Geomorphic and geological constraints on the active normal faulting of the Gediz (Alaşehir) Graben, Western Turkey

Kent, E.; Boulton, Sarah J.; Stewart, Iain S.; Whittaker, Alexander C.; Alçiçek, Mehmet Cihat

doi:10.1144/jgs2015-121

Cited by 28 publications

(43 citation statements)

References 69 publications

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“…Detrital apatite fission track data show that the southern margin of the Gediz Graben experienced two major exhumation events, one involving the whole margin during late Miocene and one involving only its western part (Salihli area) during Plio‐Quaternary times, thus generating a differential uplift of this sector (Asti et al, ). This differential exhumation is consistent with the differential evolution of slip rates on faults bounding the southern margin of the modern graben in response to fault segments interaction and linkage (Kent et al, , ).…”

Section: Geological Settingsupporting

confidence: 80%

“…Another possibility to explain the localization of the Plio‐Quaternary exhumation event deals with the evolution of faulting at the southern margin of the basin. Kent et al (, ) showed that active fault segments bounding the southern margin of the modern Gediz Graben became connected during the last 2.6–2 Myr, thus resulting in an increase in throw rates along the Salihli segment of this fault system. This increase in throw rate might have also played a role in the differential exhumation of the Gediz detachment in the Salihli area.…”

Section: Discussionmentioning

confidence: 99%

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The Gediz Supradetachment System (SW Turkey): Magmatism, Tectonics, and Sedimentation During Crustal Extension

et al. 2019

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Unraveling the evolution of supradetachment basins developed in the hanging wall of low‐angle detachment faults may be an invaluable tool in reconstructing the tectonic evolution of highly extended terrains. These basins may record major regional tectonic events related to the exhumation of metamorphic core complexes, and the reconstruction of their evolution helps to quantify the amount of extension accommodated by such processes. Here we present stratigraphic and structural field evidence and micropaleontological constraints to the Neogene‐to‐Quaternary evolution of the supradetachment Gediz Graben that developed on top of the exhuming Central Menderes Massif (SW Turkey). This basin displays three different structural styles during its evolution: (i) it initiated as a ramp basin following the activation of the Gediz Detachment in the Middle Miocene, (ii) evolved as a half graben during the late Miocene following the activation of high‐angle brittle faults at its southern margin, and (iii) reached its final symmetric graben configuration in Late Pliocene (?)‐Quaternary times following the activation of its northern margin. New micropaleontological data document a short‐lived upper Tortonian marine episode in the basin, and major along‐strike variations in exhumation are documented on its southern margin. Our reconstruction shows how sedimentary basins originally formed in the hanging wall of detachment faults may eventually end up in tectonic contact with the mylonitic footwall. Finally, we highlight the importance of magmatism in localizing the deformation in highly extended terrains and in controlling the evolution of supradetachment systems.

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Section: Geological Settingsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

The Gediz Supradetachment System (SW Turkey): Magmatism, Tectonics, and Sedimentation During Crustal Extension

et al. 2019

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“…The height of the knickpoints above the fault correlates well with the relative values of footwall relief and total throw on the active high‐angle normal faults bounding the graben, which were first presented in Kent et al (). In that study, Kent et al ., compared fault throw measurements, derived from structural and seismic analysis, with the topographic relief in the Gediz Graben between the valley floor and the top of the exhumed basin sediments along the southern margin.…”

Section: Resultsmentioning

confidence: 99%

“…(A) Simplified geological map of the Western Anatolian Extensional Province (adapted from Bozkurt, , ; Seyitoğlu et al ., ; Çemen et al, ; Kent et al, ); the box shows the location of Figures and . GG, Gediz Graben; KMG, Küçük Menderes Graben; BMG, Büyük Menderes Graben; DKBF, Datça–Kale Breakaway Fault (Seyitoğlu et al ., ), also known as the South West Anatolian Shear Zone (Çemen et al, ).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…(A) A simplified geological map showing the main lithologies in the Gediz Graben and the significant regional faults (same extent as Figure (B)), a low angle detachment and an array of high‐angle normal faults that bound the modern topographic graben (modified from Bozkurt, ; Seyitoğlu et al ., ; Çemen et al ., ; Kent et al, ). Note that the easternmost Alaşehir segment (AS) ruptured in the 1969 earthquake.…”

Section: Geological Backgroundmentioning

confidence: 99%

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Normal fault growth and linkage in the Gediz (Alaşehir) Graben, Western Turkey, revealed by transient river long‐profiles and slope‐break knickpoints

