Core complex exhumation and bivergent detachment faulting in western Anatolia: Reconciling models with geological, geophysical and thermochronological constraints

Bodur Ö., Göğüş O. H., Brune S., Şengül Uluocak E., Glerum A., Fichtner A., ...Daha Fazla

AGU Fall Meeting , California, Amerika Birleşik Devletleri, 11 - 15 Aralık 2023, ss.1

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: California
  • Basıldığı Ülke: Amerika Birleşik Devletleri
  • Sayfa Sayıları: ss.1
  • Çanakkale Onsekiz Mart Üniversitesi Adresli: Evet

Özet

The western Anatolia-Aegean back-arc is characterized by N-S oriented extension by a magnitude of Vx = 2 cm/year based on geodetic velocities. In south-central part of western Anatolia, the exhumation of Menderes Massif metamorphic core complex and the development of two oppositely dipping ductile-brittle shear zones (Gediz/Alaşehir and Büyük Menderes detachments) are the consequences of such widespread lithospheric stretching since at least 15 Ma. Despite a large number geological, geophysical and petrological studies, the tectonic genesis of core complex exhumation and the evolution of strain localization are not well understood. In order to address this problem, we employ geodynamic experiments with visco-plastic deformation within a model domain that is 500 km wide and 165 km deep. The initial condition of our model is designed to approximate the first-order lithospheric structure of central Menderes Massif where lithosphere has been thinned owing to post orogenic tectonics (delamination, dripping). Our model consists of an upper crust (25 km thick) with wet quartzite rheology, a lower crust (25 km thick) with wet anorthite rheology, and a mantle lithosphere (30 km thick) with dry olivine rheology. We conduct two sets of experiments where we investigate the impact of key parameters within a plausible range: (1) varying the extension velocities imposed on the margins of the model boundary from Vext = 1- 4 cm/year full rate. (2) varying the friction coefficient of the upper crust (0.05 to 0.1). Our results for the preferred model show ∼40° rotation of two distinct and initially steeply dipping normal faults systems around the two major domes, which we call twin-domes. The flow of the low viscosity/post orogenic lower crust is the major driving force for accommodating the extension through isostatic compensation where footwall uplift, flat moho and episodic exhumation are reconciled with a set of observations.