北方干旱区表生介质中金存在形式的研究

对北方干旱区表生介质（土壤或水质沉积物）中的金进行了7种存在形式的研究，结果表明：金主要以自然金相为主（50％）以上，其次为水溶相、吸附相和有机相等。水溶相金在北方干旱气候带普遍存在，说明此自然景观区的金矿床，其表生介质中的金具有明显的溶解作用，呈水溶相金的形式进行迁移。当环境物化条件改变时，金沉淀形成局部富集。应用野外泡塑测金法，金异常衬度大、稳定性好，具有较好的找矿效果。     

表生环境中铂、钯存在形式的研究

对贵州西部岩石、土壤、水系沉积物中铂的存在形式研究表明,贵州西部土壤、水系沉积物中的铂、钯主要由>5 μm颗粒铂、钯和≤5 μm的超微细铂、钯组成,前者的存在形式既有硫、砷化物颗粒铂,又有金属互化物类颗粒铂;后者的存在形式主要以铁锰氧化物态为主,其次为水提取态、粘土吸附和可交换态、有机结合态及与硅酸盐、碳酸盐、硫化物结合的超微细铂、钯.粒径数据的初步统计表明,硫、砷化物颗粒铂的粒径主要集中在5～10 μm之间,金属互化物类颗粒铂的粒径为8～11 μm.含量数据的统计表明,颗粒铂的含量占样品总量铂的10%～70%,超微细铂占样品总量铂的30%～90%,其中水提取态、粘土吸附和可交换态、有机结合态和铁锰氧化物态4种超微细铂占样品总量铂的20%～50%,剩下的10%～40%为与硅酸盐、碳酸盐、硫化物结合的超微细铂.     

表生条件下金的迁移形式和富集机理

本文探讨了在表生条件下金的迁移形式及其富集机理。考查了多种配合物的物质来源及稳定性。认为在表生条件下，Au（S2O3）配合物是金迁移的主要形式。     

黄铁矿中金的赋存状态和存在形式研究

经过普通光片研究和电子显微镜及其ＡｎＭａＸ射线面分析，并结合测试的结果，首次发现小秦岭金矿床的黄铁矿中存在有晶格金，金是以Ａｕ＋替代Ｆｅ２＋从而进入黄铁矿中。显微金的赋存状态主要表现为：裂隙金主要分布在呈四块状产出的黄铁矿中，包体金在不同粒级及不同产出形式的黄铁矿中均有分布，但在细粒黄铁矿中明显增多。金的出现与样品中黄铜矿的分布量呈正相关关系。此外，文中还讨论了晶格金的形成机理及其意义。     

金表生富集的吸附机制

本文确立了Au(Ⅰ)、Au(Ⅲ)氯络合物的电子结构与它们在不同吸附剂上的吸附能力之间的关系。得出结论:形成次生金矿床的原因之一是Au(Ⅲ)离子在特定矿物上的选择性吸附,使Au(Ⅰ)离子发生失衡反应而形成金属金。     

表生块金与过氧化氢

我国青海、甘肃、四川及黑龙江等省都发现有产在冻土带、红壤土及砂矿中的砂金矿和表生块金。金的化学、物理性质都很稳定,但在地表过程却十分活泼,这是地球化学家们长期以来感到困惑不解的问题之一。我们在室温蒸馏水中,观察到小金粒消失和大金粒形成的过程。这个现象表明用SO_4~(2-)、HS~-、Cl~-、腐植酸等来阐明金的溶解与长大是不合适的。从所获资料看,过氧化氢在这个过程中可能扮演着重要角色。水常常表现出不寻常的化学活性,化学家们一直追索这个谜的底。前苏联的研究人员揭     

综合分析技术在微细粒浸染型金矿金赋存状态研究中的应用

采用化学组分分析、物相分析、粒度筛析、X射线面扫描分析、矿物分离分析并结合数理统计分析等综合分析技术对微细粒浸染型金矿进行工艺矿物学研究,较为快速、准确地查明该金精矿金的赋存状态.几种分析方法互为补充,结果吻合.     

