共查询到19条相似文献,搜索用时 156 毫秒
1.
2.
3.
4.
安徽巢湖地区下三叠统牙形石生物地层分带及其全球对比 总被引:5,自引:2,他引:5
安徽巢湖地区早三叠世处于下扬子碳酸盐岩缓坡较深水区域,地层序列完整、清晰,各类化石是区域乃至全球最为丰富、序列最为完整的,是研究国际早三叠世年代地层最经典地区之一.对安徽巢湖平顶山西坡剖面、平顶山北坡剖面、马家山南剖面系统采样和精细的牙形石生物地层研究结果表明,下三叠统至少可以划分为8个牙形石带,建立了在华南具有代表性的下三叠统牙形石生物地层序列,自下而上为(1)Hindeodus typicalis带;(2)Neogondolella krystyni-Neogondolella planata带;(3)Neospathodus kummeli带;(4)Neospathodus dieneri带;(5)Neospathodus iaageni带;(6)Neospathodus pingdingshanensis带;(7)Neospathodus homeri带;(8)Neospathodus anhuinensis带.并与世界其他地区同期地层进行精确对比,为建立下三叠统印度阶与奥伦尼克阶界线的全球层型(GSSP)提供可靠依据. 相似文献
5.
海南岛保亭县南好地区"南好组"所产腕足类Xinanospirifer flabellum Rong,Xu et Yang,X.cf.sanduensis(Jing),三叶虫Latiproetus cf.latilimbatus(Grabau)和腹足类Homotoma sp.等化石证明,该组的地质时代为早志留世特里奇期晚期。对腕足类化石的深入研究结果表明,早先划分该地区下石炭统岩关阶"南好组"所依据的主要化石Eochoristites sp.,Fusella sp.,Cyrtiopsis sp.,Tenticospirifer cf.supervilis,Cyrtospirifer sp.等是误定的结果,不能用作地层划分对比的证据。因此,陈哲培等(2012)根据早已废弃的化石名单得出南好地区"南好组"属下石炭统岩关阶的结论明显有误。对南兵—南好公路剖面、南好矿区锌山等早先采获早石炭世腕足类化石产地的反复多次采集,都没有重复采到原先报道的化石种类、而全部为早志留世属种,以及南好地区迄今没有发现可靠的早石炭世化石等事实表明,该地区既不存在下石炭统,也不存在下石炭统与下志留统之间的不整合接触关系。"南好组"原选层型剖面的地质构造极其复杂、地层多次重复、叠覆关系不明、层序混乱、厚度不清,不能充当岩石地层单位的选层型,应连同"南好组"一名一并废弃。 相似文献
6.
江西省峡江县仁和地区的煤系地层过去未获化石,长期以来,一直认为属上三叠统安源煤系,本文根据最近采获的菊石,腕足类及植物化石资料,论证该区煤系地层应属晚二叠世乐平煤系,同时在区内首次发现早三叠世地层。 相似文献
7.
本文介绍了下巴颜喀拉群地层层序及划分意见,根据已采获古生物化石,将其时代归属早三叠世沉积。对下三叠统底部砾岩分布、组成岩石成分、砾石大小及沉积结构构造特征,作了详细描述,从而确认它是与下伏二叠系地层呈不整合接触的砾岩层。同时对该区下三叠统中零星分布的外来岩块(混杂堆积岩)的产出情况作了论述,认为是“滑塌堆积”产物。上述二种砾岩其成因及地质意义完全不同,应予以区别对待。 相似文献
8.
9.
10.
11.
12.
甘肃武都龙家沟盆地地层时代及发育特征 总被引:1,自引:0,他引:1
根据化石组合,龙家沟盆地的地层可划分为中侏罗统龙家沟组,上白垩统及上中新统保德组。龙家沟组是盆地的主体沉积,含有多层煤层及油页岩。保德组中发现有我国著名的“龙家沟三趾马动物群”.是保德期庙梁亚期的主要代表动物群之一。 相似文献
13.
扬子区黄龙组的划分与对比 总被引:2,自引:0,他引:2
<正> 上石炭统黄龙组一名系沿袭1930年李四光、朱森研究宁镇山脉旧义“栖霞灰岩”时所创之黄龙灰岩,或称黄龙群。笔者对川东黄龙组的岩石化学和光谱分析、岩石薄片和古生物鉴定等资料整理与综合对比,特别是利用岩石化学成份、微量元素、以及它们之间的比值来进行对比,发现川东黄龙组虽为复杂的潮坪沉积,但仍有较好的对比标志,三分段明显。自下而上三分为雷音铺段、福成寨段和川东段。与黔西威宁组所建的三个带相吻合,并对各时的沉积相进行了研究。 相似文献
14.
