北淮阳盆岭带的构造演化与铀成矿

北淮阳盆岭构造带是大别造山带的重要组成部分。佛子岭岩群代表了早古生代扬子地块北缘大别古岛弧弧前海盆的火山沉积建造,在加里东运动陆块对接过程中变形变质。石炭系梅山群具磨拉石建造特征。在华力西印支期陆内俯冲褶皱带的基础上,燕山期沿桐柏桐城断裂伸展北移,近东西向断陷盆地发育,形成盆岭构造景观。南侧大别山强烈隆升,铸就了现今大别山变质核杂岩构造格局。中生代岩浆活动是区内重要铀源,具有成矿潜力的地质体是响洪甸正长岩体和北带粗面质火山碎屑岩     

贵州织金地区稀土磷块岩矿床中稀土元素赋存状态

以稀土磷块岩矿床为研究对象,采用电感耦合等离子体光谱法和质谱法研究了3个代表性样品的基本化学组成,分析了40多个元素的含量,确定了矿物质量分数和赋存状态,研究了稀土元素在其中的分布特征。结果表明,97%以上的稀土元素呈类质同象状态部分置换磷灰石晶格中的Ca2 存在,只有小于3%的稀土元素呈被粘土质等吸附状态或离子交换(吸附)状态存在。     

德州市城区沙河街组热储地热地质特征研究

通过该井地热钻探及区内已有石油钻探研究资料,对德州市城区古近纪沙河街组地热资源的地质背景、地热地质特征等进行了综合分析研究,认为沙河街组地热资源属于层控型低温地热田,在沧东断裂以东都有分布,热储层厚度超过120m,地热水中碘、锶、铁、偏硅酸达命名浓度,具有一定的开发利用价值。     

西藏盐湖沉积物：一种潜在的铷、铯资源

铷、铯是我国战略性关键矿产资源。西藏盐湖卤水中赋存着丰富的铷、铯资源,但是品位普遍低于10 mg/L。根据热泉与盐湖锂、铷、铯等元素的补给关系和含量差异特征及铷、铯极易被黏土矿物吸附等特点,推测盐湖沉积物中赋存一定规模的铷、铯资源。为验证该推测,本文选取西藏拉果错、聂尔错、依布茶卡、当穹错、扎布耶茶卡等5个典型盐湖,采集卤水和沉积物样品各5件,开展水体中铷、铯含量和沉积物矿物成分分析,结合沉积物分相淋滤实验,得出如下结论：西藏拉果错、当穹错、聂尔错盐湖卤水铷、铯含量和资源量与其补给量差异显著,大量的铷、铯资源消耗于盐湖沉积物中;盐湖沉积物中的铷、铯含量远高于卤水。铷、铯在沉积物水溶相、碳酸盐相中含量较低,主要以吸附形式赋存于黏土矿物(主要为伊利石),吸附点位包括基面位置、难解吸的磨损边缘及层间位置。盐湖沉积物铷、铯资源量远超大型矿床规模,黏土矿物中铷、铯含量高达100 n×10-6,超过固体盐类矿产综合评价指标,相较于现有盐湖钾产品中的铷资源、含铯硅华中的铯资源开发,具有较好的开发利用性,是一种潜在的铷、铯资源。本研究成果有助于完善盐湖铷、铯富集成矿机制,并为高效开发盐湖中的铷、铯资源提供理论支撑。     

Mineral occurrence for Dachang gold deposit and its impact on gold recovery rate in Qumarleb County,Qinghai

Based on X-ray diffraction, optical microscopy and scanning electron microscopy analysis of the Dachang gold ore, it is showed that the sulfide of ore is the main carrier minerals of gold. A majority of gold is embedded in pyrite and tetrahedrite as the form of inclusion and a small amount intergrowth with pyrite and gangue mineral, occasionally the presence is in form of monomer natural gold. The main factors which influence the recovery rate are sulfide mineral particle size, and the fine grained sulfide is beneficial for the dissociation and flotation of gold bearing minerals. The monomer dissociation degree of gold bearing minerals can reach 91.3% , when the grinding fineness is less than 0. 074 mm and grain level accounts as 80%. It is not conducive to the flotation of sulfide if the grinding fineness is low or high. It is difficult to completely dissociate the monomer if there is a small amount of pyrite and arsenopyrite in the ore. Therefore, before leaching the gold, it must conduct pretreatment to reach the ideal recovery rate of the gold, like roasting oxidation, pressure oxidation and biological oxidation. The fine microscopic gold has little influence on the gold recovery rate.     

禹城市城区东营组热储地热资源赋存特征研究

山东省禹城市城区在大地构造上属于华北陆块、华北拗陷区、济阳坳陷区、惠民潜断陷、临邑凹陷南部。通过已有钻探资料及近年的勘查项目研究成果,对禹城市城区东营组热储的地热资源的地质背景、水文地质特征、地热流体化学特征等进行了综合研究分析,认为禹城市城区东营组热储属于层控型低温地热田,地下热水矿化度较大,成因主要为大气降水。     

Variability of tropical cyclone in high frequent occurrence regions over the western North Pacific

In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region E), are defined with frequency of TC's occurrence at each grid for a 45-year period(1965–2009), where the frequency of occurrence(FO) of TCs is triple the mean value of the whole western North Pacific. Over the region S, there are decreasing trends in the FO of TCs, the number of TCs' tracks going though this region and the number of TCs' genesis in this region. Over the region P, the FO and tracks demonstrate decadal variation with periods of 10–12 year, while over the region E, a significant 4–5 years' oscillation appears in both FO and tracks. It is demonstrated that the differences of TCs' variation in these three different regions are mainly caused by the variation of the Western Pacific Subtropical High(WPSH) at different time scales. The westward shift of WPSH is responsible for the northwesterly anomaly over the region S which inhibits westward TC movement into the region S. On the decadal timescale, the WPSH stretches northwestward because of the anomalous anticyclone over the northwestern part of the region P, and steers more TCs reaching the region P in the greater FO years of the region P. The retreating of the WPSH on the interannual time scale is the main reason for the FO's oscillation over the region E.     

