The Effect of Flow on Pollution and Remediation in Groundwater

1IntroductionFlow is the key mechanism by which pollutants are transmitted from one point to another in hydro-geologic systems. Groundwater flow is not indepen-dent of the geological formation within which it occurs. Hydraulic conductivity which is a measure of groundwater flow is strongly related with the am-bient geologic properties such as texture,porosity and topography. These properties do not only con-trol the rate of groundwater flow but also limit the occurrence,hence the dispersion of…     

An Alternative Index for the Onset of the Summer Monsoon over the South China Sea

1　Introduction　TheindicesfortheAsianmonsoonhavebeenstud iedinmanyworks .Recently ,thechoiceofpropermonsoonindiceshasreceivedexceptionalattentionandraisedcontroversy (WebsterandYang ,1 992 ;Goswa mietal.,1 999;Goswami,2 0 0 0 ;Wang ,2 0 0 0 ) .Us ingzona…     

Recognition and Significance of Volcanic Rocks of the Anda Depression of the Songliao Basin in Jurassic-Cretaceous

In the northern Songliao Basin, volcanics are fre-quently found and related closely to tectonic activi-ties during Early Cretaceous. The lava is mainly erupted along deep faults and distributed along the margine of the faulted depression. In deep part of Xujiaweizi area, natural gas exploration has been very successful, such as in the well Wang 9-12, well Shengshen 101 and well Fangshen 9 which are all highly-yield gas wells. Anda fault depression is lo-cated in the north of Xujia…     

Calculated Porosity of Volcanic Reservoir in Wangjiatun of the Northern Songliao Basin, NE China

1IntroductionVolcanic reservoirs are widespread in basins from China to the world,such as Songliao Basin,Subei Basin,Bohaiwan Basin, etc in China(Chen,1988;Chen and Li,1996;Dai and Jiang,1997;Dong,1988). As deeper study of volcanic reser-voirs,its calculated porosity is a difficult point for the appraisal of volcanic reservoirs (Dong,1991;Fujita-Yoshihiko,1985;Guo and Liu,1997;He,1999;Li,1999;Liu,1998;Luo and Shi,1996;Tang,1988;Uchida,1992;Wang,1997;Wang,1991;Yan and Yu,1996). Its …     

A Method for Determining Sedimentary Micro-Facies Belts Automatically

1IntroductionThe method is to find the boundary of distribu-tion of sedimentary micro-facies and draw the map of sedimentary belts based on known data of sedi-mentary facies from each layer(strata unit or sedi-mentary unit) of each well in a specific area. It is important to understand the distribution of sedimentary micro-facies. Generally determining the distribution of sedimentary facies is a primary and hard job in the stage of oil-field development. At the scale of sedimentary micro-f…     

Methane-rich fluid inclusions and their hosting volcanic reservoir rocks of the Songliao Basin, NE China

Methane-rich fluids were recognized to be hosted in the reservoir volcanic rocks as primary inclusions. Samples were collected from core-drillings of volcanic gas reservoirs with reversed δ^13C of alkane in the Xujiaweizi depression of the Songliao Basin. The volcanic rocks are rhyolite dominant being enriched in the more incompatible elements like Cs, Rb, Ba, Th, U and Th with relative high LREE, depleted HREE and negative anomalies of Ti and Nb, suggesting a melt involving both in mantle source and crustal assimilation. Primary fluids hosted in the volcanic rocks should have the same provenance with the magma. The authors concluded that the enclosed CH4 in the volcanics are mantle/magma-derived alkane and the reversed δ^13C of alkane in the corresponding gas reservoirs is partly resulted from mixture between biogenic and abiogenic gases.     

“Smashing the Moon”Accelerating Global Warming

At the beginning of the 21st century, the world is facing too many natural and artificial disasters, and man is also facing various decisions difficult to be made. The evidence for the earth warming-up is more clear year by year and natural disaster occurs frequently and economic loss in miserable situation, moreover, the evil consequence from the lose of control technologically, overage development is more serious year after year and the daily ecological envi-ronment of man is trending toward…     

Study on stability and reinforcement of a landslide on Ji''''an-Dandong highway

This study clarified the failure mechanism of a landslide on Ji'an-Dandong highway,through the detailed analysis of its geological condition.Then based on the back analysis of the broken landslide,take limit equilibrium method to evaluate the stability of the potential landslide.The result shows that the landslide is lack of safety stock,so anchor rope is designed to reinforce the landslide.     

