重力位余弦变换谱基本特征

为获得重力异常余弦变换谱的通式,提出并证明了3个定理;利用它们推导了点质量和直立矩形柱体的重力异常余弦变换谱理论公式,同时给出了重力异常余弦变换谱通式。分析了点质量和直立矩形柱体重力异常余弦变换谱的基本特征：点质量二维余弦变换谱等值线呈1/4同心圆形状,等值线随着波数的增大而变稀;直立矩形柱体谱出现了周期性变化的零等值线,该等值线将非零等值线划分为a×b个矩形区域,而且等值线值在各矩形型区域中正负交替变化,随着波数的增大,不同的矩型域中等值线值呈e指数衰减特征。     

统计地球化学的若干理论问题

本文把地质体中微粒运动表述为连续马尔科夫过程,建立了地质体中元素转移概率方程:把地质采样抽象为理想采样,建立了元素含量分布公式;把矿体分解为临界矿体,建立了储量分布公式。从而获得了地质体中元素的空间分布公式、成矿过程公式、元素对比值分布公式、矿床边界品位公式和区域成矿率公式。     

Angstrom公式参数对ET0的影响及FAO建议值适用性评价

作为计算太阳总辐射(R_s)的主要公式,Angstrom公式参数(a、b)的合理取值是计算参照腾发量(ET₀)的重要前提。针对FAO所提出的a、b建议值(a=0.25、b=0.5)在中国无辐射观测资料地区被大量使用,而其合理性尚未得到系统评价的情况,基于中国104个地面站的观测数据,在逐月时间尺度上,讨论了a、b变化对ET₀的影响,分析了a、b的地区分布规律,评价了FAO建议值所导致的ET₀计算误差,进而阐明了该建议值在中国7个区域的适用性。提出了无辐射资料情况下a、b的地区综合取值方法。主要研究结论是:①参数a、b偏差对ET₀的计算有重要影响,在中国无资料地区采用FAO建议值将导致较大的太阳总辐射(R_s)和ET₀计算误差。②大多数站点,a的率定值较FAO建议值明显偏小,而b的率定值明显偏大。新疆地区和华南地区a、b率定值分布比较集中,而在其它区域比较分散。③FAO建议参数值在东北、西北和新疆3个区域计算ET₀的适用性较好,而在西南和华南两个区域的适用性很差,计算的ET₀偏高较大。④提出的地区综合取值方法,能使R_s和ET₀的计算精度较FAO建议值显著提高。     

针对穿越重要构筑物时减少潜在水压裂隙的水平定向钻进设计

水平定向钻进管线安装的设计经常需要对钻进轨迹穿过土层的潜在水压裂隙进行评估。当轨迹穿过一个重要构筑物的下方（例如蓄水坝）时这种潜在的裂隙可以成为一个重要的设计因素。如果下层土体的水压裂隙引起钻井液流到地表,所造成的冒浆会引起水渗漏或者引发基础土体的破坏。因此,相关管理机构需要一份非常详细的关于水平定向钻进穿越过程中潜在水压裂隙和冒浆的评估。在研究HDI）穿越的水压裂隙模型过程中,对于抵抗水压裂隙和冒浆的安全系数的一个重要影响因素是土层的屈服强度。如果HDD穿越定位在高屈服强度的土层,潜在的水压裂隙将减少。该研究比较了两个HDD穿越的水压裂隙模型。第一个穿越的亚表土由中等密实的粘土纽成直到最大切削深度。第二个穿越的地下条件由中等密实的粘土覆盖在中等密实到非常密实的砂层。通过定位于密实砂层,水压裂隙和冒浆模型的结果表明较高安全系数的重要性。     

大采高综放开采覆岩破坏特征和裂隙演化规律

工作面回采过程中,覆岩破坏特征对于煤矿水灾害和瓦斯防治具有重要意义,为了进一步研究综放开采覆岩破坏特征。以山西某矿5.82m大采高工作面为试验面,采用分段注水、钻孔电视、地质雷达、微震监测探测覆岩破坏高度,对破坏过程进行了数值模拟研究,并对裂隙演化进行了相似模拟试验,同时对传统经验公式进行了修正,研究结果表明:综放开采垮落带发育高度为43.1m,断裂带发育高度为86.7m;垮落带、断裂带、导水断裂带各测试方法之间相差分别小于4.5%、7.1%、9.0%;工作面采动前,裂隙发育度低,而采动后,裂隙数量明显增多,发育度增加;近煤壁区域为裂隙聚集区,密度曲线呈“蛇”型分布;得到新的适合该矿地质条件下的覆岩导水断裂带发育高度经验公式。     

水底隧道涌水量预测方法的应用分析

讨论了水底隧道涌水的预测计算问题,利用经验法和有限元法对某拟建海底隧道工程方案的涌水量进行了预测计算和对比分析,探讨了竖向和水平走向裂隙发育情况对隧道涌水的影响。结果表明:①与有限元相比,用经验公式计算得到的水底隧道涌水量偏小;②当水底岩层张性裂隙(尤其是竖向裂隙)较发育时,隧道涌水量增长较大;③当隧道临近或穿越断层破碎带时,隧道周边的渗流场具有显著的三维特征;④如果水底隧道上覆地层中没有显著的隔水层,则由于水源无限充足,隧道的涌水量将主要受到水位相对高度和隧道围岩渗透系数的影响,与隧道上覆地层的厚度关系不大。     

