Preliminary investigation of mineralogy,petrology and chemical composition of Qingzhen enstatite chondrite     

Daode Wang  Xiande Xie 《中国地球化学学报》1982,1(1):69-81

On September 13, 1976, the Qingzhen enstatite chondrite fell near Qingzhen County, Guizhou Province (26°32′N, 106°28′E). The total mass recovered was 2.6 kg. Phenomena of the meteorite fall were recorded as well. In the present paper some of the significant observations are described. X-ray diffraction analyses and petrologic studies revealed that it is mainly composed of enstatite/clinoenstatite, plagioclase, troilite, kamacite, taenite, quartz and oldhamite. X-ray electron microprobe analyses were performed on orthoenstatite and clinoenstatite. Chemical analysis gave: SiO₂-36.48; Al₂O₃-1.64; TiO₂-0.08; Cr₂O₃-0.28; FeO-0.30; MnO-0.25; MgO-18.19; CaO-1.14; Na₂O-1.06; K₂O-0.11; H₂O⁺-0.47; H₂O^?-0.10; P₂O₅-0.39; FeS-13.35; FeO-22.94; Ni-1.81; Co-0.093; C-0.37; Cu-0.022; Zn-0.027; CaS-0.60; total-99.70 (wt.%). This meteorite has been extremely reduced; all iron is present as FeS and metallic Fe-Ni. The Qingzhen enstatite chondrite is characterized by high ratio, Si/Mg as compared with ordinary chondrites, scarcity of olivine, and enrichment in sulfur and iron. In thin sections, it is observed that round chondrules approximately account for 10–15 per cent, being porphyritic, radial, excentroradial, or excentric fan-shaped. Devitrified chondrules composed of pyroxene were also identified. It is postulated from its mineralogy, chemistry and textural characteristics that the Qingzhen meteorite should be assigned toE ₄ orEH chondrites.  相似文献   

Recent advances in geochemical exploration in China     

Xie Xuejing  Zheng Kangle 《Journal of Geochemical Exploration》1983,19(1-3)

This paper outlines the recent advances in geochemical exploration in China.The Regional Geochemistry—National Reconnaissance (RGNR) Project first proposed in 1978, continues to be the focus of geochemical exploration activities in China. Several rapid quantitative multi-element analysis systems using conventional equipment available in most Chinese geological laboratories, have been developed. Eight Geochemical Standard Reference Samples of Drainage Sediments were prepared. Large-scale orientation or pilot surveys are being carried out by nearly 2/3 of the provincial geological bureaus in China. Methods of regional and follow up surveys for high and cold mountainous terrain have been worked out.Special attention has been given to the improvement and application of mercury vapour detection techniques. A new sampler was used to enhance anomalous values. A new Zeeman effect mercury detector was constructed and tested in routine analysis of mercury. Experiments of the application of soil gas mercury survey in petroleum and uranium prospecting are briefly described.Some examples of recent geochemical success in China are given.  相似文献   

塔里木克拉通北缘库鲁克塔格地块太古宙基底组成与地壳演化     

朱文斌  林和丰  葛荣峰  董春艳  颉颃强  刘守竭  万渝生 《地质学报》2022,96(9):3084-3101

塔里木克拉通太古宙岩石主要出露在库鲁克塔格、北阿尔金、铁克里克和敦煌等四个边缘基底隆起带。库鲁克塔格地块位于塔里木克拉通东北缘，其中有可靠年代学报道的太古宙岩石主要出露在库尔勒、辛格尔、兴地和帕尔岗塔格四个地区。库鲁克塔格地块的太古宙岩石主要由长英质正片麻岩(含TTG片麻岩)和少量以包体产出的斜长角闪岩组成，真正的太古宙表壳岩较少见。本次研究在库尔勒地区对长英质正片麻岩和石英岩开展锆石SHRIMP U- Pb测年分析，2个长英质正片麻岩样品的年龄分别为2695±9 Ma和2705±8 Ma；石英岩样品中的碎屑锆石核最小年龄峰为2513 Ma，石英岩有可能是太古宙沉积岩；上述岩石样品都经历了古元古代早期 (1. 9~1. 8 Ga)高级变质作用。地球化学分析发现，库鲁克塔格地块新太古代长英质片麻岩的原岩有多种岩石类型，这些长英质岩石都形成于与俯冲作用有关的岛弧构造背景。基性的斜长角闪岩和变质辉长岩可能产出于不同的背景，一部分来源于岛弧地幔楔的部分熔融，另一部分则可能来自于大洋板内，以洋脊玄武岩为主。库鲁克塔格地块太古宙岩石具有2. 7 Ga和2. 5 Ga两个年龄峰值，2. 7 Ga岩浆事件主要发生在库鲁克塔格西部地区，锆石的εHf(t)值既有正值也有负值，表明这一时期地壳生长和改造同时并存；~2. 5 Ga的岩浆活动分布范围较为广泛，全岩εNd(t)和锆石εHf(t)值以正值为主，暗示这一时期可能存在显著的大陆地壳生长。  相似文献   

Characteristics of the mantle source region of sodium lamprophyres and petrogenetic tectonic setting in northeastern Hunan,China   总被引：2，自引：0，他引：2  

JIA Dacheng    HU Ruizhong  LU Yan  XIE Guiqing & QIU Xuelin .Key Laboratory of Ore Deposit Geochemistry  Institute of Geochemistry  Chinese Academy of Sciences  Guiyang 《中国科学D辑(英文版)》2004,47(6):559-569

