نتایج جستجو برای: oligocene

تعداد نتایج: 2183  

2016
Qian Li Jin Meng Yuanqing Wang

New cricetids (Eucricetodon wangae sp. nov., Eucricetodon sp. and Pappocricetodon siziwangqiensis sp. nov.) are reported from the lower and middle parts of the "Upper Red" beds of the Erden Obo section in Nei Mongol, China. Eucricetodon wangae is more primitive than other known species of the genus from lower Oligocene of Asia and Europe in having a single anterocone on M1, a single connection ...

2008
Tom Dunkley Jones Paul R. Bown Paul N. Pearson Bridget S. Wade Helen K. Coxall Caroline H. Lear

[1] A high-resolution record of exceptionally well preserved calcareous nannofossil assemblages from Tanzania is marked by two key transitions closely related to the climatic events of the Eocene-Oligocene transition (EOT). The first transition, at 34.0 Ma, precedes the first positive shift in dO and coincides with a distinct interval of very low nannofossil abundance and a cooling in sea surfa...

2017
Margarita Erbajeva Bayarmaa Baatarjav Gudrun Daxner-Höck Lawrence J Flynn

The genus Sinolagomys is an early representative of the family Ochotonidae, appearing first in the late early Oligocene of Central Asia. It is known in China from Shargaltein Tal, Taben Buluk, Ulan Tatal, and northern Junggaria, and a few specimens from Tatal Gol, Mongolia have been published. For most occurrences, the genus is not represented by many specimens. Extensive studies in the Valley ...

1999
J. K. TUCKER

The conoidean gastropod genus Benthofascis Iredale, 1936 is examined. This genus of Conorbidae has extant species. Three previously described species from the Recent including the type species B. biconica (Hedley), B. sarcinula (Hedley), and B. lozoueti Sysoev & Bouchet are reviewed. Three new species from the Recent, B. conorbioides sp. nov., B. pseudobiconica sp. nov., and B. angularis sp. no...

Journal: :Science 1986
S L Olson D T Rasmussén

Analysis of fossil birds from the Oligocene Jebel Qatrani Formation in the Fayum depression of Egypt, site of the oldest known hominoid primates, allows precise paleoenvironmental reconstruction of the climatic and biotic conditions that influenced some of the earliest stages of hominoid evolution. Unlike the fossil mammals of the Fayum, which belong largely to extinct groups, most of the birds...

2017
Richard Kettler E. PAPASTAVROS

Sediments and rocks recovered in CRP-2/2A coring operations contain relatively little organic matter (average TOC=0.28%) and very small amounts of solvent-soluble organic matter. Because Early Oligocene sediment included significant amounts of coal detritus, TOC values are higher in Early Oligocene rocks than in younger rocks. TOC values are highest in the fine-grained rocks deposited as part o...

2016
Jarosław Stolarski Francesca R. Bosellini Carden C. Wallace Anne M. Gothmann Maciej Mazur Isabelle Domart-Coulon Eldad Gutner-Hoch Rolf D. Neuser Oren Levy Aldo Shemesh Anders Meibom

Today coral reefs are threatened by changes to seawater conditions associated with rapid anthropogenic global climate change. Yet, since the Cenozoic, these organisms have experienced major fluctuations in atmospheric CO2 levels (from greenhouse conditions of high pCO2 in the Eocene to low pCO2 ice-house conditions in the Oligocene-Miocene) and a dramatically changing ocean Mg/Ca ratio. Here we...

2011
Michele G. Bishop

Mature, synrift lacustrine shales of Eocene to Oligocene age and mature, late-rift coals and coaly shales of Oligocene to Miocene age are source rocks for oil and gas in two important petroleum systems of the onshore and offshore areas of the Northwest Java Basin. Biogenic gas and carbonate-sourced gas have also been identified. These hydrocarbons are trapped primarily in anticlines and fault b...

2017
Adriana Oliver Oscar Sanisidro Bayarmaa Baatarjav Ichinnorov Niiden Gudrun Daxner-Höck

Gundis, or comb rats, are rodents of the family Ctenodactylidae. Extant gundis are restricted to Africa and represent a vestige of the diversity that the ctenodactylids attained at both palaeoecological and palaeobiogeographical levels. Here, we present an updated review of the Ctenodactylidae from the Valley of Lakes, Mongolia, based on the study of large collections now available. We have rec...

Journal: :Biology letters 2008
Carlos Peña Niklas Wahlberg

Satyrinae butterflies (Lepidoptera: Nymphalidae) and grasses (Poaceae) are very diverse and distributed worldwide. Most Satyrinae use grasses as host plants, but the temporal scale of this tight association is not known. Here, we present a phylogenetic study of Satyrinae butterflies and related groups, based on 5.1 kilobases from six gene regions and 238 morphological characters for all major l...

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