IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Cenozoic microbiotas from the eastern sector of the James Ross Island Group, Antarctic Peninsula
Autor/es:
CONCHEYRO, ANDREA; CARAMÉS, ANDREA; AMÉNABAR R., CECILIA; ADAMONIS, SUSANA; LIRIO, JUAN MANUEL; BALLENT, SARA; DI PASQUO, MERCEDES; MACKERN, ALAN
Lugar:
Buenos Aires
Reunión:
Conferencia; Scientific Comité on Antarctic Research y Open Science Conference, SCAR XXXI.; 2010
Institución organizadora:
Scientific Comité on Antarctic Research y Open Science Conference
Resumen:
CENOZOIC MICROBIOTAS FROM THE EASTERN SECTOR OF THE JAMES ROSS ISLAND GROUP, ANTARCTIC PENINSULA Concheyro, A.1,2,3, Caramés, A.2, Amenábar, C.R.1,2,3, Adamonis, S.3, Lirio, J.M.1, Ballent, S.2,4, di Pasquo, M.2 and Mackern, A1. 1 Instituto Antártico Argentino - Dirección Nacional del Antártico 2 Consejo Nacional de Investigaciones Científicas y Técnicas 3 Departamento de Ciencias Geológicas - Universidad de Buenos Aires 4 División Paleontología de Invertebrados - Museo de Ciencias Naturales de La Plata Keywords: diamictites, microfossils, Cenozoic Cenozoic fossiliferous deposits are analyzed in several localities of Vega and James Ross islands, focusing on their micropaleontological content. Sandwich Bluff diamictite (Vega Island) is a basal till dated as older than 5.42 Ma. It contains rare foraminifera and autochthonous dinoflagellates. Reworked nannoflora from the Lower Cretaceous is recovered, as well as reworked palynomorphs of similar age. Leal Bluff diamictite (Vega Island) ranges from 5,42 to 2.09 Ma in age. The collected macrofauna is composed by articulated bivalves, pectinids, and mussels. Microbiota is composed by Cretaceous reworked agglutinated foraminifera, abundant microforaminiferal linings, marine diatoms, dinoflagellates and scarce continental palynomorphs. These are assigned to the Late Miocene-Pliocene. The finding of an opportunistic microforaminifera test linings suggest dysaerobic environments with a high organic matter input. Cape Lamb diamictite (Vega Island) is younger than 2.09 Ma. Its well preserved macrofauna suggests a short distance of transport, and include Adammusium colbecki, brachiopods, gastropods, serpulids, spirorbids, echinoderm spines and bryozoa. A diversified foraminifers assemblage, dominated by Elphidiidae, indicates a myxohaline shelf environment, similar to the Terrapin Formation. Scarce ostracods and Cassulinidae foraminifera suggest cold antarctic waters. Frequent dinoflagellates include Spiniferites ramosus, common in shelf environments. Ekelöf diamictite (James Ross Island) is correlated with Gage Formation (3 to 3.1 Ma). Well preserved macrofauna includes articulated bivalves, pectinids, brachiopods, serpulids, balanids, gastropods, and bryozoa. Close to the diamictite´s base, foraminifera include Upper Cretaceous reworked species. Topwards, robust shell foraminifera, dominated by Ammoelphidiella antarctica, suggest a littoral environment. Ekelöf biota resembles that of Cockburn Island Formation.