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1.
对河南桐柏地区麻粒岩及其周围以前被认为是片麻岩的岩石从野外特征、结构构造、矿物成分、化学成分及峰期变质条件上进行比较，认为它们均相同。似层状、透镜状麻粒岩间以前被认为是高度风化片麻岩的岩石仍是麻粒岩，这是后期应力作用产生差异变形、退变质及风化作用的结果。这种变化不能等同于麻粒岩退变质为片麻岩。因此，桐柏麻粒岩的北侧围岩是与其呈断层接触的大理岩，南侧围岩为郭庄组上段花岗质片麻岩，麻粒岩构成一个约0．5km～2．0km宽的变质带。这对探讨桐柏麻粒岩的形成和演化具有重要意义。 相似文献
2.
河南桐柏北部秦岭群中麻粒岩相变质作用及变质矿物温压条件的研究 总被引：2，自引：0，他引：2
王奖臻 《成都地质学院学报》1990,17(1):13-22
本文提供了桐柏北部秦岭群麻粒岩中石榴石、辉石和黑云母的部分电子探针分析数据，根据岩石中矿物共生组合特征和4种地质温度计、地质压力计的计算，确定了麻粒岩相变质作用的温度、压力条件为790-850℃和0.8-1.0GPa，变质时的地热梯度为28-33℃/km，属中压麻粒岩相。 相似文献
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东南极格罗夫山镁铁质麻粒岩的变质作用 总被引：9，自引：7，他引：9
东南极内陆－格罗夫山存在一套经历了麻粒岩相变质作用的镁铁质麻粒岩和斜长角闪岩。变质反应结构显示该区多为单一的区域性麻粒岩相变质作用。但是，对含石榴石的镁铁质麻粒岩的详细工作则显示了包括3个阶段的近等温降压（ITD）的顺时针PT演化轨迹，M1：0．93GPa＞800℃：M2:0.65GPa,733-850℃;M3:0.46-0.61GPa，并有着与拉斯曼丘陵相似的演化历史。根据矿物组合和成分、变质反应结构及温压计算结果，格罗夫山镁铁质麻粒岩可能为高压麻粒岩。 相似文献
4.
山东省沂水地区麻粒岩相变质作用演化及大地构造意义 总被引：1，自引：1，他引：1
山东沂水麻粒岩相岩石出露于断裂带中，它是断裂带中最古老的岩石。主要岩石类型有孔兹岩（石榴石－石英－条纹长石－夕线石片麻岩）、紫苏辉石麻粒岩（紫苏辉石－斜长石－厂长央片麻岩）以及紫苏花岗岩等。根据矿物共生组合、变质反应，温压条件得出本区麻粒岩相岩石经历了五个阶段的变质作用，前阶段为角闪岩相变质作用，温度条件为Ｔ＝５７５℃￣６００℃，Ｐ＝０．５９ＧＰａ；峰期他阶段经历了五个阶段的变质作用，峰前阶段为角 相似文献
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冀东高级变质作用中流体演化 总被引：8，自引：2，他引：8
冀东太古宙麻粒岩相变质岩石的结构、矿物组合和反应关系反映了其变质作用经历了峰前、峰期、峰后和退化变质四个阶段。通过平衡热学计算和流体包裹体研究获得了各变质阶段Ｐ－Ｔ条件和流体性质。峰前阶段的变质条件为６５０－７３５℃，０．５－０．７ＧＰａ，平衡变质流体中水的摩尔分数是０．４９－０．９５。峰期阶段为８１２－８６０℃，０．８－１．２ＧＰ，ＸＨ２ｏ从０．４９－０．９５下降到０．３２－０．４９，捕获的流体 相似文献
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研究区主要由麻粒岩相变质的孔兹岩系组成，经历了初期、主期、峰期和晚期四个变质阶段。采用多种矿物对地质温压计方法估算，各变质阶段的温压条件分别为６５０－７００℃，０．５ＧＰａ；６７０－８３７℃，０．５３－０．７４ＧＰａ；６８７－９１１℃，０．３４－０５７ＧＰａ；６５０℃，０．３５ＧＰａ。温压条件的变化反映了变质作用 的动态力学过程，表现为顺时的Ｐ－Ｔｔ轨变。具有典型大造山带环境的变质演化特点和动力学 相似文献
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华北古陆块北缘退变榴辉岩的矿物化学与退变质作用 总被引：1，自引：0，他引：1
