In this study, soil temperature of Sivas province was estimated by the artificial neural networks (ANNs) method using data obtained from five different meteorological measurement stations situated in ...provincial borders. Nineteen years of (2000-2018) monthly mean air temperature data obtained from five different soil depths (5, 10, 20, 50 and 100 cm) was used for ANN analysis. Predicted and measured soil temperatures were strongly correlated with determination coefficient (R
2
) values ranging between 0.9767 and 0.9941. Mean Absolute Error (MAE) ranged from 0.532°C to 1.381°C, while Mean Absolute Percentage Error (MAPE) ranged from 5.692% to 16.263% and Root Mean Squared Error (RMSE) ranged between 0.694°C and 1.666°C. It was found that the predicted values are in good agreement with the measured data. However, there was a tendency to underestimate the soil temperature.
Continent-continent collision drives crustal deformation, topographic rise and geodynamic change. Africa-Eurasia convergence accommodated in the Eastern Mediterranean involved subduction of the ...Neotethyan oceanic lithosphere in Anatolia. Subduction was followed by collision of continental crust of Greater Adria with Eurasia to form the Izmir-Ankara-Erzincan suture zone. Discerning the effects of this collision from pre-collisional ophiolite obduction-related orogeny of Greater Adria is notoriously difficult. Estimates on the timing of collision in Central Anatolia are based on a forearc-to-foreland basin transition along the Eurasian margin and suggest a ~60 Ma age of initial collision. Here, we assess whether this age is also representative for collision in Eastern Anatolia and across the Cenozoic Sivas Basin that straddles the Greater Adria-Europe suture. To this end we retro-deform regional block rotations in the Pontides, the Kırşehir Block and the Taurides, building a first-order regional ‘block circuit’ around the Sivas Basin. We show that up to ~700 km of convergence must have been accommodated across the Sivas Basin after Central Anatolian Kırşehir-Pontide collision at ~60 Ma – an order of magnitude more than estimated crustal shortening, and that wholesale lithospheric subduction must have occurred throughout much of the Cenozoic. Paleocene collision would require that this subduction consumed continental lithosphere, which is unlikely. We consequently infer that oceanic subduction continued much longer in Eastern Anatolia, perhaps well into the Miocene. We postulate that prolonged oceanic subduction and slab pull drew the Eastern Taurides north relative to the Central Taurides, leading to shortening and oroclinal bending in Central Anatolia. The diachronous demise of the Neotethys Ocean in Anatolia, as a function of its paleogeography, is thus a likely driver for the strong non-cylindricity of the Cenozoic Anatolian collisional orogen.
•Continent-continent collision in Anatolia was diachronous.•After ~60 Ma, ~700 km of convergence was yet to be accommodated in Eastern Anatolia.•Convergence accommodated is an order of magnitude more than crustal shortening.•Prolonged subduction resulted from a kinked passive margin paleogeography.•Oceanic subduction in Eastern Anatolia continued longer than previously thought.
Landslides are common natural hazards in the seismically active North Anatolian Fault Zone of Turkey. Although seismic activity, heavy rainfall, channel incisions, and anthropogenic effects are ...commonly the main triggers of landslides, on March 17, 2005, a catastrophic large landslide in Sivas, northeastern of Turkey, the Kuzulu landslide, was triggered by snowmelt without any other precursor. The initial failure of the Kuzulu landslide was rotational. Following the rotational failure, the earth material in the zone of accumulation exhibited an extremely rapid flow caused by steep gradient and high water content. The Agnus Creek valley, where Kuzulu village is located, was filled by the earth-flow material and a landslide dam was formed on the upper part of Agnus Creek. The distance from the toe of the rotational failure down to the toe of the earth flow measured more than 1800 m, with about 12.5 million m
3 of displaced earth material. The velocity of the Kuzulu landslide was extremely fast, approximately 6 m/s. The main purposes of this study are to describe the mechanism and the factors conditioning the Kuzulu landslide, to present its environmental impacts, and to produce landslide-susceptibility maps of the Kuzulu landslide area and its near vicinity. For this purpose, a detailed landslide inventory map was prepared and geology, slope, aspect, elevation, topographic-wetness index and stream-power index were considered as conditioning factors. During the susceptibility analyses, the conditional probability approach was used and a landslide-susceptibility map was produced. The landslide-susceptibility map will help decision makers in site selection and the site-planning process. The map may also be accepted as a basis for landslide risk-management studies to be applied in the study area.
