نتایج جستجو برای: pliocene

تعداد نتایج: 2942  

2005
A. KITCHELL DANIEL PENA

Oxygen isotope data for a Pliocene interval from 3.6 to 2.8 million years ago show a mean increase (0.5 per mil) of benthic 6180 at about 3.2 million years ago, whereas planktic 6180 does not increase. This lack of covariance indicates that the event at 3.2 million years did not result in a permanent increase in the ice budget of either the Northern or the Southern Hemisphere. The history of co...

2013
Beth Okamura Aaron O’Dea Paul Taylor Anna Taylor

Here we explore how fossil cheilostome bryozoans can demonstrate El Niño/La Niña–Southern Oscillation (ENSO) variability in ancient tropical environments of the tropical eastern Pacific and southwestern Caribbean when used collectively to produce frequency distributions of estimates of mean annual ranges in temperature (MARTs) via zooid-size MART analysis (zs-MART). The approach is based on lin...

Journal: :Zootaxa 2014
Yusuke Miyajima Hakuichi Koike Hiroshige Matsuoka

A new fossil filefish, Aluterus shigensis sp. nov., with a close resemblance to the extant Aluterus scriptus (Osbeck), is described from the Middle Miocene Bessho Formation in Nagano Prefecture, central Japan. It is characterized by: 21 total vertebrae; very slender and long first dorsal spine with tiny anterior barbs; thin and lancet-shaped basal pterygiophore of the spiny dorsal fin, with its...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2009
Jens Matthiessen Jochen Knies Christoph Vogt Ruediger Stein

The Pliocene is important in the geological evolution of the high northern latitudes. It marks the transition from restricted local- to extensive regional-scale glaciations on the circum-Arctic continents between 3.6 and 2.4Ma. Since the Arctic Ocean is an almost land-locked basin, tectonic activity and sea-level fluctuations controlled the geometry of ocean gateways and continental drainage sy...

Journal: :Molecular phylogenetics and evolution 2010
Kai He Ya-Jie Li Matthew C Brandley Liang-Kong Lin Ying-Xiang Wang Ya-Ping Zhang Xue-Long Jiang

Nectogaline shrews are a major component of the small mammalian fauna of Europe and Asia, and are notable for their diverse ecology, including utilization of aquatic habitats. So far, molecular phylogenetic analyses including nectogaline species have been unable to infer a well-resolved, well-supported phylogeny, thus limiting the power of comparative evolutionary and ecological analyses of the...

2008
David R. Marchant George H. Denton Carl C. Swisher

An 40Ar/39Ar chronology of in-situ to near insitu volcanic ashfall deposits indicates that the surficial stratigraphy of Arena Valley extends back at least to middleMiocene time. Wet-based glacial ice occupied part of Arena Valley more than 11.3 Ma ago. Thick, northeast-flowing ice subsequently engulfed Arena Valley, again more than 11.3 Ma ago. Only minor glacier expansion occurred during Plio...

2015
Charlotte Sjunneskog Christina R. Riesselman Diane Winter Christina Riesselman

The late Pliocene – early Pleistocene sediment record in the AND-1B core from the McMurdo Sound, Ross Sea, Antarctica, displays a rich diversity and high abundance of diatoms, including several new morphologies within the genus Fragilariopsis. These new morphologies exhibit similarities to the extinct late Miocene/early Pliocene species Fragilariopsis aurica Gersonde and Fragilariopsis praecurt...

2008
Naomi E. Levin Scott W. Simpson Thure E. Cerling Stephen R. Frost

Ardipithecus fossils found in late Miocene and early Pliocene deposits in the Afar region of Ethiopia, along with Sahelanthropus tchadensis from Chad and Orrorin tugenensis from Kenya, are among the earliest known human ancestors and are considered to be the predecessors to the subsequent australopithecines (Australopithecus anamensis and Australopithecus afarensis). Current paleoenvironmental ...

2015
Molly F. Miller Ellen A. Cowan Simon H. H. Nielsen

Zoophycos is a complex three dimensional trace fossil that is abundant in deep ocean sediments worldwide, but has not been described previously from Cenozoic continental margin deposits of Antarctica. In the ANDRILL 1B core drilled through the northwest McMurdo ice shelf, Zoophycos occurs in a 17m thick unit of interglacial sediments bounded above and below by glacial surfaces of erosion. This ...

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