共查询到20条相似文献，搜索用时 46 毫秒
1.
本文对甘肃宝积山盆地中侏罗世植物群地质时代及植物区系进行了探讨,共统计植物大化石18属53种,主要包括银杏纲10属24种,真蕨纲5属22种,苏铁纲1属3种,松柏纲1属2种,楔叶纲1属2种。该植物群在组成特征上表现为银杏类、真蕨类植物繁盛,其他植物类群相对贫乏。基于该植物群特征与国内其他植物群的对比,提出其地质时代为中侏罗世Aalenian期–Bajocian期。通过哈曼、欧式距离、罗杰斯–塔尼莫特和索卡尔–施尼斯4种方法对宝积山盆地及中国北方其余11个中侏罗世植物群进行系统聚类分析,在此基础上进一步划分了中国北方植物区系。通过计算属、种相似性系数,探讨宝积山邻近植物区系间的亲缘关系,结果表明宝积山植物区系与同属西北地区的华亭植物区系关系较为亲近。 相似文献
2.
本文所讨论的材料是笔者之一(韩乃仁)于1961年夏在江西玉山李家棚附近的下奥陶统宁国页岩组中采得的(野外号码:F61001),代表一个新属新种,兹取名为“分离玉山笔石”(Yushanograptus separatus gen.et sp.nov.)。玉山笔石的特点是两个原始枝(横索)很长,分枝方式属于稜笔石式(穆恩之,1953,1956)。其尚未分枝的幼年时期,和一些纤细的对笔石,如Didymograptus gracilis T(?)rn-quist,D.congnatus Harris et Thomas 等,非常相似,每一原始枝在生长了11—12个胞管之后才开始正分枝,连续到六级以上。这种原始枝特长的特征,与联笔石(Zygograptus)相似,但分枝的形式不同。联笔石的分枝为枝笔石式,而我们的新属的分枝则为左右相间 相似文献
3.
Xiphograptus 是个鲜为人知的笔石,是 Cooper 和 Fortey 于1982年研究北欧 Spitzbergen 奥陶纪的孤立标本后建立的一个新属.其模式种为 Didymograptus formosus Bulman.\"Xiphos\" 来自希腊文,指剑形物等,以示在这个属的所有种中均有胎管刺(virgellar spine)的存在.长期来,由于我们很少发现 dichograptid 笔石具有真正的胎管刺,因此,它们曾被当作平伸对笔石 Didymograptus (Expansograptus), 根据始部构造的特征,这些平伸种与真正的 Phyllograptus 有比较密切的亲缘关系,而区别于一般的平伸对笔石.此属的定义是: \"具有平伸或下斜对笔石类笔石体习性的 phyllograptines 小的生长阶期显示了长而细的胎管刺以及th?的反胎管刺方向的起源.胎管短,约1.5mm长,始部枝狭,胞管倾角小(Cooper and 相似文献
4.
桂北兴安早奥陶世的Exigraptus和Glyptograptus并论双列有轴笔石的起源 总被引：4，自引：0，他引：4
早奥陶世宁国期中期(阿伦尼克晚期)的雕笔石,是最早出现的双列有轴笔石.由于牵涉到双列有轴笔石的起源,历来为各国笔石研究家们所注目.以前,产于我国浙西的Glyptograptus sinodentatus Mu et Lee被认为是最早出现的双列有轴笔石(穆恩之、李积金,1958),当时穆、李提出这类雕笔石的祖先\"可能是一个和Cardiograptus相似之物\".最近,穆恩之等 相似文献
5.
拟肋笔石(Pleurograptoides)在过去报道极少,据已查阅到的资料,仅在苏联中亚一带(Llandvery)产有一种P. erectus Averianow。此次在我国的首次发现,为早志留纪笔石动物群的研究提供了新的资料。本文报道的共有4种,其中1旧种、3新种,它们是Pleurograptoides erectus Averianow, P. jilinensis sp. nov., P. sinicus sp. nov., P. yitongensis sp. nov.。标本是笔者于1978年7—10月, 相似文献
6.
