Geochemistry of magmatic rocks of the Koksharovka alkaline-ultrabasic massif,primorye, and results of trace-element modeling     

R. A. Oktyabrsky  A. A. Vrzhosek  A. M. Lennikov  T. A. Yasnygina  S. V. Rasskazov  E. Yu. Moskalenko  T. A. Velivetskaya 《Russian Journal of Pacific Geology》2008,2(4):325-335

New geochemical data are presented on the magmatic rocks of the Late Jurassic Koksharovka alkaline-ultrabasic massif, which is associated with deposits of vermiculite, apatite, V-bearing titanomagnetite, and placer isoferroplatinum. The REE geochemistry and strontium, oxygen, and carbon isotopic composition of carbonatites and related ijolites and pyroxenites, together with geological observations, point to the magmatic origin of the Koksharovka carbonatites. The origin of associated magmatic rocks is discussed. Trace element modeling of partial melting of mantle sources was conducted to decipher the genesis of the melts of the Koksharovka carbonatites and host titanite-kaersutite pyroxenites.  相似文献   

Changing grading of soil: effect on critical states   总被引：6，自引：3，他引：3  

David Muir Wood  Kenichi Maeda 《Acta Geotechnica》2008,3(1):3-14

Examples of situations are presented where the grading of a soil changes during its lifetime either by crushing of particles leading to an increase of fine material or by slow transport of fine particles with seepage leading to a decrease of fine material. Such grading changes influence the basic constitutive properties of the soil, in particular properties such as critical states which are dependent on the available range of densities of packing. Discrete element modelling is used to show the dependence of critical state conditions on grading and the way in which the particle assembly seeks out new critical state conditions as the grading changes.  相似文献   

初论地幔热柱与成矿——以冀西北金银多金属成矿区为例   总被引：22，自引：8，他引：14  

李红阳  阎升好  王金锁  张建珍  王国富 《矿床地质》1996,15(3):249-256

作者通过对冀两北金、银多金属矿化集中区成矿规律和物探航磁、重力及遥感信息的综合研究,提出冀西北地区存在一个超越内蒙地轴与燕山褶皱带两个不同历史大地构造单元之上的中生代地幔热柱构造。文中例举了地幔热梓构造标志特征,探讨了地幔热柱构造地质作用（超变质作用、岩浆作用、成矿作用）及其时空演化规律,建立了地幔热柱构造的壳幔成矿模式。  相似文献   

The propagation of a single shear crack: A displacement discontinuity model     

J. -Cl. De Bremaecker  K. Wei 《Pure and Applied Geophysics》1994,142(3-4):567-585

Numerical studies using the displacement discontinuity method show that a single shear crack under compression propagates in its own direction, because such propagation results in the maximum release of strain energy. The methods of linear elastic fracture mechanics may not be used for such a closed crack, and the stress intensity factors are meaningless in that case. Laboratory observations of propagation by means of kinks at an angle of approximately 70° to the crack may be due to heterogeneities, to the effect of a preexisting crack, to end effects, to microcracking, or to some combination of these factors. Such kinks may thus be local phenomena which cannot release most of the strain energy, and are not incompatible with our numerical results which are based on a global energy balance.  相似文献   

论南岭成矿带大宝山斑岩型铜矿的特殊性及其勘查意义     

赵如意 《地质与勘探》2023,59(4):716-733

广东省大宝山矿床是南岭成矿带唯一的大型铜多金属矿床，此次研究在矿区中南部发现了细脉浸染状铜矿的新类型。为确定其是否为斑岩型铜矿的成因类型，本文在梳理南岭成矿带铜成矿条件和成矿规律的基础上，查明了矿区中南部英安斑岩的蚀变和铜矿化特征。综合研究认为南岭成矿带早侏罗世中酸性斑岩的小岩体较多，叠加多期断裂构造和碳酸盐岩建造，非常有利于铜多金属成矿物质的运移、富集。大宝山英安斑岩发育黑云母化、钾长石化、青磐岩化、绢英岩化、泥化等蚀变类型，铜矿化与绢英岩化、绿泥石化关系密切。大宝山铜矿中的英安斑岩沿逆冲推覆构造侵位并呈岩墙状产出，冷却过程中受区域构造应力产生了一组平行裂隙，岩浆房去气作用排出的热液沿裂隙蚀变围岩并充填成矿。大宝山斑岩型铜矿取得的找矿勘查成果表明，“全位成矿，缺位找矿”理念可以有效指导靶区圈定和老矿山外围（深部）找矿勘查，早侏罗世的南岭具有形成较大规模斑岩型铜矿的条件。  相似文献   

