Geological characteristics and origin of the Hadamengou gold deposit in Inner Mongolia,China

The Hadamengou gold deposit is located in the western segment of the northern margin of the North China Craton (NCC). It is hosted by Archean metamorphic rocks of the Wulashan Group. The main ore types include gold-bearing quartz vein type, gold-bearing quartz-potassic feldspar vein type, and gold-bearing altered rock type. Gold mineralization is closely related to K-feldspathization. Hydrogen and oxygen isotope data indicate that ore-forming fluids were dominated by magmatic water mixed with minor meteoric water. Sulfur and lead isotope data indicate that metallogenic materials were mainly supplied by the magmatic and Archean Wulashan Group. The gold mineralization was mainly formed during the Early Indosinian tectonic movement, which drove ore-forming fluids to the favorable depositional environment. The northern margin of the NCC is a prospective area for gold exploration. Gold deposits hosted by or related to alkaline intrusions have become one of the most important mineral exploration targets in northern China.     

酸碱环境下红层软岩泥质页岩的崩解特性试验研究

为了研究酸碱环境对泥质页岩崩解特性的影响,分别对同一风化程度的泥质页岩进行了不同pH溶液中的静态崩解试验和耐崩解试验,得到了pH值变化对泥质页岩崩解的影响规律。结果表明：pH值对泥质页岩的崩解性影响较大,pH值越小的泥质页岩的崩解性越强。崩解物的耐崩解指数随着崩解物粒径减小而增大,随着pH值的减小而减小,酸性条件对泥质页岩耐崩解性的作用效果更明显。     

Preliminary Study on Applicability of Microsatellite DNA Primers from Parasite Protozoa Trypanosoma cruzi in Free-living Protozoa

1　Introduction　Generallyknownasacodominantgeneticmarker ,microsatellitehasbeenwidelyusedinstudiesonpopu lationgenetics,high resolutiongenotyping ,genemap ping ,evolution ,linkageanalysis ,conservationbiology ,behaviouralecology ,relationsbetweenparasite…     

Study of a comprehensive assessment method of the environmental quality of soil in industrial and mining gathering areas

Industrial and mining activities have been recognized as major sources of heavy metal contamination in soil. Here, we developed a comprehensive assessment method for the soil environment in industrial and mining gathering areas based on the pressure–state–response model. Using this method, we assessed the environmental quality of soil in a typical industrial and mining gathering area in Tianjin City, China. The results are as follows: (1) The comprehensive environmental quality index of the soil in the study area was 0.532, which corresponds to an alert state and shows that the soil environment is generally poor. (2) The pressure, state, and response indexes were 0.609, 0.634, and 0.163, respectively, which suggests that the pressure in the soil environment of the study area is barely acceptable, and the state is merely passable. Furthermore, the response measures are not ideal. (3) The low response index scores indicate poor production processes, low pollutant treatment level, and unsatisfactory level of management by the enterprises in the study area. (4) The distribution of soil risks was found to be inseparably related to that of contamination sources and land use types. Furthermore, the distribution was uneven to a certain degree. Finally, we propose recommendations for the optimization, adjustment, and management of typical industrial and mining gathering areas with petrochemical, metallurgy, and other heavily polluting enterprises.     

A synsedimentary structure formation model for the Far East Jurassic-Early Cretaceous basins and uplifts,Russia

This article is to reveal and corroborate the geodynamic conditions for the formation of Cretaceous sedimentary basins of the Russian Far East. The conclusions are based on the comprehensive analysis of the extensive mapping materials and special structural field studies. It has been found that sedimentary basins developed as rift-grabens were synchronous with formation of horsts separating the basins. The imbricated-thrust structures, which are morphologically similar to the subduction-related accretionary prisms but nevertheless different in nature, were formed within the transition zone between the uplifted structures and basins. A synsedimentary supply of a mantle-derived material into basins points to a temporarily continual extension of continental lithosphere. The lithospheric plates moved apart during the strike slip faulting with the subsequent involvement of convective mantle flows and plume diapirism (continental spreading?). Because of horizontal movement of lithospheric plates, horstlike uplifts were formed in the frontal zones. In sedimentary formations overlapping the lithospheric plates, the synsedimentary imbricated-thrust structures were developed, favouring a growth of the uplifts in lateral direction toward the axial zones of rift-grabens. Synchronously with basaltic volcanic activity in the rift-graben zones, basic-ultrabasic intrusive magmatism occurred within the limits of the contiguous uplifts.     

