Glass geochemistry of pyroclastic deposits from the Aeolian Islands in the last 50 ka: A proximal database for tephrochronology

Abstract

Volcanic ash (b2 mm) erupted from the Aeolian Islands is reported distally as layers in sedimentary archives from across the central Mediterranean region. Here we present volcanic glass geochemistry of proximal tephra deposits from explosive eruptions on the islands of Vulcano, Lipari, Salina and Stromboli spanning approximately the last 50 ka using grain-specific EMPA and LA-ICP-MS. This comprehensive database of volcanic glass compo- sitions (N1000 analyses) provides a basis for proximal-distal and distal-distal tephra correlations. Tephra de- posits from the different Aeolian Islands are geochemically diverse; with some individual eruptions showing diagnostic geochemical heterogeneity recognised both stratigraphically and/or spatially. Major element glass analyses reveal that Vulcano (0–21 ka) and Stromboli (4–13 ka) have erupted potassic (shoshonitic and K-series) tephra with broadly overlapping compositions, but data presented here demonstrates that their eruptive prod- ucts can be distinguished using either TiO2 contents or their HFSE/Th ratios. Whilst individual volcanic sources often produce successive tephra deposits with near identical major and minor element compositions through time (i.e., Lipari, Vulcano), trace element glass data can help to decipher successive eruptions. Changes in LREE and Th concentrations of volcanic glasses erupted spanning approximately the last 50 ka greatly enhance the po- tential to discriminate successive eruptive units on Lipari. The new proximal glass database has been used to ver- ify new (Ionian Sea; core M25/4-12) and existing distal occurrences of Aeolian Island derived tephra enabling the reassessments of past ash dispersals. Finally, proximal and distal data have been used to establish an integrated proximal-distal eruptive event stratigraphy for the Aeolian Islands

Discovery of cryptotephra at Middle–Upper Paleolithic sites Arma Veirana and Riparo Bombrini, Italy: a new link for broader geographic correlations

“…Data for Falcone volcano and Punta del Perciato are retrieved from Albert et al . (). Trace element data are normalized to primitive mantles of Sun and McDonough ().…”

The Late Holocene tephra record of the central Mediterranean Sea: Mapping occurrences and new potential isochrons for the 4.4–2.0 ka time interval

“…Data for Salina and Lipari rhyolites are from Albert et al . (). [Color figure can be viewed at wileyonlinelibrary.com]…”

“…Data from Albert et al . (). (d) SiO 2 vs FeO tot diagram with Etnean cryptotephra analyzed in this work and compared with mid‐ and distal FG and FL equivalents.…”

“…According to the TAS and binary diagrams (Figs ), we suggest a correlation of the tephriphonolitic (SHO) C1/85b with activity at Vulcano Island. This is supported by the TiO 2 and Na 2 O concentration of Vulcano deposits, which display slightly different composition with respect to Stromboli shoshonitic products (Albert et al ., ). Tephra TIR2000‐50 in the Marsili Basin (Di Roberto et al ., ; Albert et al ., ) is likely to be the marine equivalent of C1/85b (Figs and ).…”

“…The proximal–distal correlation of TIR2000‐50 was discussed by Albert et al . () but remained unresolved. Although a perfect chemical match can be observed between C1/85b and TIR2000‐50 with ‘Palizzi A’ products emplaced at Vulcano at ca.…”