The illite and organic matter archive of the Late Palaeozoic to Mesozoic tectonothermal evolution of the Antarctic Peninsula

Abstract

This work presents new K-Ar and XRD illite data of Middle Jurassic sedimentary sequences (i.e., Mount Flora and Camp Hill formations) of the Antarctic Peninsula, providing a thermal evolution for the Mesozoic tectonic history of the Antarctic Peninsula and adjacent regions. Samples of the Camp Hill Formation at Camp Hill Peninsula/Botany Bay yielded middle Permian to early Triassic K-Ar ages, which are associated with upper to lower anchizonal conditions, reflecting the input of detrital illite derived from the Trinity Peninsula Group. Maximum temperatures of up to ca. 175 °C constrained by vitrinite reflectance data were achieved during Jurassic to Early Cretaceous burial of the Camp Hill Formation, contemporaneously with magmatism. In contrast, samples of the Mount Flora Formation show Late Cretaceous ages mainly related to upper anchizonal conditions, which result from hydrothermal processes linked with coeval igneous intrusions. Late Cretaceous arc magmatism was coupled with widespread hydrothermal activity, well-documented throughout the northern Antarctic Peninsula and South Shetland Islands.