The Medial Offshore Record of Explosive Volcanism Along the Central to Eastern Aegean Volcanic Arc: 2. Tephra Ages and Volumes, Eruption Magnitudes and Marine Sedimentation Rate Variations

Abstract

Ash plumes of numerous plinian, phreatoplinian and ignimbrite-forming eruptions from calderas and stratocones of the central and eastern Aegean Volcanic Arc dispersed ash mostly eastward across the Aegean and Mediterranean seas (e.g., Keller et al., 1978). The resulting marine ash and lapilli layers represent the major fraction of the erupted tephra volumes because the relatively small volcanic islands in the Aegean Sea provide very limited onshore depositional areas (Figure 1). Such marine tephras have previously been sampled by sediment coring across the central and eastern Mediterranean at great distances from the source volcanoes. During RV Poseidon

Volcano‐Tectonic Evolution of the Christiana‐Santorini‐Kolumbo Rift Zone

“…Assuming an age of ∼0.36 Ma for unconformity h6 (Preine, Karstens, Hübscher, Nomikou, et al., 2022) implies a rapid deposition of Unit 6 with sedimentation rates in the order of ∼1 m/kyr, which is approx. 5 to 10 times the measured sedimentation rates of the Quaternary across the CSK volcanic rift zone (Anastasakis & Piper, 2005; Kutterolf et al., 2021; Piper & Perissoratis, 2003). Such enhanced sedimentation rates have also been proposed by previous studies (Perissoratis, 1995; Piper & Perissoratis, 2003) for the Santorini‐Anafi region and could be explained by assuming that the Santorini‐Anafi Basin has been a major depocenter for volcanoclastic material from Santorini, which has been highly active during the last 0.36 Ma producing the vast Thera Pyroclastic Formation (Druitt et al., 1999).…”

“…Subsequently, volcanic activity became more explosive as demonstrated by the Kefalos Tuff ring that was formed about 0.5 Ma and by the 0.161 ka Kos Plateau Tuff eruption representing one of the largest known explosive eruptions of the Hellenic Arc, which involved a major caldera collapse south of Kos (e.g., Allen & Cas, 2001; Bachmann et al., 2010). Within the last 100 ka, there were at least two major eruptions with estimated tephra volumes exceeding 10 km 3 (Nisyros 1 and Yali 2; Kutterolf et al., 2021).…”

Holocene Marine Tephra Offshore Ecuador and Southern Colombia: First Trench‐to‐Arc Correlations and Implication for Magnitude of Major Eruptions

“…Indeed, the inland volcanic tephra may have been partly eroded or accumulated by winds or running waters after eruption and before being overlain by younger deposits. Similarly, tephra emplaced in marine sediments may have undergone some tectonic disturbance and slumping on the Ecuadorian margin, while tephra in the trench area may have been partly or totally redistributed by ocean deep‐sea currents (e.g., Freundt et al., 2021; Hopkins et al., 2020; Kutterolf, Freundt, Druitt, et al., 2021; Lowe, 2011; Wetzel, 2009). On the other hand, our data are all above 1 cm in thickness in the reconstructed depositional area of each eruption.…”

“…Providing reliable temporal and stratigraphic constraints on terrestrial and marine sedimentary archives, the study of tephra deposits is helpful in paleoseismology, tectonics, sedimentology, paleoclimatology or archeology. For instance, offshore Kamchatka peninsula and New Zealand, in the Aegean Sea and in the Lake Petén Itzá (northern Guatemala), the age model of marine tephra allows quantifying the recurrence rate of past eruptions, to correlate them with terrestrial deposits, to date marine sediments, to establish sedimentation rate models, and to constrain magnitude of past eruptions (Derkachev et al., 2020; Hopkins et al., 2020; Kutterolf, Freundt, Druitt, et al., 2021; Kutterolf et al., 2016). Tephrochronology allowed estimating the marine surface reservoir radiocarbon age during the last deglaciation offshore Chile (Siani et al., 2013), dating ice‐rafted debris deposition offshore Iceland (Lacasse and van den Bogaard, 2002), and investigating the climate/volcanism interaction at Izu‐Bonin arc (Schindlbeck et al., 2018).…”

The Medial Offshore Record of Explosive Volcanism Along the Central to Eastern Aegean Volcanic Arc: 1. Tephrostratigraphic Correlations

“…Here, we correlate ash layers between these cores and their source volcanoes on land to reconstruct an overall eastern Aegean Sea tephrostratigraphy. This forms the basis for our discussions of new constraints on eruption ages, magnitudes and intensities, as well as the variability of marine sedimentation rates along the Aegean Volcanic Arc, in the companion paper (Kutterolf, Freundt, Druitt, et al, 2021).…”