Drip tectonics and the enigmatic uplift of the Central Anatolian Plateau

Gogus, O.; Pysklywec, R. N.; Şengör, A. M. Celâl; Gün, Erkan

doi:10.1038/s41467-017-01611-3

Cited by 122 publications

(130 citation statements)

References 69 publications

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“…Prior work from the eastern United States, using the methods employed in our paper, similarly imaged shallow lithospheric low velocities (Savage et al, ). Alternatively, this high‐velocity overlain by low or average velocities could also be associated with some type of destabilized lithospheric root or delamination, as has been proposed for other tectonic settings (e.g., Göğüş et al, ; Shen et al, ; van Wijk et al, ; West et al, ). Such a mechanism would be expected to affect mantle flow (Shen et al, ; West et al, ), whereas for a stacked slabs scenario, the pattern may be stable, although prior metasomatism of the lithosphere may also enable subsequent destabilization (e.g., Snyder et al, ; van Wijk et al, ; Wang et al, ).…”

Section: Discussionmentioning

confidence: 76%

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Emry

Shen

Nyblade

et al. 2019

Geochem Geophys Geosyst

152

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Our understanding of the tectonic development of the African continent and the interplay between its geological provinces is hindered by unevenly distributed seismic instrumentation. In order to better understand the continent, we used long‐period ambient noise full‐waveform tomography on data collected from 186 broadband seismic stations throughout Africa and surrounding regions to better image the upper mantle structure. We extracted empirical Green's functions from ambient seismic noise using a frequency‐time normalization method and retrieved coherent signal at periods of 7–340 s. We simulated wave propagation through a heterogeneous Earth using a spherical finite‐difference approach to obtain synthetic waveforms, measured the misfit as phase delay between the data and synthetics, calculated numerical sensitivity kernels using the scattering integral approach, and iteratively inverted for structure. The resulting images of isotropic, shear wave speed for the continent reveal segmented, low‐velocity upper mantle beneath the highly magmatic northern and eastern sections of the East African Rift System (EARS). In the southern and western sections, high‐velocity upper mantle dominates, and distinct, low‐velocity anomalies are restricted to regions of current volcanism. At deeper depths, the southern and western EARS transition to low velocities. In addition to the EARS, several low‐velocity anomalies are scattered through the shallow upper mantle beneath Angola and North Africa, and some of these low‐velocity anomalies may be connected to a deeper feature. Distinct upper mantle high‐velocity anomalies are imaged throughout the continent and suggest multiple cratonic roots within the Congo region and possible cratonic roots within the Sahara Metacraton.

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Section: Discussionmentioning

confidence: 76%

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Emry

Shen

Nyblade

et al. 2019

Geochem Geophys Geosyst

152

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“…Note that if crustal thickening were to occur by magmatic underplating, even larger thicknesses would be required because of the greater density of underplated material. Second, thinning of the lithospheric mantle has been proposed (Bartol & Govers, 2014;Faccenna et al, 2013;G€ o g€ us¸& Psyklywec, 2008;G€ o g€ us¸et al, 2017;Schildgen et al, 2014;S¸eng€ or et al, 2003). Isostatic relationships suggest that removal of 75-125 km of undepleted lithospheric mantle could generate the required topographic response.…”

Section: 1002/2017gc007251mentioning

confidence: 99%

“…Plateau morphology and an apparent lack of crustal and lithospheric shortening have led many authors to invoke different lithospheric and asthenospheric processes in order to produce regional uplift. Examples include: steepening, tearing, and breaking off of subducting African lithosphere; delamination of Anatolian lithosphere; lithospheric dripping; and upwelling asthenospheric thermal anomalies (Bartol & Govers, 2014;Faccenna et al, 2013;G€ o g€ us¸& Psyklywec, 2008;G€ o g€ us¸et al, 2017;Schildgen et al, 2014;S¸eng€ or et al, 2003). Each of these mechanisms invokes arrival of asthenospheric mantle at shallow depths, where it provides isostatic and/or viscous topographic support.…”

Section: Introductionmentioning

confidence: 99%

Neogene Uplift and Magmatism of Anatolia: Insights From Drainage Analysis and Basaltic Geochemistry

