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1.
山东金刚石原生矿找矿前景探讨 总被引:2,自引:0,他引:2
金刚石形成于地幔深处,含金刚石的岩石只是一种运载和保存“工具”,凡是来自上地幔的岩石均有可能携带早已形成的金刚石而形成金刚石原生矿床。世界上已知金刚石原生矿除金伯利岩,钾镁煌斑岩型外,尚在橄榄岩,橄榄玄武岩,千枚岩,科马提岩,榴辉岩等岩石中发现了金刚石,可能存在金刚石原生矿新的岩石。山东位于华北地台的南东部,鲁西,鲁东基底属A型克拉通,幔源岩浆活动强烈,具备良好的金刚石原生矿成矿地质条件,已获得的大量的成矿信息和找矿线索表明,除已发现的蒙阴金伯利岩型金刚石原生矿外,应该存在着尚未发现的金刚石原生矿,找矿前景广阔,应进一步加强金刚石原生矿勘查工作。 相似文献
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中国金刚石砂矿主要分布在华北与扬子地台郯庐断裂区与沅水流域区 ,在大别山区及新疆、西藏超基性岩附近也有分布。不同时代的含金刚石金伯利岩或超基性岩带 ,经风化、剥蚀、搬运 ,形成含金刚石砂矿中间储存体 ,在水系中下游形成不同类型 (阶地、河谷、河床 )砂矿。金刚石砂矿找矿方向应是模式找矿主要有三方面 :一是矿源 ,二是中间储存体 ,三金刚石砂矿组合矿物。 相似文献
3.
湖南原生金刚石矿深部构造地质背景及成矿预测 总被引:7,自引:0,他引:7
本文确认武陵-雪峰地块是一个具有太古代结晶基底和元古代褶皱基底,相对稳定的“双基底”的微型克拉通,它有别于地夫周边坡的高波速地壳和高阻,高密度刚性上地幔,巨厚的岩石圈厚度以及巨型深断裂带,为金刚石原生矿床的形成提供了最佳深部构造条件,在建立扬子克拉通原生金刚石成矿与古板块构造演化模式的基础上,提出了金刚石原生矿床的主要矿期,并进行了成矿带划分和找矿预测,初选了找矿靶区,指出了找矿方向。 相似文献
4.
华北地台金刚石找矿前景及成矿预测 总被引:1,自引:0,他引:1
华北地台是我国最重要的金刚石成矿区,已在山东、辽宁找到具经济价值的金伯利岩型金刚石原生矿床,并且在江苏、安徽、河南、河北、山西、吉林等地发现金刚石矿点和重要的找矿信息.依据华北地台金刚石原生矿的成矿规律及物化探、重砂综合信息研究成果,将郯庐断裂带、太行山断裂带及华北地台北缘金刚石原生矿成矿区带,大致划分为4个成矿远景区. 相似文献
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金刚石包裹体矿物化学特征与华北东部克拉通岩石圈地幔属性 总被引:2,自引:0,他引:2
华北地台金刚石的包裹体中含有丰富的地幔信息.对山东蒙阴、辽宁复县两地金刚石中包裹体矿物包括橄榄石、石榴石、单斜辉石和铬铁矿的化学成分进行了深入分析,金刚石包裹体矿物的主量元素显示华北地台至少在古生代金伯利岩侵位时具高度亏损玄武质的难熔克拉通岩石圈地幔特征.应用适用于石榴石橄榄岩相的单斜辉石温压计对金刚石包裹体中透辉石进行了计算,得出华北地台金刚石形成于1 083~1 194℃、5.3-6.1 GPa的地质环境下.蒙阴和复县两地金刚石包裹体所反映的古老岩石圈地幔虽然都表现为克拉通岩石圈地幔特征,但也存在一定的不均一性.同时,通过对华北东部古生代与新生代地幔矿物的主量元素及地幔热状态的对比,结合现有的地幔岩石学和地幔地球化学的研究成果,认为软流圈物质对古老岩石圈地幔的侵蚀作用能较好地解释华北岩石圈减薄. 相似文献
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中国北方中生代富碱侵入岩钕、锶、铅同位素特征及其意义 总被引:14,自引:0,他引:14
本文根据作者近些年来对中国北方中生代富碱侵入岩钕、锶、铅同位素研究并结合前人工作得出 :在华北地台区富碱侵入岩的εNd(t)均为负值 ;而兴蒙地槽区的εNd(t)则全为正值εNd(t) εSr(t)图解上 ,前者投影点主要落在了富集地幔演化趋势线附近 ,而后者投影点主要落在了亏损地幔演化线附近。在地球不同区域铅模式图上 ,地台区钾长石铅投影点大部落在了地幔演化线附近 ,而地槽区的则落在了地幔与造山带演化线之间。以上事实说明华北地台区富碱侵入岩的物质来源与富集地幔关系密切 ,而地槽区的则与亏损地幔关系密切。同时也揭示出中生代华北地台区上地幔具有富集性 ,而兴蒙地槽区上地幔则具亏损性。 相似文献
8.
