8—氨基喹啉—5—偶氮—对苯甲酸的合成及应用—光度法测定痕量金

报道了新试剂8-氨基喹啉-5-偶氮-对苯甲酸(AQBA)的合成及分析应用。在阳离子表面活性剂CTMAB存在下,Au(Ⅲ)与AQBA在碱性介质中反应形成蓝绿色配合物,其最大吸收波长在608nm处,表观摩尔吸光系数为9.11×10~4L·mol~(-1)·cm(-1),Au量在0～1.8μg/ml范围内遵守比尔定律。所建立的新分析方法已应用于测定矿石及阳极泥中的痕量Au,结果满意。     

广西那坡马刚金矿床地质特征及找矿方向

广西马刚金矿床位于那坡褶皱带坡笨背斜的南东倾伏端。矿体受断裂构造的控制,产出与断裂构造、特定岩性、不整合界面有关,主要以含金破碎带型金矿体形式产出,赋存于矿区内NW向的断裂构造带中,少数产于辉绿岩与围岩的接触带内。结合矿床的地质特征及成因,总结了矿区内矿体的成矿规律,且指出了今后的找矿方向。     

基于MRAS证据权重模型的河南老湾地区金矿成矿预测

河南省老湾地区是桐柏—大别有色贵金属成矿带上重要的金成矿区。在综合分析该区成矿因素的基础上,提取构置了地层、韧性剪切域、脆性断束、岩浆岩、与Au有关的蚀变带和Au、As、Sb、Ag水系沉积物单元素异常等9个预测变量,基于MRAS软件,采用证据权重模型对该区金矿进行了成矿远景预测工作。本次采用0.10 kmx0.10 km的网格单元进行预测,经过各预测变量的先验概率计算、权重值统计、独立性检验和后验概率的计算等过程,划分出A、B、C三个级别的成矿远景区块,根据预测网格分布特点及该区金矿地质特征,圈出了Ⅰ级找矿远景区4处,Ⅱ级找矿远景区4处。综合分析认为:已知金矿床或矿点多数落入A级或B级成矿远景区块,C级成矿远景区块主要是在A级或B级成矿远景区块的周边,与成矿区带从中心向边缘渐变的特征相符合;圈出的Ⅰ级找矿远景区内均已发现金矿床(点),并且后验概率平均值较高,具有较好的金矿找矿潜力。     

Alteration and mineralization styles of the orogenic disseminated Zhenyuan gold deposit,southeastern Tibet: Contrast with carlin gold deposit

Orogenic disseminated and Carlin gold deposits share much similarity in alteration and mineralization.The disseminated orogenic Zhenyuan Au deposit along the Ailaoshan shear zone,southeastern Tibet,was selected to clarify their difference.The alteration and mineralization from the different lithologies,including meta-quartz sandstone,carbonaceous slate,meta-(ultra)mafic rock,quartz porphyry and lamprophyre were researched.According to the mineral assemblage and replacement relationship in all types of host rocks,two reactions show general control on gold deposition:(1)replacement of earlier magnetite by pyrite and carbonaceous material;(2)alteration of biotite and phlogopite phenocrysts in quartz porphyry and lamprophyre into dolomite/ankerite and sericite.Despite the lamprophyre is volumetrically minor and much less fractured than other host rocks,it contains a large portion of Au reserve,indicating that the chemically active lithology has played a more important role in gold precipitation compared to structure.LA-ICP-MS analysis shows that Au mainly occurs as invisible gold in fine-grained pyrite disseminated in the host rocks,with Au content reaching to 258.95 ppm.The diagenetic core of pyrite in meta-quartz sandstone enriched in Co,Ni,Mo,Ag and Hg is wrapped by hydrothermal pyrite enriched in Cu,As,Sb,Au,Tl,Pb and Bi.Different host rock lithology has much impact on the alteration and mineralization features.Carbonate and sericite in altered lamprophyre show they have higher Mg than those developed in other of host rocks denoting that the carbonate and sericite incorporated Mg from phlogopite phenocrysts in the primary lamprophyre during alteration.The ore fluid activated the diagenetic pyrite in meta-quartz sandstone leading the hydrothermal pyrite enriched in Cu,Mo,Ag,Sb,Te,Hg,Tl,Pb and Bi,but the hydrothermal pyrite in meta-(ultra)mafic rock is enriched in Co and Ni as the meta-(ultra)mafic rock host rock contain high content of Co and Ni.However,Au and As shear similar range in both types of host rocks indicating that these two elements most likely come from the deep source fluid rather than the host rocks.It was shown in the disseminated orogenic gold deposit that similar hydrothermal alteration with mineral assemblage of carbonate(mainly dolomite and ankerite),sericite,pyrite and arsenopyrite develops in all types of host rocks.This is different from the Nevada Carlin type,in which alteration is mainly dissolution and silicification of carbonate host rock.On the other hand,Au mainly occur as invisible gold in both disseminated orogenic and Carlin gold deposits.     