渝南大佛岩矿区铝土矿碎屑锆石中钪的赋存形式研究

以渝南大佛岩矿区含矿岩系铝土质黏土岩为研究对象,通过淋滤实验证明其中钪并非以独立矿物形式和大量离子吸附形式存在的。由于铝土矿含矿层位缺少有机质,也排除了钪与有机质结合的可能性。基于扫描电镜和能谱分析的结果,发现其中的碎屑锆石富含钪元素,钪广泛分布于碎屑锆石表面,且分布非常不均匀,最高重量百分比可达2.75%,最低低于检测线,且在锆石的凹坑、裂隙与锆石上重矿物的钪含量普遍较高。结合钪易与锆发生极性类质同象的特性,本研究认为该矿区原矿石碎屑锆石中的钪,很可能有类质同象、离子吸附和超显微非结构混入物三种形式。此研究成果将对今后渝南地区铝土矿伴生钪的开发利用提供理论参考依据。     

遵义松林地区下寒武统多金属磷块岩矿物组成及铀的存在形式

含铀磷块岩是中国非常规铀资源的重要类型之一,其铀的存在形式及赋存状态一直存在争议。笔者对贵州省遵义松林地区的多金属磷块岩进行了化学成分和微量元素分析,以及扫描电镜研究,结果表明:区内多金属磷块岩中Ba含量高达2339×10~(-6),Sr/Ba值为0.33~2.48,U/Th值为118~544;在Fe/Ti-Al/(Al+Fe+Mn)图中,投影点落在热水沉积区。这反映了多金属磷块岩成因上与热水沉积作用有联系。该类岩石中含有方硫镍矿、辉砷镍矿、针镍矿、辉钼矿、黄铁矿、闪锌矿、重晶石等热液成因矿物,以及鲕粒磷灰石、胶状磷灰石、重结晶磷灰石和晶质铀矿,也指示其受热水沉积作用的影响。由此认为,区内多金属磷块岩在沉积成岩过程中,携带矿质(Ni、Mo、As、Zn、Ba、U等)的热液随着温度、压力的降低,在磷块岩的微裂隙和微孔隙中共沉淀,并析出晶质铀矿和其他多金属矿物。存在于多金属磷块岩微裂隙和微孔隙中的独立铀矿物的发现,为该类型非常规铀资源的综合开发利用提供了有利依据。     

广西英罗湾红树林表土沉积的孢粉学研究

对广西英罗湾红树林的木榄（Ｂｒｕｇｕｉｅｒａｇｙｍｎｏｒｈｉｚａ）、秋茄（Ｋａｎｄｅｌｉａｃａｎｄｅｌ）、红海榄（Ｒｈｉｚｏｐｈｏｒａｓｔｙ－ｌｏｓａ）、桐花树（Ａｅｇｉｃｅｒａｓｃｏｎｎｉｃｕｌａｔｕｍ）、海漆（Ｅｘｃｏｅｃａｒｉａａｇａｌｏｃｈａ）五个群落表土孢粉样品进行系统的分析,研究结果表明：（１）红树林表土孢粉能正确反映其植被组成,红树类孢粉在组合中占４０％～７０％左右,但不同群落其比例略有差异,秋茄群落最高,达总数４８％～７７．３％,桐花树群落略低,为３９．７５％～４６．２％,高潮线堤岸的海漆群落最低,仅为１３．８％～３７．８％;（２）在红树林表土孢粉组合中,红树类花粉比例从群落中心向群落内外侧减低,不同群落亦有差异;（３）红树林表土孢粉组合混有一定的外来种类,其动力因素为风的吹扬和流水搬运,外来孢粉以松最多,其次为水龙骨科等孢子,草本花粉最少;（４）红树林孢粉组合能很好指示其生态环境,反映热带季风海洋气候,温度、降水、含盐度、有机质含量等,指示年均气温２１～２５℃、降水量１４００～２０００ｍｍ,土壤含盐度４．６％～２７．８％,有机质３％～５％的生态环境。     

庞家河微细浸染型金矿金的赋存状态

本文论述了庞家河金矿矿石中的主要在金矿物和载金矿物，金然矿石中的配分微型赋存状态矿石中金矿物主要有自然金银金矿；主要载金矿物是黄铁矿，毒砂和粘土质矿物（含绢云母和少量粉砂质）金主要为次显微金，粒度在０．０２５～０．１μｍ之间，呈小圆球状及链状的独立金矿物（自然金）充填在黄铁矿，毒砂的微裂隙度或沉淀在晶面上或吸附在晶体边缘。在氧化或半氧化矿石中，可见到一部分可见金或显微金。     

