共查询到19条相似文献，搜索用时 140 毫秒
1.
本文详细研究了宁蒗-盐源地区志留系岩石地层和牙形刺生物地层特征，自下而上建立了3个牙形刺组合带：（1）Panderodus gracilis-Panderodus simplex组合带；（2）Pterospathodus cellodni组合带；（3）Pterospathodus amorphog-nathoides组合带。从生物地层学、沉积学和区域对比的角度分析了Pterospathodus celloni带和Pterospathodus amor-phognathoides带之间的相互重叠关系，并认为其相互关系为渐变演化关系，不是突变关系。 相似文献
2.
再论华南志留系红层的时代 总被引：2，自引：0，他引：2
牙形刺P.eopennatus带的确立和P.celloni带、P.amorphognathoides带的细分,使华南Llandovery统的划分和对比发生了变化,以往归入P.celloni带的地层,极大多数都要归属到P.eopennatus带,层位变低。依据牙形刺生物地层的分析,溶溪组（下红层）的时代可能为埃隆期晚期,... 相似文献
3.
桂林泥盆纪碳酸盐台地礁组合的层序地层研究 总被引：4，自引：0，他引：4
桂林的泥盆系以发育碳酸盐台地和礁组合沉积为特征，岩相多样，地层对比和时代确定的难度较大。本文应用层序地层学原理，结合生物地层和岩石地层特征，研究桂林泥盆系露头的相结构及碳酸盐台地礁组合不同亚相的９个剖面中的不整合界面，识别出该区中、晚泥盆世地层的５个层序界面：（１）牙形刺下ｖａｒｃｕｓ亚带和中ｖａｒｃｕｓ亚带之间；（２）牙形刺ｈｅｒｍｍａｎｉ－ｃｒｉｓｔａｔｕｓ带和ｄｉｓｐａｒｉｌｉｓ带之间；（３）牙形刺下ｒｈｅｎａｎｅ亚带和上ｒｈｅｎａｎｅ亚带之间；（４）牙形刺ｅｘｐａｎｓａ带内部；（５）牙形刺ｐｒａｅｓｕｌｃａｔａ带和ｓｕｌｃａｔａ带之间。这些层序界面在岩石学上的特征为具有生物铸模溶孔的白云岩和不同规模的暴露溶蚀面。比较明显的大的海泛面有２次：（１）牙形刺ｅｎｓｅｎｓｉｓ带和ｖａｒｃｕｓ带之间；（２）牙形刺ｌｉｎｇｕｉｆｏｒｍｉｓ带和下ｔｒｉａｎｇｕｌａｒｉｓ亚带之间。 相似文献
4.
西藏北部申扎地区德日昂玛-下拉山石炭二叠系生物地层划分 总被引：4，自引：0，他引：4
吉林地质调查院在西藏北部申扎地区进行地质调查时，对石炭纪一二叠纪地层进行了详细研究，自下而上划分为永珠组、拉嘎组、昂杰组、下拉组和木纠错组，并进行了生物地层划分，在永珠组建立了Gnathodus girtyi-Gnathodus tezanus牙形刺组合、Goniatites菊石带、Choristites-Spirigerella腕足组合和Trigonatreta cf．paucicostulata-Elivella baschkirica腕足组合；昂杰组建立了Spiriferella-Costiferina腕足组合；下拉组建立了Ipciphyllure-Waagenophyllum-Wentzelellites珊瑚组合、Dielasma millepunctatum-psudoantiquatonia mutabilis腕足组合和Neoschwagerina筵带。 相似文献
5.
通过对莱芜煤田石炭系多门类化石的研究,建立了本区石炭系及牙形刺组合带,在此基础上对其地层层序及生物地层的划分和二叠系的确定进行了讨论。 相似文献
6.
广西桂林的泥盆系包含艾菲尔期（包括少部分吉维期）的碎屑岩和吉维期至法门期的碳酸盐岩。以碳酸盐沉积发育期的５个实测剖面为基础，并结合牙形刺生物地层和不同沉积单元的微相研究探讨碳酸盐合地礁组合沉积的地层问题。根据牙形刺Ｉｃｒｉｏｄｕｓ和Ｐｄｙｇｎａｔｈｕｓ的组合特征提出广布于桂东北的信都组的顶界约相当于ｖａｒｃｕｓ带的底界；根据礁前斜坡相和台内浅水相沉积中的牙形刺，四射珊瑚及腕足类的组合特征，认为台内 相似文献
7.
