Highlights of the Messel Oil Shale

The Messel oil shale, Germany, was deposited in a maar crater that formed 47 million years ago. Since 1975 the Senckenberg Research Institute in Frankfurt am Main, has conducted systematic scientific excavations of this oil shale with much success. Besides plants and insects, more than 130 species of well-preserved fossil vertebrates like reptiles, fishes, birds and mammals have been found and have made Messel world-famous. Some examples of these vertebrates are presented.     

豫西早寒武世辛集组的一个双壳类

本文所描述的双壳类卵形波杰特蛤(新种)Pojetaia ovata(sp.nov.)系采自河南方城杨楼辛集组上部灰岩之底部的碎屑灰岩层,位于Bergeroniellus层位之下。其时代应属早寒武世沧浪铺早期。可与澳大利亚南部产有Pojetaia runnegari Jell的地层相对比。本种是我国目前最低层位的双壳类。     

The “Oldest River” As An Appalachian Popular Region

Abstract

Appalachia's New River was labeled “the second oldest river in the world” during the 1970s as part of a campaign to save the river from being dammed. Despite the absence of geomorphic evidence, the promotion of the superlative age of the river was so successful that the mythical label became reality in the minds of the region's populace. The “oldest river” thus became a popular or vernacular region, defined as one perceived to exist by its inhabitants. Sources of evidence for the current existence of the oldest river as a popular region include Internet references, which typically use the positive place image of the ancient stream to enhance the value of the river valley's attributes. Geography educators and students at all levels will benefit from class research projects aimed at identifying and understanding popular regions found near their educational institutions.     

The oldest basement rock in the Yangtze Craton revealed by zircon U-Pb age and Hf isotope composition

Here we report an integrated study of zircon U-Pb age and Hf isotope composition for a gneiss sample from the Kongling terrain in the Yangtze Craton. CL imaging reveals that most zircons are magmatic, and a few of them have thin metamorphic rims. The magmatic zircons gave a weighted mean U-Pb age of 3218±13 Ma, indicating the gneiss is the oldest basement rock in the Yangtze Craton found to date. They have εHf(t) value of -2.33±0.51,and two-stage Hf model age of 3679±49 Ma,indicating that the gneiss was der...     

A Comparison about Metamorphism among the Oldest-Rock Units from Orogenic Belts of Dabie, Eastern Qinling and Eastern Kunlun of Central Mountain Ranges, China

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上海及其邻近地区新石器时代野生动物生活复原景观及其相关问题

作者在鉴定了上海几乎全部的新石器时代的脊椎动物化石的基础上,详细对比了浙江、江苏和山东同时代的动物群,重建了当时的野生生态自然景观,并讨论了一系列相关的学术问题。     

Direct U–Th dating of vertebrate fossils with minimum sampling destruction and application to museum specimens

Although vertebrate fossils are commonly abundant in museum palaeontological collections, they are only rarely accompanied by contextual data (e.g., stratigraphic and taphonomic information) that allow them to be placed independently into reliable temporal frameworks critical for testing significant evolutionary and extinction hypotheses. Moreover, where critical samples do exist in such collections, sampling for direct geochronological analyses becomes a significant concern, especially where such sampling is destructive in nature. Here we apply a direct fossil dating, micro-drilling sampling approach that minimises damage to and destruction of precious museum specimens. We carried out a systematic U–Th dating study (n = 28 ages) of an isolated museum specimen of the extinct Palorchestes azael (megafaunal ‘marsupial tapir’) originally collected in 1977 from Tea Tree Cave, Chillagoe, northeastern Australia. We obtained 21 U–Th ages and constructed ²³⁰Th-age profiles across three teeth exposed in cross-section, using micro-drilling and thermal ionisation mass spectrometry. Individual sample masses were as little as 0.18 mg (U concentration 33–82 ppm), meaning that the sampling resulted in only minimal destruction of the specimen. The results show no evidence of U leaching, suggesting that the dates represent reliable minimum ages. For independent age control, we also dated calcite that had encrusted the sample (thus, providing a minimum age; n = 6) and an older calcite clast that had been reworked into the surrounding breccia at the time of burial (thus, providing a maximum age; n = 1). U–Th ages of the teeth are older than the calcite overgrowths and younger than the reworked calcite, consistent with their demonstrable relative age relationships. Collectively, the results unequivocally bracket the age of the fossil between 199.1 ± 8.9 ka and 137.4 ± 1.1 ka (2σ), adding another rare datum to inform the timing and geographic distribution of last occurrences of the species. The benefits of our dating approach of museum fossil specimens are threefold: 1) it is minimally destructive even compared with laser-ablation method; 2) the use of U vs. apparent age approach allows direct testing for potential U leaching as occasionally seen in fossil dating; and 3) the combination of fossil and associated speleothem dating provides the most robust means of securely bracketing the age of fossils that lack firm stratigraphic control.     

Highlights of the Messel Oil Shale

The Messel oil shale, Germany, was deposited in a maar crater that formed 47 million years ago. Since 1975 the Senckenberg Research Institute in Frankfurt am Main, has conducted systematic scientific excavations of this oil shale with much success. Besides plants and insects, more than 130 species of well - preserved fossil vertebrates like reptiles, fishes, birds and mammals have been found and have made Messel worldfamous. Some examples of these vertebrates are presented.     

