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1.
岩浆不混溶作用模拟——热力学模型与数值方法 总被引：1，自引：0，他引：1
基于硅酸盐熔体不混溶相平衡实验资料,采用氧化物规则溶液的活度模型,建立了预测岩浆不混溶作用的热力学方法,研究了氧化物组分在不混溶两液相之间的分配系数与温度,压力和岩浆成分之间的关系,由此,可以预测天然岩浆不混溶作用,计算不混溶的起始温度,共轭两液相的成分及含量,计算的不混溶两液相中ＳｉＯ２,Ａｌ２Ｏ,ＦｅＯ的摩尔分数平均残差为３．０％～４．０％,其他氧化物平均残差小于１．０％,不混溶两液相的摩尔分 相似文献
2.
冀东高级变质岩石的流体包裹体研究 总被引：5，自引：5，他引：5
冀东高级变质的石榴石斜长片麻岩、含或不含石榴石的角闪二辉斜长片麻岩、紫苏花岗岩、斜长角门岩等岩石中的流体包裹体主要有４类，按形成的先后顺序依次为：（１）Ｈ２Ｏ和ＣＯ２两液相包裹体，ＣＯ２的部分均一温度是－１２℃，密度１．０４ｇ／ｃｍ３，Ｈ２Ｏ含量２１％～３９％（ｍｏｌｅ％），ＣＯ２含量５０％～７１％（ｍｏｌｅ％）；（２）ＣＯ２液相包裹体，冰点温度－５６℃～－６１℃，均一温度－７．４℃～－３５．１℃，ＣＯ２密度约为１．０５ｇ／ｃｍ３，ＣＯ２含量８２．１％～９８．４％（ｍｏｌｅ％），还有少量的ＣＨ４、Ｎ２和Ｈ２等组分；（３）Ｈ２Ｏ和ＣＯ２多相包裹体，ＣＯ２的部分均一温度７℃～２８℃，ＣＯ２密度为０．６４～０．９３ｇ／ｃｍ３，气相组分以ＣＯ２、ＣＨ４和ＣＯ为主，液相成分主要是Ｈ２Ｏ和ＣＯ２；（４）多世代盐水溶液包裹体，冰点温度－０．５℃～－２０℃，盐度０．８７％～２２．８％（ｗｔ％），盐水密度０．７～１．０５ｇ／ｃｍ３，均一温度在１５０℃～２００℃和约３００℃，存在两个峰值。不同世代的流体包裹体记录了等密度降温的Ｐ－Ｔ路径。包裹体反映的变质作用早期降温过程流体的Ｈ２Ｏ／Ｈ２Ｏ＋ＣＯ２（ｍｏｌｅ）比值降低，晚期升高 相似文献
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新疆哈图金矿成矿流体地球化学 总被引：35，自引：3，他引：32
新疆哈图金矿床赋存在石炭系基性火山岩－火山碎屑岩中,矿体受古火山口断裂系控制。矿脉内流体包裹体较为丰富,主要为气液相ＮａＣｌ－Ｈ２Ｏ包裹体和少量的ＮａＣｌ－ＣＯ２－Ｈ２Ｏ包裹体。成矿热液中富含ＣＯ２、Ｎ２、Ｎａ＋、Ｋ＋、Ｃｌ－和ＳＯ２－４,而所含的成矿元素以Ａｕ－Ａｓ－Ａｇ－Ｓｂ组合为特征。成矿热液为低盐度流体,主成矿阶段的盐度为４．１ｗｔ％～６．３ｗｔ％ＮａＣｌ,密度为０．８８～０．８０ｇ／ｃｍ３,ｆＯ２为１０－３５～１０－３１Ｐａ,Ｅｈ为０．６０～０．８０ｅＶ,为还原环境。金沉淀成矿的最佳温度为２３０～２６０℃。哈图金矿成矿热液不是典型的岩浆热液,而是受到了古大气水混入的火山晚期热液。流体不混溶、水－岩反应及古大气水的混入是造成本区金沉淀成矿的主要因素。 相似文献
4.
青藏高原五道梁冻土活动层表面二氧化碳和甲烷的排放 总被引：9，自引：3，他引：9
通过静态箱取样方法，首次获得青藏高原冻土活动层排放气体。分析测定结果表明，ＣＨ４含量为０．６３～１．５４μｇ／ｇ，平均为１．１９μｇ／ｇ，大多数样品ＣＨ４含量低于当地大气ＣＨ４含量（１．３２μｇ／ｇ）；ＣＯ２含量为０．１５％～０．２７％，平均为０．２１％，明显高于大气ＣＯ２的浓度（０．０６９％）。ＣＨ４、ＣＯ２含量具有一定的日变化特征。ＣＨ４排放率为－０．０３２～０．０４８ｍｇｍ－２ｈ－１，平均为０．００１ｍｇｍ－２ｈ－１；ＣＯ２排放率为－５６．５０３～６１．４２５ｍｇｍ－２ｈ－１，平均为０．０９５ｍｇｍ－２ｈ１。从所获得的冻土排放气体中ＣＨ４和ＣＯ２的浓度来看，这种干燥寒冷的高原冻土活动层表面ＣＨ４排放较少，ＣＯ２的排放较高 相似文献
5.
