超高密度电阻率法在隐伏断层探测中的应用

将超高密度电阻率法用于某水库坝址区隐伏断层探测。介绍了测区地质及测线布置情况,采用汉克尔变换方法模拟了层状介质模型视电阻率响应,通过反演计算结合地质钻孔资料,确定了基岩埋深及区域断层的走向。断层破碎带在电阻率剖面中呈现明显斜立条带状低阻异常,其产状与地质及钻孔资料一致,验证了超高密度电法探测的有效性。     

井下瞬变电磁法在煤矿陷落柱探测中应用

潘三矿12318面在回采过程中发现一陷落柱,为查明其分布范围、赋水、导水情况,采用井下瞬变电磁法进行探测。基于矿井内切眼、风巷、机巷的位置,采用U型观测系统布设了三条测线。将不同方向视电阻率断面图进行对比,解释该陷落柱距风巷的垂直距离在70m左右。依据视电阻率断面图高阻值在面内延伸的形态,确定了该陷落柱的长轴方向及分布范围,并断定其无富水异常。经钻孔验证,与解释结果一致,表明瞬变电磁法应用于井下进行陷落柱探测具有较高的准确性。     

矿井瞬变电磁法在水文钻孔探测中的应用

探讨了用矿井瞬变电磁法探测采煤工作面内部和掘进巷道前方的水文钻孔的位置,对其富水性进行了定性评价,总结出水文钻孔在视电阻率断面图上的响应特征,即在顺煤层方向呈圆形异常反映,而在煤层顶、底板方向呈狭长椭圆形特征。该方法在探测隐伏含水陷落柱构造方面也有较好的应用前景。     

井下瞬变电磁法在巷道底板含水性探测的应用

某矿井目前主要开采山西组煤,为保证下部太原组煤的安全开拓,需查明其底板的水文地质条件。根据该矿井的地质条件,采用井下瞬变电磁法小线框的工作方式,在一采区-530m水平及其以上相关大巷及17煤首采工作面两顺槽内布置6条测线进行探测。在资料解释中,通过设定2级异常阀值对井下富水性进行评价,查明了巷道底板的含水性。经验证,资料处理解释结果与实际揭露地质构造对应良好。     

工作面顶底板富水构造三维立体探测应用研究

通过分析断层、陷落柱等构造裂隙发育区域等富水异常体的瞬变电磁响应特征,结合某煤矿1310工作面的探测实例,介绍了在煤井工作面现场存在大量锚杆、锚网支护及金属液压支架影响情况下的瞬变电磁探测施工参数,并结合该工作面的顶底板视电阻率等值线三维切片图,解释了工作面上下各60 m范围内的富水性:低阻异常在三维视电阻率立体图中表现为2个柱状闭合异常,其中异常A是富水性较强的陷落柱响应,空间方位偏向于顶板;异常B为液压支柱等铁器干扰所致。根据解释结果,在二个异常位置共布置了10个钻孔,经验证与探测结果较吻合。     

矿井综合物探技术在南方煤矿探测岩溶突水通道中的应用

在我国南方多水患矿井治理中,一般采用矿井综合物探技术探查其岩溶突水通道,以便采取防、堵、疏、排、截等措施治理其水害。为了查明某矿井矿井井下＋352水平、＋270水平巷道内出水岩溶通道的具体走向、位置及大小,在其地表及巷道内共布置物探测线10条,其中4条地面测线,6井下测线。从高密度电法探测所得的电阻率断面图上看,其存在4个明显的低阻异常区。据此探测结果,结合地质资料进行分析,共找出5条岩溶导水通道。地质雷达探测结果对比,二者的探测结果较吻合。     

矿井瞬变电磁方法在铜川矿区东坡矿采区水文勘探中的应用

东坡煤矿东坡井田为一波状单斜构造,其在开采4、9、11号煤层时受以下三类水害威胁:石炭二叠系碎屑岩裂隙水、奥灰岩溶裂隙水、老空水。为了防止在采掘工作面发生突水事故,采用矿井瞬变电磁法同轴偶极装置沿0°、45°、135°等3个方向进行探测,根据获得的视电阻率等值线图对东坡煤矿401工作面顶、底板岩层赋水条件进行综合评价。结果表明:401工作面顶、底板上下各50m内岩层富水性相对较弱,但局部存在砂岩裂隙水;回风巷距切眼150~250m处的顶、底板中存在相对低阻异常区,推测为富水区;其他区域存在的部分低阻异常现象,可能与断层构造影响有关。     

EH-4电磁成像系统在探测工业广场保护煤柱中的应用

利用EH-4电磁成像系统对砟子煤矿工业广场保护煤柱进行了探测,以确定保留煤柱南部边界线附近是否存在采空区。探测以一条长线与二条垂直短线展开,长线查证煤柱南部边界采空区的范影响围(长度),短线查明采空区的纵向深度(宽度)。根据长测线各线段及短测线电阻率剖面图,结合预留煤柱范围内煤层底板等高线,确定在保护煤柱南部边界线附近,存在一个长520m,宽95m,平均高度105m的异常区。参考该区地质勘探资料,异常区的深度与煤层赋存深度一致,据此解释为采空区。为保障矿区安全生产,建议禁止回采工业广场南部异常区。     

工作面底板变形与破坏电阻率特征

通过建立回采过程中底板岩层变形破坏过程的地球物理数值模型,采用正演计算方法分析底板破坏带的电阻率变化特征,并在五矿8403工作面布置网络并行电法探测系统,进行现场观测。模拟数据和现场探测结果表明,煤层底板视电阻率值与工作面开采过程密切相关,在回采工作面后方电阻率剖面图出现明显高阻异常,其高阻异常位置与底板破坏位置相对应;在回采工作面前方出现相对低阻异常,其低阻分布位置与矿压引起的高应力区相当;随着工作面的推进,高、低阻异常同步变化。根据这种底板岩石的电阻率变化,结合矿井水文地质特征,可进行煤层底板破坏规律的动态勘探,有利于底板破坏突水的预测预报工作。      

双巷三维并行电法数值及物理模型试验研究

电法勘探是一种以研究地下探测目标体与周围介质之间的电性差异的地球物理探测方法,通常采用的二维电法勘探只能得到一条垂直于测线的视电阻率剖面,如果不能确定测线位置正好在异常体的正上方,这时就难给出较准确的结论。三维电阻率法采集数据量大,可获得三维电性数据体,而且可方便地根据需要实现水平及垂直切片,有着二维电法探测不能比拟的优点,实现对目标体的准确定位及全面透视。通过对构建的三维地质模型体进行数值模拟和物理模拟,表明双巷并行三维电法对地质异常体可以进行有效的探查并获得良好的探测效果。     

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