Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2026Scopus SJRQ2/r/munzur/1226
  Depositional settings and basin-fill evolution of the restricted platform system on the Intra Pontide belt during the Late Eocene-?Early Oligocene transition, western black sea region, Turkey

  Us, Muhammed Sami; Tekin, Erdoğan; Akgün, Funda; Kayseri-Özer, Mine Sezgül; Varol, Baki Erdoğan

  This study presents an integrated sedimentological, microfacies, and palynological analyses of the Late Eocene–?Early Oligocene (Priabonian–?Rupelian) Akçapınar Formation, exposed along the Soğanlı Stream in the Intra-Pontide Belt of the Western Black Sea region, Turkey. The formation, which overlies the evaporitic Pürçükören Formation and locally the Soğanlı Formation, records deposition in restricted shallow-marine to a lagoonal setting during a phase of significant tectonic and climatic reorganization. Detailed field mapping and measured stratigraphic sections, supported by petrographic, XRD, and SEM analyses, reveal mud-supported textures, limited faunal diversity, and thin-shelled gastropods, consistent with low-energy, brackish conditions. Palynological assemblages, identified here for the first time, refine the age constraints and document freshwater influence, whereas mineralogical data indicate alternating arid (smectite-rich) and humid (chlorite–illite-rich) intervals. Microfacies patterns (Mf1–Mf4) and lithofacies associations (Lf1–Lf8) were synthesized into three-dimensional depositional models, illustrating progressive basin restriction, episodic subaerial exposure, and evaporite precipitation. The multi-proxy approach, integrating sedimentology, microfacies, palynology, and mineralogy, refined the depositional model of the Akçapınar Formation, revealing facies heterogeneity driven by the interplay of tectonically induced basin isolation, relative sea-level fluctuations, and paleoclimatic oscillations during the Eocene–Oligocene transition, and providing new insights into the paleogeographic evolution of the northern Neo-Tethys during the final stages of its closure.

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• MakaleYalnız künye2026Scopus SJRQ2/r/munzur/998
  Stratigraphy, mineralogy, paleodepositional environment, and diagenetic evolution of the Pülümür evaporites (Tunceli, Eastern Anatolia, Türkiye)

  Us, Muhammed Sami

  The gypsum member of the Balpayam Formation (GMoBF) in the Pülümür Kırmızıköprü Basin (PKB), Eastern Anatolia, records a complex evaporitic system shaped by episodic tectonism, volcanism, and fluctuating hydrological conditions. Stratigraphic logging, facies analysis, and systematic sampling from outcrops and quarries enabled a detailed assessment of the evaporite succession. Petrographic data reveal pervasive secondary gypsum textures, including porphyroblastic, alabastrine, laminated, brecciated, and satin-spar fabrics preserving relics of primary anhydrite and calcite. XRD and FIB-SEM-EDS analyses identify gypsum, anhydrite, celestine, dolomite, calcite, clay minerals, and minor siliciclastic, clarifying diagenetic pathways. Diagenesis initiated with early calcite and aragonite precipitation, followed by replacement by primary anhydrite and gypsum under elevated Mg2+/Ca2+ ratios and shallow burial. Later hydration, dehydration, and rehydration cycles produced secondary gypsum with distinctive microtextures and micro-hydration channels. The PKB reflects a dual depositional system: a shallow, low-energy, restricted lagoon dominated by massive-laminated gypsum, stromatolitic textures, and organic-rich layers, and a comparatively deeper open marine setting with laminated-banded gypsum and transported gypsum arenite-rudite facies. Chicken-wire gypsum and anhydrite nodules indicate synsedimentary to early diagenetic formation under hypersaline conditions. A schematic depositional model constrains the temporal and spatial evolution of diagenetic processes, highlighting the interaction among evaporite deposition, tectonic activity, and environmental fluctuations in the southern Neo-Tethys Ocean of Eastern Anatolia.

