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通过对陕西汉中天坑群岩溶地质遗迹的广泛调查和分析,确定了宁强禅家岩、南郑小南海、西乡骆家坝和镇巴三元四个天坑群集中分布区,从地层岩性、地貌、构造等方面总结了汉中天坑群形成地质条件和分布规律,研究认为二叠纪-三叠纪巨厚的碳酸盐岩地层为天坑(群)发育的物质基础,断裂、褶皱构造是天坑(群)形成的控制条件,特别是次级构造决定了天坑发育的具体位置,新构造抬升及湿热的气候为天坑的形成提供了岩溶动力。汉中天坑群水平上呈带状成群分布,垂向上差异较大,1 000~2 000 m居多的空间分布特征。岩溶天坑的形成经历了四个阶段的演化过程。 相似文献
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陕西宁强禅家岩天坑群是汉中天坑群中 4 个相对独立的喀斯特系统之一,位于扬子陆块北缘,发育有多样的地质遗迹。文章通过大量野外勘测,总结出陕西宁强禅家岩天坑群地质遗迹的分布特点,并分析了主要地质遗迹的基本特征及形成原因,以揭示南北过渡带峡谷地貌下喀斯特的形成及演化机理。结果表明:(1)研究区形成了以天坑、台原、溶洞、峡谷以及次生化学沉积物为特色的2大类4类5亚类的地质遗迹;(2)区内喀斯特地貌典型,天坑和溶洞最为发育;(3)受峡谷深切影响,研究区内形成有4个地表喀斯特台原,其均具有相对独立的喀斯特水文地质特征,而天坑和竖井均已进入退化期;(4)在地层、岩性和构造多因素作用下,区内天坑孕育于新构造运动时期。 相似文献
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双河洞中大熊猫-剑齿象动物群化石的发现 总被引:1,自引:0,他引:1
对贵州省境内的双河洞历次科考中发现的第四纪动物群化石进行初步研究和总结,认为目前对双河洞第四纪动物群研究尚处于起步阶段,化石的发现者都是洞穴科考专家,古生物知识相对欠缺且重视不够是洞穴化石研究进展缓慢的原因。为了加快双河洞第四纪动物群的研究进程,以今年中法联合科考过程中发现的大熊猫-剑齿象动物群化石为样本,采用ICP-MS铀系定年方法对这批大熊猫骨骼化石碳酸盐岩包裹物的年龄进行测试,结果表明该化石群化石距今6.75万年,初步判定此动物群可能生存于中更新世-晚更新世早期。这批哺乳动物化石及其地层信息将为贵州(尤其是黔北)第四纪的研究提供重要资料。 相似文献
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袁氏剑齿象(新种)(Stegodon yuani sp.nov.)是根据发现于云南省大理白族自治州剑川县东山脚村附近的两颗上第三臼齿建立的。 化石产于早更新世湖泊和滨湖河流相的东山组上部粉砂质粘土层中。它稍原始于东方剑齿象(S.orientalis),而在进化水平上又稍晚于先东方剑齿象(S.praeorintalis)。 相似文献
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近年在南岭以南的广东东江流域河源地区东源县上莞镇的碧寿洞中发现较丰富的古哺乳动物牙齿化石。经鉴定为6个目5属5种,称之为碧寿动物群。根据碧寿动物群指示的古生态、化石层位、热释光测试结果和生物地层对比初步认为,该动物群与西江流域的罗沙岩动物群一样,都属于晚更新世时期的大熊猫—剑齿象动物群,生活在MIS5a时的间冰期,但罗沙岩动物群的时代略早,为(79.0±15)kaBP,而碧寿动物群则存在于末次冰期/末次间冰期之交的MIS5a之末叶。此动物群为广东东江流域历年首现,代表了当时的热带北缘森林草原的自然环境。 相似文献
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晚更新世的大熊猫广泛分布于中国华南地区,化石分布点众多,但完整保存的骨骼材料相对较少。文中报道了贵州惠水县仰天窝竖井新发现的完整大熊猫头骨化石,仰天窝竖井—白马洞因其特殊的洞穴环境为化石的保藏创造了有利条件。根据测量数据,仰天窝大熊猫个体牙齿比现生大熊猫略大,应属于巴氏大熊猫。AMS—14 C测年结果为22887~22431 a BP,时代处于末次盛冰期前后,新材料的发现为推断大熊猫在晚更新世末期的分布范围、生存演化等问题提供了难得的实证。 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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Inter-regional correlation of transgressions and regressions in the Cretaceous period 总被引:1,自引:0,他引:1
T. Matsumoto 《Cretaceous Research》1980,1(4):359-373
Well investigated platforms have been selected in each continent, and the history of Cretaceous transgressions and regressions there is concisely reviewed from the available evidence. The factual records have been summarized into a diagram and the timing of the events correlated between distant as well as adjoining areas.On a global scale, major transgressions were stepwise enlarged in space and time from the Neocomian, via Aptian-Albian, to the Late Cretaceous, and the post-Cretaceous regression was very remarkable. Minor cycles of transgression-regression were not always synchronous between different areas. Some of them were, however, nearly synchronous between the areas facing the same ocean.Tectono-eustasy may have been the main cause of the phenomena of transgression-regression, but certain kinds of other tectonic movements which affected even the so-called stable platforms were also responsible for the phenomena. The combined effects of various causes may have been unusual in the Cretaceous, since it was a period of global tectonic activity. The slowing down of this activity followed by readjustments may have been the cause of the global regression at the end of the Cretaceous. 相似文献
