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必鲁甘干钼铜矿床位于内蒙古阿巴嘎旗境内,二连-东乌旗成矿带东段,自2007年发现以来,已探明钼金属量已超过16万吨,达到大型规模。矿床赋存于印支期花岗斑岩和二叠系上统林西组接触带附近,含矿带呈NNE向展布,向SE缓倾。必鲁甘干钼铜矿床成矿阶段可划分为早、主、晚三个阶段,早阶段以硅化和钾长石化蚀变及浸染状和星点状矿化为特征,矿化较强;主阶段以硅化和绢云母化蚀变和发育乳白色含矿石英脉为特征,矿化很强;晚阶段以硅化、碳酸盐化、青磐岩化和粘土化蚀变以及发育石英方解石细脉为特征,矿化较弱。石英中流体包裹体类型主要有富液相水溶液包裹体(L型)、富气相水溶液包裹体(V型)和富CO_2包裹体(C1和C2型)。早阶段发育大量L型和少量C1型包裹体,主阶段发育大量L型和C1型以及少量V型和C2型包裹体,晚阶段主要发育L型包裹体,个别样品发育少量C1型包裹体。早、主、晚阶段均一温度分别为210~354℃、182~351℃、128~312℃,盐度分别为3.6%~9.2%NaC leqv、2.6%~9.2%NaC leqv、2.8%~9.6%NaC leqv。主阶段成矿温度、压力为232~269℃、0.54~1.55kbar;三个阶段成矿深度分别约为8.1~5.8km、5.7~5.5km、3.9~2.6km。从早阶段到晚阶段,成矿流体由中温、中等盐度、富CO_2的NaCl-H_2O-CO_2体系向中低温、低盐度、贫CO_2的H_2O-NaC l体系演化。成矿流体在演化过程中由于周期性压力脉动而导致发生流体不混溶,其可能是成矿元素发生聚集、沉淀形成矿床的重要机制。由必鲁甘干钼铜矿床围岩蚀变("贫水蚀变")、成矿流体成分(NaCl-H_2O-CO_2体系)和成矿深度(主阶段成矿深度约5.7~5.5km)推测其属陆内环境斑岩矿床。 相似文献
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珠三角地区人口分布时空格局及其变化特征 总被引：7，自引：0，他引：7
采用人口增减变化、人口商度以及人口集聚度等方法,对珠三角地区1982、1990、2000和2010年4期人口普查数据进行了分析,定量揭示了珠三角地区近30年来人口分布的时空格局及其变化特征。结果表明：1）从人口总量变化来看,1982―2010年珠三角地区人口数量增加了3 821.66万人,增长率达215.61%,远超全国平均水平;2）从人口流动状态看,1982―2010年珠三角地区以人口流入为主,其中珠三角的中部以及东部城市成为人口流入的主要地区,人口迁移流入是珠三角地区总人口增加、人口集聚程度增高的主要原因之一,但近10年珠三角地区的人口流入速率有所减缓;3）从人口集聚度上看,1982―2010年珠三角地区县市人口集聚程度普遍高于全国平均水平,并逐年增高,深圳、广州、东莞等市已成为区域人口集聚中心。 相似文献
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【目的】分析湖光岩玛珥湖流场、温度、密度、浮性频率的三维空间结构、时间演变及其与风场的关系。【方法】于2017年1-4月,用三维超声风速仪、安德拉海流计、ADCP、CTD等进行每月一次的观测,对现场风速,流速、温盐等实测数据进行分析。【结果】表层平均流速为0.05 m/s,其中,表层的平均流速在1-2月为0.03 m/s,在3-4月较大,为0.08 m/s。流向以南向或东南向为主,与观测风向大致吻合。垂向上,次表层流速较小,为0.02 m/s,近底层流速有增大的趋势。1-2月观测表层温度为18.5~21.5℃,温度随深度的增加而下降。跃层主要出现在2~5 m,温度梯度为0.2℃/m。3-4月温度升高到19~26℃,温跃层加深,出现在6~10 m,温度梯度最大达到0.8℃/m。水深2 m处,近岸水浅站位表现为高温低密,12 m处部分深水站位呈现高温。 相似文献
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The relationship between population distribution and resources, environment and social-economic development has a significant influence on the human development. This paper set up a set of index system and model methods for the assessment of the coordination between population and resources, environment and social-economic development, and it quantitatively evaluated this coordination at the provincial scale in 2000 and 2010 respectively. Based on this set of index system, the suitability degree and the spatial-temporal pattern of population distribution at the provincial scale were carefully characterized. The restriction of population distribution at the provincial scale was graded and classified, and the coordinated development strategy of population, resources, environment and social economy was finally put forward. The results showed that:(1) The environmental suitability of population distribution at the provincial scale was generally high in China, which tended to be stable from 2000 to 2010.(2) The restriction of water and land resources at the provincial scale was generally strong in China, but it tended to be weak from 2000 to 2010.(3) The coordination degree between the social-economic development and population distribution at the provincial scale was mostly at a middle level, which was in the positive upward path from 2000 to 2010.(4) The suitability of population distribution at the provincial scale was mostly at a middle level, all of which was rising from 2000 to 2010.(5) The coordination degree between population distribution and resources, environment and social-economic development at the provincial scale was divided into four grades, including basic coordination, relative coordination, awaited coordination and urgent-needed coordination.(6) The basic ways to promote the coordinated development of population, resources and environment in different regions in China can be summarized as: implementing the strategy of population agglomeration and evacuation, guiding the orderly flow of population, optimizing the spatial distribution of population and drawing up the spatial planning of population development. 相似文献
