沂水县龙泉站金矿地质特征及找矿前景

沂水县龙泉站金矿位于沂沭断裂带中段,受沂水汤头断裂控制。金矿体产于沂水汤头断裂主裂面下盘的糜棱岩化碎裂岩和花岗质碎裂岩中,已初步圈出6个金矿体。此外,在牛家小河、石崖官庄、郑家庄地区也发现有较好的矿化显示。通过综合研究,认为该地区金矿化与韧性剪切构造带关系密切,且具有较好的找矿前景。     

内蒙古绥和查干地区多金属矿床流体包裹体研究

内蒙古绥和查干铜铅锌多金属矿床是典型的热液矿床,处于大兴安岭成矿带南段、内蒙古二连-东乌旗铁铜钼多金属成矿远景区。该文对矿床中流体包裹体进行研究,结果发现,矿床划分为2个成矿期次:早阶段属中高温(320~380℃);晚阶段属中低温(140~160℃)。包裹体的捕获温度也存在2个高峰期,矿床属于中—高温热液矿床。盐度也存在2个高峰范围,第一个高峰范围在0~4%之间;第二个高峰范围在5%~9.6%之间。流体压力范围介于22.6~101.4 MPa,均值为59.9 MPa,成矿的平均深度为当时地表以下1.95 km,属中深成矿床,成矿流体具有中—高温至中—低盐度性质。2个成矿期次和矿区的2次构造运动相对应,矿体定位受断裂构造控制,属于典型的断控脉状矿床。     

福建紫金山金矿床氧化特征

本文主要详细介绍矿床氧化带特征及与矿化关系,并从地形、地理气候、地质构造、岩石性质等方面探讨其成因,以期为类似矿山提供对比借鉴。     

广东凡口铅锌矿床的走滑构造及成矿模式

广东凡口铅锌矿富存于粤北曲仁盆地北缘中、上泥盆统碳酸盐岩石中,是吴川-四会钨、锡、铅、锌多金属成矿带的重要代表性矿床之一。矿区内发育一系列与矿床形成及改造有关的NE向、NNE或NW向走滑构造。其中印支期NE向左行走滑构造是重要的成矿期构造;矿体的空间产出状态和富集程度主要受NE向走滑构造控制,但同时受燕山期与喜山期等成矿期后NNE向和NW向右行走滑伸展构造的改造和影响。矿区NE向走滑构造带的演化与发展及其相伴的岩浆等热液活动是该大型矿床形成的重要制约因素。     

万泉寺银金矿成矿作用分析

万泉寺银金矿主要产于侏罗系白旗组二段地层中。其成矿作用主要为深部成矿物质随岩浆发生反重力迁移,最终通过较大断裂上升并于较大构造带中富集成矿。本文通过对该矿区成矿特征的阐述得出几点找矿标志,以便于对同类矿床的勘查提供参考。     

Modelling the advance–retreat cycle of a tidewater glacier with simple sediment dynamics

We present a simple coupled glacier-sediment model to simulate the evolution of a tidewater glacier. The model is based on a consideration of the total mass budget of a glacier, whereas ice mechanics are fully parameterized. The calving rate at the glacier terminus is assumed to be proportional to the water depth. We show that the formation of a morainic shoal has a profound influence on the response of a tidewater glacier to climatic forcing. For a slow periodic forcing of the equilibrium-line altitude, the model glacier advances steadily into the estuary, builds up a submarine terminal moraine, and then retreats rapidly when a critical point is hit. For a slowly increasing equilibrium-line altitude, at a rate as low as 1 m per 5 years, we find terminus retreat rates of up to 10 km in 50 years. Our model suggests that, although the response of tidewater glaciers to external forcing is strongly nonlinear, the onset of retreat is controlled by climate change.     

