内蒙古西部额济纳盆地土地荒漠化发展态势及其成因

为了查明额济纳盆地荒漠化的发展趋势及其成因,通过野外调查、遥感解译、样品测试及资料收集对比,从环境地质学的角度对额济纳盆地荒漠化的发展态势和成因进行了分析研究。结果表明：目前额济纳盆地土地荒漠化呈发展态势,环境在进一步恶化。认为荒漠化过程主要受区域地质环境条件变化的影响,全球气候变化、青藏高原隆升所引起的西北地区的干旱化趋势,是研究区荒漠化发生发展的决定性因素,盆地内的构造沉积背景决定着荒漠化的类型,水环境的变化直接影响着额济纳荒漠化的发生和发展速度。同时,当前人为因素对地质环境的影响很大,人类对水资源和土地资源的不合理利用,加速了荒漠化的发展速度。     

GPS测量技术在海阳市城区控制中的应用研究

通过海阳市城区D级GPS控制网的布设,探讨了GPS控制网的布网方法和要求,阐述了GPS外业观测的质量控制措施,基线处理方法及其精度检验,讨论了已知控制点的选用方法,以及平差中应注意的问题等。     

甘肃武山温泉辉钼矿Re-Os同位素定年及其成矿意义

温泉钼矿是与印支期花岗岩有关的斑岩型钼矿床.5件辉钼矿的Re-Os同位素定年结果显示,辉钼矿Os模式年龄在212.7±2.6～215.1±2.6 Ma,其加权平均值为214.1±1.1Ma,由ISOPLOT程序获得的等时线年龄为214.4±7.1 Ma.该年龄与温泉岩体的K-Ar年龄223～226 Ma和SHRIMP U-Pb锆石年龄223±7 Ma在误差范围内类似,但偏晚,反映Mo矿化主要发生在岩浆侵入-成岩的晚期阶段.西秦岭富Mo的背景的基底岩石重熔和岩浆的分异演化对Mo的矿化具有重要意义.温泉型钼矿的发现对西秦岭印支期花岗岩成矿潜力评价具有重要的启示和指导作用.     

谈大破大立

在1958年地质设計会議上,我們对1958年任务(钨加錫15000吨)是沒有信心的。根据“权威”的論断,粤北以黑鎢为主,所有著名矿区的儲量,加起来也不过二、三千吨;已知的錫矿,除已开采的矿区外,都是几十吨、几百吨的小矿。部分地质人員說:“我們那里大片花崗岩露出地表,侵蝕很深,錫矿远     

四川盆地龙马溪组页岩微裂缝发育的“甜点”效应与机制

系统认识和明确页岩“甜点”层段中有机质和脆性矿物促进微裂缝发育的效应和机制,对于提高水力压裂效率,促进页岩气增产稳产具有重要的工程实践意义。本文系统调研了国内外页岩中有机质和脆性矿物控制下的裂缝发育机理等的研究成果,结合数值模拟,对四川盆地龙马溪组页岩“甜点”层段中微裂缝发育的效应和机制进行了全面剖析和探究。研究结果表明：四川盆地龙马溪组页岩特殊的沉积背景为裂缝的发育提供了良好的物质基础。其中有机质的不同成熟度阶段、空间分布和形状、丰度和有机孔隙都在不同程度上控制着微裂缝的形成和发育。脆性矿物在岩石破坏过程中能量的高效转化和良好的脆性响应机制,促进了裂缝的复杂化。少量裂缝的发育还受控于有机质和脆性矿物接触的力学边界、有机酸的溶蚀以及脆性矿物的嵌入等相关效应与机制,进一步突显了裂缝成因的复杂化。由此,建议未来关于页岩储层的脆性评价工作向多元组分的精细化方向发展,同时注重微米—纳米尺度下有机质和脆性矿物力学性质的表征,对于促进并深化页岩破裂机理的认识具有一定的研究价值。     

西藏南部花岗岩类稀土元素地球化学

REE abundances of granitoids in Southern Xizang were estimated to be within the range of 190 ppm (REE oxides), which are much lower than the average REE abundance of intermediate-acidic intrusive rocks in the crust. The REE abundances show a progressive decrease from late Yenshanian to late Himalayan (195--128 ppm). Four types of REE distribution patterns have been distinguished: (1) rightly deelined smooth curves, showing little Eu anomaly (δEu-values are 0.78-0.95) and relative enrichment of heavy REE (Diorite and granodiorite, fore example, are characterized by such a pattern) ; (2) rightly declined V-shape curves, displaying negative Eu anomaly(δEu: 0.50--0.70) (Biotite-granite shows sneh a pattern.) ; (3) righly declined V-shape curves with noticeable Eu anomaly (δEu : 0.36--0.39) (Two-mica granite and tourmalinemuscovite granite possess this pattern) ; and (4) rightly declined V-shape eurves with strong Eu anomaly (δEu : 0.27--0.86) (Porphyritie biotite-granite has such a pattern). In summary, the granitoids in this given area could be divided into two types, i. e.,the abyssal type (e. g. diorite, granodiorite) and the hypabyssal type (e.g. two-mica granite and tourmaline muscovite granite).     

