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1.
塔里木地区早古生代海平面波动特征:来自地球化学及岩溶的证据 总被引：13，自引：3，他引：10
下古生界是塔里木盆地内最有潜力找到大油气田的层位。通过盆地内48口钻至下古生界钻井的沉积层序与沉积相分析、9800km地震剖面的地震相分析、大量Sr、C同位素及微量元素分析,并结合相关资料,开展了寒武纪—奥陶纪的以世或期为单位的岩相古地理研究,定性探讨海平面变迁。在此基础上,运用沉积地球化学定量探讨海平面的波动。分析表明,早古生代塔里木地区经历了两次大规模的海侵与海退过程,寒武纪和奥陶纪各经历了一次。每个海侵与海退过程内各包含了两个较高频的海平面升降旋回,即早寒武世早期海侵—早寒武世中期至中寒武世晚期海退、中寒武世末期海侵—晚寒武世晚期海退、早奥陶世早期至中奥陶世中期海侵—中奥陶世晚期海退、晚奥陶世早期海侵—晚奥陶世中至晚期海退。在上述2次大规模的海侵与海退以及4个较高频的海平面升降旋回中,两次大的海侵分别发育于早寒武世早期以及晚奥陶世早中期,三次较大的海退出现于中寒武世晚期、晚寒武世末期、晚奥陶世早期。岩溶在地层格架中的发育支持了上述结论。 相似文献
2.
湖南凤凰寒武纪Fischer点图及其意义 总被引：2，自引：0，他引：2
湖南凤凰早寒武世为外陆棚环境，中、晚寒武世为台缘斜坡，经过一定校正编绘的Ｆｉｓｃｈｅｒ点图获得的海平面变化曲线显示寒武纪全球海平面上升的趋势，海洋可容空间不断加大，这与三叶虫演经有耦合关系，早寒武世区域性三叶虫多，生物分区明显，三叶虫带不能进行洲际对经，晚寒武世则相反，两个重要海进面（５３６Ｍａ和５１７．２Ｍａ）是统间界线最佳线点，与北美Ｒ２曲线比较可确认５１５－５１７Ｍａ 寒武大海泛期（长山期内 相似文献
3.
皖南东至地区寒武系层序地层研究 总被引：5，自引：2，他引：5
皖南东至地区寒武系在地层分区上可以分为下扬子地层分区、过渡地层分区和江南地层分区，生物群上出现了两区特征分子和过渡区的混生现象，并处于台地与盆地交接部位。通过对分别位于台地、斜坡和盆地露头层序地层研究，将寒武纪地层自下而上划分为三个Ⅱ类沉积层序和二个Ⅰ类沉积层序，早寒武世的三个Ⅱ类沉积层序的陆架边缘体系域不发育；中寒武世晚期到晚寒武世的二个Ⅰ类沉积层序皆由低水位体系域、海侵体系域和高水位体系域 组成三元结构。通过层序地层分析和沉积体系演化建立了相应的海平面变化曲线，自早寒武世早期本区海平面达到最高位和最大上升速率后，至寒武纪末研究区海平面总体处于下降过程，即海平面为累进式的缓慢的下降。 相似文献
4.
《西北地质》2015,(1)
华北地区沉积岩石特征表明:早寒武世辛集期主要为潮间-潮下带沉积,馒头期海平面相对稳定,毛庄期—张夏期大量的潮下鲕粒滩发育,中寒武世张夏期为寒武纪最大海侵期。随后海平面下降,晚寒武世主要表现潮坪相的白云岩沉积。通过地球化学分析表明:碳酸盐岩δ13 C多数为-1.23~0.34,总体上反映相对水体较浅的环境。早寒武世δ13C为负值,中寒武世逐渐正漂移,晚寒武世又逐渐负偏,表明该地区寒武纪海平面经历了由浅变深再变浅的变化过程,最大海侵面时期为中寒武世张夏期,与岩石特征所反映的结果一致;低负值的δ18 O说明该区域均为较为局限的海域。LREE/HREE值反映了轻稀土富集、重稀土亏损,与碳酸盐岩球粒陨石标准化后的稀土元素配分曲线一致;δEu和δCe异常、La/Yb值显示早寒武世和晚寒武世海平面均发生过几次明显波动,表明寒武纪碳酸盐岩沉积时期,沉积水体经历了几次氧化-还原环境变化。 相似文献
5.
安徽南部下扬子地区寒武系露头层序地层初步研究 总被引：2，自引：0，他引：2
露头层序地层研究表明，安徽下杨子地区寒武纪可识别出两个Ⅰ类层序及三个Ⅱ类层序，早寒武世的三个Ⅱ类层序由于同沉积断裂影响陆架边缘体系域不甚发育；中、晚寒武世的两个Ⅰ类层序由低水位体系域、海侵体系域及高水位体系域构成。由沉积体系域演化作出的海平面变化曲线不同于Ｖａｉｌ的寒武纪全球海平面变化Ⅱ级旋回，表明了皖南下扬子海盆的海平面升降受扬子板块、华夏板块的影响远大于全球海平面变化幅度。 相似文献
6.
