共查询到20条相似文献，搜索用时 62 毫秒
1.
西秦岭地区的构造演化是许多地质学家普遍关注的问题。三叠纪以来西秦岭发生了复杂的俯冲碰撞造山作用,这一时期发育的火山岩,便是这一地质事件的重要记录。本文选取西秦岭甘青交界处台乌龙一带华日组火山岩为研究对象,运用"火山旋回—火山构造—火山地层—岩性岩相"的火山岩区填图方法,在华日组火山岩中识别出喷溢相、爆发相、侵出相、喷发—沉积相、火山通道相和次火山岩相等6个岩相;台乌龙层状火山机构、色日欠破火山机构等11个火山机构;两个组合样式(台乌龙—年支北串珠式组合、下毛娘北—色日欠镶嵌式组合);划分出1个火山喷发旋回,3个亚旋回。较合理地建立起地层层序、岩相相序和演化模式。华日组火山岩的出现标志着西秦岭地区在晚三叠世已进入陆相演化阶段。 相似文献
2.
陆相火山岩区岩石地层划分的探讨 总被引：4，自引：2，他引：2
陆相火山岩区火山产物的旋回、岩相及韵律性是 火山 活动发生及演化阶段 性的反映,也是岩石地层划分应该兼顾的重要特征之一。岩石地层划分的依据是岩性岩相特 征,各岩石地层单位均有具体的岩性岩相内容,并有别于相邻的岩石地层单位。因此,陆相 火山岩区的岩石地层划分,在满足岩石地层划分要求的前提下,应把火山活动产物的自身特 点 作为重要的依据。若将岩石地层单位“群”与火山旋回、“组”与复合岩相、“段”与火山 岩相或沉积岩相、“层”与火山岩相的基本类型对应起来,可建立起岩石地层单位“群”与 火山活动阶段、“组”与火山构造演化阶段、“段”与火山活动期或间隙期、“层”与火山 作用 类型的直接联系,从而使岩石地层划分与火山活动的历史研究有机地结合起来。 相似文献
3.
冀北晚侏罗世张家口组段的划分 总被引：1，自引：0，他引：1
4冀北晚侏罗世张家口组的岩石地层单位长期以来一直没有一个较统一的划分方案,划分较为混乱,影响了其合理的地层层序的建立及区域地层对比。根据《冀北中生代陆相火山-沉积盆地1∶25万填图方法研究》项目的工作成果,提出张家口组以相序的岩石组合为基本单元将其依次划分为3个岩性段的方案。一段主要为弱喷发相序的岩石组合;二段主要为爆发相序的岩石组合;三段主要为喷发沉积相序的岩石组合。三者分别代表该组某破火山的初始爆发阶段、大规模爆发阶段和破火口塌陷沉积阶段。由此划分的岩性段可以较好地反映火山构造特征,建立合理的地层层序,有助于火山演化历史的研究,使岩石地层单位的划分与火山-沉积盆地的研究有机地结合在一起。 相似文献
4.
冀北晚侏罗世张家口组内岩石地层单位长期以来一直没有一个较统一的划分方案，使之划分较为混乱，影响了其合理地层层序的建立及区域地层对比。笔者通过“冀北中生代陆相火山一沉积盆地1：25万填图方法研究”项目的工作，提出张家口组内以相序的岩石组合为基本单元将其依次划分3个岩性段。一段主要为弱喷发相序的岩石组合；二段主要为爆发相序的岩石组合；三段主要为喷发沉积相序的岩石组合。三者分别代表该组某破火山的初始爆发阶段、大规模爆发阶段和破火口塌陷沉积阶段。由此划分的岩性段可以较好地反映火山构造特征，建立合理的地层层序，有助于火山演化历史的研究。使岩石地层单位划分与火山-沉积盆地研究有机地结合在一起。 相似文献
5.
