نتایج جستجو برای: lower eocene

تعداد نتایج: 695634  

2016
Estelle Bourdon Anette V. Kristoffersen Niels Bonde

The fossil record of crown group birds (Neornithes) prior to the Cretaceous-Paleogene boundary is scarce and fragmentary. Early Cenozoic bird fossils are more abundant, but are typically disarticulated and/or flattened. Here we report the oldest roller (Coracii), Septencoracias morsensis gen. et sp. nov. (Primobucconidae), based on a new specimen from the Early Eocene (about 54 million years ag...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Dennis V Kent Giovanni Muttoni

India's northward flight and collision with Asia was a major driver of global tectonics in the Cenozoic and, we argue, of atmospheric CO(2) concentration (pCO(2)) and thus global climate. Subduction of Tethyan oceanic crust with a carpet of carbonate-rich pelagic sediments deposited during transit beneath the high-productivity equatorial belt resulted in a component flux of CO(2) delivery to th...

2012
Camilo Montes A. Cardona D. A. Ramírez N. Hoyos J. Wilson D. Farris

The rise of the Isthmus of Panama, linked to a number of climatic, paleoceanographic, and biological events, has been studied mostly from indirect, often distal, geochemical and biotic evidence. We have upgraded existing geologic mapping in central Panama with more than 2000 fi eld stations, over 40 petrographic analyses, and more than 30 new geochronological and thermo chrono logical analy ses...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
Peter M J Douglas Hagit P Affek Linda C Ivany Alexander J P Houben Willem P Sijp Appy Sluijs Stefan Schouten Mark Pagani

Paleoclimate studies suggest that increased global warmth during the Eocene epoch was greatly amplified at high latitudes, a state that climate models cannot fully reproduce. However, proxy estimates of Eocene near-Antarctic sea surface temperatures (SSTs) have produced widely divergent results at similar latitudes, with SSTs above 20 °C in the southwest Pacific contrasting with SSTs between 5 ...

2016
N. Herold A. Goldner J. A. M. Green Matthew Huber R. D. Müller P. Markwick

We describe a set of early Eocene (∼ 55 Ma) climate model boundary conditions constructed in a selfconsistent reference frame and incorporating recent data and methodologies. Given the growing need for uniform experimental design within the Eocene climate modelling community and the challenges faced in simulating the prominent features of Eocene climate, we make publicly available our data sets...

Journal: :زمین شناسی اقتصادی 0
زهرا اعلمی نیا محمد حسن کریم پور سید مسعود همام فریتز فینگر

arghash – ghasem-abad area in ne iran is located in the rim of the sabzevar structural zone. tertiary outcrops include granite and quartz monzodiorite porphyry associated with dacite and andesite volcanic rocks. in the study area, quartz gabbro and quartz monzodiorite dykes intruded the older rocks. granite and volcanic rocks host au-sb-bearing quartz-calcite veins. mineralized veins are mainly...

Journal: :Proceedings. Biological sciences 2014
Adam Tomašových Stefano Dominici Martin Zuschin Didier Merle

Invertebrate lineages tend to originate and become extinct at a higher rate in onshore than in offshore habitats over long temporal durations (more than 10 Myr), but it remains unclear whether this pattern scales down to durations of stages (less than 5 Myr) or even sequences (less than 0.5 Myr). We assess whether onshore-offshore gradients in long-term turnover between the tropical Eocene and ...

Journal: :Journal of Paleontology 2022

Abstract A highly diverse fauna of dromioid brachyurans from the Serraduy Formation (lower Eocene) in western Pyrenees (Huesca, Spain) is described and illustrated. Recorded taxa are Mclaynotopus longispinosus new genus species, Torodromia elongata n. gen. sp., Basidromilites glaessneri ? Sierradromia gladiator Kromtitis isabenensis Basinotopus sp. Other European outcrops have yielded dromioids...

2011
ELLEN THOMAS

Upper abyssal to lower bathyal benthic foraminifera from Ocean Drilling Program Sites 689 (present water depth 2080m) and 690 (present water depth 29I4m) on Maud Rise (Antarctica) recorded changes in deep-water characteristics at high southern latitudes during the cenozoic. The benthic foraminiferal faunas show only minor differences as a result of the difference in water depths between the sit...

2007
Robert E. Kopp Timothy D. Raub Dirk Schumann Hojatollah Vali Alexei V. Smirnov Joseph L. Kirschvink

Previous workers identified a magnetically anomalous clay layer deposited on the northern United States Atlantic Coastal Plain during the Paleocene-Eocene Thermal Maximum (PETM). The finding inspired the highly controversial hypothesis that a cometary impact triggered the PETM. Here we present ferromagnetic resonance (FMR), isothermal and anhysteretic remanent magnetization, first order reversa...

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