The Byers Basin: Jurassic-Cretaceous tectonic and depositional evolution of the forearc deposits of the South Shetland Islands and its implications for the northern Antarctic Peninsula

ABSTRACT

This paper addresses the Jurassic–Cretaceous stratigraphic evolution of fore-arc deposits exposed along the west coast of the northern Antarctic Peninsula. In the South Shetland Islands, Upper Jurassic deep-marine sediments are uncomformably overlain by a Lower Cretaceous volcaniclastic sequence that crops out on Livingston, Snow and Low islands. U-Pb zircon ages are presented for the upper Anchorage Formation (153.1 ± 1.7 Ma) and the Cape Wallace granodiorite of Low Island (137.1 ± 1.7 Ma) as well as ⁴⁰Ar/³⁹Ar ages of 136–139 Ma for Low Island andesites. Data are also presented for a U-Pb age of 109.0 ± 1.4 Ma for the upper volcanic succession of Snow Island. In combination with published stratigraphy, these data provide a refined chrono- and litho-stratigraphic framework for the deposits herein referred to as the Byers Basin. Tentative correlation is explored with previously described deposits on Adelaide and Alexander islands, which could suggest further continuation of the Byers Basin towards the south. We also discuss possible correlation of the Byers Basin with the Larsen Basin, a sequence that shows the evolution of foreland to back-arc deposits more or less contemporaneously with the fore-arc to intra-arc evolution of the Byers Basin.

KEYWORDS:

• Tectono-stratigraphical evolution
• Weddell Sea
• South Shetland Islands
• Antarctic Peninsula
• Jurassic
• cretaceous
• basin evolution

Acknowledgments

The authors are grateful for the extensive logistical support provided by the Chilean Antarctic Institute (INACH) during two field campaigns to the Antarctic Peninsula. The manuscript was greatly improved by the input of the reviewers Dr. Liang Gao and Dr Eduardo Olviero. We are grateful for Dr. Alfonso Rubilar (SERNAGEOMIN) for the review of fossil specimens. Financial support was provided by the Antarctic Ring Project (ACT-105, Conicyt-Chile and INACH), the project RT0614 (INACH) and the Fondecyt Grant 1161818.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

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