本文材料是1982年夏在山东沂南界湖和苍山大炉两地上寒武统凤山组中上部灰色、灰黄色薄层钙质、泥质白云岩中采得的。与所描述的西伯利亚笔石Siberiograptus共生的笔石有Callograptus和Dendrograptus两属大量树形笔石,其中除Callograptus staufferi Ruedemann和Dendrograptus hallianus(Prout)之外,均为区域性的新种。这一笔石动物群代表凤山组内一个 相似文献
7.
1977年秋,笔者在陕西陇县曹家湾黑鹰寺沟、石拐子沟中奥陶统龙门洞组上部和耀县中、上奥陶统桃启坡组中部灰色、浅灰色薄层灰岩,发现并采得一批毛发笔石。毛发笔石Medusaegraptus的发现和描述甚少,一般均为志留纪的种属。这次在我国中奥陶统发现了不少毛发笔石,且均为新种。这些标本保存良好,数量也多,是研究这类奇特、稀少的笔石的好材料。 相似文献
8.
前言我国华北地台东北边缘下奥陶统冶里组底部发现大量的 Dictyonema flabelliforme(s. l.), 其中以 D. flabelliforme parabola -belgicum 为大宗.这些扇形网格笔石都具有裸露的胎管和极其发育的束线构造(Proximal tufts of threads).本文将对束线构造进行专门的讨论,对形 相似文献
9.
瘦魔蜂属(Leptephialtites Rasnitsyn,1975)是哈萨克斯坦晚侏罗世卡拉套生物群中魔蜂科魔蜂亚科的一个分异度比较高的类群,也曾报道于我国内蒙古宁城地区中-晚侏罗世道虎沟生物群,但没有描述和图示。本文对产自宁城道虎沟村中-上侏罗统道虎沟化石层的一块雌蜂标本进行了描述,将其归入瘦魔蜂属并建立了一新种:张氏瘦魔蜂(Leptephialtites zhangi Ding and Zhang,sp.nov.)。该新种区别于卡拉套生物群中瘦魔蜂属的所有种:前翅1-Rs脉长为其与翅痣基部距离之半(后者1-Rs脉不长于其与翅痣基部的距离),横脉1r-rs完整(后者1r-rs残存或完全消失);腹部纺锤状,最宽处在其中部(后者腹部最宽处位于其端半部)。本文还提供了瘦魔蜂属所有已知种的检索表。另外,瘦魔蜂属仅存在于卡拉套生物群和道虎沟生物群,证实了这两个生物群具有密切的关系。 相似文献
10.
1979年,笔者与黄开云、张立志等在湖南安化大福坪毛铺子测制奥陶系剖面时,发现这里上奥陶统五峰组的Tangyagraptus typicus-Yinograptus disjunctus带(W_3)出露完整,厚度适中(在湘西北区,五峰组出露不全,(W_3)带厚度不到0.3米。而在湘南区,(W_3)带的厚度则又超过500米),上、下界限清楚,笔石丰富,特征明显。安化大福坪毛铺子上奥陶统五峰组(W_3) 相似文献
11.
Abstract: Late Ordovician strophomenide brachiopods (superfamilies Strophomenoidea and Plectambonitoidea) from the upper Changwu Formation (mid Ashgill, late Katian) of Jianglütang, Chun'an County, western Zhejiang Province, consist of ten genera and 12 species. Five new species of three new genera are recognized: Chunanomena triporcata , Chunanomena sembellina , Cheramomena subsolana , Lateriseptomena modesta , and Lateriseptomena rugosa . The strophomenide brachiopods from the upper Katian strata described in this study and those from the border region of Zhejiang and Jiangxi provinces reported in previous work contain 16 strophomenoid and 12 plectambonitoid genera, and most of the strophomenoids are endemic to South China. Numerical analysis of well-documented late Katian strophomenide brachiopod faunas indicates a strong provincialism, characterized by the highly distinct North American province (Laurentia), the South China-Kazakhstan province, and the Avalonia-Baltica province (Wales, Belgium and Sweden). Surprisingly, the Girvan district of Scotland, which was a peri-Laurentian terrane during the Ordovician, contains a late Katian brachiopod fauna that is more closely related to the contemporaneous brachiopods of Avalonia-Baltica than to those of North America. 相似文献
12.