从中酸性的岩浆活动论西藏高原地壳运动特征

In view of their distinct NWW trending and their decreasing geological age from north to south, intermediate-acid magmatic rocks in the southern part of Xizang can be divided into three petrographical belts in general: (1) the Kangdese belt (120--10 m.y.). The major part of the belt is mainly composed of diorite, granodiorite, etc.,more intermediate in chemical composition and ranges from 120---70 m. y. in age; (2)the Lhangoi Kangri belt (30 m. y.) ; and (8) the Himalaya belt (20--10 m. y.). From their intruding features, spatial-temporal consistency, intruding scale, petrological characters and chemical Composition, it is suggested that these three petrographical belts secm to be closely related to plate underthrust and collision. It may be concluded that the major part of the Kangdese belt is resulted from the underthrust of the Indian Ocean Plate towards the Eurasian Continental Plate while the Lhagoi Kangri belt and the Himalaya belt are the results:of collision of the Indian sub-Continental Plate overlying the .Indian Plate with the Eurasian Continental Plate.     

2012年中国沿海海平面上升显著成因分析

2012年,中国沿海海平面变化最突出的特点是海平面升高显著。海平面总体比常年高122mm,较2011年偏高53mm,达1980年以来最高位。本文使用中国沿海及西北太平洋区域近30a的水位、海温、气温、气压和风等水文气象资料,详细分析了中国沿海海平面2012年异常偏高的成因。结果表明:2010-2012年中国沿海海平面处于2~3a、8~9a和准19a周期震荡的高位,几个周期震荡高位叠加,对海平面上升起了明显的影响;2012年,沿海气温和海温分别较常年偏高0.4℃和0.3℃,气压较常年低1.2hPa,气压达历史最低位;2012年,中国南海夏季风爆发时间较常年偏早,结束较常年偏晚,季风持续时间较常年偏长,导致2012年5-6月和8月,在黄海和东海海域,东北风持续偏强,南海海域南风偏强,风场的异常导致黄海、东海和南海沿海海水长时间堆积,是造成海平面升高的原因之一;2012年,热带气旋登陆时间集中,影响范围广,北上和影响东北地区的台风数量均为历史之最,特别是2012年8月,有6个热带气旋相继影响我国沿海,对当月海平面升高影响明显;另外,2012年副热带高压偏北、偏东、偏弱的特点对东海和南海的海平面上升也有一定影响。     

1982–2010年中国草地覆盖度变化及其与水热因子耦合性研究(英文)

GIMMS(Global Inventory Modeling and Mapping Studies) NDVI(Normalised Difference Vegetation Index) from 1982 to 2006 and MODIS(Moderate Resolution Imaging Spectroradiometer) NDVI from 2001 to 2010 were blended to extract the grass coverage and analyze its spatial pattern. The response of grass coverage to climatic variations at annual and monthly time scales was analyzed. Grass coverage distribution had increased from northwest to southeast across China. During 1982–2010, the mean nationwide grass coverage was 34% but exhibited apparent spatial heterogeneity, being the highest(61.4%) in slope grasslands and the lowest(17.1%) in desert grasslands. There was a slight increase of the grass coverage with a rate of 0.17% per year. Increase in slope grasslands coverage was as high as 0.27% per year, while in the plain grasslands and meadows the grass coverage increase was the lowest(being 0.11% per year and 0.1% per year, respectively). Across China, the grass coverage with extremely significant increase(P0.01) and significant increase(P0.05) accounted for 46.03% and 11% of the total grassland area, respectively, while those with extremely significant and significant decrease accounted for only 4.1% and 3.24%, respectively. At the annual time scale, there are no significant correlations between grass coverage and annual mean temperature and precipitation. However, the grass coverage was somewhat affected by temperature in alpine and sub-alpine grassland, alpine and sub-alpine meadow, slope grassland and meadow, while grass coverage in desert grassland and plain grassland was more affected by precipitation. At the monthly time-scale, there are significant correlations between grass coverage with both temperature and precipitation, indicating that the grass coverage is more affected by seasonal fluctuations of hydrothermal conditions. Additionally, there is one-month time lag-effect between grass coverage and climate factors for each grassland types.     

基于Hyperion影像的土地沙漠化研究

使用遥感影像数据可以提取土地沙漠化信息,通过遥感影像所表现的不同信息,可以判断土地沙漠化的发生及其发展程度等。针对EO-1Hyperion高光谱遥感影像成像的特点,探讨高光谱Hyperion影像的预处理和土地沙漠化的计算方法,研究中采用像元二分法从高光谱EO-1 Hyperion影像反演了土地沙漠化。