McNab

Ball

Hoggard

et al. 2018

Geochem Geophys Geosyst

102

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It is agreed that mantle dynamics have played a role in generating and maintaining the elevated topography of Anatolia during Neogene times. However, there is debate about the relative importance of subduction zone and asthenospheric processes. Key issues concern onset and cause of regional uplift, thickness of the lithospheric plate, and the presence/absence of temperature and/or compositional anomalies within the convecting mantle. Here, we tackle these interlinked issues by analyzing and modeling two disparate suites of observations. First, a drainage inventory of 1,844 longitudinal river profiles is assembled. This database is inverted to calculate the variation of Neogene regional uplift through time and space by minimizing the misfit between observed and calculated river profiles subject to independent calibration. Our results suggest that regional uplift commenced at 20 Ma in the east and propagated westward. Second, we have assembled a database of geochemical analyses of basaltic rocks. Two different approaches have been used to quantitatively model this database with a view to determining the depth and degree of asthenospheric melting across Anatolia. Our results suggest that melting occurs at depths as shallow as 60 km in the presence of mantle potential temperatures as high as 1400°C. There is evidence that temperatures are higher in the east, consistent with the pattern of subplate shear wave velocity anomalies. Our combined results are consistent with isostatic and admittance analyses and suggest that elevated asthenospheric temperatures beneath thinned Anatolian lithosphere have played a first‐order role in generating and maintaining regional dynamic topography and basaltic magmatism.

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“…Clockwise rotation makes the western Transverse Range sit close to the Isabella anomaly and become the most compressional place in Southern California (Bird & Rosenstock, 1984;Nicholson et al, 1994;Raikes, 1980). The downwelling Isabella anomaly may trigger mantle upwelling in its surrounding areas (Göğüş et al, 2017) where systematical negative radial anisotropies are revealed in the asthenosphere (Figure 8). The upwelling mantle flow is possibly twisted by the right-lateral strike-slip SAF when it approaches the transition between the lithosphere and asthenosphere, resulting in a rotated pattern of flow system in the horizontal direction consistent with the observed circular pattern of azimuthal anisotropy and systematical positive radial anisotropy ( Figures 5 and 8).…”

Section: 1029/2018jb015873mentioning

confidence: 99%

Lithospheric Deformation and Asthenospheric Flow Associated With the Isabella Anomaly in Southern California

Zhao

2018

JGR Solid Earth

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Both laboratory experiments and seismic observations indicate that the solid Earth is composed of strongly anisotropic materials and its dynamics can be better constrained by exploring seismic anisotropy. Due to the limited number and poor depth resolution of currently available seismic anisotropy measurements, tectonic regimes of upper mantle deformations beneath Southern California still remain enigmatic and controversial. Here we present high‐resolution three‐dimensional models of P wave azimuthal and radial anisotropy in the crust and upper mantle beneath Southern California obtained by a joint inversion of local‐seismic and teleseismic P wave data. Our results reveal significant depth‐dependent anisotropy in which fast orientations in the lithospheric mantle closely follow the strike of the San Andreas fault and those in the asthenosphere are characterized as a predominantly circular pattern centered in the robust high‐velocity Isabella anomaly beneath the Great Valley. The Isabella anomaly is possibly a remnant of the fossil Farallon slab and is currently experiencing a tectonic regime of lithospheric downwelling, contributing to the development of a circular asthenospheric flow. High‐velocity anomalies are revealed below 300‐km depth beneath areas surrounding the Great Valley, which may reflect the delaminated lithospheric segments. Different rifting processes may take place beneath the Inner Borderland and the Salton Trough whose developments are possibly related to regional mantle upwelling and lithospheric stretching, respectively.

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Drip tectonics and the enigmatic uplift of the Central Anatolian Plateau

Cited by 122 publications

References 69 publications

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Neogene Uplift and Magmatism of Anatolia: Insights From Drainage Analysis and Basaltic Geochemistry

Lithospheric Deformation and Asthenospheric Flow Associated With the Isabella Anomaly in Southern California

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