Paleobathymetric evolution of the Miocene deposits of the Gömbe sector of the Lycian Foreland and Aksu basins in Antalya, Turkey

Abstract

The evolution of the Lycian Foreland and Aksu basins are associated with the Africa-Eurasia convergence and collision of intervening continental blocks. Both basins developed around the Beydağları, a Mesozoic carbonate platform, which constitutes the main component and western limb of the Isparta Angle. The Gömbe Basin is an integral part of the Lycian Foreland Basin that comprises mainly Eocene to Late Miocene turbidites, onto which the allochthonous Lycian and Antalya nappes thrust over. The Aksu Basin, however, developed in the inner part of the Isparta Angle and is bounded by the Aksu Thrust in the east. During their evolution, these basins experienced significant bathymetric changes, possibly due to vertical motions and variations in the sediment supply. This study provides a detailed analysis of the paleobathymetric evolution of these basins. This conducted paleobathymetric study was based on the determination of the depositional depth by the abundance ratio of planktonic versus benthic foraminifera, which is the function of the water depth. The percentage of planktonic foraminifera relative to the total foraminifer population (%P) increases from shallow to deep water. However, some benthic foraminifera species are directly affected by the oxygen level of the bottom water, rather than by paleobathymetry, i.e. stress markers, and were discarded in the calculation. Additionally, the dissolution of the foraminifera has the potential for miscalculations, since planktonic foraminifera are more prone to dissolution than benthic ones. Nevertheless, the obtained quantitative results were verified and validated qualitatively by specific benthic depth markers that lived at specific depth ranges. Aksu Basin had a shallowing trend, and the sedimentation rate exceeded the subsidence in the middle of the section. Calculated depths for the Gömbe Basin indicated depths around 1000 m, which was contrary to the high sedimentation rates indicated by the turbiditic facies of the basin infills.

Deformation in SW Anatolia (Turkey) Documented by Anisotropy of Magnetic Susceptibility Data

“…The Elmalı Domain comprises lower to middle Miocene marine turbidites in an eastward thinning sedimentary wedge, marls and limestones in the east and north. These sedimentary rocks were deposited in the Lycian Foreland Basin (Şiş et al., 2020) developed in front of the SE verging Lycian nappes. The post middle Miocene sedimentary rocks in the domain correspond to the outer part of the foreland basin where extensional deformation is due to flexural bending of the down‐going block (Beydağları Platform, Figure 1) by the load of the advancing nappes (Hayward, 1984; Şiş et al., 2020).…”

“…Two mudstone‐marl sites (EL1 and SK4) yielded erratic directions ( e > 45°), and almost zero mean magnetic susceptibility (0 × 10 −6 to −4 × 10 −6 (SI) likely due to diamagnetic mineral content in the matrix, hence these sites are rejected (Table 1). Despite high magnetic susceptibility intensity (440 × 10 −6 SI), site ST6 presents a triaxial cluster and mean k 3 direction that is not normal to the bedding plane (38.3°), possibly due to remagnetization (Şiş et al., 2020). In the other nine sites, the k m values range between 44 × 10 −6 and 1,020 × 10 −6 (SI).…”

Preparing the ground for plateau growth: Late Neogene Central Anatolian uplift in the context of orogenic and geodynamic evolution since the Cretaceous

“…1 and 5C). The onshore basin contains a lower Miocene (locally Aquitanian and predominantly Burdigalian, c. 20 Ma) to Messinian sedimentary sequence of marine limestone, marine sandstone, marl, marginal marine conglomerates, and reefal limestones (Akbulut, 1977;Karabiyikoglu et al, 2000;Deynoux et al, 2005;Flecker et al, 2005;Çiner et al, 2008;S ¸is ¸ et al, 2020). Deposition of continental rocks (tufas) constrains uplift and emergence of the Antalya Basin by late Pliocene times (c. 3.5 Ma) (Glover and Robertson, 1998).…”