赣北石门寺矿区钨多金属矿床成矿地质条件

赣北石门寺矿区位于下扬子成矿省江南地块中生代铜钼金银铅锌成矿带中.根据区域地质背景和矿床地质特征,详细分析了矿区围岩、母岩和控矿断裂等成矿地质条件.矿区钨多金属矿床的围岩为晋宁晚期黑云母花岗闪长岩,判断为新元古代在不成熟陆壳基础上发育而成的火山弧同碰撞过程中形成的S型花岗岩;燕山中期似斑状黑云母花岗岩、细粒黑云母花岗岩、花岗斑岩为成矿母岩,属硅、铝过饱和钙碱性岩石,为九岭岩基在陆内碰撞挤压环境下熔融、同源演化而成的S型花岗岩;石门寺断裂与仙果山—大湖塘－狮尾洞基底断裂的交叉部位控制着矿区燕山中期含矿花岗岩的侵位和钨多金属矿床的分布,为矿区的控矿断裂.     

河南嵩县庙岭金矿地质特征与钾长石40Ar/39Ar定年

河南嵩县庙岭金矿位于华北陆块南缘熊耳山—外方山地区。矿床赋存于中元古界熊耳群火山岩中近南北向断裂带内,矿体呈似层状、透镜状产出,矿石具浸染状、细网脉状构造和微细粒它形粒状晶粒结构、交代结构,围岩热液蚀变有硅化、钾长石化、绢云母化、黄铁矿化等,矿化具有多阶段的特点,属破碎带蚀变岩型金矿。成矿热液蚀变矿物钾长石Ar-Ar法测年的结果：坪年龄为121.6Ma±1.2Ma,等时线年龄为117.0Ma±1.6Ma,表明矿床形成于早白垩世,与熊耳山地区祁雨沟、瑶沟等金矿床形成于同一时期,属与早白垩世构造-岩浆-流体活动有关的产物。     

邯郸地区主要断裂库仑破裂应力模拟与地震危险性分析

首先基于粘弹性有限元模型,结合邯郸地区活动断裂探测、历史强震数据及区内岩石圈介质分布,建立三维粘弹性有限元断层模型;然后代入运动学特征边界条件,模拟目标区活动断裂上发生地震引起的应力应变场变化;最后计算1830年磁县地震引起的周围断裂面和滑动方向上产生的库仑破裂应力变化,分析未来目标区强震危险性。根据实际地质情况和现今运动学条件模拟出的模型结果显示,磁县断裂上1830年磁县地震震中附近库仑应力减小,表明磁县断裂活动减小了1830年磁县地震震中附近的地震危险性;但在磁县断裂中、西段两端与2条北东向断裂（紫山西断裂和太行山山前断裂）交接处附近库仑应力有所加强,未来该地区的地震危险性值得关注。     

Modelling hydrological processes influenced by soil,rock and vegetation in a small karst basin of southwest China

Hydrological processes in karst basins are controlled by permeable multimedia, consisting of soil pores, epikarst fractures, and underground conduits. Distributed modelling of hydrological dynamics in such heterogeneous hydrogeological conditions is a challenging task. Basing on the multilayer structure of the distributed hydrology‐soil‐vegetation model (DHSVM), a distributed hydrological model for a karst basin was developed by integrating mathematical routings of porous Darcy flow, fissure flow and underground channel flow. Specifically, infiltration and saturated flow movement within epikarst fractures are expressed by the ‘cubic law’ equation which is associated with fractural width, direction, and spacing. A small karst basin located in Guizhou province of southwest China was selected for this hydrological simulation. The model parameters were determined on the basis of field measurement and calibrated against the observed soil moisture contents, vegetation interception, surface runoff, and underground flow discharges from the basin outlet. The results show that due to high permeability of the epikarst zone, a significant amount of surface runoff is only generated after heavy rainfall events during the wet season. Rock exposure and the epikarst zone significantly increase flood discharge and decrease evapotranspiration (ET) loss; the peak flood discharge is directly proportional to the size of the aperture. Distribution of soil moisture content (SMC) primarily depends on topographic variations just after a heavy rainfall, while SMC and actual ET are dominated by land cover after a period of consecutive non‐rainfall days. The new model was able to capture the sharp increase and decrease of the underground streamflow hydrograph, and as such can be used to investigate hydrological effects in such rock features and land covers. Copyright © 2011 John Wiley & Sons, Ltd.     