贵州镇远马坪地区作为中国第一个含金刚石母岩——钾镁煌斑岩的发现地,既是华南地区最重要的、最丰富的含金刚石母岩出露区,也是中国金刚石原生矿找矿的重点区域。以往针对该区的金刚石原生矿勘查工作重点多集中于对其寄主岩石特征的研究上,如岩体侵位方式、矿物组成、岩石地球化学特征以及侵位时代等方面(卢登蓉等,1989;罗会文等,1989;江万,1995;方维萱等,2002;杨光忠,2013),而对于金刚石本身晶貌学特征的研究较少,且受当时测试技术条件的限制,有关金刚石晶貌特征所对应的找矿信息揭示不够充分。鉴于扬子地台金刚石找矿工作的迫切需要,本文通过对镇远地区钾镁煌斑岩中金刚石矿物自身特点开展晶貌学研究,进而反演、推测其结晶和生长过程,并由此探讨寄主岩石源区特征、母岩形成条件,为扬子地台金刚石原生矿找矿研究提供新的思路。 相似文献
9.
华北地台区构造作用具有多期次板块俯冲和碰撞,昌金矿形成的有利条件。深大断裂在成岩成矿中占重要地位。本区有利的找矿方向是地台边缘金矿集中区。 相似文献
10.
略论地台区的海进、海退与相邻地槽区的造盆、造山运动伴生的原因 总被引:1,自引:0,他引:1
地台区的海进、海退 ,分别与相邻地槽区的造盆和造山运动伴生这一普遍现象 ,主要是在重力均衡作用下 ,上地幔流变层 (软流层 ,异常地幔 )物质侧向迁移所致。地槽区造盆运动 ,造成该区地壳减薄 ,从而在重力均衡作用下 ,相邻地台区的上地幔流变层物质便向该区顺层流入 ,促使其上地幔隆起。地台区上地幔流变层物质大量他流 ,势必引起地壳沉降 ,产生海进。华北地台中石炭世早二叠世早期整体沉降 ,形成了中国重要的石炭二叠纪聚煤区 ,便与其南北两侧秦岭和中亚蒙古地槽区在该时期的造盆运动有关。地槽区的造山运动 ,造成该区地壳加厚 ,从而在重力均衡作用下 ,该区隆起的上地幔流变层物质 ,又流回相邻地台区 ,促使地台区地壳抬升 ,产生海退。华北地台区晚奥陶世早石炭世的抬升剥蚀和从早二叠世晚期起转入陆相沉积发展阶段 ,便分别与南北两侧的秦岭和中亚蒙古地槽区于加里东早期和华力西晚期的造山运动相联系。 相似文献
11.
Hampton L. Carson Dr. 《GeoJournal》1992,28(2):297-302
Consideration is given to the case of a daughter population of a sexual species that becomes successfully established in an area previously lacking that species, as has occurred recently in the Krakataus. If the new area is isolated geographically and if the number of founder individuals is small, conventional wisdom foresees a reduction of genetic variability within the colony. This might obstruct genetic adjustment to new conditions. Recent studies of the genetics of such bottlenecked populations, however, show that, in some instances, genetic variability for quantitative traits may actually increase rather than decrease after a bottleneck event. Whereas loss of some quasi-neutral biochemical alleles may occur, the quantitative polygenic balances on which adaptation depends can be carried through the bottleneck into the new population. Novel phenotypes may result from natural selection during the generations that immediately follow the bottleneck. Growing shield volcanoes in particular show rapid turnover of their surfaces such that organisms surviving there must continually recolonize or become extinct. Such species, existing as metapopulations, should be prone to bottleneck effects that produce genetic shifts. Examples are given from Drosophila silvestris on the island of Hawaii. The relevance of such genetic shifts to population structure and evolutionary change in populations is discussed, emphasizing the probable role of metapopulation structure. 相似文献
12.
天然气成因类型及判别标志 总被引:29,自引:2,他引:27
本文通过前人对天然气类型划分的分析,基于多年的研究结果,以“多源复合、多阶连续”的天然气成因新模式,提出了科学的天然成因类型划分方案,并讨论了不同成因类型天然气的地球化学特征,建立了天然气成因类型的判识标志。 相似文献
13.
