丹寨汞矿卤素元素地球化学特征

丹寨汞矿是产于碳酸盐岩地层中以汞为主伴生金的浅成低温层控矿床。本文对该矿床矿石及围岩中的卤素元素分布特征进行了一定的研究。研究结果表明,（１）矿区内Ｂｒ、Ｉ的富集程度远比Ｆ、Ｃｌ高,从远矿围岩→近矿围岩→汞矿石Ｂｒ、Ｉ含量呈增加趋势,金矿石中Ｂｒ、Ｉ含量比近矿及远矿围岩含量低,且Ｉ的富集系数小于１;（２）Ｆ在金矿化岩石及近矿围岩中含量较高;（３）Ｃｌ的变化规律不甚明显,且富集系统均小于１;（４）垂     

Eh—pH相图在玉龙铜矿床次生富集作用研究中的应用

玉龙铜矿床表生成矿过程中成矿物质主要呈碳酸盐络合物的形成迁移。以孔雀石,蓝铜矿组合为主的次生富集带是在碱性,氧化的环境中形成的,所以它们相对靠近氧化带的上部及碳酸盐岩发育的地区分布。以赤铜矿,自然铜组合为主的次生氧化物富集带形成环境为弱氧化－还原,它们常靠近氧化带的中,下部分布。表生成矿环境中ＣＯ２含量高是玉龙铜矿床氧化带中黑铜矿极不发育的根本原因。『     

Magmatic source enrichment by slab-derived melts in a young post-collision setting, central Mindanao (Philippines)

Central Mindanao was the locus of a Pliocene (4–5 Ma old) arc–arc collision event followed by basaltic to dacitic magmatism starting at 2.3 Ma, representing the most voluminous volcanic field in the Philippines. Lava compositions range from calc-alkaline to shoshonitic. Adakites and Nb-enriched basalts are among the magmatic products. All the lavas are Na-rich (up to 4.88%), with Na₂O/K₂O ratios from 2.5 to 6.5. Sr, Nd and Pb isotopic compositions are similar to MORB, except for some shoshonitic lavas that have slightly less radiogenic Nd ratios. K-enrichment in basalts can be related to both fractional crystallization (FC) at moderate pressures and to partial melting of an enriched source. Trace element systematics indicate that the sub-central Mindanao mantle is characterized by the presence of garnet, phlogopite, amphibole, and perhaps some titanate phase. The enrichment of this source is attributed to the interaction of slab-derived melts, i.e., adakites, with the arc mantle. This would explain the presence of Nb-enriched basalts, transitional adakites and high-magnesium andesites, as well as the bulk Na-enrichment and relatively unradiogenic character of the central Mindanao lavas. We envision an ion-exchange type of enrichment, in which the HFSE, LILE and LREE, mobilized during slab melting, are preferentially enriched in the metasomatized mantle, resulting in a diversity of post-collision magma compositions. The MORB-like isotopic signatures of the central Mindanao lavas preclude important contributions of slab-derived hydrous fluids, sediments, continental crust or an OIB-type contaminant. Slab melting after cessation of subduction is deemed possible by thermal rebound of previously depressed geotherms. Initial contributions to mantle enrichment in post-collision sites may thus come from slab melts. In most other cases of post-collision magmatism, however, this signature can be easily masked by enrichments coming from other sources, e.g., the continental lithosphere.     

海水中~（137）Cs的快速富集与分析

以亚铁氰化铜（CuFC）作为吸附剂,采用循环吸附的方法制备用于海水中137Cs富集的富集材料,同时采用湿样制源的方法制备样品源.研究结果显示当流量在5.0、6.0 dm3/min,且富集体积保持在900 dm3以下时,对海水中137Cs的富集效率保持在85%以上,且随富集体积的变化并不明显;当流量增大到7.0、8.0 dm3/min,且富集体积从500 dm3增大到1 000 dm3时,其富集效率从85%左右下降到75%左右,呈现出明显的下降趋势;而当流量进一步增大到10 dm3/min时,富集效率急剧下降到68%左右.研究结果表明,将流量控制在5.0~8.0dm3/min且富集体积在500 dm3以下时,可以在保证较高的富集效率的同时有效地减少富集时间,达到快速富集的目的.此外,湿样制源的方式缩短了样品前处理时间,提高了样品处理效率.本研究中所使用的海水中137Cs的富集和分析方法总计耗时约需8h左右,只相当于传统分析方法耗时的1/5左右.     

