Mid-distal occurrences of the Albano Maar pyroclastic deposits and their relevance for reassessing the eruptive scenarios of the most recent activity at the Colli Albani Volcanic District, Central Italy

摘要

The Late Pleistocene Albano Maar hosted the most recent volcanic activity of the Colli Albani Volcanic District, represented at near-vent sections by a thick pyroclastic succession of seven units clustered in two main eruptive cycles dated at around 70-68 and 41-36 ka B.P., respectively. Recent stratigraphic investigations allowed us to recognise a pyroclastic succession comprising four eruptive units widely spread in the northeastern sectors of the Colli Albani volcano, up to 15 km eastward from the Albano Maar. Integrated tephrostratigraphic, morpho-pedostratigraphic, archaeological, petrological and geochemical analyses enable us to recognise them as distal deposits of the first, third, fifth and seventh Albano Maar eruptions, enlarging significantly their previously supposed dispersion area. Further tephrostratigraphic studies in central Apennine area, allowed us to identify the Albano Maar products in Late Pleistocene deposits of several intermountain basins, extending still further the dispersion area of distal ash fallout as far as 100-120 km from the vent. On the basis of the identification and the study of these previously unrecognised mid-distal Albano Maar deposits, a reappraisal of the eruptive scenarios and related energetic parameters is proposed.