光山凉亭-薄刀岭银金矿床地质地球化学特征

凉亭-薄刀岭银金矿床属构造蚀变岩型。矿体赋存于中元古界信阳群龟山岩组下段第一、二岩性层（Pt2g^cd＋di）白云石英片岩、碳质绢云石英片岩内,严格受EW向构造破碎带控制。矿化带原生晕表现为高背景值、强异常特征,As,Pb,Mo,Bi指示元素与成矿元素Ag,Au密切相关;成矿热液的运移以渗流为主、渗透为辅。本文通过对该矿床地质、地球化学特征的总结研究,建立了综合找矿标志,对区域同类型矿床的找矿评价具有一定的借鉴和指导作用。     

黑龙江省草帽山-基座山地区地球化学特征及成矿远景预测

黑龙江省草帽山-基座山地区位于大兴安岭中段华力西、燕山期铁、钨、银、金、钼、铜成矿带的北东端,呼玛县兴隆砂金矿区的南部。区内经历了漫长的沉积地层发育及多期次的强烈岩浆活动,分布有众多砂金矿床及岩金矿点,成矿条件较为优越。文章对区内1∶5万水系沉积物测量采集的样品分析数据进行了统计分析,将11种元素划分成Ag,Cu,Pb,Zn组合类型、W,Mo,Bi组合类型、As,Sb,Hg组合类型、Au组合类型,总结了区内地球化学特征及地质意义,并通过对各元素的平均值、变异系数、相关性及元素空间分布特征进行比较研究,认为Au元素含量高于全省丰度、变异系数为大(5.668),单元素异常强度高、浓度分带明显,为该区最主要的成矿元素,研究区是金成矿的有利地区。     

西准噶尔地区乌散岩体成因：来自年代学、岩石学和地球化学的证据

西准噶尔地区广泛发育古生代中酸性侵入岩,部分岩体中含有暗色微粒包体,这些岩浆岩的年代学、地球化学研究对于西准噶尔地区的岩浆混合作用机制及其区域构造演化的研究具有重要意义。乌散岩体位于西准噶尔中部,岩体包含寄主岩石石英二长岩及暗色包体石英角闪二长岩。石英二长岩中锆石LA-ICP-MS U-Pb谐和年龄为280.0±3.8Ma,表明其成岩时代应为早二叠世。里特曼指数δ为3.27~3.36,寄主岩石属于高钾钙碱性岩石系列。岩石中Rb、Th、K、La、Ce、P、Zr、Hf相对富集,Ta、Nb、Sr、Ti相对亏损,轻重稀土元素分馏明显。在Y+Nb-Rb、Y-Nb构造环境判别图解中,乌散岩体石英二长岩落入板内花岗岩投点范围内,显示具有后碰撞花岗岩的特征。由于该岩体成岩年龄明显晚于该地区蛇绿岩、岛弧火山岩以及含矿斑岩体年龄,而与后碰撞伸展环境中形成的A型花岗岩和双峰式火山岩的形成年龄相近,证明此时该地区大洋可能已经闭合,因此地球化学和区域构造特征指示乌散岩体可能形成于后碰撞构造环境。乌散岩体中暗色微粒包体广泛发育,寄主岩石与包体相互包裹,多为截然接触关系。钾长石斑晶横跨寄主岩石及包体,包体中发育的针状磷灰石,表现出岩浆混合的岩相学特征,寄主岩石与包体中不同矿物的SiO_2含量与其他主量元素含量呈良好的线性关系,表现出较好的亲缘关系,说明两者的矿物成分变化与岩浆混合有关。     

Geochemical mapping based on geological units: a case study from the Marnoso-arenacea formation (Northern Apennines,Italy)

Geochemical maps can provide us with much information on geology, earth surface processes and anthropogenic pressure and are valuable tools for ore prospecting and land management. Stream sediments represent an integral of the various possible sources of sediments upstream from the sampling point therefore there can be multiple signal sources but generally the prevailing signal source is the one related to bedrock geology. Stream sediments collected from active second-order channels including singular geological units, were selected in order to determine the geochemical characteristics of each unit. The aim of this study was to analyze their potential for using them to integrate geological interpretation and produce a geologically-oriented geochemical map. From the 770 samples collected for a regional geochemical mapping program, we selected 149 samples whose catchment basin included only one of the members recognized within the Marnoso-arenacea formation. This middle–upper Miocene (Langhian–Tortonian) turbiditic unit forms the backbone of the Romagna Apennines and has been subdivided into 14 members according to age and lithostratigraphic criteria. The results indicate that there are marked differences in the composition of the members of the Marnoso arenecea formation which indicate the provenance of the sediment and the palaeogeographic evolution of the units. By means of univariate and multivariate statistical analyses (Factor analyzes) two main types of sediment compositions are identified: Tortonian members are characterized by sialic coarse grain-sediments while the Langhian–Serravallian members are richer in carbonate fraction, slightly enriched in a mafic contribution. This study elaborated the geochemical data from a geological point of view by integrating the information available in literature to spatially extend the interpretation based on limited site observation as for petrographic studies. In general, the geochemical map based on a geological unit could be a useful tool for carrying out the geological reconstruction of a complex area.     

