IDEAN 23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
artículos
Título:
FORAMINIFERA AND PALYNOMORPHS FROM EKELÖF COAST SECTION (UPPER CRETACEOUS), SOUTHEAST JAMES ROSS ISLAND, ANTARCTIC PENINSULA: A PALAEOENVIRONMENTAL PILOT STUDY
Autor/es:
CONCHEYRO, A.; AMENÁBAR, C.R.; CARAMÉS, ANDREA
Revista:
AMEGHINIANA
Editorial:
ASOCIACION PALEONTOLOGICA ARGENTINA
Referencias:
Lugar: Buenos Aires; Año: 2016 p. 333 - 357
ISSN:
0002-7014
Resumen:
A micropaleontological analysis of foraminifera and palynomorphs obtained from a partial sedimentary section cropping out at Ekelöf Point, southeast of James Ross Island, Antarctic Peninsula, is presented. The section includes the lowest levels of the Upper Cretaceous sedimentary rocks belonging to the Hamilton Point Member of the Snow Hill Island Formation. Among the foraminifera 18 benthic taxa are recognized, 10 agglutinated and 8 calcareous. Palynomorphs includes continental and marine species. The continental assemblage contains 44 spore and pollen species. Marine assemblage consists of 10 peridinioid (P) dinoflagellate cyts species and 10 gonyaulacoids (G), being the P cysts dominant in number of specimens. The palynomorph assemblage supports a late Campanian age for the section but an earliest Maastrichtian age is not excluded. The palaeoenvironmental interpretation based on the distribution of foraminiferal morphogroups indicates an outer shelf-upper bathyal environment which matches with sedimentological data. The palaeoambiental inference based the S/D ratio (sporomorph versus dinoflagellate cysts) and the P/G ratio (peridinioid versus gonyaulacoid cysts) suggest a coastal and inner neritic settings with a continuous continental supply from the continent to the marine environment, evidenced by the slight dominance of the peridionoids over gonyaulacoids cyts. The discrepancy observed between palynological and micropaleontological-sedimentological data may be linked to the development of a short continental shelf during the Late Cretaceous, where the terrestrial palynomorphs and peridinoid cysts would quickly run down the slope and would be deposited in the deep marine environment together with gonyaulacoid cysts.