新疆西南天山阿万达金矿区赋矿围岩物源及形成时代:碎屑锆石U-Pb年代学制约

阿万达金矿位于西南天山造山带内。此次研究在简要总结其矿床地质特征基础上,对与阿万达金矿成矿密切相关的阿克苏群中硅质片岩围岩分别进行了岩石地球化学分析和LA-ICP-MS碎屑锆石U-Pb定年研究,以期对围岩的沉积环境、物源及形成时代进行讨论。岩石地球化学分析结果显示,阿万达金矿赋矿围岩中硅质片岩的原岩可能为一套成熟度较低的泥岩或砂岩,物源主要为石英岩质沉积物,沉积环境可能处于活动大陆弧内的沉积盆地内。U-Pb定年结果显示,其碎屑锆石定年数据主要形成了加权平均年龄值为405 Ma或406 Ma的年龄峰,其谐和年龄最小峰值即405 Ma可以作为其最大沉积年龄。因此笔者认为阿克苏群中硅质片岩的沉积时代并不是前人所定的长城纪,而是不老于早泥盆世。另外,这一地层的物源组成具有多样性,～405 Ma碎屑锆石占主体,可能与哈尔克山北缘火山弧内的早泥盆世岩浆活动有关;～745Ma的碎屑锆石的出现,表明其物源有少部分来自新元古代岩石;极少数～2.50 Ga的碎屑锆石的出现,反映了华北地台对本地层有物源上的贡献。     

新疆东天山沙泉子地区化探遥感综合找矿信息与金矿成矿预测

沙泉子测区是东天山地区觉罗塔格成矿带中很有前景的成矿远景区，具有形成与酸性侵入岩有关的金矿床的前景。在对区域成矿地质条件的综合研究基础上，通过对化探和遥感找矿信息的综合分析，圈定了4片具有金矿成矿地质异常的找矿靶区，其中沙泉子北东14km处为一最佳找矿靶区。     

Epithermal Gold Mineralization in Chinese Tianshan Province

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＴｉａｎｓｈａｎｒａｎｇｅ ,ｌｏｃａｔｅｄｗｉｔｈｉｎｔｈｅＸｉｎｊｉａｎｇＵｙｇｕｒＡｕｔｏｎｏｍｏｕｓＲｅｇｉｏｎｏｆＮｏｒｔｈｗｅｓｔＣｈｉｎａ ,ｅｘｔｅｎｄｓｆｏｒａｂｏｕｔ2 5 0 0ｋｍｉｎａｎＥ Ｗｄｉｒｅｃｔｉｏｎａｎｄｈａｓａｗｉｄｔｈｏｆ 5 0 0ｋｍ .ＡｓｏｎｅｏｆｔｈｅｍａｊｏｒＰａｌｅｏｚｏｉｃｏｒｏｇｅｎｓｉｎｔｈｅｗｏｒｌｄ ,Ｔｉａｎｓｈａｎｈａｓａｇｒｅａｔｐｏｔｅｎｔｉａｌｆｏｒｇｏｌｄｍｉｎｅｒａｌｉｚａｔｉｏｎｗｉｔｈｍｉｎｅｒａｌｉｚｉ…     

山东三山岛金矿床流体包裹体特征及其地质意义

三山岛金矿床位于莱州市三山岛—仓上断裂带内,矿石主要为蚀变岩和含金石英脉2种类型。随着胶东金矿床研究的深入和三山岛金矿资源的不断减少,对三山岛金矿床的成矿作用及深部开发前景问题研究具有更重要的意义。针对上述问题,对三山岛金矿床2种类型矿石的成矿流体特征进行对比研究,认为代表成矿早—中期的蚀变岩型矿石形成于中温(均一温度为325～240℃)、低盐度(2.07%～6.88%)、低密度(0.720～0.868g/cm3)、酸碱性不均匀(pH=3.27～10.43)、以氟化物和氯化物为成矿物质载体的还原性流体;代表成矿中—晚期的含金石英脉型矿石形成于中—低温(均一温度为306～160℃)、低盐度(1.05%～9.73%)、低密度(0.739～0.962g/cm3)、碱性(pH=9.25～9.85)、以氯化物和硫化物为成矿物质载体的还原性流体。成矿流体性质的转变反映了成矿流体处于由比较封闭到比较开放的构造环境的转变期,且成矿流体早期以原生岩浆水为主,后期有变质水、大气降水以及海水的参与作用。三山岛金矿成矿深度为2.5～5km,根据目前的开采深度推算其深部还有一定的资源量可供开发。     

阿希金矿地质特征及成因初探

阿希金矿产于下石炭统大哈拉军山组,第五岩性段构成的古火山机构西南缘。矿体产出形态及空间分布,严格受近南北向弧形张扭性断裂控制。主矿体呈厚大似板状体,以南北两个富集中心向NE50°倾角侧伏。矿石以石英脉型为主,其次为蚀变岩型。围岩为英安岩和角砾熔岩。属中一低温火山期后热液型金矿床。     

玲珑金矿区成矿后花岗斑岩脉的锆石SHRIMP U-Pb年龄对胶北地体演化的制约

采用SHRIMP测年技术对玲珑金矿区成矿后花岗斑岩脉的锆石进行了U Pb年龄测定,获得岩脉岩浆锆石的206Pb/238U平均年龄为119.4 Ma,同时获得大量的继承锆石年龄,范围从3 114~127 Ma。继承锆石年龄显示,胶北地体前寒武纪经历了中太古代的陆核生成阶段;新太古代花岗岩绿岩地体增生阶段;古元古代孔兹岩系的沉积阶段;新元古代蓬莱群盖层形成阶段。整个古生代,地体处于稳定的隆升受剥蚀状态,没有明显的岩浆活动。三叠纪,华南与华北克拉通碰撞,郯庐断裂带形成。晚三叠世—中侏罗世,后碰撞的巨大挤压作用导致华北克拉通南缘地壳增厚,玲珑和蚌埠荆山等花岗岩生成。中晚侏罗世,郯庐断裂带发生了巨大的左行平移,胶北地体从蚌埠—五河的东部推移到现在的位置。早白垩世,郯庐断裂由左旋压扭向右行拉张转化,导致胶北地体上郭家岭岩体生成。中晚白垩世,郯庐断裂发生了大规模的拉张,导致沂沭裂谷、胶莱盆地、青山组火山岩、金矿床形成和隆起区大量脉岩侵入。