藻源性湖泛水体显黑颗粒的元素形态分析与鉴定   总被引：6，自引：6，他引：0  

申秋实  范成新 《湖泊科学》2015,27(4):591-598

湖泛现象是我国超富营养化浅水湖泊面临的最严峻环境问题之一,水体发黑、发臭是湖泛水体最显著和基本的物理特征.针对太湖湖泛显黑颗粒缺乏从元素形态直接给出证据的问题,针对室内模拟藻体和沉积物存在下形成的湖泛水体,采用多种图谱分析技术,对厌氧截留分离的显黑颗粒物质及其化学组成和元素形态进行了分析鉴定.扫描电镜-X射线能谱分析与荧光光谱分析表明:湖泛水体显黑颗粒物质以藻类残体和悬浮沉积物颗粒物为主,其组成元素以C、O、Si为主;与未发生湖泛的对照样相比,湖泛水体显黑颗粒物样品中具有更高的Fe、S含量.X射线光电子能谱Fe、S微区分析进一步表明:湖泛显黑颗粒物样品中Fe主要以Fe(Ⅱ)的形式存在、S则以还原态S2-的形式赋存,两者具有共同化合成Fe S的充要条件.因此,缺氧厌氧条件下,湖泛水体的显黑物质组成是Fe S,它可由水体中Fe2+和ΣS2-通过化学共沉淀形成,并主要通过吸附于悬浮颗粒物之上而使得整个水柱呈现黑色,指示湖泛的暴发过程和维持状态.  相似文献   

日龙沟锡—多金属成矿区综合物探找矿方法应用研究   总被引：1，自引：0，他引：1       下载免费PDF全文

周立国  王延浩  张单乐  张晓闯 《地球物理学进展》2009,24(6):2255-2260

通过对日龙沟锡—多金属矿区物探工作的研究分析,结合地质物探工作,提出了在日龙沟寻找磁黄铁矿化热液改造型锡—多金属矿床的找矿标志和工作方法.利用该方法对矿区外围进行验证,认为矿区外围成矿条件优越,已有多个钻孔见矿.因此,可以总结出该区域寻找此类型矿体的地球物理预测模型,为该区今后的找矿工作提供经验.  相似文献   

The seasonal variability of the northern Benguela undercurrent and its relation to the oxygen budget on the shelf     

V. Mohrholz  C.H. Bartholomae  A.K. van der Plas  H.U. Lass 《Continental Shelf Research》2008

The seasonal variations in the advection and mixing of water masses in the northern Benguela were studied in relation to the oxygen minimum zone over the Namibian shelf. The used data set consists of hydrographic and current measurements from an oceanographic mooring 20 nm off Walvis Bay, monthly CTD transects from the Namibian 23°S monitoring line and recent large-scale hydrographic surveys. The current time series showed an intermittent southward continuation of the Angola Current (AC) through the Angola–Benguela frontal zone (ABFZ) into the northern Benguela, commonly known as poleward undercurrent. In austral summer hypoxic, nutrient rich South Atlantic central water (SACW) from the Angola Gyre is transported into the northern Benguela, whereas during the winter season the oxygen rich Eastern SACW (ESACW) spreads northward. The water mass analysis reveals a mixing between both water masses in the northern Benguela between the ABFZ and the Lüderitz upwelling cell (27°S). The oxygen balance over the Namibian shelf depends to a high extent on the water mass composition of the upper central water layer, controlled by the large scale and local circulation. The deviation of the measured oxygen concentration from its mixing concentration, calculated with the source water mass properties, was used to quantify the oxygen consumption. A new local definition SACW was derived to exclude biogeochemical processes, taking place in the Angola Gyre. The oxygen deficit in the northern Benguela central water amounted to about 60–80 μmol l⁻¹ at the shelf edge and increased up to 150 μmol l⁻¹ on the shelf, due to local oxygen consumption. In the austral summer anoxic bottom waters are observed at the central Namibian shelf, which correlate to an SACW fraction >55%. Periods with high SACW fraction in the water mass composition were congruent with hydrogen sulphide events detected by remote sensing.  相似文献   

微细金属硫化物分选提纯方法研究     

丰彦薇 《地质力学学报》2001,7(2):151-154

对某些微细金属硫化物进行分选和提纯,按照一般的工作流程,可能会改变矿物表面形态,影响测试效果。本文作者对我国广西金牙卡林型金矿的微细毒砂和黄铁矿进行分选和提纯时,改用纯粹水淘洗法工作流程,所选单矿物保存了矿物表面的自然形态,满足了测试工作的需要,为该矿床的研究提供了可靠的资料。   相似文献   

河南内乡板厂铜多金属硫化物矿床地质特征及成因分析     

张智慧  邓军  秦明  方荣 《矿产与地质》2013,(2):89-95

板厂铜矿床位于东秦岭造山带内,区内出露地层主要为二郎坪群细碧岩类及秦岭群大理岩类。矿体地表呈带状分布,倾向上矿体呈层状、似层状、叠瓦状重复出现。矿体与围岩呈渐变过渡关系,矿层随含矿地层硅质岩展布而展布。对24种微量元素编制的配分图解中可以看出矿化层、矿化硅质岩、无矿化硅质岩、无矿化大理岩中的微量元素配分曲线有一定的相似性,同时发现矿化硅质岩中碳酸岩条带δ18 O结果为18.809‰～21.572‰,和海底喷流沉积δ18 O范围相近。通过研究分析,认为板厂铜多金属硫化物矿床成因为海底喷流沉积金属硫化物矿床。  相似文献   

