Collision Chronology Along the İzmir‐Ankara‐Erzincan Suture Zone: Insights From the Sarıcakaya Basin, Western Anatolia

An edited version of this paper was published by AGU. Copyright 2019 American Geophysical Union.Debate persists concerning the timing and geodynamics of intercontinental collision, style of syncollisional deformation, and development of topography and fold‐and‐thrust belts along the >1,700‐km‐long İzmir‐Ankara‐Erzincan suture zone (İAESZ) in Turkey. Resolving this debate is a necessary precursor to evaluating the integrity of convergent margin models and kinematic, topographic, and biogeographic reconstructions of the Mediterranean domain. Geodynamic models argue either for a synchronous or diachronous collision during either the Late Cretaceous and/or Eocene, followed by Eocene slab breakoff and postcollisional magmatism. We investigate the collision chronology in western Anatolia as recorded in the sedimentary archives of the 90‐km‐long Sarıcakaya Basin perched at shallow structural levels along the İAESZ. Based on new zircon U‐Pb geochronology and depositional environment and sedimentary provenance results, we demonstrate that the Sarıcakaya Basin is an Eocene sedimentary basin with sediment sourced from both the İAESZ and Söğüt Thrust fault to the south and north, respectively, and formed primarily by flexural loading from north‐south shortening along the syncollisional Söğüt Thrust. Our results refine the timing of collision between the Anatolides and Pontide terranes in western Anatolia to Maastrichtian‐Middle Paleocene and Early Eocene crustal shortening and basin formation. Furthermore, we demonstrate contemporaneous collision, deformation, and magmatism across the İAESZ, supporting synchronous collision models. We show that regional postcollisional magmatism can be explained by renewed underthrusting instead of slab breakoff. This new İAESZ chronology provides additional constraints for kinematic, geodynamic, and biogeographic reconstructions of the Mediterranean domain

Is there a relationship between the diameter of the inferior vena cava and hemodynamic parameters in critically ill patients?

Introduction: The early detection of critically ill patients together with the rapid initiation of effective treatment in emergency departments(ED) increase the survival rates. Aim: This study investigated whether a correlation exists between haemodynamic parameters of critically ill patients and the diameter of the inferior vena cava (IVC). Materials and Methods: A cross-sectional study was performed included patients aged ≥18 years with an unstable haemodynamic and/or respiratory status who were referred to the ED for non-traumatic issues. IVC diameters were measured by ultrasound (US) and then central venous pressures (CVP) were measured. Anteroposterior (AP) and mediolateral (ML) diameters of the IVC, both in the inspirium (IAP, IML) and expirium (EAP, EML), were measured by US. Results: 102 patients were evaluated with a median age of 59. The relationship between the diameters of IVC and CVP was evaluated and significant correlation was found in IAP, EAP according to CVP values (p' 0.001). ROC analyses were performed and significant relationship was found between the EAP diameter with haemoglobin (Hmg), haemotocrit (Hct), and central venous oxygen saturation (ScvO2) and also significant correlation was detected between the IAP diameter and white blood cell (WBC). Discussion: We detected significant correlation between the CVP and the IVC diameter in our study compatible with recent studies besides, significant correlation was found between the diameter of the IVC and CVP values as well as between the EAP diameter and Hmg, Hct, ScvO2 levels. Conclusion: Measurement of IVC diameters, especially EAP may be useful at the monitoring of critically ill patients in ED