寒武系是塔里木盆地当前油气增储上产的重点层系,恢复寒武纪的盆地原型是油气勘探的重要基础。利用最新的钻井、地震及露头资料,以沉积相为研究实体,将盆地充填与周缘构造演化相结合,由点→线→面进行分析,恢复了塔里木盆地寒武纪不同时期的构造-沉积环境,并建立了相应的盆地充填演化模式。塔里木盆地寒武纪经历了一次完整的海侵-海退旋回,包括早寒武世早期快速海侵→中寒武世海退、晚寒武世缓慢海侵→寒武纪末海退两个次级旋回,分别对应沉积演化的2个阶段：塔西克拉通内坳陷早寒武世的碎屑滨岸-陆棚相→局限台地相→中寒武世的蒸发台地相,晚寒武世的局限台地相→寒武纪末期的台地暴露不整合;塔东克拉通边缘坳陷为深水盆地相,经历了硅质泥岩→泥岩与灰岩薄互层→碳酸盐岩的岩相演化。寒武纪塔里木原型盆地特征及演化主要受控于Rodinia超大陆的裂解,其构造-沉积格局经历了由震旦纪末的南北分异格局向中-晚寒武世的东西分异格局的演变。 相似文献
7.
库鲁克塔格地区寒武系层序地层与发育模式 总被引：2，自引：0，他引：2
新疆塔里木盆地库鲁克塔格断隆区出露的寒武系由一系列半深海-浅海沉积物构成.发育磷酸岩、硅质岩、火山岩、石膏、瘤状灰岩、风暴碳酸盐岩、鲕状灰岩、浊流碳酸盐岩等特殊类型.寒武系可划分为11个三级层序、3个二级层序和2个一级层序,反映出三级不同规模的海平面变化.三级海平面变化控制的层序具有6种发育模式,与特殊的环境和变化相联.二级层序是盆地发育不同构造阶段的产物,盆地发育包括早寒武世裂陷阶段、中寒武世断坳过渡阶段和晚寒武世坳陷阶段,分别控制了二级层序A、B和C的发育和构成.本区寒武纪分别在早寒武世和晚寒武世发生最大海泛,其中晚寒武世的海泛与全球海泛一致,但早寒武世的最大海泛是地方性的. 相似文献
8.
甘肃北山地区的寒武纪地层出露比较定整,断续分布在晚前寒武纪断陷盆地之中,岩性稳定,厚度不大,含有相当丰富的古生物化石,是研究中国寒武纪南北两大生物群的重要地区之一。1964年中国科学院兰州地质所刘光夏、陈立军等在大豁落井发现了早和晚寒武世三叶虫,为北山地区寒武纪地层的划分及对比提供了化石依据,并根据三叶虫将本区的寒武纪地层自上而下划分为,中及上寒武统:马宗山群;下寒武统大葫芦组,双鹰山组。 相似文献
9.
近期在桂西四城岭地区寒武系中新发现三叶虫Chuangia sp、Skirakiella atilimbata及Rhaptagnostus sp．等,首次发现腕足类Lingulla ef．sanfangensis等及遗迹化石Chondritessp．等一批古生物化石,填补了桂西碎屑岩型寒武系下部地层的化石空白,并将该区寒武系首次划分为芙蓉统第九阶、第十阶。江南型晚寒武世半游泳、漂游、深水混合型斜坡至次深海生物群落的发现,指示该区为次深海盆地相环境,应为江南盆地的组成部分。这一发现极大地提高了该区寒武纪地层的研究程度,在地层的划分对比、古生物学、古地理及区域大地构造研究等方面都有着重要意义。 相似文献
10.
对塔里木盆地寒武纪早、中、晚3个时期的古水深、沉积速率、构造沉降速率和拉伸系数计算结果表明,塔里木盆地在早寒武世为深度裂陷阶段,中寒武世为裂陷迁移阶段,晚寒武世为台内裂陷阶段,早寒武世与中-晚寒武世的构造差异性十分明显。早寒武世伸展引起的裂陷作用发生在塔东地区,伸展促使该区构造沉降速率远远大于台地相区,形成半深海盆地相环境。中-晚寒武世伸展向台地内部迁移,使台地内部的构造沉降速率远大于盆地相区,而台地内部较高构造沉降速率被更高的沉积速率所补偿,使得这里始终未能出现地貌上的凹地。 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.
15.
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
16.
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
17.
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
18.
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
19.
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
20.
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