牙形刺是奥陶纪地层划分的主导化石门类,目前已建立了可以全球对比的牙形刺生物化石带,但还缺乏对洲际尺度牙形刺生物带对比资料,特别缺乏精细年代控制的牙形刺生物地层资料。以研究程度较高的亚洲地区为例,梳理了亚洲内部奥陶纪牙形刺生物地层研究资料,初步建立了亚洲地区牙形刺生物地层对比格架,结合国际地质年表研究进展,提出了亚洲地区奥陶纪牙形刺研究需要解决的问题,即以目前执行的IGCP 652项目中国工作组研究任务为依托,开展我国鄂尔多斯西南缘奥陶系多重地层研究,有望获得高精度年代控制的奥陶纪牙形刺生物地层资料。 相似文献
8.
王平 《西安地质学院学报》1995,17(1):1-9
陕西镇巴火焰溪剖面部于大巴山西段，临近川陕交界，交通便利。那里晚泥盆世地层出露完好，层序清楚，化石丰富。本文就该剖面法门阶牙形刺动物群、泥盆系石炭系的界线进行了研讨，建立了该区法门阶的两个浅水相牙形刺生物组合带。 相似文献
9.
文章根据近年桂北地区1：3万区域地质调查和专题研究成果，对泥分末至早石炭世生物群作了较系统的总结，划分了若干可与区域乃至世界对比的生物（组合）带；有孔虫12个，珊瑚11个，腕足类6个，牙形刺5个，菊石、介形类各2个；并提出了年代地层划分的意见。 相似文献
10.
在广东连县－阳山煤田的二叠纪地层中首次采集到牙形刺化石计11属20种和3个未定种。通过与中国南方相应标准剖面对比，建立了4个组合带；茅口阶Neogondolella serrata-N.postserrata组合带，吴家坪阶中、下部Neogondolella liangshanensis组合带、吴家坪阶上部Neogondolella orientalis组合带，长兴阶Neogondalella changxingensis-N.subcarinada组合带。同时讨论了上统与下统、长兴阶与吴家坪阶、下三叠统与上二叠统的地层界线。 相似文献
11.
论华南志留系对比的若干问题 总被引：38，自引：13，他引：25
<正> 中国志留系的划分与对比,始于20年代。李四光等(1924)和谢家荣等(1925)研究了三峡地区的志留系,将其全部划归下统。孙云铸(1943)从沉积旋迴角度提出了我国志留系划分的三个阶段,后又发现相应的笔石辅以佐证(孙云铸1957、洪友崇1958),将峡区的志留系分别与英国的 Llandovery,Wenlock和 Ludlow三个统对比。这个方案得 相似文献
12.
作者通过对龙门山北段志留纪牙形石和笔石的研究,自下而上初步建立了该区的牙形石带:Paraspothognothodus obesus 带,Paraspothognathodus parahassi-P．guizhoweusis 组合带,Pterospathogwa-wodus oelloui 带:笔石带:Demirastriles (?) 带,Spirograptus (?) 带和 Streptograptus nodifer 带.在此基础上,将该区地层自下而上划分为:龙马溪组、磨刀垭组、后蒿坪组和宁强组,其中磨刀垭组和后蒿坪组为2个新建组。本区绝大部分地层为下志留统,只有宁强组上部可能为中志留统。 相似文献
13.
GuSongzhu FengQinglai 《中国地质大学学报(英文版)》2002,13(1):44-47
With abundant deep-water upper Permian sediments,Guizhou is an ideal place for the re-search of radiolarian biostratigraphy of Upper Permian.The sections of Sidazhai and Lekang in southern Guizhou Province are studied.Lithology and biostratigraphy of the siliceous rock sequence of uppermost Permian in the two sections are introduced.Radiolarian assemblage zones,Neoalbaillella optima assem-blage zone and Klaengspongus spinosus assemblage zone in ascending order are established for the top-most Permian of southern Guizhou.The Klaengspongus spinosus zone has been the topmost radiolarian assemblage zone of Permian,which is also correlated with former ones in a considerable depth. 相似文献
14.
笔者等近期对华北地块南缘豫皖交界处出露的一套层序连续完整的白大山群进行了剖面测制,在该套地层的碳酸盐岩中发现了中、晚奥陶世牙形刺分子Belodina compressa,Panderodus gracilis,Pseudobelodina dispansa(?)以及苔藓虫、海绵骨针、小壳类、古介形类等化石,填补了该地区一直无可靠化石记录的空白。同时依据地层层序特征、岩性组合、生物群面貌、古地理沉积环境,并结合大量灰岩薄片鉴定结果,将白大山群时代划归早古生代。同时,将华北地块南缘界限向北推移至蒋集-龙潭一线,并认为本区牙形刺生物群应属北方型牙形刺地理分区。 相似文献
15.
