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关于喀斯特洞穴发育深度问题 总被引：10，自引：1，他引：9
探讨喀斯特洞穴发育深度,必须考虑其形成的环境条件。喀斯特洞穴的形成环境可归结为两大系统:１）常温常压开放系统,主要表现为在强烈的地下水动力作用下的溶蚀作用;２）高温高压封闭系统,主要表现为在微弱的地下水动力作用下的化学溶蚀作用。热水溶蚀及混合溶蚀作用是发育深部洞穴的主要动力 相似文献
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中国南方发现大型文石笋 总被引：9，自引：0，他引：9
中国南方大量石笋剖面研究表明,石笋矿物组成有方解石、文石、方解石-文石三种类型。石笋沉积纹(微)层结构构造特征大同小异,但是文石石笋的放射状纹(微)层构造更显著。文石石笋沉积生长的气候环境是滴水多而稳定,水温低、气温略高的冷、湿的洞穴气候条件。文石转变为方解石常保留文石的针状、柱状晶形,并存在于石笋沉积生长的始终。文石结构构造转化在常温或低温、常压或低压下自调整作用的成晶成岩环境进行,其强度取决于所在洞穴气候环境、滴水在石笋的渗流和石笋的含水度。转化作用不影响同位素分馏,石笋同时全面记录古气候环境信息。研究文石石笋对重建古气候环境、成岩成矿作用都有重要理论和实践意义。 相似文献
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塔里木盆地早海西期多期次风化壳岩溶洞穴层 总被引：25，自引：5，他引：20
洞穴层是识别多期次岩溶旋回的标志,是岩溶旋回连接沉积旋回及周期性海平面变化的纽带。本文通过古地貌恢复,将从钻井剖面中识别的洞穴层归位到早石炭世古地貌剖面中,根据洞穴层总是沿稳定古潜水面发育的特点划分对比洞穴层。通过洞穴层的形成条件、充填结构分析,推断洞穴层发育序次、洞穴层与其同时期形成的沉积地层的时空对应关系,并据此对洞穴层进行盆地范围内跨地区对比、总结斜坡及岛屿两种不同的洞穴层发育模式。研究结果表明,在早海西期,塔北、塔中、和田古隆起中、下奥陶统碳酸盐岩陆块内部发育了3个期次的风化壳岩溶洞穴层,其序次为下老上新,它们是在早石炭世间歇性海平面上升过程中形成的,其同时期形成的沉积地层分别为下石炭统东河砂岩段、生屑灰岩段、下泥岩段中上部。洞穴层内部多旋回“坍塌角砾-地下河沉积”组合是斜坡内陆区潜流面的迟后上升效应,洞穴层与洞穴等时层的时空对应关系对于大型古岩溶事件的断年及洞穴层的分布预测具有重要意义。 相似文献
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北京石花洞位于房山花岗岩体边缘向形带的东北扬起端,与北京猿人遗址南北相望。地层为460Ma前形成的中奥陶统马家沟组石灰岩,洞穴大形态从25Ma前的上新世开始形成,洞内钟乳石从0.37Ma前的中更新世开始形成。在中国岩溶洞穴中,北京石花洞的层数最多,洞穴钟乳石种类齐全,裂隙渗透水沉积的石盾多、体积大,滴水沉积的石笋叠置关系明显,池水沉积的月奶石发育好,全新世石笋微层理发育清晰。该洞的大形态反映了北京西山新构造运动的期次,可以同华北地文期和永定河阶地对比,洞内钟乳石记录了中更新世以来北京西山古环境的变化,可以建立第四纪剖面,与周口店洞穴群碎屑沉积物剖面进行对比。钙板的铀系年龄为334.99～366.74ka,可定名钙板组。粗犷石笋的铀系年龄为169～235ka,粗犷石笋的电子自旋共振年龄为130～518ka,为中更新世沉积,可定名云水洞组。杆状石笋的铀系年龄为14.9±2.1～100.3±11.1ka,为晚更新世沉积,可定名石花洞组。在全新世石笋中,微层与微层之间存在厚约1μm的条带状纹线,是划分微层层数的标志,具有微层理的石笋14C年龄为为0.58～2.50ka,AMS14C年龄为为130±100～670±130a,可定名守备支洞组。 相似文献
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全球变化研究中的洞穴化学沉积物 总被引：1，自引：0，他引：1
自 2 0世纪 6 0年代以来 ,探索全球性气候变化规律和环境变迁史的研究工作在世界各国广泛开展。随着全球变化研究工作的逐渐深入 ,国际岩溶学术界也开始将注意力从溶蚀过程转向沉积过程 ,从宏观形态研究转向微观记录研究。人们逐渐认识到洞穴化学沉积物 (石笋、石钟乳、流石等 )与黄土、树轮、珊瑚、冰芯一样也是重要的自然环境历史档案 ,其中石笋由于其沉积剖面完整、年轮 (微层 )明显和组分构造有序 ,更能保存系统的、连续的同位素、微量元素组成以及年龄信息 ,从而成为综合研究几十万年以来气候与生态环境变化的理想载体。人们最早注意到… 相似文献
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在讨论地质背景与洞穴发育关系的基础上,结合
洞穴中冲、溶蚀形态特征、第四纪不同时期的沉积物剖面及沉积旋回分析、粒度分析、砾石
统计等资料,系统分析了洞穴发育过程中的古水流方向。测年资料表明,多层洞穴不同时
代的堆积物记录,反映了新构造运动和气候波动对洞穴发育的控制作用,为评价洞穴的发育
规模、展布方向及对工程的影响,提供了可靠的科学依据。 相似文献
