鲁东胶莱盆地青山组火山岩的^40Ar—^39Ar定年——以五莲分岭山火山机构为例

以五莲分岭山火山机构为例，运用高精度的^40Ar－^39Ar定年技术，对胶莱盆地青山组火山岩的形成年龄进行了精确测定。结果表明。青山组第一旋回中偏碱性富钾火山岩的形成年龄为109．9±0．6Ma，第二旋回酸性流纹质火山岩形成年龄为108．2±0．6Ma，据此确定胶莱盆地青山组火山岩应为早白垩世岩浆活动的产物。根据该组火山岩在空间上具有自西向东年龄渐新的演变趋势，表明中生代伊泽奈崎板块向欧亚板块碰撞俯冲应是制约区内火山活动的主要动力因素。     

320矿区当冲组"硅化带"的特征及成因初探

分析研究了320矿区当冲组“硅化带”的形态、成分、结构、构造特征，应用构造地球化学原理，阐述了“硅化带”及其铀化矿的形成的过程。并表现出岩控、层控、构控、时控及“沉积－构造热液再造”等特点。当冲组富铀岩层不仅成为矿提供了物质基础，而且是矿床产生的直接围岩。     

华南地区栖霞组菊花状天青石的交代及其地质意义

本文在收集大量菊花石标本的基础上，通过岩石薄片镜下鉴定及X射线衍射分析，识别了华南地区栖霞组菊花石假象内矿物的成因类型，建立了矿物交代序列，并通过对菊花石假象内各种矿物成分的电子探针分析和对交代方解石，脉方解石及其围岩的氧，碳同位素分析，探讨了菊花石交代过程中的成岩环境,合理地解释了菊花石内正延性玉髓和栖霞组内海泡石的成因。     

华南栖霞组菊花石假象内正延性玉髓的成因及其地质意义

正延性玉髓常被视为干旱蒸发沉积环境的标志。正延性玉髓亦广泛分布于华南地区栖霞组菊花石 (目前绝大多数为天青石假象 )内。本文在天青石后期矿物交代序列识别的基础上,通过对菊花石内各期次碳酸盐交代矿物的电子探针分析,发现菊花石内正延性玉髓形成于富含硫酸根离子和镁离子的成岩介质条件中。结合已有的正延性玉髓研究报道和栖霞组的沉积、成岩作用环境特征分析,认为华南地区栖霞组菊花石内正延性玉髓的形成环境与高蒸发沉积环境或高盐度成岩环境无关。因此,仅根据正延性玉髓的出现不足以确定沉积或成岩环境的盐度条件。     

对沉积混杂作用和沉积混杂岩的再认识

回顾了沉积混杂碉的研究历史，指出了沉积混杂岩的分布位置和形成机制，重新给出了沉积混杂岩的定义，依据沉积混杂作用的不同方式划分为四种类型，重力垮塌和重力汉混杂作用，冰筏混杂作用，古喀斯特混杂作用和损落混杂作用，最后探讨了海底混杂岩块的来源和搬运方式。     

The Upper Permian Sedimentary Facies and Its Role in the Dajing Cu-Sn Deposit, Linxi County, Inner Mongolia, China

Abstract: Exhaustive investigations were launched for confirming the upper Permian host rocks of the Dajing Cu-Sn Deposit, probing into the possibility that Dajing is a Sedex type deposit during cosedimentation, complementing the deficiency of previous researches and going further into substantiating the role of the upper Permian strata in the control of ore distribution. After more than two years work, we reclassified the sedimentary facies in the Dajing area and its periphery as shallow fresh water lake and delta. Indicative sedimentary structures, such as ripple marks, rain marks, and mud cracks combined with contemporary fossils, were revealed. Having measured the flow directions, performed chemical comparison, and analyzed various sediments from sourceland in the Dajing area by XRF, we consequently redivided the strata into four sedimentary members, among which P₂l₁ and P₂l₂ were concluded as significant ore-hosted strata. The upper Permian basin was a lateral rift basin. The water and sediments in the basin are much deeper and thicker in the north than those in the south.
The indicators of special sedimentary facies, such as gravity flow, brine pool and synchronogenic stratiform structure of the ore cannot be found in the Dajing area. There was no growth fault, assemblage of sulfide and sulfate, and no zonation as well.
On the basis of study in this area, taking into account the paleosedimentary environment as capriciously flowing shallow lake, which approximated the state of oxidation, we figured that the paleogeography made it prohibitively difficult to form stratiform sulfide deposits which are prone to form in deoxidized environment. It can be ruled out the possibility that the Dajing deposit is a syngenetic deposit during sedimentation.     