~~Characteristics of the mantle source region of sodium lamprophyres and petrogenetic tectonic setting in northeastern Hunan,China~~  相似文献   

Atmospheric nitrous oxide observations above the oceanic surface during the first Chinese Arctic Research Expedition   总被引：1，自引：0，他引：1  

朱仁斌  孙立广  谢周清  赵俊琳 《极地研究(英文版)》2003,14(2)

339 gas samples above oceanic surface were collected on the cruise of "Xuelong" expeditionary ship and nitrous oxide concentrations were analyzed in the laboratory. Results showed that Atmospheric average N2O concentration was 309 ±3. 8nL/L above the surface of northern Pacific and Arctic ocean. N2O concentrations were significantly different on the northbound and southbound track in the range of the same latitude, 308.0 ±3.5 nL/L from Shanghai harbor to the Arctic and 311.9 ±2.5 nL/L from the Arctic to Shanghai harbor. N2O concentration had a greater changing magnitude on the mid- and high-latitude oceanic surface of northern Pacific Ocean than in the other latitudinal ranges. The correlation between the concentrations of the compositions in the aerosol samples and atmospheric N2 O showed that continental sources had a great contribution on atmospheric N2 O concentration above the oceanic surface. Atmospheric N2O concentration significantly increased when the expeditionary ship approached Shanghai h  相似文献   

A new way to predict forecast skill   总被引：1，自引：0，他引：1  

TAN Jiqing  XIE Zhenghui  JI Liren 《大气科学进展》2003,20(5):837-841

Forecast skill (Anomaly Correlated Coefficient, ACC) is a quantity to show the forecast quality of the products of numerical weather forecasting models. Predicting forecast skill, which is the foundation of ensemble forecasting, means submitting products to predict their forecast quality before they are used.Checking the reason is to understand the predictability for the real cases. This kind of forecasting service has been put into operational use by statistical methods previously at the National Meteorological Center (NMC), USA (now called the National Center for Environmental Prediction (NCEP)) and European Center for Medium-range Weather Forecast (ECMWF). However, this kind of service is far from satisfactory because only a single variable is used with the statistical method. In this paper, a new way based on the Grey Control Theory with multiple predictors to predict forecast skill of forecast products of the T42L9 of the NMC, China Meteorological Administration (CMA) is introduced. The results show: (1) The correlation coefficients between “forecasted“ and real forecast skill range from 0.56 to 0.7 at different seasons during the two-year period. (2) The grey forecasting model GM(1,8) forecasts successfully the high peaks, the increasing or decreasing tendency, and the turning points of the change of forecast skill of cases from 5 January 1990 to 29 February 1992.  相似文献   

Salinity variation of formation water and diagenesis reaction in abnormal pressure environments     

解习农  焦赳赳  李思田  成建梅 《中国科学D辑(英文版)》2003,46(3):269-284

~~Salinity variation of formation water and diagenesis reaction in abnormal pressure environments@解习农 @焦赳赳 @李思田 @成建梅~~~~  相似文献   

异常气候对高寒区杏树生产的影响及对策          下载免费PDF全文

徐向东  孟荣贵  谢树军 《山西气象》2004,(3):21-22

杏树是雁北高寒区主栽果树品种之一，也是当地农民脱贫致富的重要收入来源。异常气候是影响当地杏树栽培优质丰产的主要障碍因素。通过近年来山西省阳高县异常天气对杏树生产的影响的分析调查，提出了相应的生产管理措施，对高寒区杏树优质丰产具有一定的指导意义。  相似文献   

北京市大气细粒子的质量浓度特征研究   总被引：24，自引：2，他引：24  

王京丽  谢庄  张远航  邵敏  曾立民  程丛兰  徐晓峰  赵习方  孟燕军 《气象学报》2004,62(1):104-111

大气能见度的降低是当今国际上比较突出的城市环境问题。北京近年的监测结果表明 ,大气中通过消光作用使大气能见度下降的气溶胶细粒子的污染程度呈现上升趋势。从 2 0 0 1年对北京市气溶胶细粒子 (空气动力学直径小于 2 .5μm的粒子 ) 4个季节的采样监测结果分析 (有效采样天数为 50d)得出 ,北京市细粒子质量浓度年平均值已超过美国国家标准的 7倍以上。研究发现细粒子的质量浓度不仅与环境条件有关 ,而且与气象条件也有着密切的关系。文中以细粒子的观测数据为基础 ,结合当时的气象条件进行细粒子浓度与气象条件定量关系的研究  相似文献   

回归诊断在梅雨期大到暴雨预报中的应用   总被引：4，自引：2，他引：4  

杨煜灿谢征  王国强 《气象科技》2004,32(2):81-85

应用回归诊断方法分析发现，梅汛期大到暴雨回归预报模型的残差分布存在着不对称现象，这种不对称现象是由高杠杆点所引起。这些高杠杆试验点的残差存在着统计天气预报意义上的不合理性，导致了回归系数LS估计的误差，从而又引起暴雨预报的误差。针对这些问题提出了大到暴雨的回归诊断预报模型。实例计算说明，回归诊断预报模型要优于常规回归预报模型。进一步分析指出，梅汛期大到暴雨回归预报模型的不合理性并非个别例子的特殊性所造成，而是由模型的数学特点所决定，因此大到暴雨的回归诊断预报模型具有普遍意义。大量的试验和多年的业务应用表明，回归诊断对提高大到暴雨预报准确率具有明显的效果。  相似文献