Continental collisions exert a profound influence on the configuration and evolution of orogenic systems. The effects of Arabia‐Eurasia collision on the geodynamics of the eastern Mediterranean are ...difficult to unravel, however, because the timing of initial collision (i.e., intercontinental contact) remains controversial. We present the first detrital and bedrock apatite fission track and (U‐Th‐Sm)/He thermochronology, and detrital zircon U‐Pb constraints from the Sivas Basin and eastern Taurides in central Anatolia (Turkey), which provide a detailed record of Cenozoic orogenesis in the hinterland of the Arabia‐Eurasia collision zone. Our results indicate rapid middle Eocene burial followed by shortening, rapid cooling (up to ~25–45 °C/myr), and initiation of the southern Sivas fold‐thrust belt (SSFTB) during the late Eocene (~40–34 Ma), consistent with evidence of a coeval basin‐wide unconformity. We interpret that rapid late Eocene cooling of the SSFTB reflects exhumation driven by the northward propagation of retroforeland contraction into the Sivas Basin from the middle to late Eocene, and we propose that these events were due to initial soft collision of the thinned Arabian passive margin by ~45 Ma. This timing of the inception of collision is supported by a regional compilation of apatite fission track data that indicates rapid cooling and hinterland exhumation throughout central and eastern Anatolia from ~45 to 20 Ma, which was synchronous with a widespread magmatic lull from ~40 to 20 Ma. The data presented here are compatible with a widely accepted transition to more mature or hard collision at ~20 Ma, probably related to the arrival of thick Arabian crust along the Bitlis suture zone.
Plain Language Summary
The continents of Arabia and Eurasia (Europe and Asia) comprise two separate tectonic plates that are currently colliding with each other. We are uncertain when collision started, which makes it difficult to understand how the collision may have triggered other tectonic changes throughout the region. We investigated the onset of collision by collecting rock samples near the boundary between these continents in central Turkey and determining how their temperature has changed through time (thermochronology). Our analyses tell us the rocks cooled down very quickly ~40 million years ago, from temperatures greater than ~120 °C (i.e., several kilometers deep in the Earth) to much lower temperatures similar to Earth's surface. We infer that rapid cooling was due to the onset of tectonic activity and the creation of a mountain chain with high rates of erosion that removed overlying rocks to bring these samples closer to Earth's surface. These new results agree well with several similar studies that show that rock cooling also occurred at the same time throughout the entire region. We conclude that rock cooling was caused by tectonic uplift and erosion triggered by initial collision of the thinned front of the Arabia plate with Turkey ~45 million years ago.
Key Points
Detrital thermochronology indicates rapid coooling and exhumation of the Sivas Basin initiated during the late Eocene (~40–34 Ma)
Initiation of the southern Sivas fold‐thrust belt was caused by the northward propagation of retroforeland contraction into the basin
Widespread exhumation across central and eastern Anatolia was caused by initial soft collision of the thinned Arabia margin by ~45 Ma
The E-W oriented Sivas foreland basin in Turkey recorded a salinity crisis during the Late Eocene resulting in evaporite accumulations thick enough to trigger intense halokinesis during the ...Oligo-Miocene. The salinity crisis is studied thanks to three sedimentological sections crossing the transition from the last marine deposits (Bözbel Formation) to the overlying evaporitic facies (Tuzhisar Formation) preserved from halokinetic deformations. The top of the Bözbel Formation presents flood-generated hyperpycnites developed in pro-delta to delta front settings. In the central part of the basin, such facies become increasingly sediment-starved with azoic calcareous facies interlayered with organic-rich shales. Such facies are ultimately capped by thick accumulations of gypsiferous turbiditic lobe deposits. Southward, the foredeep was partly isolated from the central domain due to the propagation of an anticline. There, the basal siliciclastic turbidites become increasingly gypsum-rich and are capped by a 45 m-thick mass-transport deposit enclosing olistoliths of gypsum and of ophiolitic rocks. Such gravity collapse deposits evolve upward to the same gypsiferous turbiditic lobes observed northward. Both transitional facies record the progressive confinement of the basin from the sea, likely due to the northward propagation of the fold-and-thrust belt located farther south. The evaporites started to precipitate in piggy-back evaporitic basins, along the highs of the fold-and-thrust belt, before being reworked gravitationally in the foredeep to the north, producing the high to low density gypsum turbidites. Finally, from north to south, the reworked evaporites are extensively covered by a >100 m thick, chaotic, prismatic gypsum mass likely resulting from the hydration of anhydrite grains left as a residual phase after the leaching of a significant amount of halite. The latter formed in a hypersaline marine-fed basin and have lately allowed mini-basin salt tectonics during Oligo-Miocene times.