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使用荆门站2006-2015年的大雾观测资料,从年际到月际、日际分别给出了该站点大雾发生的频次分布规律,并统计出大雾发生时及之前各气象要素场的特征,结合天气形势建立大雾的综合预报指标。结果发现,荆门市大雾主要为辐射雾,发生次数冬季最多,春季次之,秋季居中,夏季最少;08时(北京时,下同)之后持续出现1~3h的情况居多,超过5h的较少。前一日14时相对湿度≥50%,湿度越大,当日出雾可能性越大;若相对湿度≤40%,可以不考虑雾的发生。前一日02、08、14、20时与预报日当日02时这5个时次的风速均≤3m/s,当日出雾可能性较大。前几日内有降水发生,可增大预报日当日出雾概率;前一日20时天空无低云,对次日出雾有利。荆门市大雾发生时的天气形势可分为3种类型,即持续偏西气流型、弱脊过境型、槽后西北气流型;其中以槽后西北气流型出现最多,前两种类型发生的频率大致相等。 相似文献
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GPS高程拟合方法已广泛应用于各类工程测量中,是目前提高高程测量效率的有效手段。在地形复杂地区,利用分区拟合方法能更加客观地表达出似大地水准面的真实状况。以绥江县城新址边坡监测为例,利用分区拟合法进行高程拟合,并将其拟合结果与平面拟合法、二次曲面法、多面函数法、BP神经网络等经典拟合模型的拟合结果进行比较,得到分区拟合法在地形复杂地区具有更高的拟合精度的结论。 相似文献
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高分辨率遥感影像多尺度分割中最优尺度选取方法综述 总被引：1，自引：0，他引：1
目前,对高分辨遥感影像进行地物获取一般采用面向对象的理念,而影像分割是面向对象理念中至关重要的初始环节,分割结果的好坏将直接影响后续的分类工作,分割尺度的选取已经成为了当前研究的一个热点。本文详细总结了前人对高分辨遥感影像多尺度分割中最优尺度的获取方法,指出了各方法的不足之处,并提出了尺度评定的研究前景。 相似文献
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农户对气候变化适应行为的有效性评价 总被引：1，自引：1，他引：0
气候变化对以自然资源为生计基础的农业人口的影响非常显著,更好地理解农户对适应行为的有效性评价对于制定合适的适应政策、提高农民适应气候变化的能力非常重要。利用陕北黄土丘陵沟壑区农户调查样本数据,分析农户适应行为有效性感知特征,并结合调查地2000—2014年的统计年鉴数据中常用耕地面积和粮食产量指标,从客观层面验证适应行为的效果,最后运用多元线性回归分为3个模型辨识影响农户对适应行为有效性评价的显著因素。结果表明:(1)具有高适应效能感知的适应行为大部分被受访农户使用;2000—2014年研究区的粮食产量在波动中上升,说明适应行为有一定的实际效果;(2)影响农户对适应行为有效性评价的显著因素包括农户属性中的非农业收入、农业收入、种植规模、性别、看电视和赶集的频率,农户对气候变化的感知中的本地自然灾害变化、气候变化导致作物播种时间、收获时间、作物产量变化和病虫害,2005—2015年的降水等。 相似文献
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Studying the change in population distribution and density can provide important basis for regional development and planning. The spatial patterns and driving factors of the change in population density in China were not clear yet. Therefore, using the population census data in 2000 and 2010, this study firstly analyzed the change of population density in China and divided the change in all 2353 counties into 4 types, consisting of rapid increase, slow increase, slow decrease and rapid decrease. Subsequently, based on the partial least square(PLS) regression method, we recognized the significant factors(among 11 natural and social-economic factors) impacting population density change for the whole country and counties with different types of population change. The results showed that:(1) compared to the population density in 2000, in 2010, the population density in most of the counties(over 60%) increased by 21 persons per km2 on average, while the population density in other counties decreased by 13 persons per km2. Of all the 2353 counties, 860 and 589 counties respectively showed rapid and slow increase in population density, while 458 and 446 counties showed slow and rapid decrease in population density, respectively.(2) Among the 11 factors, social-economic factors impacted population density change more significantly than natural factors. The higher economic development level, better medical condition and stronger communication capability were the main pull factors of population increase. The dense population density was the main push factor of population decrease. These conclusions clarified the spatial pattern of population change and its influencing factors in China over the past 10 years and could provide helpful reference for the future population planning. 相似文献