科技管理兼盈——纪念程裕淇院士诞辰110周年     

耿元生 《地质学报》2022,96(9):2955-2966

程裕淇院士是我国著名的变质岩石学家、矿床学家和前寒武纪地质学家。中国科学院学部委员(院士)，中国人民政治协商会议第四届、第五届全国委员会委员，第六届、第七届全国政协常务委员会委员。程裕淇先生开拓了我国变质岩研究领域，提出了矿床成矿系列理论，发展了我国前寒武纪地质学。他在管理上积极推进地质行业的对外开放，促进国际合作交流，为建立中央直属的野战军队伍建言献策；在政协多次提案，推动了我国矿产资源法的立法和实施。  相似文献   

Multi-level dissipation element analysis of the surface temperature of the South China Sea     

《Dynamics of Atmospheres and Oceans》2021

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弹性波的三维有限元模拟   总被引：5，自引：0，他引：5       下载免费PDF全文

邓玉琼  张之立 《地球物理学报》1990,33(1):44-53

本文讨论了弹性波瞬态传播问题的三维有限元计算方法及当前存在的实际困难.针对要求计算机内存大和计算时间长的问题,采取了改进措施.由于采用了集中质量矩阵和修正的中心差分时间积分显格式相结合的方法,可以使计算机内存和计算时间大为减少;由于采用结点定位法,最适合用于目前发展的并行计算机系统,可使计算速度大大增快;还采用了有效激发震源法,有效激发区是随时间步进的增加而逐步增大,这不仅能节省计算时间,而且使波场的传播过程一目了然,本文计算了由两种介质组成的三维楔形问题,得到若干典型剖面的瞬时波场图及随时间变化的合成地震图.  相似文献   

Weathering and climate change since l820 AD in Hoh Xil, Qinghai-Xizang Plateau, China——Evidence from element geochemistry of lake sediments of Gulug Co Lake     

吴艳宏李世杰  夏威岚 《中国地球化学学报》2006,25(1):56-61

Element geochemistry of lake sediments has been widely used to detect climate change because element composition and ratios can reflect the weathering degree in the source area. Given the dement composition of lake sediments from Gulug Co Lake, Hoh Xil, Qing- hai-Xizang Plateau, chemical index of alteration （CIA）, index of composition variability （ICV） and other element ratios have been used to establish the weathering sequence of this area since 1820 AD. The weathering is so weak that the element composition change is more sensitive to climate change and autochthonous processes. From 1820 to 1984 AD, there were two drier periods with a wetter interval from 1870 to 1945 AD. After 1984 the weather showed a tendency of becoming wet.  相似文献   

Determination of potential hazardous elements in Can coals （Canakkale- Turkey）-I     

Gulbin Gurdal Alper Baba 《中国地球化学学报》2006,25(B08):52-53

It is known that the increasing use of coal as an energy source led to the growing environmental and health problems. But comprehensive knowledge of coal quality parameters may help to reduce some of these problems. The Canakkale-Can coalfield is located in the western part of Turkey, whose reserves are estimated at 69.3 billion tons, mainly used in the industry in the neighboring areas, specifically for the Can Thermal Power Plant. The aim of this study is to determine the coal quality parameters and examine the origin and distributions of potentially toxic trace elements in lignite which may produce environmental and health hazards in the area. The coal samples were collected from different parts of the coalfield in Can. Proximate and ultimate analyses, sulfur form analyses, X-ray powder diffraction （XRD）, inductively coupled plasma-mass spectrometry （ICP-MS）, and scanning electron microscopy （SEM） were performed on those samples to determine the geochemical profile of hazardous elements.  相似文献