نتایج جستجو برای: calcareous nannofossil
تعداد نتایج: 3540 فیلتر نتایج به سال:
New palynological and calcareous nannofossil records are presented for the Turonian–Coniacian boundary section at Salzgitter-Salder, Germany, candidate Coniacian GSSP. The proposed base of Stage is Bed 46, first appearance datum level Cremnoceramus deformis erectus, which coincident with a δ13C minimum top Navigation carbon isotope event. Palynological assemblages dominated by organic walled di...
A detailed study of calcareous nannofossil assemblages from twelve uppermost lower Barremian–lower Aptian sections in the Subbetic Domain Betic Cordillera was performed. Seven new species (Crucibiscutum bastetanum, Crucibiscutum gracile, Chiastozygus lamprostauros, Cyclagelosphaera platyaspis, Lithraphidites aichmoides, pugio, and Rhagodiscus sicutclipeus) are described, one is emended (Lithrap...
The Middle Eocene Climatic Optimum (MECO; ~40 Ma), which interrupted for ~500–600 kyr the long-term cooling trend culminating at Eocene/Oligocene boundary, still requires a comprehensive understanding of biotic resilience. Here we present high-resolution integrated foraminiferal and calcareous nannofossil study across MECO from expanded continuous Tethyan Baskil section (eastern Turkey) that of...
Abstract. The fossil record of marine microplankton provides insights into the evolutionary drivers which led to origin modern deep-water plankton, one largest components ocean biomass. We use global abundance and biogeographic data, combined with depth habitat reconstructions, determine environmental mechanisms behind speciation in two groups pelagic microfossils over past 15 Myr. compare our ...
Late Maastrichtian to Danian dinoflagellate cyst and calcareous nannofossil biostratigraphy was analyzed at the Sur Río Chico borehole, Austral Basin, Argentina. Two stratigraphical intervals from 965 1003 m below ground surface of drilled section were defined. The co-occurrence Manumiella bertodano, M. seelandica conorata in 990–1000 1000–1003 mbgs interval, associated with top Neprolithus fre...
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