•The Late Eocene salinity crisis of the Sivas Basin is investigated by studying the marine siliciclastic Bözbel and evaporitic Tuzhisar formations•Delta front to pro-delta hyperpicnites grade to evaporite turbidites sourced from thrust top piggy-back evaporitic basins•Reworked evaporites are sealed by a thick mass of prismatic gypsum formed after the leaching of large amount of halite•A depositional model of the marine siliciclastic to evaporite transition is proposed
The Sivas Basin in the Central Anatolian Plateau (Turkey), which formed in the context of a foreland fold‐and‐thrust belt (FTB), exhibits a typical wall and basin (WAB) province characterized by ...symmetric minibasins separated by continuous steep‐flanked walls and diapirs. Extensive fieldwork including regional and detailed local mapping of the contacts and margins of minibasins, and interpretation of a set of 2‐D regional seismic lines, provide evidence for the development of a shallow evaporite level separating two generations of minibasins within the WAB province. Here beds of symmetric exposed minibasins along diapir flank are younger than minibasins observed over autochthonous evaporites. Laterally away from the WAB province, increase in wavelength of the tectonic structures suggests a deepening of the decollement level. We interpret that a shallower evaporite level developed in the form of an evaporite canopy, triggered by significant lateral shortening. The Upper Eocene‐Lower Oligocene autochthonous Tuzhisar evaporite level was remobilized by the northward migrating sedimentary load and the tilting of the southern basin margin during propagation of the foreland fold‐and‐thrust belt. Asymmetric and symmetric primary minibasins were overrun by an allochthonous sheet forming a canopy. A second generation of salt withdrawal minibasins subsided into the allochthonous salt sheet. The polygonal pattern of the WAB province influences the growing fold‐and‐thrust belt system during the late stage of the secondary minibasins development. The Sivas FTB basin is the result of the interaction between fold‐and‐thrust belt propagation, evaporite remobilization, and interaction between evaporite flow and sedimentation in the minibasins.
Key Points
Field analogue of a minibasin province in foreland fold‐and‐thrust belt
Evidence of salt canopy limiting two generations of minibasin
Evolution of minibasin province in fold‐and‐thrust belt
The Kösedağ region, is located in Central-Eastern Anatolia, contains a lot of base metals (Pb–Zn, Cu) and Au occurrences. The region is explored by numerous mining companies and MTA. In this ...research, hydrothermal alteration mapping by hyperspectral Hyperion satellite data was carried out to contribute to these explorations in a part of the region. Hydrothermal alteration is one of the initial steps in the exploration of such metallic occurrences. This study area was chosen to test the accuracy of the hyperspectral data results with those of field and laboratory study results. The in situ alteration map was prepared during field surveys and numerous samples analyses. These samples were investigated by microscopy and XRD examinations. The minerals which are belonging to argillic, sericitic, propylitic, and FeOx (iron oxide) hydrothermal alterations were determined. These minerals were checked and confirmed on the surfaces of altered samples by using ASD fieldspec 4 hi-res. The mixture tuned matched filtering (MTMF), which is one of the widely used spectral classification methods, was applied on the Hyperion data to determine the distributions of these alteration minerals in the study area. The results have shown that the comparison of field and laboratory studies and MTMF results coincided with an overall accuracy of over 86% and a kappa coefficient of 0.80. The alteration map has been generated using the MTMF method, has been the first hyperspectral research of the hydrothermal alteration mineralogy in the region. Consequently, the generated map can be used as a basic alteration map during exploration studies of hydrothermal base metal mineralizations in the region.
Sıcak Çermik, Delikkaya and Sarıkaya are important travertine fields with active hot springs located 31 km west of Sivas. Based on their morphology, most of the travertines are classified as ...fissure-ridge travertines. Eroded sheet-type, terraced, and self-built channel types of travertine are also present at a few locations. Faults and fissures formed in the underlying İncesu Formation, and fissures developing in the fissure-ridge travertines are linked to one another. Tectonic deformation forming the fissure-ridge travertines resulted from NE-SW extension associated with a NW-SE compressional regime related to the Central Anatolian Thrust Belt and Sivas Backthrust. U/Th series age dating results indicate that the travertine deposition extends back to 400 ka and yields ages of 11.400 (±500) to 364.000 (+201.000/-76.000) from the fissure-ridge travertines. Age data and fissure width observations indicate that a ~0.06 mm/year extension rate is associated with the compressional regime in the Sivas Basin. On average, fissure-ridge travertines formed over intervals of 56.000 years, and indicate that a major regional seismic event with a magnitude of 7.4 has occurred here with this order of frequency. The Pamukkale travertines in Western Turkey are one of the most spectacular natural heritage sites in the world, as well as a site of active tectonic studies, and are now protected for these reasons. As shown by this study, the Sıcak Çermik travertines are of comparable interest and should receive similar protection.
Caravanserais, which are some of the most important monuments of Anatolian Turkish Architecture, are not only the buildings which provide security of routes but also the buildings which reflect the ...social status of patrons. Turks have always given particular importance to development and securtiy of Anatolian road system since they began to rule Anatolian territories. They built substantial caravanserais like fortresses between particular distances on the route to provide security. Alacahan Caravanserai, which is located on the route between Sivas and Malatya and frequently used in the Middle Ages, has been chosen as a subject in this study. Although it has reached today steadingly, lack of an inscription makes hard to date the building. In previous studies it has been generally accepted that it was built during Bagdad campaign of Murad IV. In this study, the building is dated in accordance with some architectural evidence and historical sources.
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