Petrogenesis of Jurassic granitoids in the west central Lhasa subterrane,Tibet, China: the Geji example

The Jurassic magmatic and volcanic rocks are widespread along the west central Lhasa subterrane. However, the petrogenesis of these rocks is poorly understood because of lacking high-quality geochronology and geochemical data. Here, we present new zircon U–Pb age and Hf isotopic data, whole-rock geochemical and Sr–Nd–Pb isotopic data for the Songduole and Qiangnong plutons in Geji area. LA-ICP-MS dating of zircon yield crystallization ages of 172.1 ± 1.9 and 155.9 ± 1.2 Ma for the Songduole and Qiangnong plutons, respectively. Geochemically, Songduole and Qiangnong granodiorite are characterized by high MgO (2.63–3.49 wt%), high Mg# (49–50), and low TiO₂ (0.48–0.57 wt%). Besides, all rocks show metaluminous, calc-alkaline signatures, with strong depletion of Nb, Ta, and Ti, enrichment of large-ion lithophile (e.g. Rb, Th, K), and a negative correlation between SiO₂ and P₂O₅. All these features are indicative of arc-related I-type magmatism. Five samples from the Songduole granodiorite have whole rock (⁸⁷Sr/⁸⁶Sr)_i of 0.71207–0.71257, ε_Nd(t) values of ?15.1 to ?13.9, zircon ε_Hf(t) values of ?17.4 to ?10.5, (²⁰⁶Pb/²⁰⁴Pb)_t ratios of 18.402–18.854, (²⁰⁷Pb/²⁰⁴Pb)_t ratios of 15.660–15.736, and (²⁰⁸Pb/²⁰⁴Pb)_t ratios of 38.436–39.208. Samples from the Qiangnong granodiorite have (⁸⁷Sr/⁸⁶Sr)_i of 0.71230–0.71252, ε_Nd(t) values of ?15.1 to ?14.2, zircon ε_Hf(t) values of ?12.6 to ?6.4, (²⁰⁶Pb/²⁰⁴Pb)_t ratios of 18.688–18.766, (²⁰⁷Pb/²⁰⁴Pb)_t ratios of 15.696–15.717, and (²⁰⁸Pb/²⁰⁴Pb)_t ratios of 38.546–39.083. These geochemical signatures indicate that the two plutons most likely originated from partial melting of the ancient Lhasa lower crust with obvious inputs of mantle-derived melts. Combined with regional geology, our results indicate that the Jurassic magmatism in the west central Lhasa subterrane most likely resulted from the southward subduction of the Bangong Ocean lithosphere beneath the central Lhasa terrane.     

大兴安岭北段塔河南部早白垩世侵入岩年代学和地球化学

以大兴安岭北段塔河南部基性、中性和酸性侵入岩(SiO2=5127%~7490%)为研究对象,通过锆石U Pb年代学、Hf同位素和岩石地球化学分析,探讨了其岩石成因和构造环境。测定的2件样品锆石U Pb定年结果分别是(1269±08) Ma和(1234±09) Ma,侵位于早白垩世。在哈克(Harker)图解中,多数样品主量元素和微量元素随SiO2含量增加具有很好的线性演化趋势(除K2O和Rb外)。微量元素总体显示富集Pb和大离子亲石元素K、Rb、Ba等,亏损高场强元素Nb、Ta、Ti、P等,并具有相似的Sr、Nd同位素特征((87Sr/86Sr)i=0705 517~0706 827,εNd(t)=-682~079)。综合研究认为,塔河南部早白垩世侵入岩的岩浆源区是与俯冲有关的熔流体交代的石榴子石二辉橄榄岩相和尖晶石二辉橄榄岩相的混合源区,且以石榴子石二辉橄榄岩相为主,在岩浆快速上升的过程中主要经历了分离结晶作用,最后形成一套宽谱系的岩浆演化序列。结合中国东北地区火山岩展布方向、古地磁资料、蒙古—鄂霍茨克洋闭合时间以及古太平洋板块俯冲方向等已有成果,认为大兴安岭北段塔河南部的侵入岩产出在与蒙古—鄂霍茨克洋闭合有关的后碰撞环境。