Genetic types of diamond mineralization 总被引:1,自引:0,他引:1
A. A. Marakushev Sang Longkang You Zhendong I. A. Zotov N. N. Pertsev N. A. Paneyakh 《中国地球化学学报》1998,17(1):12-28
The paper describes the proposed models of diamond formation both in meteorites and in kimberlite and lamproite bodies, metamorphic
complexes and explosive-ring structures (“astroblemes”). The diamond distribution in meteorites (chondrites, iron meteorites
and ureilites) is restricted to taenite-kamasite phase. The diamond generation here is tied up with the first stage of evolution
of the planets. This stage is characterized by high pressure of hydrogen, leading to the formation of the planet envelope.
The second stage of planet evolution began with the progressive impoverishment of their atmospheres in hydrogen due to its
predominant emission into the space and to progressive development of oxidative conditions. The model appears to have proved
the relict nature of diamond mineralization in meteorites.
Diamond and other high-pressure minerals (its “satellites”) were crystallized without any exception in the early intratelluric
stages of peridotite and eclogite-pyroxenite magma evolution just before the magma intrusion into the higher levels of the
mantle and crust where diamond is not thermodynamically stable. The ultramafic intrusive bodies (bearing rich relict diamonds)
in the base of a platform appear to be the substrata for the formation of kimberlite-lamproite magma chambers as a result
of magmatic replacement. The model explains the polyfacial nature of diamondiferous eclogites, pyroxenites and peridotites
and discusses the process of inheritance of their diamond mineralization by kimberlites and lamproites.
Diamond productivity of metamorphic complexes is originated by the inheritance of their diamonds from the above-mentioned
primary diamondiferous rocks. Large diamondiferous explosive-ring structures were formed by high-energy endogenic explosions
of fluid which came from the Earth’s core. This high energy differs endogenic impactogenesis from explosive volcanism. It
proceeds at very high temperature to create diaplectic glasses (monomineral pseudomorphs) —the product of isochoric melting,
at the pressure high enough for the stable formation of very high-density minerals (coesite, stishovite, diamond, lonsdaleit,
and chaoite).
The research project was financially supported by the Russian Foundation of Fundamental Sciences (93-05-8566, 96-05-64307,
and 96-05-00026c0) and China National Natural Science Foundation (No.49794041, No.49611121831). 相似文献
14.
《International Geology Review》2012,54(3):518-525
Commercial uranium deposits and those likely to become commercial in the near future are genetically classified as magmatic, hydrothermal, exogenous, metasedimentary, and deposits of questionable origin. A brief discussion of each type is included. — C.E. Sears. 相似文献
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Morozov Yu. A. Matveev M. A. Smulskaya A. I. Kulakovskii A. L. 《Doklady Earth Sciences》2019,484(2):129-133
Doklady Earth Sciences - The study of two varieties of pseudotachylytes (PST) in granitoids of the Riphean complex on the Barents Sea coast of the Kola Peninsula (Rybachii and Srednii peninsulas)... 相似文献
17.
乱石岗滑坡形成机制分析 总被引:2,自引:0,他引:2
乱石岗滑坡位于汉源罗卜岗新县城规划区中部,滑坡体积110.7×104m3,属大型滑坡,现今滑坡体在天然或暴雨状态下处于稳定状态。对滑坡形成机制进行深了入分析。 相似文献
18.
The most generally used method for estimating the basin-wide sequence and scaling of first and last occurrences, based on
their occurrence in local sections, is Shaw’s graphic correlation method. The key step in this method is the determination
of the line of correlation (LOC), which represents the best estimate of the correlation between two local sections, or between
a local section and a composite standard. In general, available techniques for fitting the LOC for multiple sections are tedious,
subjective, or computationally expensive. A new method employing genetic algorithms can dramatically reduce the effort involved
in determining the LOC and produces stable biostratigraphic correlations and composite range charts objectively and efficiently.
Genetic algorithms are an artificial intelligence technique that excels in locating the optimum solution from a large number
of alternative choices. In the case of the LOC, the alternative choices are the number of line segments comprising the complete
line and the positions of each segment’s beginning and end points. For a given number of segments, a wide range of alternative
LOCs can be rapidly evaluated and a potential optimum fit determined. It is also possible to estimate the point when no further
refinement of the fit by adding line segments is necessary. Genetic algorithms can also be applied to other methods for quantitative
biostratigraphy. 相似文献
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《International Geology Review》2012,54(10):1084-1092