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长白山玄武岩区地热异常区遥感识别 总被引：1，自引：0，他引：1
利用Landsat TM5遥感影像多光谱和热红外数据,对长白山玄武岩区地表温度场进行了反演。在此基础上,综合分析了研究区地表温度场、温泉和地热井分布特征、布格重力场及磁场4个因子,采用判别分析方法建立并验证了判别函数,对研究区地热异常区进行了识别。研究结果表明:研究区地表温度异常区主要分布在长白山天池火山口周围,此外,在区内3个中生代沉积盆地(抚松盆地、松江盆地和长白盆地)也有孤立状的高温区域分布,地表温度异常像素所占比例为2.993%;研究区潜在地热资源异常区可分为环长白山天池火山口区域、松江河—抚松县及二道白河—松江镇一带的抚松盆地和松江盆区、仙人桥地区以及长白县—十四道沟一带的长白盆地区,其中环长白山天池火山口区域地热潜在概率值均大于0.9,最大值达到1.0。该研究为地热异常区的识别提供了一条新的思路。 相似文献
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贵州典型喀斯特地貌区农村聚落空间分布研究——以清镇红枫区、毕节鸭池区和关岭-贞丰花江区为例 总被引：7，自引：3，他引：4
为探索贵州喀斯特地貌区农村聚落空间分布的特点,选取具有代表性的清镇红枫区(高原盆地地貌区)、毕节鸭池区(高原山地地貌区)以及关岭—贞丰花江区(高原峡谷地貌区)三个典型区域作为研究对象。首先利用区域重心分析的方法,以聚集维数和聚集维数图来分析各研究区的聚落在区域重心上的集聚程度,再进一步通过GeoDa软件,使用Moran I和LocalMoran's I系数及相应散点图分析区域聚落整体和局部的分布情况。分析结果表明,高原山地区和高原盆地区聚落均存在集聚性,且集聚程度存在内部差异,其中高原山地区聚落向人口重心集聚,高原盆地区聚落向住宅重心集聚,集聚和半集聚聚落在高原盆地区最多。由于喀斯特地形复杂,各个研究区内部聚落在水平空间分布上均存在一定差异,依照集聚程度不同喀斯特地貌区农村聚落的分布规律为高原盆地区＞高原山地区＞高原峡谷区。 相似文献
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北方槽区泥盆纪生物地理区的特征 总被引：5，自引：0，他引：5
<正> 1977年,北方槽区古生代地层会议之后,《地层学杂志》(1979年,3卷3期)发表了“天山—兴安区古生代地层研究新进展”(以下简称“进展”)一文,提出了一些新颖的见解,反映了我国当前北方槽区地层古生物研究的水平。对“进展”一文提出的泥盆纪时,北方槽区“实为介于旧世界区和阿伯拉阡区之间的一个独立生物地理区”的论断,笔者认为有商榷的必要。因为它涉及到生物地层学研究的一些概念问题。 相似文献
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通过进行岩溶区和非岩溶区牧草田间对比试验,测定植被在生长季内(6-8月)的养分动态变化,并结合N/P化学计量学的原理和方法,研究了岩溶区牧草的养分限制状况。结果表明:(1)在生长季节的6-8月,岩溶区4种牧草N、P养分浓度都具有显著的随月份的增长而减少的趋势。从岩溶区和非岩溶区所测定的4种牧草养分结果来看,岩溶区牧草的N素平均值为22.79mg/g,非岩溶区牧草的N素略小于岩溶区,为22.15mg/g;岩溶区的P素平均值为6.03mg/g,非岩溶区牧草的P素小于岩溶区,为5.35mg/g。(2)无论是岩溶区还是非岩溶区,牧草的N/P与N的相关性最大,相当系数都大于0.6,与非岩溶区不同的是,岩溶区牧草的N/P与Ca的相关性也很大,而非岩溶区的则较小。(3)岩溶区牧草植物体Ca、Mg总含量分别是非岩溶区的2和1.5倍。不同种类的牧草对Ca、Mg的吸收和累积能力有较大的差异,本研究中的类玉米其钙含量远远小于其它3种牧草的钙含量。 相似文献
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“四深”微生物是指深海、深地、深空和深时环境的微生物,特别是细菌、古菌、真菌、病毒等。人们对“四深”微生物的了解非常有限,是亟待突破的地球生物学前沿领域。“四深”微生物的研究对理解地球生命起源、界定生物圈的边界条件、促进地球科学与生命科学以及行星科学之间的交叉融合具有不可替代性的贡献。随着我国深海、深空、深地等重大工程计划的推进,一系列与“四深”微生物有关的前沿科学问题不断提出,包括地质微生物与气候环境的相互作用、地质微生物的生物安全与生态安全、地质微生物参与的隐匿地质过程等。特别是,“四深”环境活性氧自由基对微生物的影响、地质病毒对生物演化和地质过程的影响等前沿领域都亟待突破。活性氧自由基能对生物分子、细胞、组织和器官,乃至整个生物圈的演化以及微生物地质作用都产生重要影响。病毒引发了现代和近代诸多全球性疫情爆发,地质病毒则可能对生物的背景灭绝和大灭绝以及一些地质过程产生影响。 相似文献
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Zuwei WANG Xin LIU Hui ZHANG 《中国地球化学学报》2006,25(B08):86-86
Four soluble inorganic salts were used to examine their influences upon cadmium forms in the alkaline soil and the contents of cadmium absorbed by plants. After KCl solution added in the soil, the contents of effective form of cadmium in the soil increased from 28% to 122%, carbonate form decreased from 2% to 47%, iron-manganese oxidation form increased from 20% to 150%. As to the organic combination form, when the KCl solution of lower concentration was added in the soils, the organic combination form contents of cadmium would decrease, while the KCl solution of higher concentration was added in the soils, the organic combination form contents of cadmium would increase. After CaCl2 solution was added in the soils, the contents of effective form of cadmium in the soils increased from 7% to 33%, the carbonate form contents of cadmium decreased from 10% to 60%, the contents of the iron-manganese