The Geodynamic Implications of Passive Margin Subduction in Northwest Turkey

International audienceThe number of subduction zones that facilitated the northward translation of the Anatolide-Tauride continental terrane derived from Gondwana to the southern margin of Eurasia at the longitude of western Turkey is debated. We hypothesized that if two north dipping subduction zones facilitated incipient collision in western Turkey, a late Cretaceous arc would have formed within the Neotethys and along the southern margin of Eurasia. To determine if an island arc formed within the Neotethys we investigated the sedimentary record of the Central Sakarya basin, which was deposited along the southern margin of Eurasia from 85 to 45 million years ago. Detrital zircon deposited within the lower levels of the Central Sakarya basin (the Değirmenözü Formation) are associated with south to north-directed paleocurrents and exhibit a unimodal late Cretaceous age peak sourced from isotopically juvenile mantle melts. Zircon maximum depositional ages from the Değirmenözü Formation cluster between 95 and 90 Ma and are 5–10 Myr older than biostratigraphic depositional ages. Between 95 and 80 Ma, a 12-unit shift from mantle to crustal derived εHf values occurs in the overlying Yenipazar Formation. We explain the absence of Paleozoic, Eurasian-sourced detrital zircon, the rapid shift from mantle to crustal derived εHf values, and lag time in terms of passive margin subduction within an isolated intra-oceanic subduction zone, whose island arc was reworked from south to north into the Central Sakarya basin during incipient collision. Thus, widely outcropping late Cretaceous plutonic rocks within Eurasia must have belonged to an additional convergent margin

Early to Mid-Holocene Lake level and temperature records from the terraces of Lake Sunnet in NW Turkey

Lake Sunnet, a freshwater landslide-dammed lake in NW Anatolia, comprises a10 m thick widespread of Early-to-mid Holocene deltaic sediments. Paleo-environmental interpretation of these deposits coupled with a high-resolution data (18 yrs/sample) of stable O and C isotopes, magnetic susceptibility and total organic and carbonate contents, allows an understanding of the nature of the mid-Holocene climatic transition as well as the short duration extreme events in relatively humid NW Turkey. Detailed sedimentological logging showed that four phases of progradation of deltaic sand bodies over pro-delta muds occurred. It is suggested that they correspond to phases of increased precipitation. A sudden vertical transition from lacustrine muds to subaerial colluvial facies at 5.9 ka cal BP is considered to be due to lake level drop related to water deficit. Oxygen isotope data suggest that the Mid-Holocene transition with high mean summer temperatures initiated at 7.3 ka cal BP and continued until the end of the section, with an interruption by a humid event between 6.8 and 6.0 ka cal BP. Centennial extreme events characterized by sharp delta O-18 positive shifts (1-2 permil) are also encountered at 9.2, 8.9, 8.2, and 7.6 ka cal BP. A comparison of the Lake Sunnet record with previous Aegean and Sea of Marmara palynological and sea surface temperature data shows a good fit in terms of the timing and nature of mid-Holocene transition and Early Holocene cold events. The Lake Sunnet stable isotope record particularly suggests gradually increasing summer temperatures and hence continentality during the mid-Holocene cooling in the Mediterranean

Tectono-stratigraphy of the Orhaniye Basin, Turkey: Implications for collision chronology and Paleogene biogeography of central Anatolia

International audienceLocated along the İzmir-Ankara-Erzincan Suture (IAES), the Maastrichtian-Paleogene Orhaniye Basin has yielded a highly enigmatic-yet poorly dated-Paleogene mammal fauna, the endemic character of which has suggested high faunal provincialism associated with paleogeographic isolation of the Anatolian landmass during the early Cenozoic. Despite its biogeographic significance, the tectono-stratigraphic history of the Orhaniye Basin has been poorly documented. Here, we combine sedimentary, magnetostratigraphic, and geochronological data to infer the chronology and depositional history of the Orhaniye Basin. We then assess how our new data and interpretations for the Orhaniye Basin impact (1) the timing and mechanisms of seaway closure along the IAES and (2) the biogeographic evolution of Anatolia. Our results show that the Orhaniye Basin initially developed as a forearc basin during the Maastrichtian, before shifting to a retroarc foreland basin setting sometime between the early Paleocene and 44 Ma. This chronology supports a two-step scenario for the assemblage of the central Anatolian landmass, with incipient collision during the Paleocene-Early Eocene and final seaway retreat along the IAES during the earliest Late Eocene after the last marine incursion into the foreland basin. Our dating for the Orhaniye mammal fauna (44-43 Ma) indicates the persistence of faunal endemism in northern Anatolia until at least the late Lutetian despite the advanced stage of IAES closure. The tectonic evolution of dispersal corridors linking northern Anatolia with adjacent parts of Eurasia was not directly associated with IAES closure and consecutive uplifts, but rather with the build-up of continental bridges on the margins of Anatolia, in the Alpine and Tibetan-Himalayan orogens

