Burial and exhumation history of the Georgian sector of the central Greater Caucasus

Abstract

<p>The integration of low-temperature thermochronological and thermal maturity analyses constrains the maximum temperatures experienced during burial by the sedimentary fill of the central sector of the Greater Caucasus basin and the timing of its structural inversion. Raman spectroscopy, illite percentage and stacking order in illite-smectite mixed layers, illite crystallinity index, and Rock-Eval Pyrolysis analyses indicate that the maximum paleotemperatures experienced by the Greater Caucasus basin fill increase progressively from about 100 °C in the southern foothills of the central Greater Caucasus to close to 400 °C approaching the axial zone of the orogen. Apatite fission-track and apatite and zircon (U-Th)/He analyses along the same transect yielded ZHe ages between about 137 and 5 Ma, AFT central ages between about 37 and 4 Ma, and AHe ages between about 10 and 2 Ma, with progressively younger ages approaching the axial zone of the Greater Caucasus. Statistical inverse modelling of thermochronological data, integrating thermal maturity results and all other geological and geochronological constraints available, points to episodic exhumation during structural inversion of the central Greater Caucasus basin. Such basin was first partially inverted in Late Cretaceous/Paleocene times following Northern Neotethys closure along the Sevan-Akera suture zone; renewed basin inversion occurred since Middle-Late Miocene times as a consequence of far-field compressional stress transmission from the Arabia-Eurasia hard collision along the Bitlis-Zagros suture zone. It should be emphasised that this sequence of events applies only to the central portion of the Greater Caucasus and by no means should be extended to the other parts of such a large and complex orogenic system.</p>

Interpretation and analysis of seismic and analog modeling data of triangle zone: a case study from the frontal part of western Kura foreland fold-and-thrust belt, Georgia

“…The KFFTB is located between the LC and the GC double wedge orogens (Figure 2A), which accommodates the crustal shortening due to far-field effects of the collision between the Arabian and Eurasian plates (e.g., Alania et al, 2021;Gusmeo et al, 2021).…”

“…The Kura foreland basin (KFB) developed mainly during the Oligocene-early Miocene through loading by the LC retro-wedge and the GC pro-wedge (Alania et al, 2021). On the basis of growth strata age and detrital apatite fission-track data, the onset of deformation in the KFB started in the Middle-Late Miocene (Alania et al, 2017;Gusmeo et al, 2021). Recent and historical earthquakes indicate that the LC-GC convergence zone is tectonically active (e.g., Tsereteli et al, 2016).…”