oxidation form of cadmium increased from 5% to 90%, the organic combination form of cadmium increased from 5% to 73%. After KH2PO4 solution was added in the soils, the contents of effective form of cadmium in the soils decreased from 20% to 46%, the carbonate form contents of cadmium decreased from 14% to39%, the contents of the iron-manganese oxidation form of cadmium increased from14% to 95%, the organic combination form of cadmium increased from 5% to 65%. After K2CO3 solution was added in the soil, the effective form contents of cadmium decreased from 5% to 22%, the carbonate form contents of cadmium increased from 12% to 64%, the contents of organic combination form of cadmium in the soils were similar to those of the carbonate form, increasing by 3%-38%. The content variation of the iron-manganese oxidation form of cadmium was slight after K2CO3 solution was added in the soils. 相似文献
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Paul L. Younger 《Geoforum》2007,38(5):828-840
Pro-poor water engineering aims to deliver water services to individuals and communities in a manner that yields obvious and significant net-benefits to the poorest people. Technology transfer in the field of pro-poor water engineering has too often been seen as one-way (north to south), with industrialised nations exporting their supposedly superior technologies and organisational priorities to the ‘grateful poor’ in the under-developed world. While north-to-south technology transfer can boast significant successes, failures are more numerous, arguably due to the contrast between technocratic (northern) and communitarian (southern) traditions of water management. There is much the northern countries might learn from the southern perspective. One concrete example illustrates how direct experience of community-based, NGO-fostered development of borehole water supplies in Bolivia led to the conscious adaptation of this model for application to problems of remediation of severe contamination of streams in a former mining district in the UK. This application was highly successful, leading to the development of robust community organisations that have gone on to tackle other social and environmental problems. This experience has in turn prompted the testing of the low-cost, technological approaches to acid drainage treatment developed in the UK case for potential application to similar problems in Bolivia. Following further ‘acclimatisation’ of the technology, field trials proved successful and led to plans for full-scale application of the approach with community-based NGOs in Bolivia. Lessons are drawn for furthering the implementation of pro-poor, participative strategies in water management in both the North and the South, with brief critical analyses of Participación Popular in Bolivia, and of both policy and polity in relation to community engagement in aspects of water management in Europe. 相似文献
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新疆准噶尔晚古生代陆壳垂向生长（Ⅰ）——后碰撞深成岩浆活动的时限 总被引：71，自引：56，他引：71
