The illite and organic matter archive of the Late Paleozoic–Mesozoic tectonothermal evolution of the Antarctic Peninsula

This work presents new K–Ar and X-ray diffraction illite data for Middle Jurassic sedimentary sequences (i.e. Mount Flora and Camp Hill formations) of the Antarctic Peninsula, providing the thermal evolution of 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–early Triassic K–Ar ages that are associated with upper–lower anchizonal conditions, reflecting the input of detrital illite derived from the Trinity Peninsula Group. Maximum temperatures of up to c. 175°C, constrained by vitrinite reflectance data, were achieved during the Jurassic–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 that is well documented throughout the northern Antarctic Peninsula and South Shetland Islands.