Foraminifera in Cenozoic Paleoenvironments

INTRODUCTION Microfossilsaregenerallythemostversatileand “useful”offossilsforbothcorrelationandagedeter minationandpaleoenvironmentalanalysis.Among microfossilstheforaminiferaarepre eminent(Fig. 1).Wefindinthesamesample—beitoutcropor subsurface,onshor…     

寒武系崮山阶三叶虫生物地层新认识

由于Diceratocephalus已在华北的若干地点找到,如莱芜九龙山、淄博黑石寨和泰安大汶口,Dicerato-cephalus三叶虫亚带可以提升为三叶虫带,这样崮山阶便包含了4个三叶虫带(自上而下)Diceratoceph alusarma-tus带、Drepanura premesnili带、Blackwelderia paronai带和Damesella paronai带。     

Devonian of the isle of Rügen

Summary In the Rügen area of northern Germany, Old Red Sandstones, ranging from Late Emsian to Givetian in age, unconformably overlie deformed Ordovician strata. The Middle Devonian Old Red passes conformably up into a Late Devonian carbonate facies and then into the Lower Carboniferous, apparently without a break.     

黔东南Oryctocephalus indicus的分布及其意义

本文通过对黔东南两条新测剖面的整理、已有剖面的进一步挖掘和已有剖面的资料的整理,厘定出几个寒武系第三统底界附近有代表意义的三叶虫属种在这些剖面中产出层位。经过对比研究,认为Oryctocephalus indicus在黔东南分布广泛,个体清晰,层位稳定并延伸较长,可以作为很好的标准化石。     

A new record of Colpocoryphe (Trilobita) from the Skiddaw Group of the Cross Fell inlier,northern England

The trilobite Colpocoryphe sp. is described for the first time from the Kirkland Formation, Llanvirn, of the Skiddaw Group in the Cross Fell inlier. It is considered to be closely related to a form previously recorded from the upper Arenig of the Lake District. This new record supports the previously suggested Gondwanan aspects of the northern England Avalonian fauna during the early Ordovician. Copyright © 2000 John Wiley & Sons, Ltd.     

华南地区奥陶纪头足类生物相及其分区

在研究华南地区奥陶纪头足类生态特征基础上,根据头足类的生态类型及其保存条件等特征,识别出18个头足类生物相,即开阔台地[WT5”BX]Proterocameroceras生物相,局限台地Pseudoectenolites-Xiadongoceras生物相,开阔台地Retroclitendoceras-Pararetrocli tendoceras生物相,开阔台地Pronajaceras-Mamagouceras生物相,陆棚斜坡—盆地Cyclostomiceras-Bactroceras生物相,开阔台地 Cameroceras-Cyrtovaginoceras生物相,开阔台地 Coreanoceras-Manchuroceras生物相,陆棚斜坡—盆地Kaipingoceras-Kyminoceras生物相,内陆棚Bathmoceras-Protocycloceras生物相,中部陆棚Dideroceras-Ancistroceras生物相,深水陆棚 Lituites-Cyclolituites 生物相,滞流盆地Lituites-Trilacinoceras生物相,深水盆地Paraendoceras-Sactorthoceras,深水陆棚Sinoceras-Michelinoceras-Disoceras生物相,深水陆棚Beloitoceras-Jiangshanoceras生物相,深水陆棚—盆地Eurasiaticoceras生物相,浅海陆棚—斜坡Jiangxiceras-Yushanoceras生物相,深水盆地Michelinoceras[WT5”BZ]生物相,并阐述各生物相的组成、生态特征及其生态环境。根据头足类生物相在时间和空间上的组合规律,划分出3个头足类生物相区,即扬子生物相区、黔东—湘西生物相区（过渡型生物相区）和湘中—浙西生物相区,并讨论了各生物相区在不同时期内头足类生态类型和生物相分异特征、海平面升降、环境演变特征以及其与油气的关系。认为在低海平面或海平面下降阶段中生物相分异明显,而在高海平面阶段中则分异较小。     

Rugose corals from the Upper Ordovician Sholeshook Limestone of southwest Wales with an assessment of the coral affinities and biofacies

