Subducted, detached, and torn slabs beneath the Greater Caucasus

Mumladze, T.; Forte, Adam M.; Cowgill, Eric; Trexler, Charles C.; Niemi, Nathan A.; Yıkılmaz, M. B.; Kellogg, Louise H.

doi:10.1016/j.grj.2014.09.004

Cited by 55 publications

(96 citation statements)

References 89 publications

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“…Subcrustal structure of the western GC indicates that a mechanism may exist in the form of dynamic topography related to either slab detachment (Mumladze et al, 2015) or crustal delamination (Ershov et al, 2003). We cannot resolve between these two with our data, but slab detachment is the simpler explanation.…”

Section: Using Accretion Models To Reconcile Along-strike Patterns Inmentioning

confidence: 59%

“…2b) and are largely a two-sided orogenic wedge (Forte et al, 2014;Mosar et al, 2010) characterized by well-defined foreland fold-thrust belts ( Fig. 1, Mosar et al, 2010) and are underlain by a north dipping subducted slab extending to at least 160 km depth (Mumladze et al, 2015). Thermochronometric data suggest more rapid uplift of ∼1 mm/y in the center of the range, with slower rates of exhumation as low as 0.1 mm/y along the tips (Avdeev, 2011;Avdeev and Niemi, 2011;Král and Gurbanov, 1996;Vincent et al, 2011).…”

Section: Tectonic Settingmentioning

confidence: 95%

“…Basement is exposed in the western GC (Fig. 2b) and the GC lack a subducted slab or significant underthrusting (Mumladze et al, 2015). In contrast, east of 45 • E the GC lack exposure of basement (Fig.…”

Section: Tectonic Settingmentioning

confidence: 99%

“…For example, (1) small rainfall events often do not generate enough runoff to incise into bedrock (e.g., Molnar et al, 2006) and thus mean rainfall may be a poor proxy for the geomorphically effective climate; and (2) base-level in this region is intimately linked with the history of the Caspian Sea, which experienced a partially climate driven 1-1.5 km base-level drop between 5.5 and ∼3.0 Ma ) that possibly drove increased exhumation of portions of the Caucasus draining into the Caspian (e.g., Ballato et al, 2015). With respect to tectonics, there may be an additional source of uplift in the western GC due to (1) slab detachment (Mumladze et al, 2015) or delamination (Ershov et al, 2003); and/or (2) an along-strike change in the accretion rate or crustal structure within the GC (Forte et al, 2014). Climatic and tectonic mechanisms make distinct predictions in terms of the spatial distribution of metrics of topography, climate, and uplift and erosion rates throughout the Caucasus regions.…”

Section: Introductionmentioning

confidence: 99%

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Decoupling of modern shortening rates, climate, and topography in the Caucasus

Forte

Whipple

Bookhagen

et al. 2016

Earth and Planetary Science Letters

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The Greater and Lesser Caucasus mountains and their associated foreland basins contain similar rock types, experience a similar two-fold, along-strike variation in mean annual precipitation, and were affected by extreme base-level drops of the neighboring Caspian Sea. However, the two Caucasus ranges are characterized by decidedly different tectonic regimes and rates of deformation that are subject to moderate (less than an order of magnitude) gradients in climate, and thus allow for a unique opportunity to isolate the effects of climate and tectonics in the evolution of topography within active orogens. There is an apparent disconnect between modern climate, shortening rates, and topography of both the Greater Caucasus and Lesser Caucasus which exhibit remarkably similar topography along-strike despite the gradients in forcing. By combining multiple datasets, we examine plausible causes for this disconnect by presenting a detailed analysis of the topography of both ranges utilizing established relationships between catchment-mean erosion rates and topography (local relief, hillslope gradients, and channel steepness) and combining it with a synthesis of previously published low-temperature thermochronologic data. Modern climate of the Caucasus region is assessed through an analysis of remotely-sensed data (TRMM and MODIS) and historical streamflow data. Because along-strike variation in either erosional efficiency or thickness of accreted material fail to explain our observations, we suggest that the topography of both the western Lesser and Greater Caucasus are partially supported by different geodynamic forces. In the western Lesser Caucasus, high relief portions of the landscape likely reflect uplift related to ongoing mantle lithosphere delamination beneath the neighboring East Anatolian Plateau. In the Greater Caucasus, maintenance of high topography in the western portion of the range despite extremely low (<2-4 mm/y) modern convergence rates may be related to dynamic topography from detachment of the north-directed Greater Caucasus slab or to a recent slowing of convergence rates. Large-scale spatial gradients in climate are not reflected in the topography of the Caucasus and do not seem to exert any significant control on the tectonics or structure of either range.

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Section: Using Accretion Models To Reconcile Along-strike Patterns Inmentioning

confidence: 59%

Section: Tectonic Settingmentioning

confidence: 95%

Section: Tectonic Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Decoupling of modern shortening rates, climate, and topography in the Caucasus

Forte

Whipple

Bookhagen

et al. 2016

Earth and Planetary Science Letters

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“…Crustal thicknesses and implications of subducted slabs are adapted fromZor (2008) andSkolbeltsyn et al (2014) and lithospheric thicknesses from numerous works includingAngus et al (2006). Note thatMumladze et al (2015) have recently proposed magmatism in the Greater Caucasus to relate to a further north-dipping subduction zone beneath this region.…”

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confidence: 99%

Petrogenesis of mafic collision zone magmatism: The Armenian sector of the Turkish–Iranian Plateau

et al. 2015

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Transition from a singly vergent to doubly vergent wedge in a young orogen: The Greater Caucasus

2014

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The Greater Caucasus Mountains, due to their youth (~5 Ma), provide an opportunity for insight into the early stages of orogen development during continent-continent collision. However, their recent tectonic evolution and first-order architecture remain unclear. Here we investigate the evolution of the orogen by integrating new observations of the fluvial geomorphology and neotectonics of the range with prior work on seismicity, geodetic strain, bedrock geology, and foreland basin structure. We find that the range contains four zones along strike that differ in structural architecture, topography, and first-order tectonic history. In particular, two south directed, singly vergent zones at the western and eastern tips of the orogen are separated by both a central doubly vergent zone that is dominated by north directed deformation and an eastern doubly vergent zone in which south directed thrusting dominates. We hypothesize that the along-strike changes in vergence and locus of deformation reflects different stages in the development of a doubly vergent orogen, with the tips of the range preserving an early, singly vergent form and the center recording a more advanced orogen. The differences between the two doubly vergent zones seem to be driven by the initial stages of collision between the structurally thickened crust of the Greater and Lesser Caucasus orogens, which initiated at~5 Ma.

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Subducted, detached, and torn slabs beneath the Greater Caucasus

Cited by 55 publications

References 89 publications

Decoupling of modern shortening rates, climate, and topography in the Caucasus

Decoupling of modern shortening rates, climate, and topography in the Caucasus

Petrogenesis of mafic collision zone magmatism: The Armenian sector of the Turkish–Iranian Plateau

Transition from a singly vergent to doubly vergent wedge in a young orogen: The Greater Caucasus

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