Mineralogy of the Boroo Gold Deposit in the North Khentei Gold Belt,Central Northern Mongolia

Mineral assemblages and chemical compositions of ore minerals from the Boroo gold deposit in the North Khentei gold belt of Mongolia were studied to characterize the gold mineralization, and to clarify crystallization processes of the ore minerals. The gold deposit consists of low‐grade disseminated and stockwork ores in granite, metasedimentary rocks and diorite dikes. Moderate to high‐grade auriferous quartz vein ores are present in the above lithological units. The ore grades of the former range from about 1 to 3 g/t, and those of the latter from 5 to 10 g/t, or more than 10 g/t Au. The main sulfide minerals in the ores are pyrite and arsenopyrite, both of which are divisible into two different stages (pyrite‐I and pyrite‐II; arsenopyrite‐I and arsenopyrite‐II). Sphalerite, galena, chalcopyrite, and tetrahedrite are minor associated minerals, with trace amounts of bournonite, boulangerite, geerite, alloclasite, native gold, and electrum. The ore minerals in the both types of ores are variable in distribution, abundance and grain size. Four modes of gold occurrence are recognized: (i) “invisible” gold in pyrite and arsenopyrite in the disseminated and stockwork ores, and in auriferous quartz vein ores; (ii) microscopic native gold, 3 to 100 µm in diameter, that occurs as fine grains or as an interstitial phase in sulfides in the disseminated and stockwork ores, and in auriferous quartz vein ores; (iii) visible native gold, up to 1 cm in diameter, in the auriferous quartz vein ores; and (iv) electrum in the auriferous quartz vein ores. The gold mineralization of the disseminated and stockwork ores consists of four stages characterized by the mineral assemblages of: (i) pyrite‐I + arsenopyrite‐I; (ii) pyrite‐II + arsenopyrite‐II; (iii) sphalerite + galena + chalcopyrite + tetrahedrite + bournonite + boulangerite + alloclasite + native gold; and (iv) native gold. In the auriferous quartz vein ores, five mineralization stages are defined by the following mineral assemblages: (i) pyrite‐I; (ii) pyrite‐II + arsenopyrite; (iii) sphalerite + galena + chalcopyrite; (iv) Ag‐rich tetrahedrite‐tennantite + bournonite + geerite + native gold; and (v) electrum. The As–Au relations in pyrite‐II and arsenopyrite suggest that gold detected as invisible gold is mostly attributed to Au⁺¹ in those minerals. By applying the arsenopyrite geothermometer to arsenopyrite‐II in the disseminated and stockwork ores, crystallization temperature and logfs₂ are estimated to be 365 to 300 °C and –7.5 to –10.1, respectively.     

Gold Mineralization of the Gatsuurt Deposit in the North Khentei Gold Belt,Central Northern Mongolia

Mineral assemblages, chemical compositions of ore minerals, wall rock alteration and fluid inclusions of the Gatsuurt gold deposit in the North Khentei gold belt of Mongolia were investigated to characterize the gold mineralization, and to clarify the genetic processes of the ore minerals. The gold mineralization of the deposit occurs in separate Central and Main zones, and is characterized by three ore types: (i) low‐grade disseminated and stockwork ores; (ii) moderate‐grade quartz vein ores; and (iii) high‐grade silicified ores, with average Au contents of approximately 1, 3 and 5 g t^?1 Au, respectively. The Au‐rich quartz vein and silicified ore mineralization is surrounded by, or is included within, the disseminated and stockwork Au‐mineralization region. The main ore minerals are pyrite (pyrite‐I and pyrite‐II) and arsenopyrite (arsenopyrite‐I and arsenopyrite‐II). Moderate amounts of galena, tetrahedrite‐tennantite, sphalerite and chalcopyrite, and minor jamesonite, bournonite, boulangerite, geocronite, scheelite, geerite, native gold and zircon are associated. Abundances and grain sizes of the ore minerals are variable in ores with different host rocks. Small grains of native gold occur as fillings or at grain boundaries of pyrite, arsenopyrite, sphalerite, galena and tetrahedrite in the disseminated and stockwork ores and silicified ores, whereas visible native gold of variable size occurs in the quartz vein ores. The ore mineralization is associated with sericitic and siliceous alteration. The disseminated and stockwork mineralization is composed of four distinct stages characterized by crystallization of (i) pyrite‐I + arsenopyrite‐I, (ii) pyrite‐II + arsenopyrite‐II, (iii) galena + tetrahedrite + sphalerite + chalcopyrite + jamesonite + bournonite + scheelite, and iv) boulangerite + native gold, respectively. In the quartz vein ores, four crystallization stages are also recognized: (i) pyrite‐I, (ii) pyrite‐II + arsenopyrite + galena + Ag‐rich tetrahedrite‐tennantite + sphalerite + chalcopyrite + bournonite, (iii) geocronite + geerite + native gold, and (iv) native gold. Two mineralization stages in the silicified ores are characterized by (i) pyrite + arsenopyrite + tetrahedrite + chalcopyrite, and (ii) galena + sphalerite + native gold. Quartz in the disseminated and stockwork ores of the Main zone contains CO₂‐rich, halite‐bearing aqueous fluid inclusions with homogenization temperatures ranging from 194 to 327°C, whereas quartz in the disseminated and stockwork ores of the Central zone contains CO₂‐rich and aqueous fluid inclusions with homogenization temperatures ranging from 254 to 355°C. The textures of the ores, the mineral assemblages present, the mineralization sequences and the fluid inclusion data are consistent with orogenic classification for the Gatsuurt deposit.     

