Mantle flow uplift of western Anatolia and the Aegean: Interpretations from geophysical analyses and geodynamic modeling


KOMUT T. , Gray R., Pysklywec R., Göğüş O. H.

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, cilt.117, 2012 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 117
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1029/2012jb009306
  • Dergi Adı: JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH

Özet

The Western Anatolian and Aegean region demonstrates a complex geologic history of horizontal and vertical tectonics. Active normal faulting and exhumation zones indicate that Western Anatolia has experienced significant extension since the Oligocene-Early Miocene (similar to 30 Ma). Our geophysical analyses demonstrate that the region is also uplifted relative to an elevation that would be expected given an isostatic response to the lithosphere structure. Namely, topography "residuals" indicate a residual uplift of about 1500 m over similar to 200 km sections of Western Anatolia and the Aegean. Admittance functions between free-air gravity and topography indicate that the regional topography is isostatically uncompensated and as it approaches similar to 50 mGal/km at the longest wavelengths, the uncompensated topography is likely owing to an underlying mantle flow component. Using forward geodynamic modelling we consider an idealized section of Western Anatolian lithosphere based on tomographic inversions and examine the magnitude and pattern of surface topography to reconcile with the geophysical observables. The models consistently show a plateau-type uplift (and horizontal extension) through Western Anatolia with an amplitude and wavelength consistent with the residual topography calculations. Together, the geophysical analyses and modelling provide independent quantitative evidence that the thin Anatolian-Aegean lithosphere is being buoyed upwards by underlying mantle flow. The mantle flow may be associated with active lithosphere delamination beneath the region; a process that would also explain the ongoing crustal extension.

The Western Anatolian and Aegean region demonstrates a complex geologic history of

horizontal and vertical tectonics. Active normal faulting and exhumation zones indicate

that Western Anatolia has experienced significant extension since the Oligocene-Early

Miocene (30 Ma). Our geophysical analyses demonstrate that the region is also uplifted

relative to an elevation that would be expected given an isostatic response to the

lithosphere structure. Namely, topography “residuals” indicate a residual uplift of about

1500 m over 200 km sections of Western Anatolia and the Aegean. Admittance functions

between free-air gravity and topography indicate that the regional topography is

isostatically uncompensated and as it approaches 50 mGal/km at the longest

wavelengths, the uncompensated topography is likely owing to an underlying mantle flow

component. Using forward geodynamic modelling we consider an idealized section of

Western Anatolian lithosphere based on tomographic inversions and examine the

magnitude and pattern of surface topography to reconcile with the geophysical

observables. The models consistently show a plateau-type uplift (and horizontal extension)

through Western Anatolia with an amplitude and wavelength consistent with the residual

topography calculations. Together, the geophysical analyses and modelling provide

independent quantitative evidence that the thin Anatolian-Aegean lithosphere is being

buoyed upwards by underlying mantle flow. The mantle flow may be associated with

active lithosphere delamination beneath the region; a process that would also explain the

ongoing crustal extension.