Cryptotephra in marine sequences of the Ross Sea, Antarctica: implications and potential applications

Marine sediments of Antarctica contain tephra, fragmented material produced by explosive eruptions of Antarctic volcanoes and widely dispersed by wind. Tephra are preserved specially when sequences suffer small disturbance and sedimentation rate are high. If fingerprinted, dated and linked to a volcanic source, tephra become time-synchronous markers for independent correlations between geological archives. Tephra are also significant for volcanological reconstructions to derive the type, magnitude, age and recurrence of eruptions. Tephra record can be significantly extended by examining successions for the presence of cryptotephra (non-visible tephra). These are essential to increase the number of eruptions recognizable of any magnitude and in distal occurrences. Recently, for the first time in Antarctica, a cryptotephra record was found in a core from the Joides Basin (Ross Sea; Di Roberto et al. 2019). This discovery widens the tephra research possibilities, allowing far-reaching objectives to be tackled. On these bases, an innovative and multi-disciplinary project called CHIMERA - CryptotepHra In Marine sEquences of the Ross Sea, Antarctica: implications and potential applications - granted by PNRA proposes to: 1) re-examine marine sediment cores located in the continental shelf basins of the western Ross Sea; 2) identify, date and fingerprint cryptotephra intercalated in these marine sequences; 3) make marine cryptotephra easily identifiable as a stratigraphic markers; 4) synchronize and correlate these levels with Antarctic tephra archives extrapolating information into regional/continental framework and 5) use these stratigraphic markers for the paleoenvironmental reconstructions, mainly addressed to the ice shelf oscillations during the different glacial/interglacial conditions of the Late Quaternary.