KANG Jianli ZHANG Zhaochong ZHANG Dongyang HUANG He DONG Shuyun ZHANG Su 《《地质学报》英文版》2011,85(4):801-813
In the southwestern Tianshan,the geologic ages of many strata and their depositional environments are still poorly constrained because of complex structures.The Mada'er area is located in the Kuokesaleling belt,Southwestern Tianshan.The cherts from the former Wupata'erkan Group contain abundant radiolarian fossils,including 10 species which are identified as late Devonian to early Carboniferous in age.Eleven chert samples have SiO_2 contents ranging from 88.80 wt%to 93.28 wt%, and 2.02 wt%to 3.72 wt%for ... 相似文献
15.
《International Geology Review》2012,54(6):1030-1056
The article describes Carboniferous and Lower Liassic coal measures in Franz Josef Land, and a "2-ft coal bed" at the base of the Carboniferous motley sandstones observed by Fisher in Cook Cliffs at the south end of Prince George Land. Until recently the Cook Cliffs coal was identified by Dibner as "Paleozoic redeposited in Upper Triassic time." Later Dibner reassigned the coal and related beds to the Upper Triassic. Some doubt on this age is cast by the fact that the only coals on Spitzbergen are Lower Carboniferous. Ye. M. Andreyeva studied the coal's spores and found only Lower and Middle Carboniferous species. Traveling southeast of Wilczek Land in 1935, Yermolayev recovered coals he believed to be Paleozoic. Based on these finds, there is a strong likelihood of Paleozoic coals on Franz Josef Land. The Upper Triassic Vasil'yevsk Formation contains Noric to Rhaetic plants and spores. At Goristyy Cape (Champ Island) two brown coals occur; one is 1 m thick; 55 m higher is a 2-m bed coked at the top by an overlying basalt flow. The petrography of the coals is discussed. The Tegetthof Formation, based on its plant fossils, is Lower Liassic, compatible with sections on Spitzbergen. Next higher are Aalenian siltstones, Bathonian and sandy limestones with Volgian clams. Still higher are Lower Cretaceous volcanics with intercalated sandstones, shales and coals, divisible into the Tikhaya Cove Formation and Salisbury Formation. Altogether there are 13 coal beds in Franz Josef Land, ranging from Carboniferous up into the Lower Cretaceous (with 9 coal beds). Interesting petrographic details are included.—B. N. Cooper. 相似文献
16.
17.
E. Ja. Leven 《Stratigraphy and Geological Correlation》2012,20(3):240-260
Sections of the Bashkirian Stage of Southwestern Darvaz (the Pamir Mountains) are described. Based on fusulinids, the presence of all four Bashkirian substages was established. The Bashkirian beds transgressively overlie clastic-volcanic series of the Lower Carboniferous, and are conformably overlain by the Moscovian (Vereian). Upper Kashirian unconformably overlies both the Vereian beds and all earlier beds, up to of the Lower Carboniferous. An unconformity can be assumed within the Bashkirian, because the lower Bashkirian strata are missing from certain sections. The Bashkirian beds have no evidence of synsedimentary volcanism, which had completely ceased by the end of the Early Carboniferous. Fusulinids most characteristic of the Bashkirian substages are figured. 相似文献
18.
天山古生代洋盆开启、闭合时限的岩石学约束——来自震旦纪、石炭纪火山岩的证据 总被引:83,自引:13,他引:83
天山及邻区各微地块上分布有震旦纪—早寒武世火山-沉积岩系,寒武系底部均发育含磷层,震旦系中见2~3层大致可对比的冰碛岩,暗示各微地块当时可能是一个统一大陆块的组成部分。震旦纪—早寒武世大陆拉伸→大陆裂谷火山活动是天山古生代洋盆开启的前兆,意味着早寒武世为天山古生代洋盆开启时限的下限。中天山巴仑台微地块中的下石炭统马鞍桥组底部的粗碎屑岩,是碰撞造山中晚期的地质记录。它意味着天山古生代洋盆已经闭合。石炭纪时,天山造山带已进入新的造山后裂谷拉伸阶段,发育有大规模大陆裂谷双峰式火山活动和花岗质岩浆活动。早石炭世是天山古生代洋盆闭合时限的上限。 相似文献
19.
1:25万三道岭幅区调项目重新划分和厘定了博格达小区的地层系统,特别是对石炭纪地层的研究,有了一些新的进展,包括:在原塔克尔巴斯陶组内发现不整合界面,从而将该组解体,其下部层位岩性、岩相和古生物特征可以和托斯巴斯陶组对比,从而将它们重新厘定为黑山头组,时代为早石炭世中晚期,并发现该组在下涝坝与下伏上泥盆统康古尔塔格组为整合接触;将塔克尔巴斯陶组上部层位厘定为姜巴斯套组,依据发现的Choristites等腕足化石,笔者认为该组上部应该已经存在晚石炭世地层;依据地层接触关系、古生物化石以及锆石U-Pb年龄,将七角井组的地质时代厘定为晚石炭世早期,它和柳树沟组为同时异相沉积;在祁家沟组顶部灰岩中发现了有孔虫等丰富的微体化石,认为它的时代是晚石炭世中期,和阿什喀腊组为同时异相沉积。 相似文献