Supergene Geochemistry of Gold and Oxidation Zone of the Sain Us Gold Deposit in the Inner Mongolian Arid Region

The Sain Us gold deposit is a typical auriferous sulphide quartz vein deposit in the InnerMongolian arid steppe climatic region. The oxidation zone has been controlled by the arid cli-mate since the beginning of the Holocene. Gold supergene evolution is characterized by enlarge-ment of gold grains, complication of the gold form, raising of the gold grade and increase of thegold fineness; besides, gold and silver have two enrichment peaks at the same depth, which is insharp contrast to the unimodal enrichment of gold and silver and the occurrence of gold aboveand silver below in a humid climatic region. Sun pumping is the main cause for the bimodalenrichment of gold and silver. Illite 2 M_1 is one of the main causes for the upper enrichment peakof gold and silver.     

Remote Sensing Study of Gold Biogeochemical Effects in the Western Guangdong-Hainan Region1—A Case Study of the Hetai Gold Deposit

Abstract The vegetation has been poisoned by gold in the western Guangdong-Hainan region. The gold content of the leaves there is as high as 10-1961 times the abundance, the chlorophyll content is 10%-30% lower than that of the vegetation in metamorphic terrains and 10%-20% higher than that in granite terrains, and the carotenoid content is 10%-44% lower than the background value. The water content of leaves is 10% to 20% lower than the background value. The cells of leaves are deformed and broken. The leaf surface shows colour spots and becomes yellow or dark green. The spectral reflectance of the leaf surface is 5%-30% higher than the background value; the spectral shape has shifted 5-15 nm to the short wavelength. The gray scales of eanopy on images of Landsat TM and airborne imaging scanner (AIS) are 10%-100% higher than the background values. On Landsat TM and AIS false colour images, plants poisoned by gold display a yellow color, which disinguishes them from background plants. According to the spectral and image features of gold biogeochemical effects, the author has constructed a gold information system and expert prediction system, and thus two gold target areas and two gold prospect areas have been identified rapidly, economically and accurately in the western Guangdong-Hainan region which is extensively covered by vegetation.     

陕西略阳铧厂沟金矿床金的赋存状态研究

陕西略阳县铧厂沟金矿床为一正在开采的小型金矿床。利用野外观察、显微镜观察、电子探针扫描等综合分析技术对金矿石中金的赋存状态进行了研究。结果表明,金主要以独立矿物相存在,金的载体矿物主要为黄铁矿,其次为石英、白云石、黄铜矿、砷黝铜矿。金矿物均为自然金(成色为945～982),未发现含银自然金及银金矿等矿物。金的嵌布类型有包裹金、裂隙金、粒间金和连生金4种。矿石中自然金的粒度主要以显微微粒金(0.010～0.005 mm)为主(约占44%),其次是显微细粒金(0.020～0.010 mm)(约占22%)和显微极微粒金(0.005～0.001 mm)(约占19%)。显微中粒金—巨粒金数量较少(约占14%),但其面积含量较高(约占57%),对于矿石品位和储量来说非常重要。还讨论了铧厂沟金矿床自然金嵌布特征的地质意义以及金成色较高的成因。