Last glacial emplacement of methane-derived authigenic carbonates in the Sea of Japan constrained by diatom assemblage,carbon-14, and carbonate content

We studied diatom assemblages and CaCO₃ contents of methane-derived authigenic carbonates from the eastern margin of the Sea of Japan and assessed the formation time of these samples. Radioactive ¹⁴C date was determined in selected samples to obtain the maximum age of the time. The results of our study suggest mass formation of carbonate nodules in a glacial period within ∼40 ky, consistent with a published U/Th dating result of carbonate nodules in the study area. Diatom assemblages and contents in the carbonate nodules (abundance of ∼10⁶/g, dominance of neritic-littoral species, warm/cold water species ratio lower than ∼25) differ from the near-seafloor sediments in the study area, which have characteristics of Holocene sediments in the Sea of Japan, and suggest cementation of glacial sediments. Laminated sediments in some nodule samples are glacial sediments because laminations are records of a low sea level period in the semi-enclosed ocean. Similarity of diatom assemblages and contents in all carbonate samples is another evidence of glacial sediments in nodules. Glacial sediments with oceanic cold water species as low as Holocene sediments restricts the sediment age to before 20 cal. ky BP. Carbonate contents higher than 78 wt% suggest the cementation of poorly compacted sediments near the seafloor, and the date of carbonate cementation is, therefore, close to that of the cemented sediments. Most carbonate nodule samples in this study were formed in a glacial period and detection of ¹⁴C restricts this period to within ∼40 ky.     

应用能谱扫描电镜与X射线衍射等分析技术研究西藏扎西康铅锌矿中伴生元素锰的赋存状态

西藏扎西康铅锌多金属矿床是我国首次发现的喷流沉积-热泉水改造型锰铁锑铅锌银矿床,已有研究表明矿床中除了铅锌矿还伴生有银、锑、铜、硫、锰、砷等多种元素。本文在化学多元素分析和光学显微镜镜下鉴定的基础上,结合能谱扫描电子显微镜和X射线衍射分析等手段对扎西康铅锌矿中伴生组分Mn的含量、矿物种类、嵌布和包裹等特性进行了研究。分析结果表明,原生矿石的主要成矿元素Pb和Zn的含量分别为6.00%和4.00%,伴生元素Mn的含量平均达到4.36%;原生矿石中的主要矿物为方铅矿、闪锌矿,其次为黄铁矿、毒砂和菱锰矿等。原生矿石中伴生元素Mn主要以独立的菱锰矿和铁菱锰矿形式存在,与闪锌矿和方铅矿密切共生,是成矿早期重要的载矿矿物,嵌布在石英、黄铁矿、闪锌矿和毒砂的粒间、边部及空隙间,其次以类质同象形式赋存于菱铁矿和菱锌矿中。进一步对扎西康铅锌矿选冶产物中的伴生元素Mn的含量和赋存状态进行研究,研究表明Mn具有较高的综合利用价值,在原生矿石、铅精矿、锌精矿和尾矿中的质量分数分别为4.36%、0.51%、0.95%和5.36%,显示Mn很少一部分进入铅精矿和锌精矿,而绝大部分进入尾矿;Mn在尾矿中仍主要以菱锰矿形式存在,存在形式与原生矿石相比未发生改变,可通过强磁选工艺从铅锌尾矿中综合回收利用Mn。     

中国内生钼矿床辉钼矿的微量元素特征研究

近年来,金属硫化物微量元素研究取得了重大进展,但主要局限于少数常见的硫化物,如黄铁矿。辉钼矿作为内生金属矿床最常见的金属硫化物之一,目前对其微量元素的研究成果还很少,对微量元素的赋存状态及其揭示的成因意义还不明。文章尝试性地对中国57个内生独立钼矿床或共伴生钼矿床中的辉钼矿进行了ICP_MS微量元素分析。结合元素的地球化学性质及前人的研究成果,认为除Re、Os等少数元素可成类质同象存在于辉钼矿中以外,推测大部分微量元素可能以固溶体出溶、机械混入物或流体包裹体等形式存在于辉钼矿中。各矿床中辉钼矿微量元素相对于中国陆壳富集Cu、Zn、Pb、W等常见的成矿元素,暗示不同地质环境下不同时代和矿床类型的成钼流体搬运的成矿元素具有一致性和普遍性,这是造成钼多金属矿床金属元素矿化分带的基础。辉钼矿的主要微量元素呈对数正相关,受矿床类型和产出环境影响不大;辉钼矿Co/Ni比值多数1,集中于0.01~0.57,不同矿床类型的Co/Ni比值具有一定规律性:当w(Co)30μg/g时,斑岩型和矽卡岩型矿床中辉钼矿的Ni含量比较稳定;当w(Co)30μg/g时,Ni含量比较高;石英脉型矿床的Co/Ni比值变化较大,且小于斑岩型矿床的Co/Ni比值。在内生金属矿床中,辉钼矿主要形成于还原性环境中,但石英脉型矿床的形成条件与斑岩型矿床相比,其氧化性明显增强。根据分析结果和前人研究成果,推测成钼流体应为富CO2和Cl-(个别还富含F-)以及部分还原性气体成分(H2、CO、CH4等)的成矿流体。