冀北地区金矿床He、Ar、Pb同位素组成及其成矿物质来源   总被引：13，自引：0，他引：13  

王宝德  牛树银  孙爱群  李红阳 《地球化学》2003,32(2):181-187

成矿物质来源一直是成矿理论研究和找矿实践的焦点问题。选择了冀北地区3个幔枝构造金矿集中区11个金矿床黄铁矿及部分围岩进行了He、Ar同位素测定。研究表明,冀北地区主要金矿的3He/4He的值域为(0.93～7.30)×10-6,平均3.55×10-6;R/Ra=0.66～4.93,平均2.53;40Ar/36Ar=426～2073,40Ar平均为8.20×10-7cm3/g,4He/40Ar平均为2.17。矿区外围片麻岩和花岗岩的3He/4He值仅为(0.001～0.55)×10-6,反映来源上有明显差别。3He和4He在He同位素浓度图上落于地幔区附近。64个Pb同位素数据表现为矿质以幔源为主,确有部分壳源物质加入。研究认为,本区成矿物质应源于地球深部,随地幔柱多级演化,深部成矿流体由地球深部迁移到浅部,期间不可避免地存在壳幔流体的混合作用,故其值域往往界于地幔和地壳之间。  相似文献   

时频测控技术的发展   总被引：11，自引：1，他引：11  

周渭  王海 《时间频率学报》2003,26(2):87-95

目前，在所有的物理量中时间与频率标准的物理实现具有最高的准确度和稳定度，它们的发展不但在计量技术中，而且在几乎整个高科技领域中起着十分重要的作用。这方面的发展一直受到发达国家的高度重视。根据近年来与国外同行的技术交流和了解的情况，对时频测控技术的发展和影响等作了介绍。  相似文献   

Compositional Geometry and Mass Conservation   总被引：1，自引：0，他引：1  

Robert F. Shurtz 《Mathematical Geology》2003,35(8):927-937

A geometrical structure is imposed on compositional data by physical and chemical laws, principally mass conservation. Therefore, statistical or mathematical investigation of possible relations between data values and such laws must be consistent with this structure. This demands that geometrical concepts, such as points that specify both mass and composition in linear space, and lines in projective space that specify composition only, be clearly defined and consistent with mass conservation. Mass thus becomes the norm in composition space in place of the Euclidean norm of ordinary space. Coordinate transformations inconsistent with this geometry are accordingly unnatural and misleading. They are also unnecessary because correlation arising from the constant mass presents no unusual difficulty in the analysis of the underlying quadratic form.  相似文献   

Tectonic controls on metamorphism, partial melting, and intrusion: timing and duration of regional metamorphism and magmatism in the Ni de Massif, Turkey     

Donna L. Whitney  Christian Teyssier  Annia K. Fayon  Michael A. Hamilton  Matt Heizler 《Tectonophysics》2003,376(1-2):37-60

Mafic high-pressure granulite, eclogite and pyroxenite xenoliths have been collected from a Mesozoic volcaniclastic diatreme in Xinyang, near south margin of the Sino-Korean Craton (SKC). The high-pressure granulite xenoliths are mainly composed of fine-grained granoblasts of Grt+Cpx+Pl+Hbl±Kfs±Q±Ilm with relict porphyritic mineral assemblage of Grt+Cpx±Pl±Rt. P–T estimation indicates that the granoblastic assemblage crystallized at 765–890 °C and 1.25–1.59 GPa, corresponding to crustal depths of ca. 41–52 km with a geotherm of 75–80 mW/m². Calculated seismic velocities (V_p) of high-pressure granulites range from 7.04 to 7.56 km/s and densities (D) from 3.05 to 3.30 g/cm³. These high-pressure granulite xenoliths have different petrographic and geochemical features from the Archean mafic granulites. Elevated geotherm and petrographic evidence imply that the lithosphere of this craton was thermally disturbed in the Mesozoic prior to eruption of the host diatreme. These samples have sub-alkaline basaltic compositions, equivalent to olivine– and quartz–tholeiite. REE patterns are flat to variably LREE-enriched (La_N/Yb_N=0.98–9.47) without Eu anomaly (Eu/Eu*=0.95–1.11). They possess 48–127 ppm Ni and 2–20 ppm Nb with Nb/U and La/Nb ratios of 13–54 and 0.93–4.75, respectively, suggesting that these high-pressure granulites may be products of mantle-derived magma underplated and contaminated at the base of the lower crust. This study also implies that up to 10 km Mesozoic lowermost crust was delaminated prior to eruption of the Cenozoic basalts on the craton.  相似文献   