新疆三塘湖盆地牛东地区卡拉岗组火山旋回和期次的划分与对比 总被引：2，自引：0，他引：2
以系统取心资料及其分析化验资料为基础,结合测井和地震资料,根据火山岩的岩性、电性、岩石化学等特征和不同岩性岩相的地震反射特征,将三塘湖盆地马朗凹陷牛东地区卡拉岗组火山岩地层划分为层、韵律、期次、亚旋回等不同单元。以期次(层组)作为该区火山岩地层划分对比的基本单元,这也是在地震剖面上能识别和连续追踪的基本或最小地层单位,并对该区火山岩地层进行了划分与对比。研究表明:该区卡拉岗组火山活动以裂隙式喷发为主,分布规律表现为层组的厚度、数目由西南向东北呈明显的减薄(少)趋势;牛东地区卡拉岗组已经揭示的火山岩厚度在1000 m以上,可以划分为8个火山期次,4个亚旋回。 相似文献
6.
现行火山岩区填图是以岩石地层单位划分的群－组－段为基础,其中组是最基本的填图单位。由于火山作用的特殊和火山活动的同期异常性等,这一划分还不能全面合理地反映火山岩区的基本面貌和火山作用过程,特别是调研主体－火山构造。以福建省东部中生代火山岩为例,提出以火山旋回－火山构造单元－岩相（组合）作为火山岩区的三级填图单位,其中火山构造单元为基本的填图单位。 相似文献
7.
8.
针对冀北陆相火山岩区填图中Ⅳ级火山构造划分中存在的问题,论述了Ⅳ级火山构造的区别,指出划分Ⅳ级火山构造,要在对火山岩岩性、岩相、火山构造调查的基础上,全面分析认识测区火山活动及其岩浆演化的过程和火山构造特征,注重空间范围和活动时限,在调查建造的同时要重视改造的分析研究。认为在一个Ⅳ级火山构造中Ⅳ级火山构造类型应相同或相似,并对冀北火山岩区岩石地层单位的建立提出了独到的见解。 相似文献
9.
内蒙古东乌旗德勒乌拉组的建立及其构造环境初探 总被引：2，自引：0，他引：2
研究区位于西伯利亚板块东南缘古生代陆缘带内,晚古生代火山岩广泛发育,是研究古亚洲构造域地质演化的重要地区。通过内蒙古1∶5万东乌旗阿拉坦合力地区的地质调查,发现原宝力高庙组(CPbl)火山岩实际上是由下部安山质火山岩为主和上部粗面质火山岩为主的2套火山-沉积地层组成。这2套地层不仅岩性组合不同,而且地球化学特征以及地层时代等方面也存在明显差异,故将其解体为2个岩石地层单位。建议下部以安山质火山岩为主的地层保留原宝力高庙组的称谓,而将上部以粗面质火山岩为主的岩石地层新建为德勒乌拉组。新建的德勒乌拉组可分为2个段:下段为粗安质含角砾熔岩、河湖相砂砾岩;上段为以溢流相为主的粗面岩,该组与下伏老地层为角度不整合接触关系,其岩石化学特征为高钾钙碱性火山岩系列,锆石U-Pb年龄为(302.3±1.7)~(309.7±1.1)Ma,属晚石炭世。综合研究表明,德勒乌拉组形成于早海西同碰撞-碰撞后伸展过渡的陆相构造环境。德勒乌拉组的建立为内蒙古兴安地层区石炭纪火山地层的划分与对比、海西构造层的划分以及区域地质构造演化程式等方面的后续工作提供了重要依据。 相似文献
10.
冀北中生代陆相火山—沉积地层的填图单位(组内非正式岩石地层单位)，长期以来一直没有较统一的划分方案。根据该区地层的岩石成因组合和岩层相变规律的研究，提出火山岩系组内以相序的岩石组合划分岩性段填图，可以较好地反映火山岩的构造特征，有助于火山演化历史的研究；沉积岩系组内以沉积体系的岩石组合划分岩性段填图，可以生动地反映盆地的沉积特征和充填样式，有助于沉积层序的建立和盆地分析。这样，岩石地层单位(或填图单位)划分与火山—沉积盆地研究就可以有机地结合在一起。 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
15.
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
16.
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
17.
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
18.
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
19.
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
20.
正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of 相似文献