Climatic implications of correlated Upper Pleistocene glacial and fluvial deposits on the Cinca and Gállego Rivers (NE Spain) based on OSL dating and soil stratigraphy

We correlate Upper Pleistocene glacial and fluvial deposits of the Cinca and Gállego River valleys (south central Pyrenees and Ebro basin, Spain) using geomorphic position, luminescence dates, and time-related trends in soil development. The ages obtained from glacial deposits indicate glacial periods at 85 ± 5 ka, 64 ± 11 ka, and 36 ± 3 ka (from glacial till) and 20 ± 3 ka (from loess). The fluvial drainage system, fed by glaciers in the headwaters, developed extensive terrace systems in the Cinca River valley at 178 ± 21 ka, 97 ± 16 ka, 61 ± 4 ka, 47 ± 4 ka, and 11 ± 1 ka, and in the Gállego River valley at 151 ± 11 ka, 68 ± 7 ka, and 45 ± 3 ka. The times of maximum geomorphic activity related to cold phases coincide with Late Pleistocene marine isotope stages and Heinrich events. The maximum extent of glaciers during the last glacial occurred at 64 ± 11 ka, and the terraces correlated with this glacial phase are the most extensive in both the Cinca (61 ± 4 ka) and Gállego (68 ± 7 ka) valleys, indicating a strong increase in fluvial discharge and availability of sediments related to the transition to deglaciation. The global Last Glacial Maximum is scarcely represented in the south central Pyrenees owing to dominantly dry conditions at that time. Precipitation must be controlled by the position of the Iberian Peninsula with respect to the North Atlantic atmospheric circulation system. The glacial systems and the associated fluvial dynamic seem sensitive to 1) global climate changes controlled by insolation, 2) North Atlantic thermohaline circulation influenced by freshwater pulses into the North Atlantic, and 3) anomalies in atmospheric circulation in the North Atlantic controlling precipitation on the Iberian Peninsula. Our scenario of glacial and fluvial evolution during the Late Pleistocene in northern Spain could be extrapolated to other glaciated mountainous areas in southern Europe.     

基于GIS矿产勘查靶区优选技术

靶区优选是矿产勘查中的一个关键环节, 它既是矿产资源预测成果的直接体现形式, 同时又是联系矿产资源预测与勘查工作部署的桥梁.然而, 由于人们认识上的不完备性和缺乏相应的技术手段支撑, 使得靶区优选常被忽视或简化.探讨了靶区优选的地质基础原则, 建立了靶区优选的技术流程, 研发了基于GIS支持下靶区优选计算机辅助决策模块, 并以云南省个旧地区与岩浆活动有关的锡铜多金属矿靶区为例进行了示范研究.结果表明靶区优选技术及相应的软件能够客观地反映不同靶区的特征, 提高靶区优选的智能化程度和工作效率.      

山东枣庄杨家堡子铁矿床地质特征及成因探讨

杨家堡子铁矿位于山东省枣庄市峄城区峨山镇,隶属苍峄铁成矿带,矿体赋存于新太古代泰山岩群山草峪组上部的变质岩中。该矿床内圈定磁铁矿体11个,求得铁矿石(333)资源量3 378.2万t,矿床平均品位TFe 33.30%,mFe 22.64%。主矿体为Ⅲ-6矿体,占矿床总资源量的83.69%,其长度1 137 m,最大斜深1 065 m,埋深707~1 369m,形态复杂程度中等,品位变化属均匀类型。含矿岩石为磁铁石英角闪岩。矿石中的主要有用组分为Fe,伴生元素含量较低,均无综合回收利用价值,有害组分S、P的含量均较低,经选矿后可达到炼钢及炼铁要求。矿石结构主要有粒状变晶结构和柱状变晶结构;矿石的构造主要为条带状构造,块状构造的矿石较少,但品位相对较高。矿石自然类型为原生磁铁矿石,工业类型属需选磁性铁矿石。该矿床成因与苍峄铁矿一脉相承,为典型的BIF型铁矿。根据区内以及邻区的见矿情况结合磁异常特征分析,杨家堡子矿区有良好的找矿前景。     

莫桑比克东部沿海锆钛砂矿矿石质量特征——以赞比西亚省5004C矿区为例

滨海砂矿是目前全球最大的潜在海洋矿产资源之一,仅次于石油与天然气。莫桑比克东部沿海滨海砂矿资源丰富,在世界上占有重要地位。该文结合莫桑比克赞比西亚省5004C矿区锆钛砂矿,分析矿石结构与构造、矿石物质组成、矿物含量及变化等矿石质量特征,为莫桑比克东部沿海锆钛砂矿的勘探和开发提供有利信息。