Late Middle Pleistocene deposits at Norton Farm on the West Sussex coastal plain,southern England

The coastal plain of West Sussex, southern England, is internationally important because of the sequence of discrete high‐sea‐level events preserved at various elevations across it. New evidence is presented from a site at Norton Farm, near Chichester, on the Lower Coastal Plain, where Pleistocene marine sands, fining upwards into silts, occur between 5.3 m and 9.1 m OD. The sequence reflects a regressive tendency at the transition from an interglacial to a cold stage. The marine sands have yielded foraminifera, ostracods and molluscs that indicate a declining marine influence through the sequence, culminating in a tidal mudflat, strongly weathered in places. Cool‐climate foraminifera (including Elphidium clavatum, Cassidulina reniformis and Elphidium albiumbilicatum) and ostracods have been recovered from the marine sands. Some species with an apparent preference for warmer water conditions, however, are also present. Freshwater taxa washed into the terminal marine sediments include some cold climate indicators, such as Pisidium stewarti and P. obtusale lapponicum. Additional evidence for cool climatic conditions during the deposition of the upper part of the marine sequence is provided by the lack of tree taxa in the pollen record and by features of the micromorphology. The marine sediments probably began accumulating during OIS 7, a conclusion based on their elevation, on amino acid ratios from shells, but especially on vertebrate evidence, particularly the presence of a small form of horse, together with a large, distinctive, form of northern vole (Microtus oeconomus). The occurrence of cool climate indicators in these marine sediments may demonstrate a lag between the climatic deterioration and the expected glacio‐eustatic fall in relative sea‐level. This evidence appears to support the conclusions drawn from the study of coral terraces in Barbados. Such a scenario would provide the conditions necessary for the emplacement of the large erratic boulders reported from the Lower Coastal Plain of West Sussex. Copyright © 2000 John Wiley & Sons, Ltd.     

澄江动物群的核心价值:动物界成型和人类基础器官诞生

澄江动物群以富含多门类精美软躯体构造化石享誉学界,是寒武纪大爆发主幕的见证者;它亲眼目睹了地球动物树上几乎所有主要门类祖先的首次大聚会。对该动物群30多年的大规模调查研究大体上可以划分为3个阶段。始自1984年的第一个10年(1984—1994年),早期动物树上的基础动物亚界和原口动物亚界的大量门类被发现,然而对后口动物亚界全然无知。第二个10年研究(1995—2005年),基础动物亚界和原口动物亚界中的更多门类被发现;而最重要的进展,是西北大学团队主导的早期后口动物大发现使后口动物亚界的基本框架被构建,由此地球三分动物树首次成型。第三个10年及其以后时期(2005年之后),3个动物亚界中进一步添加了一些新的门类认知;综合20世纪40年代以来对埃迪卡拉生物群、寒武纪第一世和第二世的珍稀动物群研究成果,学界开始思考三分动物树分步成型与多幕式寒武纪大爆发事件的内在关联,提出了三幕式寒武纪大爆发新假说。澄江动物群研究具有多方面的科学价值,包括动物群结构研究,生态环境研究等,然其核心学术价值主要集中在如下两个方面:(1)作为寒武纪大爆发的主幕见证者,澄江动物群首次创建了地球上三分动物树的完整谱系框架。三幕式寒武纪大爆发假说揭示了地球上动物门类由低等到高等、分阶段爆发创造的本质内涵,即历时约0.4亿年的三幕式寒武纪大爆发与动物树阶段性快速成型的内在耦合性。第一幕发生于埃迪卡拉纪晚期,它诞生了众多基础动物亚界门类(包括大量绝灭门类),也可能出现了少量原口动物的先驱分子;第二幕发生于寒武纪的第一世,除了延续基础动物门类的繁盛外,更创生了原口动物亚界里的主要门类(包括蜕皮类和触手担轮类);第三幕发生于寒武纪第二世(以澄江动物群为代表),不仅延续了基础动物和原口动物门类的兴盛,更重要的是诞生了后口动物亚界里的所有门类。至此,整个三分动物树的框架成型,寒武纪大爆发创新事件宣告基本结束。文章还对几个重要动物类群的生物学属性进行了评述。第一鱼昆明鱼目是已知唯一的最古老脊椎动物,而云南虫、海口虫既不是脊椎动物(即高等脊索动物),也不属于低等脊索动物,而是一类特殊的低等后口动物;长江海鞘是可信的始祖尾索动物,它支持了经典的尾索动物起源假说;古虫动物门首创鳃裂构造,对后口动物亚界的起源探索提供了关键信息。(2)澄江动物群具有深刻的人文哲学意义,所发现的古虫动物门创造的“第一鳃裂”,昆明鱼目创造的“第一头脑”“第一脊椎”“第一心脏”,为达尔文在《人类的由来》中关于人类的主要基础器官起源悬案的破解提供了关键证据。澄江动物群承上启下,其各种形态解剖学信息对解读埃迪卡拉生物群以及寒武纪相关化石库中绝大多数生物类型都具有重要的参考价值。