Tephrochronological study in the quaternary Val d’Agri intermontane basin (Southern Apennines, Italy)

Abstract

In the south-eastern depocentre of the Val d'Agri basin (Southern Apennines), a volcanic ash layer crops out interbedded within poorly structured alluvial fan deposits of Late Pleistocene age. Textural, depositional and pedological features of this weathered layer suggest a primary deposition from a pyroclastic fall-out of volcanic ash.

Quaternary evolution of the intermontane Val d'Agri Basin, Southern Apennines

“…The tephra is composed of alkali trachytic and porous ash, partially weathered and could be correlated with the Ionian tephra Y-7 (Zembo, 2007) dated at 56 ± 4 ka (Allen et al, 1999). This fact is justified by the absence of amphibole and the presence of a conspicuous amount of aegirine-augite to aegirine clinopyroxenes with minor apatite, titanite, zircon (Zembo et al, 2008). Thus, we may exclude all the volcanic centers of the Campanian district except for the Ischia volcano, as it contains amphibole (Keller, 1978;Wulf et al, 2004).…”

“…Luminescence ages from Vallone dell'Aspro alloformation, which can be compared with tephrocronology (Zembo et al, 2008), indicate that the deposition of most of the unit is bracketed between ∼ 56 and ∼ 32 ka. This was the time of southwards tilting of the basin floor, development of an axial alluvial system and progradation of transverse alluvial fans.…”

“…is the indirect and relative timing of the terrace that developed at the surface of the Valle dell'Aspro alloformation that has been attributed to the middle-late Pleistocene (Di Niro et al, 1992;Bianca and Caputo, 2003). Traces of activity from far-away volcanic centers are represented by an ash layer and the overlying re-worked volcanogenic sedimentary deposits (Zembo, 2008;Zembo et al, 2008;Fig. 3).…”

“…The continental sedimentary record of these basins documents the Quaternary tectonic and volcanic evolution of the Southern Apennines, as well as the climate dynamics of the Mediterranean region. Specifically, the Val d'Agri Basin (hereafter VAB) offers a chance to delineate the middle-late Pleistocene history through the study of its well-exposed alluvial units that host evidence of syn-sedimentary tectonic activity, regional volcanism (documented by well-preserved tephra; Zembo et al, 2008) and climate changes (Zembo, 2007(Zembo, , 2008.…”

Use of soils and palaeosols on volcanic materials to establish the duration of soil formation at different chronological scales

“…During recent years, new tephra-palaeosol records have established the landscape history in different volcanic regions (e.g. von Suchodoletz et al, 2009;Inoue et al, 2011;Zembo et al, 2011). The organic-rich volcanic palaeosols are widely used as source of radiocarbon dates to develop tephrostratigraphic schemes (e.g.…”