准噶尔是新疆北部古生代造山带的重要组成部分，以广泛发育晚古生代后碰撞花岗岩为特征，是中亚造山带中显生宙陆壳生长作用非常显著的地区之一。根据新近获得的SHRIMP锆石U-Pb年龄，并参考已经发表的锆石U-Pb年龄，本文重新厘定了准噶尔晚古生代后碰撞深成岩浆活动的时限。按照最新的国际地质年表中石炭纪和二叠纪划分方案（Gradstein et a1．，2004），准噶尔后碰撞深成岩浆活动是从早石炭世中-晚维宪期开始、于早二叠世末期结束的。东准噶尔后碰撞深成岩浆活动发生在330-265Ma之间，而西准噶尔后碰撞深成岩浆活动的时限在340-275Ma之间，持续时间分别约65Ma。但是，在东准噶尔，后碰撞深成岩浆活动集中在330～310Ma和305～280Ma两个时段发生，而在西准噶尔，后碰撞深成岩浆活动的高峰发生在310～295Ma之间。准噶尔晚古生代后碰撞深成岩浆活动在空间上没有受到重要地质界线（如蛇绿岩带）的分隔控制，在有的地方花岗岩还可以侵位在蛇绿岩带之中。而晚古生代后碰撞深成岩浆活动不但在准噶尔分布广泛，而且在准噶尔北邻的阿尔泰造山带和南邻的天山造山带中均有出现，具有广泛的区域性。 相似文献
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Benjamin R. Jordan Haraldur Sigurdsson Robert Rogers 《Geochimica et cosmochimica acta》2007,71(14):3581-3591
An analysis of 70 samples, collected from Miocene-age ignimbrites in 68 locations in Nicaragua and Honduras, indicates that geochemical processes and a subduction zone geometry similar to those in the modern arc were also present in the paleoarc. Samples were plotted along two transects, parallel and perpendicular to the inferred paleoarc. Most of the oxide plots exhibit flat profiles along the arc from NW to SE, except for SiO2, which decreases. FeO, CaO, TiO2, and MgO increase from NW to SE. There are no clear trends in the oxides from SW to NE, except K2O. K2O increases to the SW. Most trace elements show little to no variation along the province from NW to SE, with the exception of La, Ce, Rb, Ba, Th, Nb, Ta, Pb, and Sr, which all appear to decrease in abundance from NW to SE. While Ba increases to the SW, toward the paleotrench, it also shows remarkable variation parallel to the arc, with highs in Nicaragua, and decreasing concentrations to the NW and SE. This trend is especially apparent in Ba/La with lows near 1 in the NW and highs approaching 80 in Nicaragua. This trend is similar to that of the modern arc, which suggests that the geometry of the arc in the Miocene was very similar to that of the modern arc. In addition, the data also becomes more scattered to the southeast as a basement boundary is crossed (determined by gravity-anomaly mapping), probably due to a higher degree of contamination by continental crust. 相似文献
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南疆近60 a来冰雹灾害时空变化特征分析 总被引：4，自引：1，他引：3
冰雹是新疆主要灾害性天气之一, 利用新疆南疆各地州1949-2008年发生的冰雹频次及其造成的受灾农田面积、 经济损失、 死亡牲畜等资料, 分析了南疆冰雹频次时空变化特征及各县市雹灾灾情.结果表明: 南疆冰雹发生频次近60 a间呈明显上升趋势, 1950年代至1980年代中期发生频次较低, 1986年开始发生频次显著上升, 至1991年达最高值, 由1996年起又减少到2003年谷底.冰雹发生主要集中在3-10月, 其中6月频次最多, 年均3.6次, 其次5月为3.1次. 巴州、 阿克苏、 喀什和克州以春末到夏季型降雹为主, 和田以春季型降雹为主.冰雹一天之内多发生在白天到傍晚时段, 持续时间多为1~20min. 南疆冰雹空间分布上西北部多于东南部, 山脉的背风坡多于迎风坡, 山间盆地多于开阔平原.对各地州而言, 阿克苏冰雹发生频次最多, 属于严重雹灾区; 喀什和巴州次于阿克苏, 属于重雹灾区; 克州与和田冰雹发生频次较少, 属于中雹灾区. 冰雹受灾农田面积和经济损失随着工农业生产总值的增长而增加, 而且增长速度比经济增长速度快. 建议加大防雹投入力度, 建立人工防雹系统, 以减少雹灾损失, 遏制工农业发达地区雹灾损失严重和随着国民经济的增长雹灾损失增加的现象. 相似文献
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关于沉积学发展的思考 总被引：13，自引：0，他引：13
笔者对地质学领域中一些学科近10多年以来的突破性进展做了扼要的评述,以及对沉积学发展中一些重要事件做了简短的回顾之后,提出了在当前高新科技时代有关研究工作的一些看法。认为在沉积学的研究中,必须采用高新技术,与其它学科同步进入高科技时代;要更新传统的观念;研究中注意学科渗透交叉,发展新的学科分支;注意全球变化的研究;研究工作要更加密切结合经济发展的需要。 相似文献
