Τίτλος:
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
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
We use the tephrostratigraphic framework along the Aegean Volcanic Arc
established in Part 1 of this contribution to determine hemipelagic
sedimentation rates, calculate new tephra ages, and constrain the
minimum magnitudes of (sub)plinian eruptions of the last 200 kyrs.
Hemipelagic sedimentation rates range from similar to 0.5 cm/kyr up to
similar to 40 cm/kyr and vary laterally as well as over time.
Interpolation between dated tephras yields an eruption age of similar to
37 ka for the Firiplaka tephra, showing that explosive volcanism on
Milos is similar to 24 kyrs younger than previously thought. The four
marine Nisyros tephras (N1 to N4) identified in Part 1 (including the
Upper (N1) and Lower (N4) Pumice) have ages of similar to 57 ka, similar
to 63 ka, similar to 69 ka, and similar to 76 ka, respectively. Eruption
ages for the Yali-1 and Yali-2 tephras are similar to 55 ka and similar
to 34 ka, respectively. The Yali-2 tephra comprises two geochemically
and laterally distinct marine facies. The southern facies is identical
to the Yali-2 fall deposit on land but the western facies has slightly
less evolved glass compositions. Overall, erupted plinian and
co-ignimbrite fall tephra volumes range from <1 to 56 km(3) (excluding
possible caldera fillings and ignimbrite volumes), and 80% of the
eruptions had magnitude 5.5 M <= 7.2 (M = log(m)-7; m = erupted magma
mass in kg). Twenty percent of the tephras represent 3.2 M < 5.5
eruptions. The long-term average tephra magma mass flux through highly
explosive eruptions of Santorini is estimated at similar to 40 kg/s. The
analogous data for the Kos-Yali-Nisyros volcanic complex is less-well
constrained but similar to Santorini.
Συγγραφείς:
Kutterolf, S.
Freundt, A.
Druitt, T. H.
McPhie, J. and
Nomikou, P.
Pank, K.
Schindlbeck-Belo, J. C.
Hansteen, T. H.
and Allen, S. R.
Περιοδικό:
Geochemistry, Geophysics, Geosystems
Εκδότης:
AMER GEOPHYSICAL UNION
Λέξεις-κλειδιά:
tephrochronology; Agean Sea; sedimentation rates; eruptive volumes and
masses; arc volcanism
DOI:
10.1029/2021GC010011
