Petrography and provenance of the Marambio Group, Vega Island, Antarctica

• Published in: Antarctic Science
• Main Author: Pirrie, Duncan
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Cambridge University Press 1994
• Subjects: Earth Sciences; Antarctic; Antarctic Peninsula; Marambio; Vega Island; Cape Lamb; Sandwich Bluff; Herbert Sound; Antarc*; Antarctic Science; Antarctica
• Online Access: http://nora.nerc.ac.uk/id/eprint/516708/; https://doi.org/10.1017/S0954102094000775

Late Cretaceous sedimentary rocks assigned to the Santa Marta (Herbert Sound Member) and López de Bertodano (Cape Lamb and Sandwich Bluff members) formations of the Marambio Group, crop out on Cape Lamb, Vega Island. Although previous studies have recognized that these sedimentary rocks were derived from the northern Antarctic Peninsula region, the work presented here allows the provenance and palaeogeographical evolution of the region to be described in detail. On the basis of both sandstone petrography and clay mineralogy, the Herbert Sound and Cape Lamb members reflect sediment input from a low relief source area, with sand grade sediment sourced from low grade metasediments, and clay grade sediment ultimately derived from the weathering of an andesitic source area. In contrast, the Sandwich Bluff Member reflects a switch to a predominantly andesitic volcaniclastic source. However, this sediment was largely derived from older volcanic suites due to renewed source area uplift, with only a minor component from coeval volcanism. Regional uplift of both the arc terrane and the western margin of the James Ross Basin was likely during the Maastrichtian.