Buscar
Mostrando ítems 1-10 de 97
Late Cambrian acritarchs from the Santa Rosita Formation: implications for the Cambrian-Ordovician boundary in the eastern Cordillera of northwest Argentina
(Sociedade Brasileira de Paleontologia, 2003-12)
Marine phytoplankton from the Late Cambrian are described for the first time in the Eastern Cordillera of northwest Argentina. The acritarch assemblage was recovered from an offshore lower mudstone unit towards the base ...
Acritarchs of peri-Gondwana at the Lower and Middle Ordovician stage boundaries
(Instituto Superior de Correlación Geológica, 2003-08)
Although acritarchs have been studied mostly for stratigraphic purposes (often in sediments devoid of other fossils), their biostratigraphic potential has not yet been fully exploited in the Ordovician. While another group ...
The palaeobiogeographical spread of the acritarch Veryhachium in the Early and Middle Ordovician and its impact on biostratigraphical applications
(Taylor & Francis Ltd, 2014-03)
The genus Veryhachium Deunff, 1954, is one of the most frequently documented acritarch genera, being recorded from the Early Ordovician to the Neogene. Detailed investigations show that Veryhachium species first appeared ...
Acritarchs of Las Ventanas Formation (Ediacaran, Uruguay): Implications for the timing of coeval rifting and glacial events in western Gondwana
(Elsevier Science, 2008-07)
Acritarchs and other organic-walled microfossils occurring in siltstones of the Las Ventanas Formation (Quebrada de Viera and El Perdido members) are systematically described and illustrated. The assemblage includes the ...
Acritarchs and Tasmanites from the Permo-Carboniferous beds of the Paraná BasinAcritarcos e tasmanites do Permo-Carbonífero da bacia do Paraná
(Instituto Geológico, Secretaria do Meio Ambiente, São Paulo, 2002)
A new record of late Ediacaran acritarchs from La providencia group (Tandilia System, Argentina) and its biostratigraphical significance
(Pergamon-Elsevier Science Ltd, 2019-08)
A well preserved assemblage of organic-walled microfossils is described from the Alicia and Cerro Negro formations of the La Providencia Group. The microbiota is dominated by Leiosphaeridia species (L. minutissima, L. ...
First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages
(Wiley Blackwell Publishing, Inc, 2018-04)
First Appearance Datums (FADs) of selected, easily recognizable acritarch morphotypes are assessed to determine their potential contribution to correlation between Lower and Middle Ordovician stages and substage divisions ...
First record of Palaeostomocystis subtilitheca in Holocene marine sediments from the Beagle Channel, southern Tierra del Fuego, Argentina
(Elsevier, 2015-06)
This study documents the occurrence of Palaeostomocystis subtilitheca in Holocene sediments from the Beagle Channel area, southern Argentina, and represents the first record of this acritarch in high latitudes of Southern ...
The palynological record across the Ordovician/Silurian boundary in the Cordillera Oriental, Central Andean Basin, northwestern Argentina
(Elsevier Science, 2016-01)
The Hirnantian “glacial horizon” has been recognized across the Central Andean Basin (Puna, Cordillera Oriental, Sierras Subandinas and Sistema de Santa Bárbara) in northwestern Argentina. It is represented by glaciofluvial ...
Lower Ordovician (late Tremadocian?- Floian) palynomorphs from the Llanos Basin, Colombia: Biostratigraphic and paleogeographic significance
(Elsevier Science, 2019-06)
Four core and fifteen cutting samples of well RH-2 from the Ordovician of the Llanos Basin, Colombia, were palynologically analyzed. They yielded mostly diverse and well-preserved marine palynomorph assemblages, dominated ...