Geoelectrical survey over perched aquifers in the northern part of Upper Sakarya River Basin,Türkiye

In this study, a groundwater exploration survey was conducted using the DC Resistivity (DCR) method in a hydrogeological setting containing a perched aquifer. DCR data were gathered and an electrical tomography section was recovered using conventional four-electrode instruments with a Schlumberger array and a two-dimensional (2D) inversion scheme. The proposed scheme was tested over a synthetic three-dimensional (3D) subsurface model before deploying it in a field situation. The proposed method indicated that gathering data with simple four-electrode instruments at stations along a line and 2D inversion of datasets at multiple stations can recover depth intervals of the studied aquifer in the hydrogeological setting even if it has a 3D structure. In this study, 2D inversion of parallel profiles formed a pseudo-3D volume of the subsurface resistivity structures and mapped out multiple resistive (>25 ohm·m) bodies at shallow (between 50–100 m) and deep sections (>150 m). In general, the proposed method is convenient to encounter geological units that have limited vertical and spatial extensions in any direction and presents resistivity contrast from groundwater-bearing geologic materials.     

综合物探方法在深部接替资源勘探中的应用

文章介绍了双频道激电仪和EH4电磁仪的原理及两种仪器综合应用的方法.阐述了两种仪器在获取不同地质信息时,具有各自的优点.在结合地质情况的基础上,综合分析利用两方法所提供的地质信息,得出的结论与钻探结果吻合.表明两种方法的综合应用是有效的.文章还提出应充分掌握物探仪器的优缺点,综合利用,以提高勘探的准确性和效率.     

勉略宁地区锰矿成矿环境及找矿方向

勉略宁地区的锰矿可分火山喷发一沉积(变质)型和沉积型两种类型，具有多个赋矿层位；通过对该地区锰矿地质特征及成矿环境的分析对比，归纳总结了该地区两种类型锰矿的成矿特点，为该区锰矿的进一步找矿方向提供参考。     

Analysis of artificial corner reflector’s radar cross section: a physical optics perspective

Among many of the differential interferometric synthetic-aperture radar technologies, artificial corner reflectors (ACR) are widely used in monitoring earthquake deformation and urban subsidence due to their relative stability on synthetic-aperture radar (SAR) acquisition. Apparently, the detection and extraction of ACRs on remotely sensed images would be of utmost importance. Many different geometric types of ACRs are designed to achieve maximum detection. Among them, dihedral, rectangle trihedral, and pyramidal ACRs are the most commonly employed. The cost and difficulty of deploying ACRs in the field, however, render comparison among the three types rather impractical, if not impossible. The current study attempts to tackle the issue from a physical optics perspective. Adopting radar cross section (RCS) as the measure of ACRs’ detectability, we examined the relationships between the ACRs’ RCS under vertical polarity with various parameters including the radar incident angles, width and heights of the ACRs and the azimuthal angles. The analyses indicate that under vertical polarity, among the three types of ACRs, the rectangle trihedral ACR is the most tolerant to its deploying surroundings. To verify the physical optics analysis results, we collected ENVISAT data from a variety of deployed ACRs in the Yan-Huai Basin, China, and derived their reflectance characteristics. The field data agree with the theoretical analyses. From this practice, it seems that the physical optics method might prove to be a rather economical and effective approach to design and select appropriate ACRs in field deployment.     

广西云开地区区域成矿模式

通过对广西云开地区区域成矿特点和区域构造演化阶段的讨论,选择区内主要矿床的控矿地质因素、成矿时代、物质来源等特征进行对比,并根据典型矿床成矿模式概括区域成矿模式。指出加里东期、华力西-印支期、燕山期为本区矿床的成矿期,这是对广西云开地区成矿环境的认识进一步深化,以期指导区域矿产评价和找矿部署工作。     

贵州农业地质工作的若干思考

本文在明确农业地质学概念、内涵及其意义的基础上,简要叙述了贵州农业地质背景与条件,初步提出了该工作的基本思路和分层次部署农业地质工作的建议.     

大地电磁测深法在铜镍矿勘查中的应用

文章介绍了大地电磁勘探的基本原理,结合在新疆哈密地区图拉尔根铜镍矿区的实际应用,从野外数据采集到资料处理和地质解释对该方法的实际效果进行了剖析,所获异常得到钻探证实为厚大矿体。文章还对该方法的适用条件进行了分析,并给出了在荒漠戈壁地区进行大地电磁勘探的一些可以借鉴的经验。     

甘肃构造—地层区划新方案

地层区划是依据地层记录的特征、属性在时空上的差异和阶段性所进行的空间划分。本文采用分阶段地层区划的方案,从古构造格局、古地理状态、古生物面貌、古气候带分布入手,将全省划分为6个阶段,不同阶段按大区、区、分区进行了划分。本省地层区划的地质意义,一是可促进全省地层学及相关学科研究工作的开展,二是对岩石地层单位的对比、清理和新建具指导意义,三是有利于基础地质调查和矿产勘查工作的部署与开展。     