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全面介绍北京石花洞发现与研究的历史、取得的重大成果,以及在岩溶学研究领域所起的作用。石花洞位于北京西山,发现于明朝正统十一年,开发于20世纪80年代。岩溶学研究表明,石花洞洞层多（8层）,石盾多（200多个）,为世界罕见。在全国范围内,首次发现月奶石,首次发现碳酸钙微层理,首次发现膜足硬肢马陆穴居动物。笔者从地质学、气象学和环境学全面研究了石花洞,测绘精度达到1：200,进行了氡浓度研究。从溶蚀形态来看,石花洞8层溶洞展示北京西山的8次隆升;从沉积形态来看,石花洞中的粗犷石笋代表中更新世沉积,杆状石笋代表晚更新世沉积,微层理石笋代表全球转暖以来的全新世沉积,奠定了首次建立第四纪石笋剖面的基础。 相似文献
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勒穆尚洞是位于列日市东南的一个巨大的喀斯特洞穴,作者对位于上层与下层通道连接处的沉积物进行了孢粉研究,根据沉积物性质不同,剖面可分两部分,下部由河流相的砂砾组成,上层为数层石笋质盖板。最上层的石笋质盖板经放射性钍(?)铀(?)法测定,年代为距今10.5万a。 根据孢粉分析,石笋质盖板层可能形成于距今10.5万a的里斯—玉木间冰期中期,当时气候温暖潮湿,生长有以榛、栎、赤杨、千金榆为主,伴有一些椴、榆、常春藤等的阔叶林,洞穴处于低洼积水的环境。剖面下部的砂砾是在此温暖期之前由地下河在不同气候条件下多次堆积而成。 此外,本文还讨论了古植被及古气候的变化以及该洞穴的演化历史。 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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Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003). 相似文献
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正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.) 相似文献
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正20141243Chen Ge(Hangzhou Research Institute of Petroleum Geology,PetroChina,Hangzhou 310023,China);Si Chunsong Study on Sedimentary Numerical Simulation Method of Fan Delta Sand Body(Journal of Geology, 相似文献
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正20142599Chen Sanming(Guangxi Key Laboratory of Concealed Deposits Exploration,Guilin University of Technology,Guilin541004,China);He Yuzhou Block Model and Reserves Estimation of Panzhihua Iron Deposit Based on 3D Geological Modeling(Journal of Guilin University of Technology,ISSN1674-9057,CN45-1375/N,33(4),2013,p.610-615,9illus.,1table,15refs.) 相似文献
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正20140594 Bai Daoyuan(Hunan Institute of Geology Survey,Changsha 410016,China);Zhong Xiang Faults in the Jingzhou Basin and Their Tectonic Settings(Geotectonica et Metallogenia,ISSN1001-1552,CN44-1595/P,37(2),2013,p.173-183,6illus.,59refs.)Key words:basin evolution,tectonic setting,South China In the Upper Paleozoic and Jurassic se- 相似文献
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正20141912Cao Hui(State Key Laboratory for Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)Gravitational Collapse and Folding during Orogenesis:A Comparative Study of FIA Trends and Fold Axial Plane Traces(Geology in China,ISSN1000-3657,CN11-1167/P,40(6),2013,p.1818-1828,9illus.,35refs.,with 相似文献