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Critiques of the neoliberal governance of agricultural systems have led to a number of political responses which attempt to address the socio-environmental consequences of the dominant regime. In this paper two case study regions (South Australia and England) have been chosen to represent variations in agricultural policy and to highlight subsequent outcomes on the sustainability of agriculture. Interviewed governance stakeholders highlighted issues in regard to the agricultural governance of each area, from social and environmental consequences of minimal policy intervention in South Australia, to issues created by greater economic support in England. As such, the distinct variations in agricultural regimes will continue to demand scholarly attention, in order for the value of diversity within the sector to be more widely understood. The study concludes that it is likely agricultural support will continue to decline in both case study regions. Importantly, however, innovative policy mechanisms that aim to reduce local risks and value local agricultural priorities, without requiring significant financial support, might be the most promising way forward in regard to agricultural system sustainability. 相似文献
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华南加里东运动初探 总被引：12，自引：0，他引：12
华南加里东运动包含了郁南运动、北流运动(崇余运动)和广西运动,具多幕陆内造山特点。其影响范围包括扬子板块东缘"江南隆起"以东、以南广大地区。华南加里东构造带总体呈东西向展布,南部桂西右江盆地-粤南地区泥盆系不整合于下伏的寒武系之上,中部桂东-粤中-闽西-赣南-湘南地区泥盆系不整合于奥陶系之上,靠近"江南隆起"的湘中-浙西地区泥盆系不整合于志留系之上,但钦防盆地志留系与泥盆系整合接触。寒武系-志留系为同造山盆地的复理石沉积。从寒武纪-志留纪同造山盆地由南向北迁移,盆地展布、物源供给等显示"南山北盆"的盆山格局和造山带"由南向北"挤压的趋势。 相似文献
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Rice research for food security and sustainable agricultural development in Asia: Achievements and future challenges 总被引：1，自引：0，他引：1
Rice is the major staple food of Asia, and an important source of employment and income in rural areas, particularly in low-income countries. Research has contributed significantly in achieving food security by increasing the yield potential of rice in irrigated systems, reducing the crop maturity period and achieving yield stability by developing resistance against major insects and diseases in the modern high-yielding varieties. Poverty is, however, still extensive in fragile rainfed rice ecosystems where rice yield has remained low, as scientists have yet to develop high-yielding varieties resistant to abiotic stresses and problem soils. Rice production needs to be increased by another 70% over the next 30 years to meet growing food needs. This has to be achieved with less land, less water, and less labor to accommodate the demand for these inputs from the expanding nonagricultural sectors. The challenge to the rice research community is to make further shifts in yield potential of rice for the irrigated systems, to close the yield gaps in the rainfed systems through developing resistance of high yielding varieties to abiotic stresses, and greater understanding of the interactions between genotypes and environment, developing durable resistance against pests and diseases to reduce farmers' dependence on harmful agrochemicals, and to increase efficiency in the use of water, labor and fertilizers. As further intensification of rice cultivation is inevitable, scientists must understand the negative environmental side-effects of increasing rice productivity, to develop appropriate mitigation options. 相似文献