测氡仪器工作状态选取浅析

在仪器标定检查工作中,常常会涉及到工作状态的选取问题。工作状态选取是否合适,将直接影响着观测数据的准确性。本文仅介绍笔者在工作中遇到的几种异常情况及通过实验识别仪器正常与否的方法。笔者深感在台站仪器老化日异严重的今天,认真识别仪器性能是否正常的重要性。     

Distributed jobs on EGEE Grid infrastructure for an Earth science application: moment tensor computation at the centroid of an earthquake

The Centroid Moment Tensor is a good summary of the fault rupture happening during an earthquake. We here describe a method for its determination in case of large earthquakes (with magnitude greater than 6.5) recorded world-widely by permanent digital seismic stations networks, as well as how deploying it on a Grid computing facility finally enabled its fast completion. Two different approaches of this process used over the last years are herein detailed and discussed. Some important impacts of this work are then highlighted and future trends are foreseen.     

京承三期高速公路高边坡勘察方法探讨

京承高速公路的密云沙峪沟—北京市界段位于地质构造剥蚀低山丘陵区,全线桥隧工程比例高,工程多为深挖高填路段,路基挖方边坡的稳定性问题十分突出。在施工阶段进行了工程地质测绘、勘探、及现场试验,运用工程岩体质量RMR分类法和赤平极射投影法评价坡体的稳定性,为优选道路边坡加固方案提出了合理化建议。经施工实践证明,其建议效果良好。     

Observations of volcanic emissions from space: current and future perspectives

Volcanoes worldwide pose a major threat to humans at both local and global scales. The effective monitoring of volcanoes is essential to manage and reduce risk associated with the threat that they pose. The measurement of volcanic cloud composition can provide important clues to the underlying volcanic processes and can be indicative of impending eruption. Hazards posed by plumes to humans and animals are significant, as well as the potential climatic impacts and the threat to aircraft by the ingestion of volcanic ash all justify careful monitoring. Recent advances in instrument technology have allowed for high resolution monitoring of volcanic clouds from satellite-based instruments. There exists a suite of instruments with varying spatial, spectral and temporal resolutions, which when used in conjunction can provide detailed information about cloud properties. Such instruments have the capability to quantify sulphur dioxide, ash and aerosol content as well as the spatial and vertical distribution of species. Here we present an overview of the range of instruments useful for such monitoring, outline their functionality and describe the potential of future missions.     

X射线荧光光谱分析方法的共享

探索了在同一类型X射线荧光光谱仪器之间分析方法共享的可能性。基于量值归一的原理,使用标准化样品建立了两台仪器之间测量数据的可比性,使一台X射线荧光光谱仪建立的分析方法,能够简单转移到其他同一类型的X射线荧光光谱仪上使用,可以获得同样的分析精确度和准确度,从而实现分析方法的共享。实验数据表明,建立的方法简单、实用,能够节约分析方法建立过程中的人力、物力和资源,又能够更好地发挥科学仪器的作用,促进分析方法的标准化和网络化。     

车载台式能量色散X射线荧光光谱仪在地球化学勘查现场分析中的应用

充分发挥小型实验室设备的功能以提高现场快速分析的能力。在内蒙和新疆两地覆盖区的钻探现场,采用车载化台式偏振能量色散X射线荧光光谱仪,对由轻便钻采集的覆盖层和基岩样品进行了贱金属分析。共采集、制备和分析了约400件钻探样品,采用能量色散X射线荧光光谱法、波长色散X射线荧光光谱法和电感耦合等离子体质谱法对这些样品进行比对分析。现场分析数据与实验室分析数据(各方法的平均值)的比对结果表明,K、Ca、Ti、V、Cr、Mn、Fe、Ni、Cu、Zn、Ga、As、Rb、Sr、Y、Zr、Nb、Ba、Pb、Th等20余种元素的分析数据的一致性良好;含量超过10μg/g时,除了V和Ba外,其他元素的平均相对偏差均小于25%。在现场作为质控样品分析4个地质标准物质GBW07301～GBW07304,测定结果表明,除了低含量的Cu和Ga外,上述其他18种元素均符合地质行业标准地质矿产实验室测试质量管理规范(1∶20万)规定的误差要求。应用研究表明,设计的仪器车载化方案可行,现场分析方法快速、准确,适用于野外钻探、化探等急需现场数据支持的工作。     

Selective dissolution of late cretaceous and earliest tertiary calcareous nannofossils: Experimental evidence

The effects of carbonate dissolution on the taxonomic composition of ancient nannofossil assemblages were investigated by deploying them on a deep mooring at depths of 1039 m–5500 m for 117 days in the Sargasso Sea. The relative proportions of only a few taxa change significantly with increasing dissolution: Cruciplacolithus primus is by far the most susceptible and Micula staurophora by far the most resistant species. The average dissolution indices calculated for the deployed assemblages closely follow the gradients of other dissolution indicators in the North Atlantic.     