The bryozoan fauna from the Xiazhen Formation (Katian, Upper Ordovician) of northeast Jiangxi Province, southeast China is reported here. Seventeen species of bryozoans belonging to fifteen genera and four orders are identified: Homotrypa yushanensis, Homotrypa sp., Prasopora yushanensis, Trematopora sp., Monotrypella sp., Rhombotrypa sp., Orbignyella sp., Constellaria jiangxiensis, Constellaria sp., Stictopora nicholsoni, Trigonodictya parvula, Ptilodictya ensiformis, Stictoporella sp., Pseudopachydictya sp., Nematopora sp., Arthrostylidae sp. indet., and Chasmatoporidae sp. indet. Four of these genera have been reported previously but nine genera (Trematopora, Monotrypella, Rhombotrypa, Orbignyella, Trigonodictya, Ptilodictya, Stictoporella, Pseudopachydictya, and Nematopora), one rhabdomesine and one fenestrate are found for the first time in the Late Ordovician strata of South China. Our palaeogeographical analysis suggests that the bryozoan association is typical for the Katian, which is mostly widespread in Laurentia, Siberia, Baltica and Mediterranean, and displays palaeobiogeographical relationships to the Laurentia–Siberia Province. 相似文献
13.
《Palaeoworld》2023,32(2):252-265
Heliolitine tabulate corals are extremely rare in pre-Katian (Upper Ordovician) rocks worldwide, hindering the understanding of their origin and early evolution. Here, we systematically study new heliolitine material from the upper member (Sandbian) of the Huadan Formation in the Yunnan-Sichuan border area, Southwest China, which includes Protaraea ningnanensis, Plasmoporella kiaeri, Wormsipora sp. and Heliolites spinosus. The findings indicate that Protaraea and Heliolites are ancestral forms of coccoserids and typical tubular heliolitines, respectively, and that the absence of trabecular septa is probably a primitive feature of plasmoporellids. The refined Ordovician stratigraphy of this area implies that the coccoserid Protaraea ningnanensis Lin, 1965 from the lower member (late Darriwilian) of the Huadan Formation is the earliest known heliolitine, which further indicates that all heliolitines might have evolved from Protaraea. The comparison of Protaraea with other early tabulate corals also suggests an independent heliolitine origin from auloporinids and sarcinulinids. 相似文献
14.
中国奥陶纪晚期的孢型植物组合以隐孢子为主,不含真正三缝孢,称为Tetrahedraletes medinensis-Dy-adospora murusattenuata-Laevolancis chibrikovae(MMC)组合;中国志留纪早期孢型植物组合以隐孢子为主,包括四分体和单分体,缺失二分体,出现真正三缝孢,并产生不同的类型(光面、具纹饰、具弓形脊等类型),被称为Tet-rahedraletes medinensis-Laevolancis chibrikovae-Ambitisporites avitus/dilutus(MCA)组合。孢型植物化石的某些相似性表明:华南和塔里木板块可能分布于相近的低古纬度,气候特征具有一定的可比性,代表近赤道的热带气候;至少在志留纪早期,华南和印支板块与冈瓦纳大陆距离较近,可能处于同一古气候带,代表相似的生物古地理特征。 相似文献
15.
《Palaeoworld》2023,32(2):303-332
Ordovician silicified ostracods of the western Yangtze Platform, South China, are documented for the first time from the Huadan Formation of Qiaojia County, northeastern Yunnan Province, Southwest China. Twenty-one species of 17 genera are identified with new taxa including Vendona spinifera n. sp. and Nikitinella songliangensis n. sp. These two species, together with Medianella gigantea are the most common constituents of the fauna. Faunal comparison shows close connections between South China, Baltica, the Argentine Precordillera, Kazakhstan, Tarim, and Sibumasu during this time interval. This fauna is considered to be related to a nearshore carbonate environment, and biostratigraphical analysis of it supports a late Darriwilian to early Katian age for the Huadan Formation. 相似文献
16.
贵州黄花冲下奥陶统湄潭组疑源类 总被引：4，自引：0，他引：4
对贵州黄花冲奥陶系湄潭组Azygograptus suecicus带疑源类组合研究表明,该组合可以与扬子区陕南、川东南、黔北、黔南、湘西、鄂西等地同期组合对比,并根据特征分子产出判别该组合应划归环冈瓦纳疑源类生物地理区。鄂西宜昌大湾组疑源类组合与黄花冲湄潭组疑源类组合的差异系环境因素所致。 相似文献
17.