晋北娄烦吕梁群变质相带的划分及其成因研究   总被引：1，自引：0，他引：1       下载免费PDF全文

卢保奇  王赐银 《地球学报》2003,24(4):325-329

晋北娄烦吕梁群由一套经受过两期不同性质变质作用的泥砂质岩、基性火山岩和酸性流纹岩组成。早期为吕梁期变质作用,其结果使该区地层构造形迹总体上呈NE走向;晚期为西川河韧性剪切断裂所产生的区域变质作用,其结果使该区地层走向由早期的NE向扭转为近SN向,且使地层层序发生倒转,并与递增变质带的形成关系密切。选取该区中对变质温度和压力变化反映较敏感的原岩为泥砂质岩石的袁家村组和裴家庄组地层为研究对象,采用电子探针微区分析(EPMA)对沿地层走向上连续分布的特征变质矿物及矿物共生组合特征进行研究,并利用矿物对地质温度计估算该区不同采样点的变质温度和压力条件,对研究区进行变质相带的划分,确定各变质相带的变质温、压条件,并探讨其成因。研究结果表明,袁家村组和裴家庄组为等化学系列地层。沿该地层走向上:西川河断裂以北地区,从北向南,特征变质矿物绿泥石、黑云母、石榴石、十字石和蓝晶石依次规律出现;西川河断裂以南地区,红柱石和夕线石依次规律出现。根据特征变质矿物的空间分布规律、首次出现的地点及矿物共生组合特征,划分出5个变质带:绿泥石带、黑云母带、石榴石带、十字石-蓝晶石带和红柱石-夕线石带。这一完整的递增变质带可与苏格兰高地的巴罗型相媲美。矿物对地质温度计估算结果。  相似文献   

THE OPTIMAL GRAINSIZE COMPOSITION OF SUSPENDED SEDIMENT OF HYPERCONCENTRATED FLOW IN THE MIDDLE YELLOW RIVER     

XU Jiongxin Professor  Institute of Geography  Chinese Academy of Sciences  Beijing  China 《国际泥沙研究》1997,(3)

LINTRODUCTIONThetributariesofmiddleYellowRiverarefamousintheworldforthehighestsuspendedsedimentconcentrationandsedimentyield.Forexample,atWenjiachuanstationofKuyeheRiverthemeasuredhighestsuspendedconcentrationis1700kg/m',andthemeanannualsedimentyieldis25000t/(kln'.a).Theformationofhyperconcentratedflowsandtheirinfluenceonerosionprocessesareofgreatimportancenotonlyfromatheoreticalpointofviewbutalsoforpracticalpurposes.Therefore,scientistsfromChinaandallovertheworldhavedrawntheirintensio…  相似文献   

云南老王寨金矿区煌斑岩的源区成分模拟   总被引：2，自引：1，他引：2  

黄智龙  王联魁 《矿物学报》1997,17(3):316-320

本文在总结云南老王寨金矿区煌斑岩的主要元素、过渡元素、亲石元素、稀土元素和同位素地球化学特征的基础上．利用岩石学混合计算方法对其源区成分进行了模拟，进而讨论了矿区这类岩石的成因。地球化学和模拟计算均表明，老王寨金矿区煌斑岩来源于交代富集地幔，板块俯冲（印度板块向欧亚板块俯冲）富含ALK、LREE及不相容元素的海底沉积物被带入地幔脱水形成的流体是引起本区地幔交代作用的主要因素。  相似文献   

湘西沃溪金锑钨矿床中石英的矿物学研究          下载免费PDF全文

邵靖邦  樊江  王濮  翁玲宝  陈代璋 《岩石矿物学杂志》1997,(1)

通过对矿床中不同世代及不同地质产状石英的颜色、形态、物理性质、化学成分、晶胞参数、结晶度的研究及Ｘ射线分析及红外光谱、电子顺磁共振谱等近代物理分析方法的测试，找出了矿化石英与非矿化石英及不同类型矿化石英的标型特征，这些标型特征具有重要的找矿勘探意义  相似文献   

五台山西部狐狸山含金韧性剪切带的地球化学研究     

刘志宏  王安建  李晓峰  周继华 《吉林大学学报(地球科学版)》1996,(1)

狐狸山金矿区，在无蚀变作用参与的韧性变形过程中，岩石化学成分发生了明显的变化。但大多数微量元素含量变化不大，稀土元素配分模式基本不变，它们可以反映原岩的特点。蚀变糜棱岩型矿体与围岩相比，稀土配分模式、亲硫元素Ａｕ、Ａｇ、Ｃｕ和两性元素Ａｓ、Ｓｂ含量差别显著，尤其是Ａｕ含量，前者是后者的百倍～几万倍，金的成矿作用主要与韧性变形后期富金流体的蚀变作用关系密切。  相似文献   

Characteristics of Volcanic Rocks in the Shoshonite Province, Eastern China, and Their Metallogenesis   总被引：17，自引：0，他引：17  

Wang Dezi  Ren Qijiang  Qiu Jiansheng  Chen Kerong  Xu Zhaowen  Zeng Jiahu Department of Earth Sciences  Nanjing University  Nanjing  Jiangsu 《《地质学报》英文版》1996,70(3):246-259

The shoshonite province in eastern China is characterized by extensive distribution (ca. 80000 km2) of Late Jurassic-Early Cretaceous (165-100 Ma) shoshonite series with subordinate high-K calc-alkali series. It was formed in a dominantly tensile stress field. In comparison with their analogues in island arcs and active continental margins in other countries, the volcanic rocks in the shoshonite province have their specific characteristics in petrology, mineralogy and geochemistry as well as related mineralization association, which are the comprehensive reflection of the special composition and structure of the mantle and crust of the province and the special Mesozoic regional tectonic setting.  相似文献