论滇中砂岩铜矿浅、紫交互带赋矿及其金属硫化物分带之成因与成矿作用演化     

胡煜昭  吴鹏  冉崇英 《地质论评》2013,59(5):893-899

康滇古大陆裂谷的发生和演化造就了楚雄盆地,沉积出煤、铜、盐旋回与含矿建造和矿床组合.铜矿的生成(特别是改造富集)与煤(有机质)、盐(热卤水)密切相关.大姚—牟定式砂岩铜矿以其规模最大而具代表性.它的成矿作用的演化是从风化沉积作用到成岩作用、后生作用再到改造作用.作用的结果是分别产生含铜有机质沉积体、成岩矿层、后生矿层和改造富矿体.层状矿体赋存于砂岩浅紫交互带是氧化性流体与还原性流体相汇于斯而发生氧化—还原反应沉积成岩的结果.其金属硫化物的生成顺序与分带是遵循S、O、Fe、Cu热液体系中矿物共生组合规律的,随介质条件、四元素浓度的差异而变化.  相似文献   

论硫化氢生成的地质条件   总被引：1，自引：0，他引：1  

陈安定  李剑锋  代金友 《海相油气地质》2009,14(4):24-34

根据硫化氢的赋存环境、组成特征和热还原反应模拟试验等,提出硫化氢生成需具备五项基本地质条件:(1)地层中富含石膏;(2)富含还原剂—烃类物质;(3)较大埋深或较高的地温条件;(4)地层水作为介质和反应场所;(5)严密的封存体系。热还原反应必须在有水条件下才能进行,硫酸盐水解后的硫酸根是硫化氢的直接供体。硫化氢的生成实际经历了一个天然气向地层水的溶入和脱出过程,两者的密切关系造成含硫化氢天然气通常出现在气-水界面附近,密封条件极好的岩性气藏或构造气藏当中,构造低部位或气藏下倾方向。但是,后期构造抬升有可能造成硫化氢与地层水的分离。  相似文献   

安徽省铜陵新桥锰矿床矿石物质组分及其赋存状态和找矿意义分析     

张青  袁晓玲  张鹏 《安徽地质》2009,19(4):260-263,267

通过对矿石物质组分及其赋存状态研究,发现安徽铜陵新桥锰矿床的锰除主要赋存在菱锰矿中外,有约30％赋存在方解石和金属硫化物中,而且金属硫化物中含有大量金。认为方解石和金属硫化物中锰的大量存在是选矿过程中锰回收率低的主要原因;该矿床具有较高的金综合利用价值,对寻找金属硫化物富集带有重要的找矿意义。  相似文献   

锍镍试金富集-等离子体质谱法测定煌斑岩中铂族元素   总被引：8，自引：4，他引：4       下载免费PDF全文

石贵勇  孙晓明  张燕  韦慧晓  刘邦 《岩矿测试》2008,27(4):241-244

试金配料中适量加入铁粉,控制硫化铁在锍扣中的含量在20%~40%,获得的锍扣直接用水浸泡粉化后加盐酸分解,分解结束后趁热过滤,沉淀用1mL王水溶解,定容后上机测定,Cs作内标。改进后的方法空白水平进一步降低,检出限得到显著改善,分析流程简化。采用改进后的锍镍试金富集-等离子体质谱法测定了云南哀牢山金矿带煌斑岩和国家一级标准物质GBW 07288(GPt-1)、GBW 07290(GPt-3)中的铂族元素(PGEs)含量,方法检出限为0.001~0.01ng/g,精密度(RSD,n=5)为7.49%~16.6%。  相似文献   

Iron mineralisation in Mio-Pliocene sediments of the Tamra iron mine (Nefza mining district, Tunisia): Mixed influence of pedogenesis and hydrothermal alteration     

Sophie Decre  Thierry De Putter  Johan Yans  Bchir Moussi  Philippe Recourt  Fakher Jamoussi  Delphine Bruyre  Christian Dupuis 《Ore Geology Reviews》2008,33(3-4):397-410

The Tamra iron mine (Nefza mining district, N. Tunisia) has been exploited for about one century. There are, however, very few publications modelling the mineralisation within this 50 m-thick Messinian–Zanclean sedimentary series. We present the result of a detailed sedimentological, mineralogical and geochemical study on the siliciclastic sediments heavily mineralised in iron. In their present state of preservation, these are rather unusual sediments, wherein most of sedimentological information is obliterated by iron impregnation. The whole series consists of a succession of fining-upward sequences (a few meters in thickness) that are capped by clay-bearing variegated and mottled horizons, each sequence being interpreted as a shallowing-upward sequence topped by an emersive horizon corresponding to a paleosoil. We propose that alteration and/or pedogenesis by the downward percolation of meteoric fluids accounts for most of the initial iron concentration, while a hydrothermal overprint, linked to the neighbouring Miocene magmatic rocks and associated mineral deposits (Sidi Driss Fe–Pb–Zn mine), accounts for the existing extreme iron enrichment. The proposed model is likely to apply to several other iron mines linked to the Miocene magmatic activity in the whole Maghreb area, and especially along the Apenninic thrust front (locally known as Tell-Rif front).  相似文献