石英裂变径迹蚀刻条件的对比实验研究   总被引：5，自引：0，他引：5  

刘春茹  刘秀明  王世杰  张峰 《地球化学》2007,36(3):323-327

通过 40%的 HF溶液、KOH饱和溶液和 19 mol/L的 NaOH溶液这三种常用方法对大、小颗粒石英进行裂变径迹蚀刻实验的对比发现,用环氧树脂固定的小颗粒石英样品,不宜用 KOH饱和溶液(150 ℃)和 19 mol/L的 NaOH溶液(沸点,约 120 ℃)作为裂变径迹的蚀刻剂,宜用 40%的 HF溶液;三种方法均适宜于大颗粒石英,但不同的蚀刻方法蚀刻效率不同, 40%的 HF溶液(29 ℃)的蚀刻效率最高,且操作简单、安全性高.40%的 HF溶液最佳蚀刻时间为: 温度在 4 ℃左右(冬季)时为 40 min,温度在 29 ℃左右(夏季)时为 30 min,可在全年室内常温条件下操作.  相似文献   

460铀-钼矿床控矿因素及矿床成因探讨   总被引：3，自引：2，他引：3  

沈光银 《矿产与地质》2007,21(5):509-514

460矿床是上世纪80年代在冀北沽源中生代火山断陷盆地西部发现的大型铀-钼矿床。在对该矿床野外实地调研的基础上，结合矿床地质详查和矿床专题科研报告的综合分析，对矿床的控矿因素进行了系统总结。研究结果表明，矿床受NE向断裂（F45）和火山构造的联合控制；火山活动晚期沿断裂和中心式火山机构侵入的次流纹斑岩体是矿床定位的决定性因素；铀-钼矿化主要产于次流纹斑岩体产状变异部位或接触带附近；容矿构造为次流纹斑岩体接触带构造、隐爆角砾岩和J3z^3-5川层流纹岩中的层间裂隙带。研究认为，铀矿化受断裂构造、火山机构、岩浆活动、热液蚀变等作用的复合控制，其中火山口-火山通道相的次流纹斑岩体是主要的控矿因素。  相似文献   

西藏羌塘盆地侏罗系白云岩储层中油砂资源评价   总被引：2，自引：0，他引：2  

周文  邓虎成  伊海生  李勇  谢润成  林家善 《矿物岩石》2007,27(4):85-91

西藏羌塘盆地是一个烃源岩发育厚度大、分布广的大型中生代海相沉积盆地,构造活动对早期形成的油气藏破坏和改造强烈,为油砂富集成矿提供了条件。通过对盆地中发现的隆鄂尼和昂达尔错两个矿点进行勘察。矿点油砂主要富集于中侏罗统布曲组,分析认为其形成和分布受燕山晚期形成的大型古隆起带的控制,早期形成的古油藏带在后期构造过程中遭受破坏和抬升,使顶部布曲组含油白云岩被抬升剥蚀风化形成现今的油砂矿。采用含油率法对油砂矿带进行了资源量的计算,结果表明两个矿带的油砂地质资源总量为93 099.76×104t。通过类比认为整个盆地油砂资源潜力巨大,可以成为油砂资源主要的勘探地区。  相似文献   

高力罕凹陷地浸砂岩型铀成矿条件浅析及远景预测     

黄汉嘉  李元久  姜山  李彦林  李占春 《华东地质学院学报》2007,30(4):316-320

高力罕凹陷为二连盆地乌尼特坳陷的一个组成部分,由有相似构造发育史的分散小湖盆(洼槽)集合而成的沉积盆地。结构复杂,表现出分割性强,多洼槽多沉积中心,岩相变化大的特点。通过对高力罕凹陷的构造特征、结构特征、沉积特征、岩性发育特征及铀成矿条件的分析,认为高力罕凹陷具有良好的铀矿找矿前景。提出该地区的找矿方向,具有一定的参考意义。  相似文献   

Geobiological interpretation of the oxygen-deficient deposits of the Middle Permian marine source rocks in South China:A working hypothesis     