Oxytocin system social function impacts in children with attention-deficit/hyperactivity disorder

PMID = 2617493

Gypsum Karst Landscape in the Sivas Basin

The Tertiary Sivas Basin, Central Anatolia, includes one of the most outstanding gypsum karst terrains in the world, covering an area of 2140 km2. This gypsum karst significantly contributes to enrich the diversity of karst landscapes in Turkey and constitutes an excellent natural laboratory for understanding their evolution because it develops and degrades much faster than carbonate karst landscapes. The ENE–WSW trending Sivas gypsum karst terrain is 280 km long and 55 km wide. The karst landscapes are mainly developed on Oligocene gypsum deposits. Sivas gypsum karst terrain has a wide variety of well-developed karst features such as karren, different types of dolines (solution, collapse and suffosion), blind valleys, karst springs, swallow holes (ponors), karstified paleo-valleys, caves, unroofed caves, natural bridges, gorges, uvalas and poljes. Solution dolines, which riddle a large part of the area, are the most common landform. The Kızılırmak River and its tributaries drain the Sivas Basin. Therefore, Quaternary evolution of the Kızılırmak River has played an important role in the long-term evolution of the karst landscape in the basin. Karst development in some parts of the basin has also been affected by halokinetic structures

The Büyük Menderes River: Origin of Meandering Phenomenon

The Büyük Menderes River is the longest river that discharges into the Aegean Sea, with a length of 615 km. It is one of the main rivers dominating in the geomorphology of western Turkey, with its drainage basin that reaches to 24,000 km2. The river is also very important because of its meandering channel patterns. The term ‘meandering’ in geomorphology, architecture and art originates from the ancient name of this river: Maiandros. Its catchment area mainly consists of three courses located in the main grabens of the region. The upper course of the Büyük Menderes River is located in the Baklan-Dinar Graben, while the middle and lower courses are in the Denizli and Büyük Menderes grabens, respectively. The aim of this study is to describe the meandering channel features of this river in its current course from its source to its mouth, and related landforms and landscapes. © 2019, Springer Nature Switzerland AG

Natural radioactivity levels of great soil groups in Seferihisar Geothermal Region, Turkey

In this study, measurement of natural radioactivity and analyses of physical properties of soil were carried on great soil groups around the Seferihisar Geothermal Region. The radioactivity levels in soils were analyzed using scintillation gamma spectroscopy. The, 232 activity concentrations for 226Ra Th, and 40K range from 7.1 to 32.0 Bq kg(-1), 15.2 to 35.9 Bq kg-1 and 223.1 to 802.2 Bq kg(-1), respectively. Obtained data was compared with average values given by UNSCEAR and the other studies. The radium equivalent activity (Raeq) in soil samples ranges from 42.2 to 144.7 Bq kg-1 which are lower than the suggested maximal admissible value of 370 Bq kg(-1) recommended by OECD. In addition, the value of external exposure dose has been determined from the content of natural radionuclides in soil. The absorbed dose rates change between 20.6 and 70.9 nGy 11-1 with a mean value of 46.7 nGy 11-1 which is lower than the global average value of 55 nGy 11-1. The annual effective dose rates varied from 25.2 to 87.0 ia.Sv year-1 with an average value of 57.3 ia.Sv year-1. Obviously, all the calculated values were lower than this value, and therefore the environment of Tuzla Fault can be regarded as an area with normal natural background radiation