Nannofossils, foraminifera and microforaminiferal linings in the cenozoic diamictites of Cape Lamb, Vega Island, Antarctica

• Main Authors: Concheyro, A., CaraméS, A., Amenábar, C.R., Lescano, M.
• Format: Journal/Newspaper
• Language: unknown
• Subjects: Antarctica; Calcareous nannofossils; Cenozoic diamictites; Foraminifera; James ross basin; Microforaminiferal linings; Cenozoic; diamictite; dinoflagellate cyst; micropaleontology; nanofossil; palynology; palynomorph; pollen; spore; James Ross Island; Snow Hill Island; Vega Island; West Antarctica; Antarc*; Antarctic; Antarctic Peninsula; Ross Island
• Online Access: https://hdl.handle.net/20.500.12110/paper_01380338_v35_n1_p1_Concheyro

Micropaleontological and palynological samples from three Cenozoic diamictites at Cape Lamb, Vega Island, James Ross Basin were analysed. Fossiliferous samples yielded reworked and autochthonous assemblages of Mesozoic calcareous nannofossils, impoverished Cretaceous foraminifera together with Neogene species, as well as Late Cretaceous dinoflagellate cysts, pollen, spores and abundant Cenozoic microforaminiferal linings. The recovered nannoflora indicates Early Cretaceous (Hauterivian-Albian) and Late Cretaceous (Santonian-Early Campanian) ages, suggesting an intensive reworking of marine sediments. The presence of the Early Cretaceous species Nannoconus circularis Deres et Acheriteguy in the diamictite represents its first record for the James Ross Basin. The scarce foraminiferal fauna includes Pullenia jarvisi Cushman, which indicates reworking from lower Maastrichtian-lower Paleocene sediments, and also the Neogene autochthonous Trochammina sp. aff. T. intermedia. The innerorganic layer observed inside this specimen appears to be identical to microforaminiferal linings recovered from the same sample. Palynomorphs found in the studied samples suggest erosion from the underlying Snow Hill Island and the López de Bertodano Formation beds (upper Campanian-upper Maastrichtian). These recovered assemblages indicate either different periods of deposition or reworking from diverse sources during Cenozoic glaciation, originating in James Ross Island and the Antarctic Peninsula with the influence of local sediment sources.