Yan Jiaxin  Liu Xinyu 《Frontiers of Earth Science》2007,1(4):431-437

To decipher the origin of oxygen-deficient shelfal deposits is significant for tracing the distribution of marine source rocks and interpreting the evolution of depositional environment. The origin of the Middle Permian Chihsia Formation in South China remains a puzzle for long with its evident oxygen-deficient features but diverse benthos. This paper shows a typical Chihsian depositional rhythm composed of the massive and the laminated limestones with ecological and geochemical features. Massive bioclastic limestone from the rhythm was aerobic in paleoxygenation condition indicated by both the ecological and geochemical features. However, a contradictory oxygenation was inferred for the “laminated” counterpart from the rhythm, with the ecological signal being aerobic and the geochemical one being anoxic. The difference in ecological and geochemical indications was interpreted as the instability of paleoxygenation condition in shelf environments, caused by an enhanced paleoproductivity. Rhythmic occurrence of the oxygen-deficient condition might have been stemmed from paleo-Tethyan paleocurrents flowing across South China. __________ Translated from Earth Science—Journal of China University of Geosciences, 2007, 32(6): 789–796 [译自: 地球科学—中国地质大学学报]  相似文献   

The geochemical study of fluvio-lacustrine aquifers in the Kathmandu Basin (Nepal) and the implications for the mobilization of arsenic     

Jaya K. Gurung  Hiroaki Ishiga  Mohan S. Khadka  Nav R. Shrestha 《Environmental Geology》2007,52(3):503-517

The geochemical analyses of fluvial-lacustrine aquifer sediments of the Kathmandu Valley have been made as a step in assessing the environment for the mobilization of arsenic in groundwater. Elements measured by X-ray fluorescence (XRF) include 4 major oxides (Fe₂O₃, TiO₂, CaO, P₂O₅) and 14 trace elements (As, Pb, Zn, Cu, Ni, Cr, V, Sr, Y, Nb, Zr, Th, Sc and TS). Elution tests of 15 selected core samples were also carried out to determine the potential leaching of arsenic from the sediments. The XRF results show that average bulk concentrations of the major oxides and trace elements are similar to modern unconsolidated sediments and average upper continental crust. However, the abundance of elements varies with grain size, with higher concentrations in finer-size grades. Variations in elemental abundances within the basin are strongly controlled by sediment facies. The elution tests show that greater amounts of arsenic are generally eluted from the fine sediments, although the rates are variable. The results overall suggest that As concentrations in the bulk sediments are not a controlling factor for elevated As in the Kathmandu Basin groundwater, and the roles of other factors such as redox conditions and organic matter contents are likely to be more significant.  相似文献   

Approaches for modeling longitudinal dispersion in pore-networks     

R.C. Acharya  S.E.A.T.M. Van der Zee  A. Leijnse 《Advances in water resources》2007

The purpose of this study is to quantify the dispersivity in the longitudinal direction by upscaling pore scale mixing over a network domain and to verify the dispersivity with that obtained through the more rigorous upscaling technique, the Brownian particle tracking model (BPTM). We model a porous medium with a network of pore-units that are comprised of pore bodies and bonds of finite volume. Such a pore-unit is assumed to be a mixing cell with the steady state flow condition for a single fluid. Dispersivity can be obtained by solving the mixing cell model (MCM) for the concentration in each pore-unit and by averaging the concentrations for a large number of pore units (as a function of time and space). A minimal size of network that ascertains an asymptotic value of dispersivity was determined and verified with large size pore networks. This numerically computed dispersivity is compared with the results from the BPTM for the same porous medium and flow conditions. We show that the dispersivity obtained from the MCM is equally reliable for the heterogeneous pore-networks and can be estimated as a function of pore size heterogeneity. For homogeneous networks with the MCM, the iteration time step plays an important role. On the other hand, for networks with the BPTM, the assumption of intra-bond velocity profile affects the results.  相似文献   

福建三明盆地工程地质特征     

王高旺 《福建地质》2002,21(2):99-102

福建三明盆地工程地质条件对三明市工程建设和城市规划起决定性作用。三明盆地是个构造断陷盆地，地质构造复杂，岩土体工程地质条件复杂，应根据不同建筑场地合理规划工程建设，确定工程勘察手段及工作量，确保工程建设经济、合理及安全。  相似文献   

贵州贞丰县烂山沟金矿床地质特征及其找矿前景     

张震 《贵州地质》2002,19(4):235-239

作者以烂山沟卡林型金矿勘查成果资料为依据，着重阐述该矿床的地质特征，初步总结了它的挖矿条件和找矿标志，并提出其找矿方向。  相似文献   

内蒙古-辽宁努鲁尔虎金矿带控矿条件分析     

黄再心 《黄金地质》2002,8(4):43-47

胬鲁尔虎金矿带位于华北地台北缘，内蒙地轴东段南侧，天山-阴山EW向复杂构造带东段北侧，带内金矿床和金矿（化）点主要集中分布在老变质岩，区域性深大断裂带。华力西期，燕山期岩浆岩均发育的地区，明显受地层，构造，岩浆岩“三位一体”综合控制。控矿条件包括构造，地层，岩浆岩和区域变质。  相似文献