نتایج جستجو برای: lower paleogene

تعداد نتایج: 692919  

2017
Serge Lallemand Jean-Claude Sibuet

The basis of this study is a new bathymetric map of the northeast Atlantic compiled from previously published maps made from conventional echosounder data, plus all Sea Beam data acquired on board the R/V JEAN CHARCOT since 1977. As most of the Sea Beam data have been obtained on the continental margin from Porcupine Seabight to the south of the Iberian Peninsula, a precise picture of the conti...

2011
Gareth J. Dyke Xia Wang Michael B. Habib

The plotopterids (Aves, Plotopteridae) were a group of extinct wing-propelled marine birds that are known from Paleogene-aged sediments (Eocene to Miocene), mostly around the Pacific Rim (especially Japan and the northwest coast of North America). While these birds exhibit a strikingly similar wing morphology to penguins (Spheniscidae), they also share derived characters with pelecaniform birds...

2017
Jiangfeng Guo Duoxi Yao Ping Chen Jian Chen Fengjun Shi

Arsenic is one of the toxic trace elements in coals, which is harmful to both the ecological environment and human health. Based on published literature and the data obtained by our research group, a total of 5314 As concentrations of Chinese coals were analyzed. The arithmetic mean of arsenic content in Chinese coals is 6.97 mg/kg. Choosing the percentage of provincial coal resources in nation...

Journal: :Geosciences 2021

After the Cretaceous/Paleogene boundary (KPB) catastrophic mass extinction event, an explosive evolutionary radiation of planktic foraminifera took place in consequence prompt occupation empty niches. The rapid evolution new species makes it possible to establish high-resolution biozonations lower Danian. We propose two biostratigraphic scales for low-to-middle latitudes spanning first million ...

Journal: :Journal of Systematics and Evolution 2021

Menispermaceae are a pantropical and temperate family with an extensive fossil record during the Paleogene period, especially in North America Europe, but much less evidence from Asia. The latest indicates succession of tropical to subtropical flora on central Tibetan Plateau Paleogene. However, biogeographic histories these floras still unresolved. Here, we report endocarps leaves Middle Eocen...

Journal: :Frontiers in Earth Science 2021

Fold-and-thrust belts and their associated structures are among the most common geological features of convergent margins. They provide significant information about crustal shortening mountain-building processes. In subaerial belts, where erosional rates high growth strata mostly eroded, methodologies such as that presented here can insights into to formation. Two 2D cross-sections located in ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Mary T Silcox Claire K Dalmyn Jonathan I Bloch

Extant primates are distinctive among mammals in having relatively large brains. As stem primates, Paleogene plesiadapiforms provide direct information relevant to the earliest stages in the evolution of this characteristic. Here we describe a virtual endocast reconstructed from ultra high resolution X-ray computed tomography data for the paromomyid plesiadapiform Ignacius graybullianus (USNM 4...

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