This is a pre-publication version. Readers are recommended to consult the full published version for accuracy and citation."Ross Sea. Our study has shown that multi-proxy data derived from laminated sediments can provide hitherto unknown detail regarding past summer sea ice dynamics in coastal Antarctic regions.
We report the discovery of an important new cryptotephra within marine sediments close to Cape Hallett (northern Victoria Land), in the western Ross Sea, Antarctica. The cryptotephra is fully characterized for its texture, mineralogy and major- and trace-element data obtained on single glass shards. On the basis of geochemical composition, the cryptotephra is unequivocally correlated with the proximal deposits of an explosive eruption of the poorly known Mount Rittmann volcano, situated in northern Victoria Land. The cryptotephra is also correlated with a widespread tephra layer, which was erupted in 1254 C.E. and is present in numerous ice-cores and blue ice fields across East and West Antarctica. The characteristics of the tephra indicate that it was produced by a prolonged, moderate energy, mostly hydromagmatic eruption. This is the first time that a cryptotephra has been identified in marine sediments of the Ross Sea and in ice cores. It provides an important new and widespread stratigraphical datum with which the continental cryosphere and marine sedimentological records in Antarctica can be correlated. Moreover, from a purely volcanological point of view, the discovery further confirms the occurrence of a long-lasting, significant explosive eruption from Mount Rittmann in historical times that produced abundant widely dispersed fine ash. The study also highlights the inadequacy of current hazard assessments for poorly known volcanoes such as Mount Rittmann, located at high southern latitudes.
In the framework of geosite management, specific targeted symbols for geomorphological legends are still lacking. Concerning geosites of geomorphological interest, geomorphological mapping requires targeted symbols in relation to goals and applications, either concerning geomorphic hazards and risk detection or the enhancement of resources, in particular those related to cultural heritage and, hence, geoheritage. A new methodology for mapping geo(morpho)heritage on geomorphological maps is presented in this paper. Nine iconic examples from the Italian landscape, selected in different morphogenetic and morphoclimatic contexts, are proposed to test the methodology in relation to point, polyline and polygon features. Moreover, guidelines for mapping are suggested according to the importance of the site and to the complexity of processes characterizing each case study.
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