Volcanism straddling the Miocene–Pliocene boundary on Patmos and Chiliomodi islands (southeastern Aegean Sea): insights from new 40Ar ∕ 39Ar ages
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Published:2023-10-11
Issue:2
Volume:5
Page:391-403
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ISSN:2628-3719
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Container-title:Geochronology
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language:en
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Short-container-title:Geochronology
Author:
Boehm Katharina M., Kuiper Klaudia F., Uzel BoraORCID, Vroon Pieter Z., Wijbrans Jan R.ORCID
Abstract
Abstract. The island of Patmos, in the eastern Aegean Sea, consists
almost entirely of late Miocene to Pliocene volcanic rocks. The magmatism in
the Aegean is governed by subduction of the African plate below the Eurasian
plate, back-arc extension, slab rollback, slab edge processes and westward
extrusion of central Anatolia to the west along the Northern Anatolian Fault
into the Aegean domain. The evolution of the Aegean basin is that of a
back-arc setting, with a southerly trend in the locus of both convergent
tectonics and back-arc stretching, allowing intermittent upwelling of arc,
lithospheric and asthenospheric magmas. Here, we present new 40Ar/39Ar age data for Patmos and the nearby
small island of Chiliomodi to place this volcanism in a new high-resolution
geochronological framework. High-resolution geochronology provides a key to
understanding the mechanisms of both the tectonic and magmatic processes
that cause the extrusion of magma locally and sheds light on the tectonic
evolution of the larger region of the back-arc basin as a whole. The volcanic series on Patmos is alkalic, consistent with a back-arc
extensional setting, and ranges from trachybasalt to phonolites, trachytes
and rhyolites, with SiO2 ranging from 51.6 wt % to 80.5 wt %, K2O ranging
from 2 wt % to 11.8 wt % and extrusion ages ranging from 6.59 ± 0.04 (0.14) Ma to 5.17 ± 0.02 (0.11) Ma. Volcanism on Patmos and adjacent
Chiliomodi can be understood as a combination of mantle and crustal tectonic
processes including the influence of transform faults and rotational crustal
forces that also caused the widening of the southern Aegean basin due to two
opposite rotational poles in the east and west and rollback of the
subducting slab south of Crete.
Funder
Netherlands Research Centre for Integrated Solid Earth Sciences
Publisher
Copernicus GmbH
Subject
Paleontology,Stratigraphy,Geology
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