地壳形变与地下水异常关系研究进展

地壳形变异常是地壳构造变动中直接的表现，也是物理含义最为明确的地震前兆之一。地下水异常能够提供多种形式的构造活动过程(包括地震)。这两类异常能够以不同的力式和特点反映出地震孕育过程中伴随的前兆信息，并成为地震预报的重要手段；而它们之间既相互联系又相互影响。因此，对两类异常关系的研究对于识别地震前兆特别是短临前兆至关重要。归类了地震孕育模型及其前兆异常机理，并对前兆异常机理进行归纳整理和简述，然后从机理和前兆方面综述了地壳形变与地下水异常关系的研究成果。     

综合物化探在河北某斑岩型铅锌矿床中的应用及找矿效果

河北某铅锌矿床作为燕山地区唯一具有中等规模的斑岩型铅锌矿床,被发现后多年的地质勘查工作无大的找矿突破。经综合整理研究历年物化探及地质资料,结合开展大功率的激电中梯扫面等系列工作,认为本区化探异常元素分带明显,激电异常发育,成矿系列完整,找矿潜力大。经钻探验证,于斑岩体外围及接触带发现了厚大的铅锌富矿体,于深部发现了铜钼矿体,形成了斑岩型矿床完整的成矿系列,实现了本区新的找矿突破,使其具有了成为大型铅锌矿床的潜力,进一步扩大了本区资源前景。     

河南信息南广场基坑支护技术

河南信息南广场基坑支护工程,分别采用了桩锚支护、微型桩+预应力锚杆复合土钉墙支护和微型桩复合土钉墙支护体系,具体介绍了护坡桩、预应力锚索、微型桩、预应力锚杆、土钉墙、花管桩设计施工方案以及基坑监测变形异常后采用的应急处理方案,技术成果为类似工程的设计施工提供参考。     

基于元素含量和空间变异系数的化探异常信息识别

化探异常信息识别是化探数据分析最重要的任务之一, 也是化探数据在资源勘查领域受到广泛关注的最重要原因, 前人对化探异常信息识别做过大量研究, 这些研究中的大多数主要关注化探示踪元素的含量, 近而根据含量指标计算异常阈值, 而对示踪元素在空间中的分布特征关注较少。本文选择 1: 20万比例尺的克拉玛依幅为研究区, 根据区内金矿的矿床地球化学特征选择Ag、As、Au和Sb等4种元素为本区内金矿的示踪元素, 以地球化学元素分散晕形成理论为依据, 使用GIS技术和Matlab软件绘制研究区内4种金矿示踪元素的综合地球化学异常图。结果表明, 与传统阈值方法得到的化探异常图相比, 本文得到的化探异常图能够更好地指示研究区内已知金矿。     

Inverse steptoes in Las Bombas volcano,as an evidence of explosive volcanism in a solidified lava flow field. Southern Mendoza-Argentina

Here we describe the unusual genesis of steptoes in Las Bombas volcano- Llancanelo Volcanic Field (LVF) (Pliocene – Quaternary), Mendoza, Argentina. Typically, a steptoe forms when a lava flow envelops a hill, creating a well-defined stratigraphic relationship between the older hill and the younger lava flow.In the Llancanelo Volcanic Field, we find steptoes formed with an apparent normal stratigraphic relationship but an inverse age-relationship. Eroded remnants of scoria cones occur in “circular depressions” in the lava field. To express the inverse age-relationship between flow fields and depression-filled cones here we define this landforms as inverse steptoes.Magnetometric analysis supports this inverse age relationship, indicating reverse dipolar magnetic anomalies in the lava field and normal dipolar magnetization in the scoria cones (e.g. La Bombas). Negative Bouguer anomalies calculated for Las Bombas further support the interpretation that the scoria cones formed by secondary fracturing on already solidified basaltic lava flows.Advanced erosion and mass movements in the inner edge of the depressions created a perfectly excavated circular depression enhancing the “crater-like” architecture of the preserved landforms.Given the unusual genesis of the steptoes in LVF, we prefer the term inverse steptoe for these landforms. The term steptoe is a geomorphological name that has genetic implications, indicating an older hill and a younger lava flow. Here the relationship is reversed.     

