略谈矿产勘查新规范中存在的几个问题

在几年的工作实践中发现矿产勘查新规范存在一些问题,主要是量化度不够、操作性较差、关键词语多解或模糊,特别是在地质普查间距、储量估算方面不易理解掌握,造成地质工作的普遍简单化.     

黔北喀斯特型铝土矿勘探工程间距的选择——以苟江铝土矿区水井坎矿段Ⅱ矿体生产勘探为例

本文以苟江铝土矿水井坎矿段Ⅱ矿体用50×50m工程间距进行勘探与25×25m工程间距进行生产勘探后,对其矿体形态、厚度控制及储量变化进行对比分析,以探寻此类矿床勘探应如何选用工程间距,才能更合理地对矿体进行控制,满足生产设计的要求。     

Archean (about 2500 Ma) anatexis in eastern North China Block

Two Neoarchean alkaline feldspar-rich granites sourced from partially melted granulite-facies granodioritic orthogneiss have been here recognised in the eastern part of the North China Block (NCB). These poorly foliated granites have previously been assumed to be Mesozoic in age and never dated, and so their significance has not been recognised until now. The first granite (AG1) is a porphyritic syenogranite with megacrystic K-feldspar, and the second (AG2) is a quartz syenite with perthitic megacryst. Zircons from the granites yield LA-ICP-MS U-Pb ages of 2499 ± 10 Ma (AG1), and 2492 ± 28 Ma (AG2), which are slightly younger than the granodioritic orthogneiss that they intrude with a crystallisation U-Pb age of 2537 ± 34 Ma. The younger granites have higher assays for SiO₂ (71.91% for AG1 and 73.22% for AG2) and K₂O (7.52% for AG1 and 8.37% for AG2), and much lower assays for their other major element than the granodioritic orthogneiss. All of the granodioritic orthogneiss and granite samples have similar trace element patterns, with depletion in Th, U, Nb, and Ti and enrichment in Rb, Ba, K, La, Ce, and P. This indicates that the granites are derived from the orthogneiss as partial melts. Although they exhibit a similar REE pattern, the granites have much lower total REE contents (30.97×10⁻⁶ for AG1, and 25.93×10⁻⁶ for AG2), but pronounced positive Eu anomalies (Eu/Eu* = 8.57 for AG1 and 27.04 for AG2). The granodioritic orthogneiss has an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.70144, εNd(t) value of 3.5, and εHf(t) values ranging from −3.2 to +2.9. The orthogneiss is a product of fractional crystallisation from a dioritic magma, which was derived from a mantle source contaminated by melts derived from a felsic slab. By contrast, the AG1 sample has an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.6926 that is considered too low in value, εNd(t) value of 0.3, and εHf(t) values between +0.57 and +3.82; whereas the AG2 sample has an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.70152, εNd(t) value of 1.3, and εHf(t) values between +0.5 and +14.08. These assays indicate that a Sr-Nd-Hf isotopic disequilibrium exists between the granite and granodioritic orthogneiss. The elevated εHf(t) values of the granites can be explained by the involvement of Hf-bearing minerals, such as orthopyroxene, amphibole, and biotite, in anatectic reactions in the granodioritic orthogneiss. Based on the transitional relationship between the granites and granodioritic orthogneiss and the geochemical characteristics mentioned above, it is concluded that the granites are the product of rapid partial-melting of the granodioritic orthogneiss after granulite-facies metamorphism, and their crystallisation age of about 2500 Ma provides the minimum age of the metamorphism. This about 2500 Ma tectonic-metamorphic event in NCB is similar to the other cratons in India, Antarctica, northern and southern Australia, indicating a possible connection between these cratons during the Neoarchean.     

藏南拉康温泉地质特征及雄曲河谷两岸地热分布不均成因分析

西藏山南地区洛扎县雄曲河拉康段在600 m距离内出露温泉4处,仅1处位于河谷右岸;平硐勘查显示两岸岩性、产状、构造一致,地热异常却仅在左岸平硐内部显著,右岸平硐地热异常不明显.本次研究以此异常为出发点,通过片麻状花岗岩不同切面导热实验、片麻状花岗岩与板岩相同切面导热实验,温泉水δ2H,δ18O同位素测试分析等方法,探究...     