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The Afyon stratovolcano exhibits lamprophyric rocks, emplaced as hydrovolcanic products, aphanitic lava flows and dyke intrusions, during the final stages of volcanic activity. Most of the Afyon volcanics belong to the silica-saturated alkaline suite, as potassic trachyandesites and trachytes, while the products of the latest activity are lamproitic lamprophyres (jumillite, orendite, verite, fitztroyite) and alkaline lamprophyres (campto-sannaite, sannaite, hyalo-monchiquite, analcime–monchiquite). Afyon lamprophyres exhibit LILE and Zr enrichments, related to mantle metasomatism. 相似文献
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正20140751 Guo Xincheng(Geological Party,BGMRED of Xinjiang,Changji 831100,China);Zheng Yuzhuang Determination and Geological Significance of the Mesoarchean Craton in Western Kunlun Mountains,Xinjiang,China(Geological Review,ISSN0371-5736,CN11-1952/P,59(3),2013,p.401-412,8 相似文献
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正20141058 Chen Ling(Key Laboratory of Mathematical Geology of Sichuan Province,Chengdu University of Technology,Chengdu610059,China);Guo Ke Study of Geochemical Ore-Forming Anomaly Identification Based on the Theory of Blind Source Separation(Geosci- 相似文献
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正20141334 Chen Kun(Institute of Geophysics,China Earthquake Administration,Beijing100081,China);Yu Yanxiang Shakemap of Peak Ground Acceleration with Bias Correction for the Lushan,Sichuan Earthquake on April20,2013(Seismology and Geology,ISSN0253-4967,CN11-2192/P,35(3),2013,p.627-633,2 illus.,1 table,9 refs.)Key words:great earthquakes,Sichuan Province 相似文献
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正20141624 Cai Xiongfei(Key Laboratory of Geobiology and Environmental Geology,Ministry of Education,China University of Geosciences,Wuhan 430074,China);Yang Jie A Restudy of the Upper Sinian Zhengmuguan and Tuerkeng Formations in the Helan Mountains(Journal of Stratigraphy,ISSN0253-4959CN32-1187/P,37(3),2013,p.377-386,5 illus.,2 tables,10 refs.) 相似文献
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正20142263Lü Shaojun(Geological Survey of Jiangxi Province,Nanchang 330030,China)Early-Middle Permian Biostratigraphical Characteristics in Qiangduo Area,Tibet(Resources SurveyEnvironment,ISSN1671-4814,CN32-1640/N,34(4),2013,p.221-227,2illus.,2tables,22refs.)Key words:biostratigraphy,Lower Permian,Middle Permian,Tibet 相似文献
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正20142560Hu Hongxia(Regional Geological and Mineral Resources Survey of Jilin Province,Changchun 130022,China);Dai Lixia Application of GIS Map Projection Transformation in Geological Work(Jilin Geology,ISSN1001-2427,CN22-1099/P,32(4),2013,p.160-163,4illus.,2refs.) 相似文献
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正20140692 Duo Tianhui(No.402 Geological Team,Exploration of Geology and Mineral Resources of Sichuan Authority,Chengdu611730,China);Wang Yongli Computer Simulation of Neptunium Existing Forms in the Groundwater(Computing Techniques for Geophysical and Geochemical Exploration,ISSN1001-1749,CN51-1242/P,35(3), 相似文献