Geo-paleontological re-significance of the Cockburn Island (James Ross Basin, West Antarctica)

GELFO J. N.; ACOSTA HOSPITALECHE, CAROLINA; PEREZ, L. M. ; SOSA, M. A.; REGUERO, M.

Hobart OSC

Congreso; SCAR Open Science Conferences; 2020

Scientific Committee on Antarctic Research

Cockburn Island is located in the northwest of the Weddell Sea between Marambio/Seymour and James Ross islands, less than a hundred kilometres from the Antarctic Peninsula. The stratigraphic units recognized were already correlated with the known sequence of the James Ross Basin, including the Snow Hill Island Formation (Cretaceous), the lower allomembers of La Meseta Formation (Paleocene-Eocene), and Neogene rocks unconformable lying at the top. The upper plateau is formed by a Miocene?Pliocene flat level of volcanic rocks of the James Ross Island Volcanic Group and small pockets of the Pliocene Cockburn Island Formation ("Pecten−conglomerate"). Framed in a geo-paleontological project focused on the James Ross Basin, the firsts prospecting activities were carried out during the last austral summer. Specimens collected during this first stage from the Pecten-conglomerate, allows the preliminary identification of new taxa as Cheilostomata bryozoan cf. "Anasca" and cf. "Ascophora". Subsequently, our project will focus on the Cockburn Island through: 1) A comprehensive study of fossil specimens from the "Pecten-conglomerate" to test the hypothesis of environmental conditions consistent with an interglacial period, and an ice-free coastline, 2) The evaluation of Cockburn Island Formation as a Geo-Heritage topic, and 3) Paleontological fieldwork in the almost vertical cliffs with Cretaceous and Paleogene units. Particularly the Paleocene-Eocene levels, which in contrast to the deltaic/estuarine outcrops of La Meseta Formation in Seymour Island, should have a more continental influence due to its proximity to the source area.