金川铜镍硫化物样品中锇同位素比值的高精度分析

采用两种独立的190Os稀释剂、4个不同的化学流程,用等离子体质谱仪、TRITON热表面电离质谱仪和MAT-262固体质谱仪3种质谱仪器,在4个实验室分别对采自金川铜镍硫化物样品的187Os/188Os同位素比值进行分析,样品分析数量达到56个。4个实验室获得的结果分别为0.3356±0.0018(n=12,2s)、0.3363±0.0008(n=6,2s)、0.3363±0.0010(n=18,2s)和0.3353±0.0034(n=20,2s)。采用ISOPLOT软件对所得56个数据进行加权平均计算,得到187Os/188Os同位素比值为0.33602±0.00022(置信度95%)。两台TRITON热表面电离质谱仪测量的结果几乎完全一致,且精度高于MAT-262固体质谱仪和等离子体质谱仪。比较了碱熔和Carius管两种溶样方法,结果表明,对于所研究的样品,用Carius管溶矿方式可以将含锇矿物完全溶解。     

湖南锡铅锌矿勘查与社会经济可持续发展研究

湖南锡铅锌资源丰富，保有储量列全国第四位，是我国重要的锡铅锌矿工业基地之一，锡铅锌矿业对满足省内外消费需求、促进出口贸易、创造就业机会及发展相关产业起着十分重要的作用．然而，湖南锡铅锌资源保证程度不高，现有锡铅锌保有储量保证年限均在10a以下，很难满足日益增长的国内外需要．作者认为采取“合理部署国土资源大调查工作，加强老矿山周边及深渐找矿工作，建立矿业权市场、加大地勘投入，努力提高资源综合利用水平”等措施可应对社会经济可持续发展对锡铅锌勘查的挑战．     

不同方法(仪器)测定水中铀氡数值的可比性试验与成果

本文对4种水中铀含量分析方法和5种型号水中氡浓度测定仪器测定水中铀氡数值的配对试验进行了总结。确定了不同方法(仪器)测定值间的可比性,求出了测定值换算成标准值的修正式。为在区域铀矿水化学找矿资料整理中。进行不同方法(仪器)测定水中铀氡数值的一致性处理提供了方法。     

Numerical simulation of sea breeze characteristics observed at tropical coastal site,Kalpakkam

Sea breeze characteristics around Kalpakkam tropical coastal site are studied using an Advanced Regional Prediction System (ARPS) mesoscale model, which is non-hydrostatic, compressible atmospheric prediction model following the terrain coordinate system. Various options such as surface physics, atmospheric radiation physics, Coriolis force, microphysics, cumulus parameterization and 1.5 level TKE closure scheme for diffusion are included in the model. A joint meteorological field experiment was carried out by IITM-Pune and IGCAR at Kalpakkam by deploying state-of-the-art sensors and tether balloon systems for observing the height profiles of meteorological parameters. The data obtained from the field experiment are used here to compare the results from numerical simulations. From the simulated results, it is seen that duration of the sea breeze is 6 hours which agrees well with the observations. The height of the Thermal Internal Boundary Layer (TIBL) is also simulated from the vertical profiles of potential temperature. Simulated wind speed and wind directions are compared with the 50 m tower data and potential temperature profiles are compared with the kytoon data. Results are in good agreement with the observed values except during night time wherein a small difference is seen in the wind speed.     

A simple and general methodology to calibrate seismic instruments for debris flow quantification: application to Cotopaxi and Tungurahua volcanoes (Ecuador)

Debris flows are hazardous phenomena occurring at volcanoes, and monitoring them has proved as challenging as imperative in several cases. The use of seismic instruments to measure and study the physical properties of debris flows has witnessed significant progress in the last years, with the use of improved sensors, innovative methodologies and high-resolution analysis. However, the application of such studies to the practical task of providing early warnings remains limited by the significant amount of infrastructural and technological resources commonly required for their deployment. In Ecuador, debris flows at volcanoes are detected by means of seismic instruments which are usually part of broader monitoring networks, thus requiring calibration to provide quantitative information about the flows and feed early-warning systems. In the present work, a theoretical approach based on the Buckingham Π-theorem is used to determine an expression that linearly correlates the seismic signal produced by a transiting debris flow with its discharge rate, for instruments installed in different substrata and at variable distances from the drainage. The expression is experimentally tested with Acoustic Flow Monitors and Broad-band seismometers installed in the vicinity of drainages at Tungurahua and Cotopaxi volcanoes, where actual debris flows occurred in relation to eruptive activity. The experiments consist in comparing the measured peak amplitude values of the seismic signal envelopes with the estimated peak discharge rates of several events. The results confirm the validity of the theoretical expression with linear correlations observed between the seismic amplitudes and the discharge rates, thus defining calibration expressions that can be generally applied to varied environments and instruments. The seismic instruments calibrated through this methodology can provide instantaneous and reliable predictions of debris flow discharge rates within less than an order of magnitude and only requiring limited data processing and storage. Such level of prediction could help to improve early warning systems based on seismic instruments installed in locations where more developed instrumental arrays are unavailable or unpractical.