Sedimentary characterization of coastal environments on Deception Island, Maritime Antarctica

Deception Island, situated in the South Shetland Archipelago, Maritime Antarctica, has unique characteristics such as a young and active stratovolcano, which dates back approximately 0.75 Ma. Recently, the island has witnessed glacier retreat, leading to more frequent occurrences of ice-free areas with exposed soil. This phenomenon highlights the intricate interactions between volcanic activity and regional climate warming, reflecting in the formation of the sedimentation environment. This study focuses on the sedimentary characteristics of four subaerial profiles distributed along coastal areas. Sediment samples were collected during the OPERANTAR XXXVI expedition, and underwent a range of analyses including granulometric, morphoscopic, geochemical, isotopic and statistical examinations. The granulometric and morphoscopic analyses suggest that sediments are transported and reworked over relatively short distances from their original source, reflecting rapid sedimentation processes. Iron (Fe) was identified as the most abundant element, likely linked to both tephra deposits from volcanic activity and the early stages of chemical weathering. The isotopic analyses suggest contributions from both local (autochthonous) and distant (allochthonous) sources, primarily involving Antarctic lichens and animal excrement, which are transported by meltwater flows. In conclusion, the sedimentation dynamics on Deception Island are primarily influenced by the volcanic eruptions that occurred between 1967 and 1970. However, glacial and periglacial processes are significant as well, with meltwater flows, liquid precipitation and sediments contributions from glaciers and permafrost, playing a critical role in developing fluvio-glacial deposits in the region. This study enhances the understanding of the complex environmental interactions at Deception Island in the context of ongoing climate change.