三疣梭子蟹(Portunus trituberculatus)微卫星位点的分离和序列分析

采用磁珠富集法,利用生物素标记的(GT)15寡核苷酸探针从三疣梭子蟹基因组DNA的Sau3A1酶切的500-1000bp片段中筛选微卫星序列.洗脱的杂交片段克隆到PMD18-T载体上构建富集微卫星基因组文库后,通过PCR筛选检测出阳性克隆进行测序.在56条测序序列中有49条非冗余序列包含有重复次数不少于5次的微卫星位点,阳性序列比例达到87.5%.其中perfect类型微卫星最大的重复次数为47次.在47条非冗余序列中,共有40条(85.1%)微卫星重复序列两端有侧翼序列能够进行引物设计.本研究中筛选的微卫星位点将为下一步的三疣梭子蟹种群遗传结构分析、经济性状的QTL定位提供遗传标记.     

黔西北上二叠统峨眉山玄武岩风化壳中铌富集机制初探

近年越来越多的研究显示,贵州西北一带的峨眉山玄武岩风化壳上存在一套富铌、锆、钛、镓、稀土的多金属矿层,主要与风化壳中的黏土岩有关,不过,其中有关铌的赋存状态和富集机制仍有待研究.文章对黏土岩物质来源做出厘定,认为风化壳黏土岩层主要来源于高钛的峨眉山玄武岩,铌、锆、稀土等元素也继承自玄武岩.铌主要赋存于铁铝质黏土岩中(w...     

BIOLOGICAL AND CHEMICAL STUDIES OF SEA-SURFACE MICROLAYER （SML） IN DAYA BAY, CHINA IIA. BIOLOGICAL AND CHEMICAL CHARACTERISTICS OF THE SML AND THE CORRELATION AMONG THEM

Two cruises for multi-discipline investigation were conducted in October and November,1998 in Daya Bay to collect: (1) samples from five levels including sea-surface microlayer (SML), subsurface (SSL), surface, body (mid-column) and bottom water; and (2) observational data on chlorephylla and notri-eras, and important factors such as turbidity, BOD, COD, TN, TP and phytoplanklon. Results showed that there was no enrichment of chlorophyll-a in the SML, but quite notable enrichment of some organic matter and nutrients. Compared with the findings in earlier researches, PO4^-P and SiO3-Si have decreased, and the N/P ratio has increased obviously to even more than 100 in the SML. It is concluded preliminarily that PO4-P and SiO3-Si mainly determine phytoplankton growth in Daya Bay at present.     

粤东北嵩溪银-锑矿有机质中银的异常富集及其矿床勘探意义

运用电子探针测定了粤东北嵩溪黑色页岩型Ag-Sb矿床岩石中海相镜质体和固体沥青两种不同类型有机质中银的含量。矿区有机质中银含量的变化在100×10^-6～350×10^-6范围内,是原岩石中银含量的几十至上百倍。有机质中银的平均值也高出该矿床工业开采矿石品位的数倍之多,具有显著的银异常富集特征。本项研究认为有机质中银的异常值主要来源于嵩溪黑色页岩矿源层的原岩和含矿流体。在沉积成岩和后期热液改造过程中,有机质能够通过化学络合作用和还原作用捕获矿源层中岩石和含银流体中的成矿元素银,并使之进一步富集(或沉淀)在固体沥青中;据此建议矿区中沥青的分布和沥青中银矿化的特征可作为矿床勘探中一种新的找矿标志。     

低温开放体系中元素迁移富集及其初步实验：以贵州微细浸染型金矿床为例

贵州赋存于沉积碉中的微细浸染型金矿床为低温开放体系中经复杂地质地球化学作用形成。在综合研究该类矿床地质地地正规化地球化学，矿床组合和元素组合的基础上，拟定实验方案，总结出元素迁移富集的规律。     

浮游生物对某些化学物质在海洋微表层中富集所起的作用

本文综合分析了浮游生物对有机物、痕量金属、氮磷营养盐在海洋微表层中富集所起的作用。浮游植物和部分浮游细菌释放的溶解有机物大部分具有表面活性且能与痕量金属络合,它们能靠Gibbs吸附富集于微表层,并促成与络合的痕量金属的富集。浮游细菌对微表层中富集的含氮和含磷有机物的分解可能是促成氮磷营养盐在微表层中富集的重要原因。