递增变质作用过程中化学元素的演化规律———以山西五台群变质同位地层为例

山西五台群文溪组和柏枝岩组岩石学特征和岩石化学、微量元素及稀土元素特征研究表明，这两个组中相应层位地球化学特征基本一致。递增变质作用使岩石贫Ｎａ２Ｏ、Ｋ２Ｏ及大离子亲石元素和相对富集ＦｅＯ、ＭｇＯ及铁族元素。由于变质作用仅使稀土元素总量发生微小变化，而不改变其总体分布型式，所以稀土元素是指示岩石形成与演化的良好指示剂     

浙闽近海瓯江凹陷新生代地质构造发展特征

瓯江凹陷的上白垩统和下第三系建造序列具体反映了断凹演化。断陷阶段分为初始开裂、强裂裂开、全面裂陷和频繁振荡。凹陷阶段沐现了海浸—沉降—填满全过程,凹陷由数个剖面上呈箕状的菱形次级小断块组成。这种结构及发展特征既与弧后垃开体制有关,也与瓯江凹陷处于中生代地体碰撞带有关。瓯江凹陷是东海陆架弧后裂陷盆地的一部分。     

湘乡东山天然饮用含锌矿泉的地质特征及形成机理

湘乡市东山天然饮用矿泉水,是我省首次发现的大型含锌矿泉。它发育在北东向东台山含水断层带上,该断层长60km以上,倾向北西,斜贯湘乡境内,向西南通过歇马花岗岩体。在泉区,沿断层带发育一条硅化破碎带,最厚处达150m。断层上盘为白垩—第三系红层,下盘为板溪群,均为不透水层,对矿泉起遮挡保护作用。本矿泉水量丰富,每昼夜可取水2000t。泉水中锌和偏硅酸含量,已达到国家天然饮用矿泉水标准,另含10种人体必需的微量元素,属少见的优质矿泉。     

Quantitative assessment of future development of cooper/silver resources in the Kootenai National Forest,Idaho/Montana: Part I—Estimation of the copper and silver endowments

Faced with an ever-increasing diversity of demand for the use of public lands, managers and planners are turning more often to a multiple-use approach to meet those demands. This approach requires the uses to be mutually compatible and to utilize the more valuable attributes or resource values of the land. Therefore, it is imperative that planners be provided with all available information on attribute and resource values in a timely fashion and in a format that facilitates a comparative evaluation.The Kootenai National Forest administration enlisted the U.S. Geological Survey and U.S. Bureau of Mines to perform a quantitative assessment of future copper/silver production potential within the forest from sediment-hosted copper deposits in the Revett Formation that are similar to those being mined at the Troy Mine near Spar Lake. The U.S. Geological Survey employed a quantitative assessment technique that compared the favorable host terrane in the Kootenai area with worldwide examples of known sediment-hosted copper deposits. The assessment produced probabilistic estimates of the number of undiscovered deposits that may be present in the area and of the copper and silver endowment that might be contained in them.Results of the assessment suggest that the copper/silver deposit potential is highest in the southwestern one-third of the forest. In this area there is an estimated 50 percent probability of at least 50 additional deposits occurring mostly within approximately 260,000 acres where the Revett Formation is thought to be present in the subsurface at depths of less than 1,500 meters. A Monte Carlo type simulation using data on the grade and tonnage characteristics of other known silver-rich, sediment-hosted copper deposits predicts a 50 percent probability that these undiscovered deposits will contain at least 19 million tonnes of copper and 100,000 tonnes of silver. Combined with endowments estimated for identified, but not thoroughly explored deposits, and deposits that might also occur in the remaining area of the forest, the endowment potential increases to 23 million tonnes of copper and 190,000 tonnes of silver.