Taoqupognathus为潘德尔刺类的一多分子器官属。其特征明显：单维,片状,具有不同发育程度的后缘隆起。该属仅在澳大利亚东部和中国上奥陶统分布,已知有4种,而且具有较精确的区域对比价值。形态特征的支序分析显示：在晚奥陶世中期（Eastonian),T.philipi-T.blandus-T.tumidus谱系代表了该属的主要演化趋向。Taoqupognathus属的分布表明,澳大利亚东部和中国在当时有着密切的生物地理联系。该属可能在Eastonian早期起源于新南威尔世中部地区,在中－晚Eastonian期时达到发展高潮,并已扩展到中国各板块。继而可能在Eastonian末期和Bolindian早期全部绝灭。 相似文献
18.
特马豆克阶是奥陶系底部第一个阶,笔石是特马豆克阶高分辨率地层划分与对比的重要化石类群。江南斜坡带是我国早奥陶世特马豆克期漂浮笔石分异度和丰度最高的相区之一,位于该区的湖南益阳南坝剖面,发育有完整的上特马豆克阶笔石地层,特马豆克阶-弗洛阶界线附近地层连续,上特马豆克阶笔石地层研究已取得较大进展,但下特马豆克阶地层缺乏系统研究。近年来,通过对该剖面笔石标本的不间断采集,新识别出下特马豆克阶笔石带Rhabdinopora flabelliformis parabola带。到目前为止,湖南益阳南坝剖面特马豆克阶可以识别出5个笔石带,自下而上依次为:Rhabdinopora flabelliformis parabola带、Adelograptus tenellus带、Aorograptus victoriae带、Araneograptus murrayi带以及Hunnegraptus copiosus带。基于目前已识别出的笔石带,参考国内外同期笔石地层资料,本文详细讨论华南特马豆克期笔石带序列,并与国内外同期地层进行精确对比。 相似文献
19.
《Palaeoworld》2023,32(2):202-218
Strata equivalent to the majority of the Ordovician shallow-water sediments in South China occur in the western Yangtze region (present-day southwestern Sichuan and northeastern Yunnan, Southwest China), but remain to be properly documented largely due to their inaccessibility. Our research in the past decade has led to the recognition of spatial and temporal patterns, and hence a substantial stratigraphic revision of these rocks, with part of the results having been published in a series of papers. Here, we outline a unified and refined Ordovician stratigraphy of the region built chiefly on a summary of these new data, presenting a robust timeframe for exploring the environmental and biotic events during the Ordovician on a basin-wide scale in South China. 相似文献
20.
Abstract: Re-examination of newly collected topotype material confirms that the type species of Yangtzeella , Y . poloi , a widespread Early and Mid Ordovician syntrophiidine brachiopod in South China, has a finely costellate shell rather than being smooth as previously thought. Thus, the subgenus Yangtzeella ( Vadimella ) Nikitina et al ., established on the basis of fine costellae, is invalidated. Among 15 species of Yangtzeella , five species are recognized as valid based on multivariate analyses: Y . poloi , Y . unsulcata , Y . songziensis , Y . kueiyangensis and Y . igori , among which the type species was the oldest known. Six are synonymized: Y . septata , Y . reticulata , Y . lensiformis , Y . depressa , Y . yichangensis and Y . minuta . Four are rejected from Yangtzeella : Y . extensa , Y . similior , Y . yohi and Y . poloi var. minor . Regional biostratigraphy indicates that Yangtzeella first appeared in a relatively deep-water setting on the Lower Yangtze Platform (South China palaeoplate) during late Tremadoc time ( Scolopodus warendensis conodont biozone) and then expanded to the deeper Jiangnan Slope as well as to the shallower Upper Yangtze Platform. The genus experienced two episodes of heightened abundance and diversity on the Upper Yangtze Platform during late Dapingian and mid Darriwilian times, respectively. Outside South China, Yangtzeella occurs sporadically in a few microplates or terranes, such as Tarim, Chu-Ili (southern Kazakhstan) and Taurides (southern Turkey) during the Dapingian and Darriwilian. Worldwide, Yangtzeella became extinct by the end of the Darriwilian. 相似文献