The Oxfordian sedimentary successions studied in the Swiss Jura, in Normandy, and in the Soria and Cazorla regions of Spain display complex facies evolution and stacking patterns. Based on biostratigraphy and absolute age dating, it is suggested that the shallow-water depositional settings in the Jura, Normandy, and the Soria region as well as the deeper-water environments in the Cazorla region, recorded climatic and sea-level fluctuations in the Milankovitch frequency band. Beds and bedsets corresponding to 20-, 100-, and 400-ka cyclicities can be identified. Facies evolution inside such small-scale sequences and also in the larger sequences of million-year scale is interpreted in terms of sequence stratigraphy. Superposition of high-frequency cyclicity on a longer-term sea-level trend led to multiplication of diagnostic surfaces: sequence-boundary and maximum-flooding zones in the large-scale sequences can thus be defined. These zones are correlated between closely spaced sections, but also from the Swiss Jura to Normandy and to Spain. The narrow time lines given by Milankovitch cyclicity then allow comparison of facies evolution in the different regions on a scale of 100 ka or less. By filtering out local effects of differential subsidence and sediment supply, a long-term sea-level curve valid for the northwestern margin of the Tethys ocean can be reconstructed for the Middle to Late Oxfordian. Differential subsidence is implied from varying thicknesses of the sequences as well as from the distribution of siliciclastics which have been channelized through depressions. Tilted blocks, reduced sedimentation, or increased input of siliciclastics appearing at the same time in all study areas point to a widespread regional tectonic event. Distribution through the sequences of climate-dependent facies components such as corals, ooids, palynomorphs, and siliciclastics indicates that climate changes were dependent on atmospheric circulation patterns and thus on paleolatitude. Rainy periods and related increase of siliciclastics in the Swiss Jura were more abundant during low sea-level stands, whereas in the Soria region they coincided with sea-level highs. Through the combination of high-resolution sequence stratigraphy and cyclostratigraphy, and supported by biostratigraphy and absolute dating, it becomes possible to analyze paleoenvironmental changes in a very narrow time framework. 相似文献
16.
针对保山地层区熊洞剖面原属栗柴坝组的灰岩进行了牙形石样品分析,总计建立了5个牙形石带,分别为Pterospathodus pennatus procerus带、Kockelella walliseri带、Ancoradella ploeckensis带、Polygnathoides siluricus带和Polygnathus nothoperbonus带。该剖面第8层原属栗柴坝组,Polygnathus nothoperbonus分子的出现证实其为下泥盆统埃姆斯阶的地层,应归为向阳寺组。剖面总体对应志留系温洛克统底部到下泥盆统埃姆斯阶中部,中间缺失志留系罗德洛统卢德福特阶—下泥盆统埃姆斯阶之间的8～10个标准牙形石带,说明该地区后期可能受构造作用影响,志留系和泥盆系界线为断层接触。该剖面牙形石序列的建立一定程度上完善了滇西保山地层区志留系生物地层的研究程度,为下一步该区生物地层格架的建立奠定了基础。 相似文献
17.
Ordovician complexes of the convergent margins of lithospheric plates are established in the Paleozoides of the southern Urals. Several types of Ordovician sections that make up allochthons and characterize different geodynamic settings are thoroughly studied and dated on the basis of conodont biostratigraphy. The geochemistry and petrology of volcanic rocks bear information on the evolution of the Paleoural ocean and the convergent relationships of plates from the end of the Llanvirnian. The suprasubduction volcanic activity in the Late Ordovician gave way to within-plate volcanism of extension zones, the development of which continued into the Early Silurian. 相似文献
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19.
Z.N. Pojarkova 《Cretaceous Research》1984,5(1):1-14
Northeastern Central Asia during the Albian and Early Cenomanianwas one of the peripheral basins of the Central Asian region. The similarity of their freshwater molluscs makes it possible to correlate isolated series in these two regions. Subsequently, a pulsating transgression of the Tadzhik Sea invaded northeastern Central Asia which became a part of the Central Asian Province of the Tethys. The complicated palaeogeography means that there are many different local biostratigraphic successions. The relations between these have been worked out from an integrated study of the biostratigraphy, palaeogeography, ecology and biogeography. Marked endemism amongst the molluscs, sometimes total, limits correlation with other regions of the Tethys; in particular, correlation of some of the local biozones (or “lones”) with western European zones is still uncertain. 相似文献