Seismic characterization of reservoirs with multiple fracture sets using velocity and attenuation anisotropy data

Knowledge about the spatial distribution of the fracture density and the azimuthal fracture orientation can greatly help in optimizing production from fractured reservoirs. Frequency-dependent seismic velocity and attenuation anisotropy data contain information about the fractures present in the reservoir. In this study, we use the measurements of velocity and attenuation anisotropy data corresponding to different seismic frequencies and azimuths to infer information about the multiple fracture sets present in the reservoir. We consider a reservoir model with two sets of vertical fractures characterized by unknown azimuthal fracture orientations and fracture densities. Frequency-dependent seismic velocity and attenuation anisotropy data is computed using the effective viscoelastic stiffness tensor and solving the Christoffel equation. A Bayesian inversion method is then applied to measurements of velocity and attenuation anisotropy data corresponding to different seismic frequencies and azimuth to estimate the azimuthal fracture orientations and the fracture densities, as well as their uncertainties. Our numerical examples suggest that velocity anisotropy data alone cannot recover the unknown fracture parameters. However, an improved estimation of the unknown fracture parameters can be obtained by joint inversion of velocity and attenuation anisotropy data.     

A fracture study by using bipole–bipole cross-well logging

Electrical Resistivity Tomography (ERT) can provide images of subsurface electrical structure between two boreholes. Data quality control is a key issue before ERT inversion. However, there is no effective data quality control method on an ERT survey. In this paper, a method called common current gather for a bipole–bipole array (CCGbb) was proposed to check ERT data quality in a rapid way. Synthetic models were conducted to compare the response difference between pole–pole array and bipole–bipole array. A field work at granite area was tested to verify the applicability of the proposed CCGbb method. From the results of this study, we suggested that conducting CCGbb before ERT inversion and a cross-borehole tracer test for both field data quality control and possible water conducting fractures (WCFs) delineation.     

江西省会昌县淘锡坝大型锡矿床构造控矿机制探讨

淘锡坝锡矿床是近年探明储量达大型的锡矿床,是一种新的锡矿类型-隐爆层间裂隙带型。文章介绍了该矿床的地质特征和矿化特征,对矿区的构造进行了重点解剖,对构造控矿机理进行了探讨,提出火山机构及北东向断裂是矿区的控岩构造,控制了白垩纪成矿花岗岩体的侵入就位。而火山岩中大范围的隐爆层间裂隙带是良好的容矿构造,矿体赋存其中呈似层状,局部膨大形成厚达数十米的＂锡矿包＂。通过研究构造与矿化富集的内在联系,总结了该矿床的成矿规律。     

不同岩溶储水结构分析与地球物理勘察

岩溶区储水结构是寻找地下水最为有利的靶区。在可溶岩与非可溶边界呈串珠状发育的岩溶泉、漏斗等,常指示地下岩溶强烈发育,接触界面的可溶岩为找水的有利部位。在背斜轴部,由于来自侧翼的挤压作用,灰岩、白云岩等硬脆性岩石易形成张性裂隙密集带,成为地下水的有利赋存部位。断裂、构造裂隙密集带使地下水互为沟通,成为良好的储水载体。在这...     

北武夷蔡家坪铅锌矿床硫化物特征、矿床成因类型及成矿时代

北武夷蔡家坪矿床是近年来新发现的一个中型铅锌矿床.矿床赋矿围岩为侏罗系水北组(J1s)、漳平组(J2z)砂岩,铅锌矿体多产在断裂旁侧破碎带及流纹斑岩与砂岩接触带.在野外调查基础上,通过显微镜下观察及电子探针分析,对矿区主要金属硫化物进行了细致研究.初步将成矿过程划分为沉积成矿期、岩浆热液期与表生期,其中岩浆热液期包括中...     

鄂尔多斯盆地南部直罗油田长8油层油气沸腾包裹体群研究

运用激光拉曼光谱、包裹体充填度测定等方法对鄂尔多斯盆地直罗油田富南3井、6井长8油层裂缝岩芯充填物中包裹体群进行分析,发现富南3井、6井与英旺油田英16井长8油层中油气沸腾包裹体群完全相同,密集分布的气泡不停晃动,证实油气沸腾包裹体群不是孤立的、偶然的地质现象。富南3井、6井和英16井长8油层裂缝岩芯的原始裂缝性质为滑动-剪切裂缝和剪切裂缝,在区域构造的作用下,反复发生拉张-挤压交替活动;在拉张发生的瞬间,与裂缝沟通的油层里的原油发生减压沸腾,原油中的轻质馏分和其他流体进入裂缝空间;在随后的挤压发生时,裂缝基本封闭,一部分流体返回原来的油层,一部分被挤到别的裂隙空间形成新的油藏;残留在裂缝里的碳酸钙,在较高的地层压力下逐渐结晶,并把残留的轻质馏分包裹,形成油气包裹体;这些油气包裹体形成压力较高,又包裹着成分类似液化气的轻质馏分,在常温常压下就处于沸腾状态;这样的过程反复进行,在裂缝充填物中形成了沿着晶体生长线以及成片、成带分布的油气沸腾包裹体群。上述油气沸腾包裹体群的形成过程就是油气的地震泵运移机制,丰富了油气运移地震泵地质模型。