江西省峡江铀矿床两期印支期花岗岩的年代学、岩石地球化学和岩石成因——对华南印支期构造背景和产铀花岗岩成因的指示

位于江西省的峡江铀矿床为华南一个典型的花岗岩型铀矿床,铀矿体产在金滩花岗岩体中。野外地质调查和锆石U-Pb同位素定年工作表明金滩花岗岩体主要由两期的印支期花岗岩组成,其中含矿的等粒状二云母花岗岩形成于239±1Ma,而主体的斑状黑云母花岗岩则形成于226±2Ma。二云母花岗岩具有较高的SiO₂含量（74.09%~74.53%）和明显低的TiO₂、CaO和MgO含量,铝饱和指数为1.20~1.46,含有白云母和石榴子石等过铝质矿物,属于典型的强过铝S型花岗岩。斑状黑云母花岗岩的地球化学特征略微不同于二云母花岗岩,相对富集高场强元素和稀土元素,具有明显更低的Rb/Sr比值以及更小的Eu负异常,铝饱和指数变化为1.05~1.13,属于弱过铝到强过铝花岗岩。同位素组成上,两者都具有较低的ε_Nd（t）值（二云母花岗岩：-9.0~-8.8;斑状黑云母二长花岗岩：-9.8~-9.4）和古元古代的模式年龄（二云母花岗岩：1.73~1.75Ga;斑状黑云母二长花岗岩：1.77~1.80Ga）。地球化学和同位素特征表明金滩岩体中的这两期印支期花岗岩应该都为S型花岗岩。较高的Rb/Sr比值和较低的CaO/Na₂O比值表明二云母花岗岩主要由富粘土的泥质沉积岩部分熔融而来,而斑状黑云母二长花岗岩则主要由贫粘土的碎屑沉积岩部分熔融而来。金滩岩体中的两期印支期花岗岩分别对应于华南印支期同碰撞挤压和碰撞后伸展期的岩浆作用。二云母花岗岩含有更高的U含量,矿物学以及地球化学特征与华南其他的典型产铀花岗岩类似。对比研究表明,华南印支期产铀花岗岩的形成应与同碰撞期挤压背景下的泥质沉积岩的部分熔融有关。     

新疆东天山葫芦岩体岩石学与地球化学研究

葫芦岩体位于康古尔—黄山韧性剪切带东段,地表出露面积0.75km²。主要岩石类型有辉长闪长岩、辉长岩、辉石岩、辉橄岩、橄揽岩。岩相之间多呈渐变过渡关系,局部也有侵入接触。主量元素化学组成基本上属拉斑玄武岩系列。岩石相对富集LREE、适度亏损高场强元素(Nb、Ta、Ti)。岩浆演化过程中发生了较弱的同化混染作用。橄榄石、斜方辉石、单斜辉石和斜长石的分离结晶作用是岩浆演化的主要机制。四件样品ε_Nd(t)值(＋6.4~+7.1),一件样品的ε_Sr(t)=+3.4,其余三件的ε_Sr(t)值(-10.1~-9.3),²⁰⁶Pb/²⁰⁴Pb(18.091~18.513)、²⁰⁷Pb/²⁰⁴Pb(15.459~15.528)、²⁰⁸Pb/²⁰⁴Pb(37.526~38.126)。元素地球化学和Nd、Sr、Pb同位素体系表明,源区软流圈来源的岩浆中混入了富集岩石圈地幔来源的岩浆。稀土元素地球化学证明,熔融作用发生于尖晶石稳定域内。由此可见,岩体是尖晶石稳定域内占主体的软流圈地幔与富集岩石圈地幔相互作用的结果。     

Use of molecular approaches in hydrogeological studies: the case of carbonate aquifers in southern Italy

Waterborne pathogens represent a significant health risk in both developed and developing countries with sensitive sub-populations including children, the elderly, neonates, and immune-compromised people, who are particularly susceptible to enteric infections. Annually, approximately 1.8 billion people utilize a faecally contaminated water source, and waterborne diseases are resulting in up to 2.1 million human mortalities globally. Although groundwater has traditionally been considered less susceptible to contamination by enteric pathogens than surface water due to natural attenuation by overlying strata, the degree of microbial removal attributable to soils and aquifers can vary significantly depending on several factors. Thus, accurate assessment of the variable presence and concentration of microbial contaminants, and the relative importance of potentially causative factors affecting contaminant ingress, is critical in order to develop effective source (well) and resource (aquifer) protection strategies. “Traditional” and molecular microbiological study designs, when coupled with hydrogeological, hydrochemical, isotopic, and geophysical methods, have proven useful for analysis of numerous aspects of subsurface microbial dynamics. Accordingly, this overview paper presents the principal microbial techniques currently being employed (1) to predict and identify sources of faecal contamination in groundwater, (2) to elucidate the dynamics of contaminant migration, and (3) to refine knowledge about the hydrogeological characteristics and behaviours of aquifer systems affected by microbial contamination with an emphasis on carbonate aquifers, which represent an important global water supply. Previous investigations carried out in carbonate aquifers in southern Italy are discussed.     

Active and break spells of the Indian summer monsoon

In this paper, we suggest criteria for the identification of active and break events of the Indian summer monsoon on the basis of recently derived high resolution daily gridded rainfall dataset over India (1951–2007). Active and break events are defined as periods during the peak monsoon months of July and August, in which the normalized anomaly of the rainfall over a critical area, called the monsoon core zone exceeds 1 or is less than −1.0 respectively, provided the criterion is satisfied for at least three consecutive days. We elucidate the major features of these events. We consider very briefly the relationship of the intraseasonal fluctuations between these events and the interannual variation of the summer monsoon rainfall.