基于GIS的甘肃北山花岗岩裂隙密度地质统计分析

以甘肃北山花岗岩中发育的构造裂隙(主要指节理)为研究对象,采用高精度GPS、罗盘等对其进行现场测量,获取裂隙的迹长及产状信息,并将信息导入ArcGIS平台建立裂隙属性数据库; 进而应用地质统计分析理论,以裂隙面密度P21为地质统计分析的区域性变量,探索花岗岩岩体裂隙空间分布特征; 然后借助ArcGIS软件平台建立变异函数模型,利用地质统计学的普通克里金插值方法得到整个区域的面密度预测分布图。结果表明:芨芨槽块段所测某区域裂隙面密度值的半变异函数变程值在20～30m之间,NS和EW方向有明显差异,由此知该区域裂隙面密度分布具有显著空间自相关性,但分布特征不均匀; 此结论对北山花岗岩裂隙空间分布特征的深入研究以及三维裂隙网络建模具有重要参考价值。     

青藏高原多年冻土区典型高寒草地生物量对气候变化的响应

多年冻土区冻土生态系统对气候变化极其敏感,利用在长江黄河源区实测的高寒草甸和高寒草原植被生物量数据以及青藏高原降水、气温以及地温等的空间分布规律,建立了长江黄河源区高寒草甸与高寒草原等主要高寒生态系统地上与地下现存生物量对气候要素变化的多元回归模型.预测分析表明:如果未来10 a气温增加0.44℃·(10a)^-1,在降水量不变的情况下,高寒草甸和高寒草原地上生物量分别递减2.7%和2.4%,如果同时降水量小幅度增加8 mm·(10a)^-1,则地上生物量可基本保持现状水平略有减少;在气温增加2.2℃·(10a)^-1,在降水量不变的情况下,高寒草甸和高寒草原地上生物量年分别平均减少达6.8%和4.6%,如果同期降水量增加12 mm·(10a)^-1,高寒草甸地上生物量可基本维持现状水平略有增加,而高寒草原地上生物量则递增5.2%.高寒草原植被地上生物量对气候增暖的响应幅度显著小于高寒草甸,而对降水增加的响应程度大于高寒草甸.明确高寒草地植被生物量随气候变化的演变趋势,对于青藏高原生态环境保护和研究气候变化对青藏高原生态系统碳循环和河源区水循环的影响具有重要意义.     

中低渗高阶煤煤岩毛管压力数学表征

毛管压力对煤层气开发具有重要意义。为定量表征中、低渗高阶煤煤岩毛管压力曲线,开展了中、低渗高煤阶煤岩高压压汞实验,利用得到的毛管压力数据回归建立了新的毛管压力曲线双参数和单参数数学模型,并研究了参数a、b间关系,以及参数a、b对毛管压力的影响及其影响因素。结果表明,本研究拟合建立的新毛管压力模型能够很好地拟合中、低高阶煤样的高压压汞实验测试得到的毛管压力数据,拟合程度达到98%以上,为定量表征高阶煤储层毛管压力提供了经验公式。根据本文建立的新毛管压力经验公式,在以SHg为横坐标,以lnPc-lnPmin-ln(SHg^0.5)为纵坐标的在直角坐标系中,SHg与lnPc-lnPmin-ln(SHg^0.5)成幂指数关系lnPc-lnPmin-ln(SHg^0.5)=aSHgb,因此可通过最小二乘法拟合计算参数a和b值,进而可以得到相应煤样的毛管压力数学模型。参数a和b呈负幂函数关系,其关系式为,基于该关系式,可进一步得到单一参数毛管压力数学模型为,则lnPc-lnPmin-ln(SHg^0.5)和在双自然对数坐标中成线性关系,通过最小二乘法进行线性回归得到直线斜率即为b值,进一步简化了毛管压力模型。利用新数学模型开展数值模拟,发现煤样毛管压力随参数a和b增加而增加;参数a和b与孔渗的关系表明,参数a随渗透率、孔隙度增加而降低,成线性关系,而参数b则随渗透率、孔隙度增加而增加,均成指数关系。     

新疆南天山高压变质岩石的抬升机制

对南天山蓝片岩的变质作用p-T-t轨迹、蓝片岩和相关岩石的构造变形特征以及区域地质特征的综合研究表明,南天山高压变质岩石经历了两个抬升阶段。早期阶段,蓝片岩在增生楔下部的下地壳深处滞留了约100Ma,仅因浮力作用发生轻微抬升,速率约0.05-0.1mm/a。晚期阶段,推覆作用和剥蚀作用快速抬升蓝片岩浅构造层次,速率可能大于1-2mm/a,以致保存蓝闪绿片岩相矿物组合。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861