Kent

Boulton

Whittaker

et al. 2016

Earth Surf Processes Landf

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The Gediz (Alaşehir) Graben is located in the highly tectonically active and seismogenic region of Western Turkey. The rivers upstream of the normal faultbounded graben each contain a nonlithologic knickpoint, including those that drain through inferred fault segment boundaries. Knickpoint heights measured vertically from the fault scale with footwall relief and documented fault throw (vertical displacement). Consequently, we deduce these knickpoints were initiated by an increase in slip rate on the basinbounding fault, driven by linkage of the three main fault segments of the highangle graben bounding fault array. Fault interaction theory and ratios of channel steepness suggest that the slip rate enhancement factor on linkage was a factor of 3. We combine this information with geomorphic and structural constraints to estimate that linkage took place between 0.6 Ma and 1 Ma. Calculated pre and postlinkage throw rates are 0.6 and 2 mm/yr respectively. Maximum knickpoint retreat rates upstream of the faults range from 4.5 to 28 mm/yr, faster than for similar catchments upstream of normal faults in the Central Apennines and the Hatay Graben of Turkey, and implying a fluvial landscape response time of 1.6 to 2.7 Myr. We explore the relative controls of drainage area and precipitation on these retreat rates, and conclude that while climate variation and fault throw rate partially explain the variations seen, 5/18/2017 Normal fault growth and linkage in the Gediz (Alaşehir) Graben, Western Turkey, revealed by transient river longprofiles and slopebreak knickpoin… 2/29 lithology remains a potentially important but poorly characterised variable.

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Complex erosional response to uplift and rock strength contrasts in transient river systems crossing an active normal fault revealed by ¹⁰Be and ²⁶Al cosmogenic nuclide analyses

Boulton,

Rodés,

Fabel

et al. 2024

Earth Surf Processes Landf

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Understanding the influence of bedrock lithology on the catchment‐averaged erosion rates of normal fault‐bounded catchments and the effect that different bedrock erodibilties have on the evolution of transient fluvial geomorphology remain major challenges. To investigate this problem, we collected 18 samples for 10Be and 26Al cosmogenic nuclide analysis to determine catchment‐averaged erosion rates along the well‐constrained Gediz Fault system in western Türkiye, which is experiencing fault‐driven river incision owing to a linkage event ~0.8 Ma and has weak rocks overlying strong rocks in the footwall. Combined with existing cosmogenic data, we show that the background rate of erosion of the pre‐incision landscape can be constrained as <92 mMyr−1, and erosion rates within the transient reach vary from 16 to 1330 mMyr−1. Erosion rates weakly scale with unit stream power, steepness index and slip rate on the bounding fault, although erosion rates are an order of magnitude lower than slip rates. However, there are no clear relationships between erosion rate and relief or catchment slope. Bedrock strength is assessed using Schmidt hammer rebound and Selby Rock Mass Strength Assessments; despite a 30‐fold difference in erodibility, there is no difference in the erosion rate between strong and weak rocks. We argue that, for the Gediz Graben, the strong lithological contrast affects the ability of the river to erode the bed, resulting in a complex erosional response to uplift along the graben boundary fault. Weak covariant trends between erosion rates and various topographic factors potentially result from incomplete sediment mixing or pre‐existing topographic inheritance. These findings indicate that the erosional response to uplift along an active normal fault is a complex response to multiple drivers that vary spatially and temporally.

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Geomorphic and geological constraints on the active normal faulting of the Gediz (Alaşehir) Graben, Western Turkey

Cited by 28 publications

References 69 publications

The Gediz Supradetachment System (SW Turkey): Magmatism, Tectonics, and Sedimentation During Crustal Extension

The Gediz Supradetachment System (SW Turkey): Magmatism, Tectonics, and Sedimentation During Crustal Extension

Normal fault growth and linkage in the Gediz (Alaşehir) Graben, Western Turkey, revealed by transient river long‐profiles and slope‐break knickpoints

Complex erosional response to uplift and rock strength contrasts in transient river systems crossing an active normal fault revealed by ¹⁰Be and ²⁶Al cosmogenic nuclide analyses

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Geomorphic and geological constraints on the active normal faulting of the Gediz (Alaşehir) Graben, Western Turkey

Cited by 28 publications

References 69 publications

The Gediz Supradetachment System (SW Turkey): Magmatism, Tectonics, and Sedimentation During Crustal Extension

The Gediz Supradetachment System (SW Turkey): Magmatism, Tectonics, and Sedimentation During Crustal Extension

Normal fault growth and linkage in the Gediz (Alaşehir) Graben, Western Turkey, revealed by transient river long‐profiles and slope‐break knickpoints

Complex erosional response to uplift and rock strength contrasts in transient river systems crossing an active normal fault revealed by 10Be and 26Al cosmogenic nuclide analyses

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Product

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Complex erosional response to uplift and rock strength contrasts in transient river systems crossing an active normal fault revealed by ¹⁰Be and ²⁶Al cosmogenic nuclide analyses