TefRchronology and mArker events for Correlation of natural archives in the RosS Sea, Antarctica

Marine sediment sequences from polar regions, in addition to being potential paleoclimatic and paleoenvironmental records, may contain intercalated deposits emitted during large explosive volcanic eruptions called tephra. These are usually dispersed over very large areas, up to thousands of square kilometers, and constitute marker horizons. When dated and properly characterized geochemically and tephra are extremely useful for synchronizing stratigraphic and climatic events and more generally for correlating natural archives, while at the same time, offering an accuracy that is difficult to achieve with other methods. Especially in Antarctica, where the usual methods of dating sedimentary series have limitations in their application (both because of the lack of carbonate material and because of problems concerning the weathering of organic matter), the study of tephras (tephrochronology) can substantially contribute to improving the chronological picture of the area by aiding local and/or global paleoclimatic research. In this context and within an innovative and multidisciplinary research framework, the project proposes to 1) recover late Quaternary sediment sequences from the Ross Sea continental shelf, through sampling for the first time specifically defined for tephrochronological research (e.g. downwind of major active volcanoes and in areas where tephra preservation is optimal); 2) identify, date, and characterize in detail (sedimentological characteristics, texture, mineral phases, major and trace element composition) potential regional markers (tephra) identified within the aforementioned sediments through state-of-the-art analytical techniques and tools; and 3) describe and interpret the lithofacies intercalated with them. Cores related to the Ross Sea collected in previous campaigns and preserved in Italian or foreign archives may also be studied to complete the study dataset.

Tephrochronological studies of specially selected marine sediment sequences can ensure a strong advance in the current knowledge of the Antarctic area and a crucial contribution to improve its reference chronostratigraphy. In addition, the results obtained in the project will contribute to the significant advancement in the knowledge of the eruptive history of Antarctic volcanoes (age, frequency, intensity of eruptions, volumes emitted, etc.) and enable investigation of possible feedback relationships between volcanic activity and the cryosphere (e.g., regional increase in volcanic activity caused by melting of ice caps or changes in glacial dynamics due to volcanic activity).