First integrated tephrochronological record for the last ~190 kyr from the Fucino Quaternary lacustrine succession, central Italy
Academic Article
Publication Date:
2017
abstract:
We present the first integrated tephrochronological study (major and trace elemental glass composition,
Sr and Nd isotope analyses, and 40Ar/39Ar dating) for the last one tenth (~82 m) of the ~900 m-thick
Quaternary lacustrine succession of the Fucino Basin, the largest and probably only Central Apennine
intermountain tectonic depression that hosts a continuous lacustrine succession documenting the Plio-
Quaternary sedimentary history up to historical times. Major element glass compositions, determined
using a wavelength-dispersive electron microprobe (WDS-EMPA), yielded the geochemical fingerprinting
needed for a reliable identification of most of the 23 stratigraphically ordered tephra layers
under investigation. These include tephra from Italian volcanoes such as Campi Flegrei, Etna, Colli Albani,
Ischia, Vico, Sabatini, and undefined volcanic sources in the Neapolitan area and Latium region. The
recognition of key Mediterranean marker tephra layers (e.g. X-5 and X-6) is supported by trace element
data acquired by Laser Ablation Inductively Couple Plasma Mass Spectrometry (LA-ICP-MS). The Sr and
Nd isotope compositions of selected layers where also determined for circumscribing the volcanic source
of distal tephra and for supporting correlations with individual eruptive units. We also propose a new,
more expeditious covariation diagram (CaO/FeOtot vs Cl) for identifying the volcanic source of trachytic to
phonolitic and tephrytic to phonolitic tephra, that are the most common compositions of pyroclastic
rocks from volcanoes of Campania and Latium regions. Finally, we present five new 40Ar/39Ar age determinations,
including a new, analytically well-supported, and more precise 40Ar/39Ar age for the
widespread Y-7 tephra, and the first 40Ar/39Ar age determinations for one tephra from the Sabatini
volcanic district (~126 ka) and one tephra from Neapolitan volcanic area (Campi Flegrei?; ~159 ka). These
newly dated tephra are widely dispersed (e.g. Monticchio, southern Italy, Adriatic Sea and Lake Ohrid,
Macedonia-Abania) and have thus the potential to become important Mediterranean MIS 5 and MIS 6
tephrochronological markers. Altogether the new geochemical data and 40Ar/39Ar ages precisely
Iris type:
01.01 Articolo in rivista
Keywords:
40 39 Ar/ Ar geochronology; Central Mediterranean; Sr-Nd isotopes; Tephrochronology
List of contributors:
Galli, Paolo; Peronace, Edoardo; Regattieri, Eleonora; Giaccio, Biagio; Messina, Paolo; Sottili, Gianluca
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