硅酸盐熔体结构与岩浆液态不混溶作用 总被引：4，自引：0，他引：4
本文简述了硅酸盐熔体结构和岩浆液态不混溶作用的基本特征，计算了玄武岩中基质和液态不混溶共轭熔体对的ＮＢＯ／Ｔ值，发现三者具有不同的熔体结构，据此总结出硅酸盐熔体结构与岩浆液态不混溶作用之间的内在联系。同时利用硅酸盐熔体结构解释了组分对岩浆液态不溶混作用的影响。 相似文献
6.
白银厂矿田早中寒武世火山岩地球化学及成因分析 总被引：16，自引：3，他引：13
白银厂矿田早中寒武世火山岩主要为玄武岩－碱性玄武岩－安山岩－玄武安山岩－玄武粗安岩－英安流纹岩－流纹岩。其中基性和中基性岩类为碱性系列和亚碱性系列,碱性玄武岩主要为钾质玄武岩系列。酸性岩类为钙碱性系列。岩石全碱含量平均为５．７６％,Ｋ２Ｏ／,Ｋ２Ｏ／Ｎａ２〈１,Ｆｅ２Ｏ／ＦｅＯ平殚为０．７４;ＴｉＯ２绝大部分样品含量小于１％（在酸性火山岩中含量较低：０．２％～０．８３％,平均为０．５３％;基性和中 相似文献
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北塔山地区石英脉红外光密度特征及其意义 总被引：1，自引：0，他引：1
新疆北塔山东南部及小哈甫提克地区石英脉中Ｈ２Ｏ的相对光密度绝大部分大于１．０大部分在３～５之产变化,ＣＯ２的相对光密度大于０．１,大部分在０．３～０．５之间的变化,随着石英脉中Ｈ２Ｏ的相对光密度平均值由于２．５０→３．９５→４．８７,Ｈ２Ｏ与ＣＯ２的相对光密度比值的平均值由６．４３→７．２０→１３．３４,金的平均含量由零逐渐升高,含金石英脉由近地表深部,Ｈ２Ｏ和ＣＯ２相对光密度平均值分别为４．９５ 相似文献
8.
大别山金鸡寨花岗岩体岩石化学特征及侵位机制初步探讨 总被引：2，自引：0，他引：2
】大别山金鸡寨花岗岩体位于大别山碰撞造山带东端,紧邻郯庐断裂,是由碱长石英正长岩和碱长花岗岩组成。这两种岩石的组成矿物均为碱性长石、石英、斜长石、角闪石、黑云母、磁铁矿及副矿物榍石、磷灰石,但矿物含量不同。它们的岩石化学特征也不相同：（１）碱长石英正长岩中常量元素的平均含量（ｗｔ％）ＳｉＯ２为６７．１１％,Ａｌ２Ｏ３为１７％,Ｎａ２Ｏ＋Ｋ２Ｏ为１０．９７％,其中Ｋ２Ｏ＞Ｎａ２Ｏ,微量、稀土元素均较富集,但高场强元素、轻稀土含量及ＬＲＥＥ／ＨＲＥＥ均大于碱长花岗岩中的相应数值。（２）碱长花岗岩中常量元素的平均含量（ｗｔ％）ＳｉＯ２为７５．１３％,Ａｌ２Ｏ３为１３％,Ｎａ２Ｏ＋Ｋ２Ｏ为８．２３％,其中Ｋ２Ｏ＞Ｎａ２Ｏ,微量、稀土元素含量较高,但大离子亲石元素、重稀土元素含量则大于碱长石英正长岩中的含量。根据野外调查、岩石学特征及常量、微量、稀土元素研究表明,这两种岩石是同一岩浆不同演化阶段的产物,是于造山后形成的Ａ型花岗岩,其形成经历了部分熔融和结晶分异两个阶段,源岩可能来自于北大别变质杂岩。金鸡寨岩体的侵位是以“半汽球”膨胀机制进行的,并与龙井关断裂密切相关。 相似文献
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为探讨长英质岩浆作用过程中金属成矿元素的地球化学行为及其成矿意义，我们进行了常压下花岗岩－ＫＢＦ３－Ｎａ２ＭｏＯ４－ＷＯ３体系的实验研究。结果表明，高温（１２５０℃）条件下呈均一状态的花岗岩－ＫＢＦ４－ＮａＭｏＯ４－ＷＯ３体系，当温度降低时发生液态不混溶，从中分离出含矿熔体的小液滴，体系中的Ｍｏ（Ｗ）几乎全部富集在这种小液滴中。含矿熔体中极富含Ｃａ、Ｍｇ和Ｐ，而贫Ｓｉ、Ａｌ和Ｋ，Ｈ２Ｏ和Ｆ富集在含矿熔体中。此实验结果表明：长英质岩浆中液态不混溶作用的发生可以使成矿元素Ｗ和Ｍｏ富集到与硅酸盐熔体不混溶的独立的非硅酸盐熔体中。这种熔体在适当的地质条件下继续演化可形成类似镁铁质岩浆演化过程中常出现的岩浆熔离型矿床。本实验结果可能为斑岩矿床的形成机理提供一种新的解释。 相似文献
11.
Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
12.
Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
13.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
14.
Emmanuel Skourtsos Daniel Vachard Alexandra Zambetakis-Lekkas Rossana Martini Louisette Zaninetti 《Comptes Rendus Geoscience》2002,334(12):925-931
Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931. 相似文献
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正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.) 相似文献
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正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.) 相似文献
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正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.) 相似文献
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正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus., 相似文献
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正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an 相似文献