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    Aeolian imprints of multiple Mediterranean invasions of the Black Sea during Pleistocene
    (ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2022) Erginal, Ahmet Evren; Kıyak, Nafiye Güneç; Makaroğlu, Özlem; Bozcu, Mustafa; Öztürk, Muhammed Zeynel; Selim, Hamit Haluk; Nowacyzk, Norbert R.; Kaya, Nurcan; Öztürk, Tuğba; Karabıyıkoğlu, Mustafa; Polymeris, Georgios S.
    Climate changes determined the repeated connections between the Black Sea, Caspian Sea and Mediterranean Sea. The landlocked anoxic Black Sea basin was exposed to several transgressions throughout Quaternary by the Mediterranean Sea through the Straits of Istanbul (Bosphorus) and by the Caspian Sea through the Manych-Kerch spillway. Sedimentological records of these connections are limited mostly to the marine terrace deposits of Marine Isotope Stage (MIS) 5e while the pre-MIS 5e period remains uncertain due to a lack of robust facies and chronological data from deep-sea sedimentary sequences. Here we discuss the imprints of multiple Mediterranean transgressions during Middle Pleistocene in the Black Sea based on facies analysis and the optical age of coastal carbonate aeolianites. Contrary to today’s hydro-climate of the Black Sea, the aeolianites bear witness to the transformation of the Black Sea into a warm inland sea during successive Mediterranean invasions. Prior to the onset of aeolian deposition, paleosols were formed on the Eocene-aged hardened sandy silts, suggesting strongly washed soil. This is evidenced by no calcium carbonate and a high Rb/Sr ratio, with quartz amounting to of 99.8%. According to our OSL ages, carbonates deposited on the shelf plain under higher temperature and increased evaporation conditions in MIS 15 and the later interglacial phases were transported to the coastal sand dunes during the transitional phases of MIS 15–14, MIS 13–12, MIS 11–10 and MIS 9–8. We suggest that the carbonate-rich and ooid-containing aeolianites were repeatedly formed in the multiple Mediterranean transgression stages, beginning with an increasingly severe dry phase following the Brunhes-Matuyama magnetic reversal.
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    Co-seismic beachrock deformation of 8th century AD Earthquake in Middle Strand of North Anatolian Fault, Lake Iznik, NW Turkey
    (ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2021) Erginal, Ahmet Evren; Erenoğlu, Ramazan Cüneyt; Yıldırım, Cengiz; Selim, Hamit Haluk; Kıyak, Nafiye Güneç; Erenoğlu, Oya; Ulugergerli, Emin; Karabıyıkoğlu, Mustafa
    A historical earthquake-related co-seismic deformation observed on beachrock beds along the southern shoreline of Lake Iznik is discussed as a new paleoseismic record for an 8th century AD earthquake in the Middle Strand of the North Anatolian Fault, NW Turkey. Electrical Resistivity Tomography (ERT) images beneath the beachrock surface allowed monitoring of the subsurface trace of a normal fault dipping north along a 100 m surface rupture. No strike-slip deformation exists along the rupture, suggesting that the deformation in the beachrock is connected with a secondary structure, and that the main surface rupture was under the lake waters. The deformed beds of the beachrock, dated using Optically Stimulated Luminescence (OSL) to 1.3 ± 0.15 ka, are overlain by an undeformed secondary deposition of beds dated to 1.2 ± 0.09 ka. This allows us to narrow down the time of the faulting and implying that it was most likely a result of the AD 715 earthquake.
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    Mineralogical, petrological, and geochemical characteristics of Şenkaya Chrysoprase, Turkey
    (TÜBİTAK, 2022) Selim, Hamit Haluk; Güçtekin, Aykut; Şahin, Ferhan; Kaya, Mustafa; Tanç Kaya, Beril; Güner, Elanur; Taş, Kamil Ömer; Karakaş, Ahmet; Kantarçeken, Yasemin
    Şenkaya chrysoprase is a gemstone and can be found near the Turnalı village located in the west-northwest of Şenkaya (Erzurum) county in the uplifted Kırdağ of Northeast Anatolia of Turkey. Chrysoprase only found in Şenkaya County and known with the same name commercially in Turkey is a light-dark green and cryptocrystalline structure gemstone encountered in the Örükyayla Mélange. Samples were collected from the field for defining mineralogical-petrographical, XRD, XRF, ICP-MS, optical cathodoluminescence microscopy (OCLM), FTIR-Raman and stable isotopic properties of Şenkaya chrysoprase. According to mineralogical and petrographic examination, Şenkaya chrysoprase has generally heterogeneous color distribution in macroscale and has 5 Mohs mineral hardness. Microquartz filling (10%–15%) was seen in the microexamination with serpentine as main component with partly massive opal type silica. The XRF analyses indicate that many samples had high SiO2 values (91.45–94.38 wt%). As a result of trace elements, rare earth elements, Au-Pt group analyses using ICP-MS, Ni (167–387 ppm) and Co (12.57–74.78 ppm) values are quite remarkable. In the OCLM studies, few metallic minerals which could produce CL and could spread CL in different colors due to some trace activator elements were observed. Oxygen isotopic (?18OV-SMOW) values obtained from three chrysoprase samples are 24.8‰, 27.7‰ and 30.63‰, respectively and mean formation temperature is 96–99 o C.