Tephra in caves: Distal deposits of the Minoan Santorini eruption and the Campanian super-eruption

Abstract

Tephra deposits in caves are not only significant as stratigraphic markers. The comparatively sheltered position of cave environments, protected from rainfall, may preserve original distal tephra deposition features, unlikely to have survived in the open landscape. Most reported findings of tephra in caves are from the Campanian supereruption, which originated in the area of Naples (Italy). These findings facilitate evaluation in different caves of facies variability and modes of tephra deposition, derived from the same eruption. The Campanian volcanic event, about 40,000 years ago, was the largest eruption in Europe and the Mediterranean region during the late Pleistocene. Another major volcanic event during the Quaternary was the more recent Santorini eruption in the eastern Mediterranean (Aegean Sea) during the Late Minoan cultural period, approximately 3600 years ago. This was the largest Holocene eruption in the region, but tephra deposits in caves from this event appear to be very rare. We present here the first ever finding of a visible tephra layer from the Minoan Santorini eruption in a cave. The pure tephra, situated in the Pelekita cave in eastern Crete near Kato Zakros, has a thickness of up to 9 cm. Geochemistry analyses of major elements by electron probe micro-analysis (EPMA) and trace elements by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) prove the tephra to be derived from the Minoan Santorini eruption. Radiocarbon dating also fits the time frame of this eruption. Our findings indicate that the tephra layer in the Pelekita cave is an air-fall deposit. The lower boundary of the tephra layer is sharp and wavy, draping over the underlying irregular cave surface. Particle size distribution of the tephra is bimodal and typical for suspended aeolian transport. The consistently smaller size of heavier feldspar particles adjacent to larger but lighter volcanic glass particles, in thin sections of undisturbed samples, corroborate emplacement of the tephra inside the Pelekita cave from high-altitude fallout.

An overview of Alpine and Mediterranean palaeogeography, terrestrial ecosystems and climate history during MIS 3 with focus on the Middle to Upper Palaeolithic transition

“…The CI tephra occurs in the above-mentioned sites either as a relatively proximal, thick primary pyroclastic succession (e.g., Serino openair site; Accorsi et al, 1978;Giaccio et al, 2006) or as a discrete layer, with a sharp lower contact with underling sediments, made of purely volcanic material (i.e., glass shards or pumice fragments with mineral accessories) with no or negligible contamination by clastic sediments. These features are consistent with a sub-primary (re)deposition of ash layers by the wind or run-off shortly after its emplacement as primary fallout along landforms nearby sheltered or open-air archaeological sites (e.g., Bruins et al, 2019). Specifically, at Castelcivita site, both Plinian pumice and co-ignimbritic ash layers are recorded in their eruptive stratigraphic order, suggesting that the two eruptive units were transported and redeposited in the cave immediately after their fall (fall and rolling process) (Giaccio et al, 2008;Giaccio et al, 2006).…”

Advancing Santorini’s tephrostratigraphy: New glass geochemical data and improved marine-terrestrial tephra correlations for the past ∼360 kyrs

“…Research on Santorini's distal tephrostratigraphy was initiated in the 1960s by the first detection of the Minoan (Z-2) tephra in Eastern Mediterranean deep-sea sediments (e.g., Heezen, 1965, 1967;Keller and Ninkovich, 1972;Keller et al, 1978;Watkins et al, 1978;Vinci, 1985), on the islands of Crete, Milos and Rhodes (e.g., Vitaliano and Vitaliano, 1974;Doumas and Papazoglou, 1980;Bruins et al, 2019), and in Asia Minor (e.g., Sullivan, 1988). Subsequent studies of marine sediment cores from the southern Aegean and Levantine Seas identified six further visible tephra layers of Santorini provenance in deeper stratigraphic positions that, according to their occurrence in different foraminiferal stratigraphic zones, are labelled as Y-2 (CR), Y-4 (Cape Tripiti), X-1 (USC1), W-2 (MP), V-1 (LP2) and V-3 (LP1) tephras (e.g., Keller et al, 1978;Federman and Carey, 1980;Vinci, 1985;Fabbro et al, 2013) (Fig.…”

Global tephra studies: role and importance of the international tephra research group “Commission on Tephrochronology” in its first 60 years

“…Eden et al, 1992Eden et al, , 1996Neall et al, 2001;Matsu'ura et al, 2012;Obreht et al, 2016), and caves and rock shelters, have also yielded cryptotephras (e.g. Barton et al, 2015;Bruins et al, 2019;Hirniak et al, 2020), as have stalagmites (Klaes et al, 2022). Here, we list further examples including benchmark methodological papers, regional reviews, and recent papers on long sedimentary sequences that collectively emphasize the growing importance of cryptotephrochronological research: Turney (1998), Hunt (1999b), Hall and Pilcher (2002), van den Bogaard and Schmincke (2002), Davies et al (2004), Gehrels et al (2008, Wastegård and Davies (2009), Swindles et al (2011, 2019, Lawson et al (2012), Matsu'ura et al (2012, Wastegård and Boygle (2012), , Riede andThastrup (2013), Smith et al (2013), Abbott et al (2018aAbbott et al ( , b, 2020a, Menke et al (2018), Wulf et al (2018), , Leicher et al (2019), Jones et al (2020), Freundt et al (2021, Jensen et al (2021), andKinder et al (2021).…”

“…We record the names of those who have held positions as elected officers or who convened conferences or workshops on behalf of the global tephra community. The contributions of various individuals to the discipline of tephrochronology, addressed in some cases in our article, have been reported in special editorials, historical articles, or obituaries (see Einarsson, 1982;Vucetich, 1982;Björnsson, 1983;Royal Geographical Society, 1983;Noe-Nygaard, 1984;Steinthórsson, 1985Steinthórsson, , 2012Lowe, 1990a;Wilson, 2005;Self and Sparks, 2006;Tonkin and Neall, 2007;Froese et al, 2008b;Lowe et al, 2008aSlate and Knott, 2008;Hunt, 2011;Moriwaki et al, 2011a;Benedik-tsson et al, 2012a;Alloway et al, 2013;Kile, 2013;Thomas and Lamothe, 2014;Lundqvist et al, 2019;Bunting et al, 2020;Mazei et al, 2020;Hopkins et al, 2021a;Stork-Bullock Mortuary, 2021).…”

“…The special volume of ensuing papers, published as a double issue of the Journal of Quaternary Science (Abbott et al, 2020b), includes 27 scientific articles and is entitled "Crossing new frontiers: extending tephrochronology as a global geoscientific research tool". The volume was dedicated to the memory of Richard Payne (Abbott et al, 2020a;Bunting et al, 2020).…”