key requirement for informed decision making for land use planning and management of natural resources that aim to move towards increasing the sustainability of landscapes. The negotiations of the purposes of landscapes and the services they should provide are difficult as there is an increasing number of stakeholders active at different levels with a variety of interests present on one particular landscape.Traditionally, land cover data is at the basis for mapping and spatial monitoring of ecosystem services. In light of complex landscapes it is however questionable whether land cover per se and as a spatial base unit is suitable for monitoring and management at the meso-scale. Often the characteristics of a landscape are defined by prevalence, composition and specific spatial and temporal patterns of different land cover types. The spatial delineation of shifting cultivation agriculture represents a prominent example of a land use system with its different land use intensities that requires alternative methodologies that go beyond the common remote sensing approaches of pixel-based land cover analysis due to the spatial and temporal dynamics of rotating cultivated and fallow fields.Against this background we advocate that adopting a landscape perspective to spatial planning and decision making offers new space for negotiation and collaboration, taking into account the needs of local resource users, and of the global community. For this purpose we introduce landscape mosaicsdefined as new spatial unit describing generalized land use types. Landscape mosaics have allowed us to chart different land use systems and land use intensities and permitted us to delineate changes in these land use systems based on changes of external claims on these landscapes. The underlying idea behindthe landscape mosaics is to use land cover data typically derived from remote sensing data and to analyse and classify spatial patterns of this land cover data using a moving window approach. We developed the landscape mosaics approach in tropical, forest dominated landscapesparticularly shifting cultivation areas and present examples ofour work from northern Laos, eastern Madagascarand Yunnan Province in China.

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Southern China, especially Yunnan, has undergone high tectonic activity caused by the uplift of Himalayan Mountains during the Neogene, which led to a fast changing palaeogeography. Previous study shows that Southern China has been influenced by the Asian Monsoon since at least the Early Miocene. However, it is yet not well understood how intense the Miocene monsoon system was. In the present study, 63 fossil floras of 16 localities from Southern China are compiled and evaluated for obtaining available information concerning floristic composition, stratigraphic age, sedimentology, etc. Based on such reliable information, selected mega- and micro-floras have been analysed with the coexistence approach to obtain quantitative palaeoclimate data. Visualization of climate results in maps shows a distinct spatial differentiation in Southern China during the Miocene. Higher seasonalities of temperature and precipitation occur in the north and south parts of Southern China, respectively. During the Miocene, most regions of Southern China and Europe were both warm and humid. Central Eurasia was likely to be an arid center, which gradually spread westward and eastward. Our data provide information about Miocene climate patterns in Southern China and about the evolution of these patterns throughout the Miocene, and is also crucial to unravel and understand the climatic signals of global cooling and tectonic uplift.

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The Miocene Lincang leaf assemblage is used in this paper as proxy data to reconstruct the palaeoclimate of southwestern Yunnan (SW China) and the evolution of monsoon intensity. Three quantitative methods were chosen for this reconstruction, i.e. Leaf Margin Analysis (LMA), Climate Leaf Analysis Multivariate Program (CLAMP), and the Coexistence Approach (CA). These methods, however, yield inconsistent results, particularly for the precipitation, as also shown in European and other East Asian Cenozoic floras. The wide range of the reconstructed climatic parameters includes the Mean Annual Temperature (MAT) of 18.5-24.7 °C and the Mean Annual Precipitation (MAP) of 1213-3711 mm. Compared with the modern Lincang climate (MAT, 17.3 °C; MAP, 1178.7 mm), the Miocene climate is slightly warmer, wetter and has a higher temperature seasonality. A detailed comparison on the palaeoclimatic variables with the coeval Late Miocene Xiaolongtan flora from the eastern part of Yunnan allows us to investigate the development and interactions of both South Asian and East Asian monsoons during the Late Miocene in southwest China, now under strong influence of these monsoon systems. Our results suggest that the monsoon climate has already been established in southwest Yunnan during the Late Miocene. Furthermore, our results support that both Southeast Asian and East Asian monsoons co-occurred in Yunnan during the Late Miocene.