水下滑翔机器人运动分析与载体设计

水下滑翔机器人是一种新型水下机器人,具有噪声低、航行距离远、续航时间长、成本低等特点。分析了水下滑翔机器人的驱动机理和运动实现,给出了水下滑翔机器人典型运动的仿真结果,并以正在设计的一水下滑翔机试验样机为研究对象,描述了样机的整体结构布局,详细研究了浮力调节机构、俯仰调节机构和横滚调节机构的实现方法,并就样机中各执行机构的设计实现进行了论述。     

中哈俄阿尔泰稀有金属矿床时空分布、成因及成矿规律

中哈俄阿尔泰发育许多大型—超大型稀有金属矿床,是世界著名的稀有金属成矿省.该成矿省可分为3个稀有金属成矿带,自西南向东北依次为哈萨克斯坦Kalba-Narym、中国阿尔泰和俄罗斯山区阿尔泰等.这3个成矿带稀有金属矿床以伟晶岩型为主,但伟晶岩与花岗岩关系及其伟晶岩成因不一致:在哈萨克斯坦Kalba-Narym成矿带和俄罗...     

Impacts of confining pressure and safety thickness on water and mud inrush in weathered granite

Abstract

Due to the strong disintegration and water erosion of completely weathered granite, water and mud inrush disasters are apt to take place in this zone during underwater tunnel construction. The pore, compactness, seepage path length, fracture geometries and their interconnections for water and mud transfer are strongly influenced by confining pressure and waterproof-resistant slab safety thickness. In order to inspect the influence, a series of experiments based on a self-designed testing system and non-Darcy testing method were performed. The results indicated that the water and mud inrush evolution increased with the increase of confining pressure and decreased with the increase of safety thickness. In particular, the confining pressure mainly influences the initial evolution stage, and a critical safety thickness to prevent water and mud inrush is obtained. Besides, the non-Darcy testing method results shows that the water and mud inrush evolution affects the influence of non-Darcy flow. For example, while the safety thickness was smaller than the critical value, the evolution was large and unstable and its behavior transferred into nonlinear. In this case, the flow changed to non-Darcy flow.     

ASTER数据的煤矿区水体信息提取

为实现多光谱数据对煤矿区水体信息提取,以萍乡市芦新岭及周边煤矿为试验区,在国内外学者对水体指数法提取水体信息和应用的启发下,对试验区不同地物的波谱特征进行分析。本文首先利用数学统计方法建立一种ASTER数据综合归一化差异水体指数模型SWI ASTER_xy,然后利用这一模型对试验区进行水体信息提取。试验表明,该模型能够有效地提取矿区各类水体,还可以运用在ASTER数据（或其他多光谱数据）对不同区域不同地物的提取,在遥感地物定量提取上具有很好的效果和潜力,具有一定的推广价值。     

东昆仑祁漫塔格地区乌兰乌珠尔早古生代花岗岩锆石U-Pb年代学、地球化学及其地质意义

为确定东昆仑祁漫塔格乌兰乌珠尔地区片麻状黑云母花岗岩和二长花岗岩的形成时代、岩石成因、源区性质和构造背景,对该岩石样品进行了锆石U-Pb年代学、地球化学和锆石Hf同位素研究.结果显示:片麻状黑云母花岗岩加权平均年龄为457.5±2.3 Ma,铝饱和指数A/CNK介于0.98～1.02,属准铝质岩石,Na2O/K2O比值...     

浙江洪公铝质A型花岗岩类的岩石地球化学及其构造环境

初步研究表明,以往被认为是典型的I型花岗岩质岩石的浙江洪公岩体应为铝质A型花岗岩质岩石。该岩体以高钾为特征,K2O 达5％以上,K2O/ Na2O＞1.2,准铝-过铝质（A/NKC=0.80 ～1.14）;FeO*/MgO比值大（平均14.20）,高于M型、S型和I型花岗岩;富含稀土元素（ΣREE=313.09×10-6～523.73×10-6）,具有较高的Ga/Al（′104）值（2.92～4.29）和（Zr+Nb+Ce+Y）元素组合值（551.5′10－6～987.4′10－6）,而亏损Ba、Sr、P、Ti等;Nd同位素模式年龄为1.3—1.6Ga,反映洪公岩体主要起源于地壳物质的部分熔融。区域背景、构造被动定位特点和地球化学综合分析表明,洪公岩体形成于拉张的构造环境。