Limestone horizons of Upper Ordovician (Katian) age in southwest Wales contain diverse fossil faunas including rugose corals. The existence of Ordovician Rugosa in Wales was first reported by Murchison in the 1830s, but since then hardly any specimens have been documented systematically until this present study. Newly collected material from the area around Llanddowror (Carmarthenshire) has now confirmed the diversity of rugose corals in the Sholeshook Limestone (Katian age), an arenaceous limestone originating from the shelf edge of the palaeocontinent Avalonia. The majority of the specimens are preserved as moulds. This means that in many instances preservation of the fossils was insufficient for specific identification; nevertheless, it was possible to document a diverse rugose coral fauna, including Helicelasma, probable Grewingkia and Kenophyllum, and a potential early mucophyllid. While associated with considerable difficulties, as some diagnostic features of Rugosa are not visible in moulds, it is demonstrated here that the work with such specimens can result in faunal information which would otherwise be unobtainable. An assemblage of rugose and tabulate corals in the Sholeshook Limestone can be differentiated from a similar assemblage in the neighbouring Robeston Wathen Limestone which has a slightly different lithology. The fauna has strong similarities with other Avalonian (Irish, English, Belgian) as well as Baltic (Estonian and Norwegian) rugose coral faunas. Copyright © 2012 John Wiley & Sons, Ltd.     

岐口凹陷新近系生物-遗迹相及环境解释

岐口凹陷新近系包括明化镇组和馆陶组.通过新近系中的孢粉、介形虫和遗迹组构的系统研究, 识别出孢粉53个属种, 并建立了两个孢粉组合, 分别为Magnastites (粗肋孢) -Ulmus (榆粉) -Taxodiaceae pollenites (杉粉) 组合和Polygonaceae-Chenopodiaceae组合; 发现介形虫12个属种, 介形类以金星介科分子为主, 少数湖花介科分子, 以壳形单一、壳壁薄、表面光滑的类型为主, 表现了典型的非海相淡水介形类面貌; 划分出4种遗迹组构类型, 分别为Scoyenia遗迹组构、Skolithos遗迹组构、Palaeophycus遗迹组构和强扰动组构.在此基础上, 探索了生物与环境的关系, 划分了A、B、C、D、E5种生物-遗迹相带, 分别代表泛滥平原、蓄水注地或泛滥平原小型湖、河道及水下分流河道边部、滨浅湖和前三角洲沉积环境.      

常山美丽饰边虫Euloma changshanense Lu（三叶虫）的蜕壳及其古环境意义?

Euloma changshanense Lu采自浙江江山下奥陶统,是一个蜕壳老壳的部分及自由颊腹边缘的印痕。从这后期破损的残壳分析其蜕壳过程,认为两自由颊在头前中间连接,蜕壳时在虫体拱曲时脱落于头前,但还在新壳之上,后被新的虫体顶走,只残存自由颊腹边缘在头前的印痕。这反映了三叶虫在蜕壳过程中有一停顿休息时间,而新的虫体常常顶走或拖走老的头壳上的自由颊和唇瓣,使老壳留下缺失的背壳部件。蜕壳过程是瞬间发生的,即只有原地埋葬才能保存这一状态,说明当时三叶虫处于比较宁静的水中,又处于沉积物供给充足的环境,在蜕壳过程中或不久即被沉积物掩埋。浙江江山印渚埠组的厚度较大,上面直接覆盖着大湾阶底部的Azygograptus suecicus带;而相邻不远的江西玉山印渚埠组顶部,上覆为玉山阶的底部Tetragraptus approximatus带,证明印渚埠组是穿时的。而两个地方的印渚埠组顶部都常产有Euloma changshanense Lu,说明此三叶虫虽为下奥陶统常见化石,但延续时间较长,在特马豆克晚期到整个玉山阶都存在,也说明印渚埠组沉积厚度较大,但整个沉积环境变化不大,即使三叶虫Euloma changshanenes等种属也很少变化。这是研究三叶虫蜕壳及其生态替换、演变的好层位。     

山东张夏期(中寒武世晚期)三叶虫生物地层

根据山东长清张夏虎头山至黄草顶、淄博市淄川区峨庄乡黑石寨谢家峪及新泰县九龙村九龙山的中寒武世晚期地层剖面的新材料 ,分析了山东张夏期三叶虫的地层分布 ,讨论了张夏组的顶底界线 ,扼要地比较了张夏期的 6个多节类三叶虫带与华南过渡区的 4个球接子带。