郯庐断裂带南段两侧花岗岩地球化学特征:对大别造山带中-下地壳流动的限定

大别造山带形成于印支期华南、华北板块陆-陆碰撞过程中。大别造山带造山后发生了山根减薄,其可能的动力学机制为岩石圈拆沉或中-下地壳的塑性流动。为了检验大别造山带是否在造山后发生过中-下地壳流动,本次工作从对比郯庐断裂带南段两侧大别造山带及洪镇、月山地区花岗岩地球化学特征入手,对同样位于郯庐断裂带南段东侧的徐桥岩体开展地球化学研究,为大别造山带造山后是否经历过中-下地壳流动提供证据。本次工作对徐桥岩体的研究表明,该岩体侵位时间为127Ma左右;具有较高的Si O_2和全碱含量;明显富集Rb、Th、U、Pb等大离子亲石元素(LILE),亏损Nb、Ta、Ti等高场强元素(HFSE);稀土元素配分图解中表现为轻稀土富集和重稀土亏损的右倾配分模式,具有较弱的Eu负异常。徐桥岩体的地球化学特征与造山带东侧的月山岩体类似,且与下扬子地区沿江地区侵入岩基本一致。但同样位于造山带东侧的洪镇岩体,其地球化学特征与月山、徐桥岩体明显不同,而与大别造山带一致的地球化学特征,说明两者可能具有相似的源区。基于以上分析,笔者推断洪镇花岗岩的物质来源可能为大别造山带加厚的地壳。而大别造山带东侧出现造山带地壳物质的现象表明造山带在造山后发生过地壳的塑形流动。由于大别造山带中-下地壳物质穿过郯庐断裂带南段,表明郯庐断裂带造山后大规模左行平移事件应发生于大别造山带地壳流动变形之前。     

厦门城市隐伏断层控制性地球化学探测

本文介绍了地球化学探测方法作为控制性探测隐伏断层的有效手段,在厦门城市隐伏断层的探测中得到了充分的应用。通过地球化学试验探测,可确定地球化学探测的异常下限值,同时在采取了一系列质量保障措施后,增强了判断异常点的可靠性,研究表明地球化学探测异常点呈明显的线性分布。经浅层地震探测验证,地球化学探测解译的断层分布位置与浅层地震探测断点吻合程度较高,表明该方法用于城市隐伏断层探测是有效可行的。     

Removal of Pathogens by River Bank Filtration at Haridwar,India

Measurements of river water quality at Haridwar, India, taken during 2005–2006 show that the river water does not meet the World Health Organization and Bureau of Indian Standards criteria of drinking water quality, especially with respect to total coliform and fecal coliform. This study investigates the removal of pathogens at a river bank filtration site in Haridwar. Using the quality of river water and the quality of abstracted water from a nearby production well, semi‐empirical models based on the concept of filtration coefficient are developed and tested for their effectiveness in removing pathogens under varying bacteriological quality of source water. A two‐tier model, which includes the effect of clogged layer, is developed to obtain an equivalent filtration coefficient. This coefficient is found to be linearly related with natural logarithm of the concentration of pathogens in the source water. Copyright © 2012 John Wiley & Sons, Ltd.     

甘肃北山地区白山堂铜矿地质特征及成矿流体研究

北山地区是我国重点成矿区带,蕴含很大的矿产资源潜力。以往工作发现斑岩型铜矿是北山地区重要的成矿类型,白山堂铜矿是其代表性斑岩型铜矿,但该矿至今一直未开展成矿流体的相关研究。本文进一步研究矿床地质特征,系统开展了矿床流体包裹体研究,发现其流体包裹体形态简单、多为气液两相,中低温(成矿期含矿石英脉均一温度230℃～260℃及160℃～170℃,共生黄铜矿爆裂温度约301℃)、低盐度[w(NaCleq)]为11%～15%,均值11.32%及3.4%～7.7%,均值4.8%)、中等密度(约0.95～1.00 g/cm3)、中低压力(约5×103～101×103 kPa)等物理化学特征,综合认为流体具有中低温热液脉型矿化特征,结合地质特征及近矿外围一系列环绕石板泉二长花岗岩分布的中低温热液脉型-矽卡岩型-斑岩型Cu、Fe、Pb和Zn等矿化分带模式,认为白山堂铜矿为中低温热液脉型矿化类型,代表岩浆热液系统演化到晚期阶段的产物,并认为环绕石板泉二长花岗岩周缘的系列斑岩型-矽卡岩型-热液脉型矿化存在某种联系。     

http://www.sciencedirect.com/science/article/pii/S1674987111001393

To study on the significance and basis of acidolysis index to China marine gas hydrate exploring,since 2006,111 samples derived from Leg 164 and 204 of the Ocean Drilling Program (ODP) were analyzed in...     

论铁氧化物铜金型(IOCG)矿床地球化学岩相学填图新技术研发

在铁质苦橄岩—铁质安山岩、钛铁辉长岩—钛铁质闪长岩和二长岩—二长斑岩岩体附近,同岩浆侵入期脆韧性剪切带中构造岩相和热液角砾岩相,它们是铁氧化物铜金型(IOCG)矿床含矿岩相学类型。总体垂向蚀变分带为:上部为粘土化—绢云母化—赤铁矿蚀变带,中部钾质蚀变相带(电气石—铁质)+热液角砾岩化相带,下部钠质蚀变相(铁质)—热液角砾岩化带。围绕二长斑岩—二长闪长岩舌状侵入体形成电气石蚀变岩相带,属于汽成热液蚀变中心。大型—超大型IOCG矿床具有多期蚀变相系叠加特征,不同成因的热液角砾岩化相带发育、异时同位多期蚀变岩相叠加和汽成热液蚀变相发育等是寻找大型—超大型IOCG矿床标志。