Abstract
The origin of widespread volcanism far from plate boundaries and mantle
plumes remains a fundamental unsolved question. An example of this
puzzle is the Anatolian region, where abundant intraplate volcanism has
occurred since 10 Ma, but a nearby underlying plume structure in the
deep mantle is lacking. We employed a combination of seismic and
geochemical data to link intraplate volcanism in Anatolia to a trail of
magmatic centers leading back to East Africa and its mantle plume,
consistent with northward asthenospheric transport of over
~2500 km distance. Joint modeling of seismic imaging and
petrological data indicates that the east Anatolian mantle potential
temperature is higher than the ambient mantle (~1420C).
Based on multiple seismic tomography models, the Anatolian upper mantle
is likely connected to East Africa by an asthenospheric channel with low
seismic velocities. Along the channel, isotopic signatures among
volcanoes are consistent with a common mantle source, and petrological
data demonstrate similar elevated mantle temperatures, consistent with
little cooling in the channel during the long-distance transport.
Horizontal asthenospheric pressure gradients originating from mantle
plume upwelling beneath East Africa provide a mechanism for high lateral
transport rates that match the relatively constant mantle potential
temperatures along the channel. Rapid long-distance asthenospheric flow
helps explain the widespread occurrence of global intraplate magmatism
in regions far from deeply-rooted mantle plumes throughout Earth
history.