Metallogenic regularity and mineral prediction of metallic deposits in Baiyin mine field and its periphery of Gansu Province

Through the mineral prospecting project in Baiyin mine field and its periphery of Gansu Province, the authors have delineated twelve 1:50 000 aeromagnetic anomaly areas, seven 1:50 000 high magnetic anomaly areas and sixty-four 1:50 000 geochemical prospecting anomaly areas. Besides, four mineral occurrences and six mineralized spots were found, including copper, lead, zinc etc. The temporal and spatial distribution of mineralization and the paragenesis and combination rules of mineral resources were also expounded, after a comprehensive study of the metallogenic geological conditions, 1:50 000 geochemical and geophysical anomalies and the characteristics of mineral occurrence distribution. The “multi-type” prospecting prediction model was concluded in the study area. Nine key metallogenic prospective areas were delineated, including three type A, two type B and four type C prospective areas. Four target prospecting areas were delineated, including one type A, one type B and two type C target prospecting areas.     

安徽马头斑岩型钼铜矿床元素富集贫化规律及其找矿意义

本文在安徽马头斑岩型钼铜矿床中元素含量随主成矿元素Mo含量变化的基础上,对元素的富集贫化特征进行了系统研究,筛选出了富集和贫化元素,并对具有代表性的富集和贫化元素的矿化指示意义进行了探讨。结果发现,矿床中元素的富集和贫化在地表岩石中均有明显反映,综合利用富集元素的正异常和贫化元素的负异常能更有效指示出矿化带的产出位置,这无疑对此类隐伏矿床的地球化学勘查具有重要意义,也为其他类型矿床的地球化学勘查提供了思路。     

新疆喀默什特地区隐伏断裂高精度磁测解释

喀默什特南部戈壁覆盖区存在东西向正磁异常带,长约11km,在进行高精度磁法测量后推测为基性或超基性物质反磁化的反映。为了给出正磁异常带合理的解释,沿异常带垂直方向布设1：10000剖面,通过离散小波分解对剖面磁测数据进行精细化处理,得到不同深度范围内异常的分布。结合欧拉反褶积运算、归一化总梯度处理及空间域解析延拓进一步判断异常特征,发现该异常主要由断裂引起,为塔什纳拉他乌推覆体所引起的断裂在喀默什特南部的延伸段。     

亚欧中纬度关键区正位势高度距平场配置与中国冬季区域性极端低温事件的联系

基于中国地面台站观测资料和NCEP再分析资料,研究了欧亚中纬度500 hPa高度场关键区正异常配置及其与中国冬季区域性极端低温事件(Regional Extreme Low Temperature Events, RELTE)的联系。结果表明,发生RELTE时乌拉尔山(简称乌山)、贝加尔湖(简称贝湖)和雅库茨克—鄂科斯克海(简称雅鄂)附近的某一区域出现高度场正异常的概率为0.83,即欧亚关键区500 hPa正高度距平场的相互匹配是形成RELTE的直接原因。在此基础上,将三个关键区域高度场异常配置分为7种类型:乌山型、贝湖型、雅鄂型、乌山—贝湖型、乌山—贝湖—雅鄂型、乌山—雅鄂型、贝湖—雅鄂型。不同类型异常模态对应的RELTE在空间分布、持续时间和强度等各有差异,如:乌山型对应RELTE以全国型为主,平均持续天数达14.2天;乌山—雅鄂型对应的RELTE以东北—华北型为主,事件平均持续天数为14.1天。此外,不同类型的异常配置均对应有超前于RELTE的前期特征,平均超前时间为1~8天不等。超前天数的空间分布、高度场异常的时间演化,进一步揭示了乌山以西和雅鄂以东两个方向高度场异常的发展并形成多种环流异常模态的过程,也验证了RELTE存在前期信号的可能性。     

High resolution local Moho determination using gravity inversion: A case study in Sri Lanka

The seismic data incorporated in global Moho models are sparse and therefore the interpolation of global Moho depths on a local area may give unrealistic results, especially in regions without adequate seismic information. Gravity inversion is a useful tool that can be used to determine Moho depths in the mentioned regions. This paper describes an interactive way of local Moho depth determination using the gravity inversion method constrained with available seismic data. Before applying inversion algorithms, the Bouguer gravity data is filtered in various stages that reduce the potential bias usually expected in Moho depth determination using gravity methods with constant density contrast assumption. A test area with reliable seismic data is used to validate the results of Moho computation, and subsequently the same computation procedure is applied to the Sri Lankan region. The results of the test area are in better agreement with seismically determined Moho depths than those obtained by global Moho models. In the Sri Lankan region, Moho determination reveals a fairly uniform thin crust of average thickness around 20 km. The overall result suggests that our gravity inversion method is robust and may be suitable for local Moho determination in virgin regions, especially those without sufficient seismic data.