华北古陆块北缘退变榴辉岩呈透镜状产于角闪岩相变质的早元古宙红旗营子群黑云斜长片麻岩中，岩相学研究显示它经历了峰期榴辉岩相、减压过程中的高压麻粒岩相和角闪岩相变质作用。峰期榴辉岩相的矿物组合为石榴子石、绿辉石、金红石和石英等，变质条件为680～730℃和大于1．40～1．50GPa。在退变质早期，绿辉石分解形成钠质透辉石和斜长石(An=20．4～30．7)的蠕虫状后生合晶，榴辉岩转变成高压麻粒岩；晚期的退变质作用表现为高压麻粒岩相矿物组合转变成由钙质角闪石和斜长石(An=31．6～54.8)组成的角闪岩相矿物平衡共生组合。在结构上，主要表现为石榴子石颗粒边部的次变边、保留石榴子石假象的粒状后生合晶和保留辉石假象的蠕虫状后生合晶等，其变质温压条件为530～610℃和0．67～0．81GPa。 相似文献
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怀安蔓菁沟早前寒武纪高压麻粒岩混杂岩带地质特征,岩石学和同位素… 总被引：7，自引：10，他引：7
华北克通北缘中段怀安蔓菁沟高压麻粒岩混杂岩带产在太古宙怀安杂岩南缘与花岗岩带交界处，由高压其性麻粒岩，辉长质麻粒岩，英云闪长质麻粒岩和少量夕线石榴片麻岩相间排列的席状岩层物估算的早期高压变质作用条件：Ｔ＝８００Ｃ，Ｐ＞１．４ＧＰａ。环绕斑晶的后成合晶反应边矿物组合的变质条件为：Ｔ＝８２０Ｃ，Ｐ为０．７－０．９ＧＰａ。全岩Ｓｍ－Ｎｄ等时时线年龄２．６５Ｇａ，矿物Ｓｍ－Ｎｄ等年龄１．８２Ｇａ，锆石Ｕ－ 相似文献
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阿尔泰基性麻粒岩的发现：来自矿物学的证据 总被引：5，自引：10，他引：5
新疆北部阿尔泰造山带富蕴乌恰沟一带首次发现代表中、下地壳深变质作用的基性麻粒岩详细的野外和室内研究表明阿尔泰基性麻粒岩主要由粗粒和细粒的麻粒岩组成(SiO2含量为47．83～53．57％)。两者的矿物组合相近，为斜方辉石 单斜辉石 斜长石 角闪石 黑云母。角闪石和黑云母成分富镁，可能与岩石的成分富镁有关、基性麻粒岩的岩石地球化学成分显示其富Mg/(Mg Fe^2 )和亏损U，Th，K及Rb，而且其原岩为钙碱性玄武岩，是岛弧构造环境下形成的产物。矿物化学特征表明斜方辉石中Mg／(Mg Fe^2 )介于0．65～0．71之间，为紫苏辉石，具高MgO FeO，低Al2O3和Ca／(Ca Mg Fe)，而单斜辉石具低TiO2和Al2O3的特点，说明它们皆为变质成因。部分角闪石和褐色黑云母富钛，指示它们为高温下形成的产物。这些特征证实了上述岩石为基性麻粒岩。角闪石和黑云母氟和氯含量较低以及水速度较高，暗示其流体成分氟和氯在变质作用过程中不起主导作用。根据麻粒岩中矿物共生组合、期次和矿物温压计估算，麻粒岩形成的峰期和退变质温压条件分别为750～780℃，0．6～0．7GPa和590～620℃，0．23～0．37GPa，前者属高温中压条件，阿尔泰地区基性麻粒岩的发现为进一步研究阿尔泰地区深部下地壳的组成和结构以及深化阿尔泰地区、新疆北部甚至中亚地区大陆动力学过程和机制都具有重要意义。 相似文献
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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
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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
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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
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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