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• MakaleYalnız künye2021Scopus SJRQ2/r/munzur/2458
  Late Eocene to Late Miocene palaeoecological and palaeoenvironmental dynamics of the Ereğli-Ulukışla Basin (Southern Central Anatolia)

  Akgün, Funda; Kayseri-Özer, Mine Sezgül; Tekin, Erdoğan; Varol, Baki; Şen, Şevket; Herece, Erdal; Gündoğan, İbrahim; Sözeri, Koray; Us, Muhammed Sami

  The Ereğli-Ulukışla Basin which is the focus of this study is situated at the south-eastern edge of the Central Anatolian Cenozoic basins (Tuzgölü, Haymana, Çankırı-Çorum, and Sivas), and is divided into two sub-basins, the Aktoprak (AT) and Hacıbekirli-Tepeköy (HT). These sub-basins mainly comprise a stratigraphically discontinuous and laterally variable series, represented by ‘fluvio-lacustrine’ siliciclastic and carbonate sediments deposited over a wide range of environments, including meandering and braided rivers, coastal fluvial and fan deltas, mixed carbonate-siliciclastic shores, dry lake flats, and coal-bearing swamps. In the Ereğli-Ulukışla Basin, higher palaeotopographic conditions existed in the AT because of the uplift of the Central Anatolian Plateau during late Middle Miocene (Serravallian)-early Late Miocene (Tortonian) and the subsequent uplift of the Taurus Mountains in the latest Miocene (Messinian) as deduced in the Tepeköy region (northeast) of the HT sub-basin. Diversity and abundance of archaic pollen (Normapolles) in the pollen biostratigraphy decreased from the Eocene to Oligocene, while forms with advanced angiosperm morphology (post-Normapolles), were observed with the increase in post-Normapolles during the Miocene. The dominance of woody angiosperms in the pollen assemblages, and increasing variety and abundance of ‘open herbs’ and shrub pollen from the Early Miocene to Late Miocene defines an important change in flora. Furthermore, the palaeoclimatic conditions changed from humid-subtropical to warm-temperate during the sediment deposition in the Ereğli-Ulukışla Basin. Recurrent arid phases during the Late Miocene are indicated by the deposition of reddish caliche conglomerates in broad dry lake flats (HT), and evaporites in local playa lakes (AT), respectively.

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  AtıfScopus18·OpenAlex15

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• MakaleAçık Erişim2020Scopus SJRQ3/r/munzur/3364
  Early Miocene seed like plant remain fossils and facies associations from the Nallıhan district (NW Turkey)

  Görmüş, Muhittin; Kadioğlu, Yusuf Kağan; Varol, Baki Erdoğan; Us, Muhammed Sami

  Seed like fossils recognized by their distinctive orbicular in shape are seen in the early Miocene of the Nallıhan area (NW Türkiye). We examined more than one hundred specimens and facies associations for interpreting of fossil morphology and its paleoenvironment. The fossils as dark crystallized dots on the bedding surface of clayey limestones are characterized by a thick edged lenticular shape with a smooth one side and concave another side with circular nucleus. Their internal structures have circular a few whorlings, too often radial calcitic lamellae on the upper side and a few circular coiling at the bottom side. SEM, EPMA and RAMAN data of soft nucleus, hard part, filling materials and surrounding sediments support its plant origin. The Paleogene aged Kızılbayır formation and early Miocene aged Karadoruk and Akpınar formations include the following facieses: non-channelized red sandstone and mudstone (F1), channelized “confined” reddish-beige pebbly sandstone and conglomerate (F2), medium to coarse siliciclastics (F3), mudstones interbedded with sandstones (F4), thin bedded clayey limestone bearing plant fossils (F5) medium to thick bedded limestone (F6) and rhythmic siliciclastics - clayey limestone including coal occurrences (F7). Abundant plant fossils indicate a planted shallow lake margin with low topography during the early Miocene.

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• MakaleAçık Erişim2019Scopus SJRQ2/r/munzur/3795
  Microborings as indication of cryptic life modes in the foraminifer Orbitoides: Maastrichtian sediments of the Haymana and Nallihan districts (Ankara, Turkey)

  Görmüş, Muhittin; Demırcan, Huriye; Kadioğlu, Yusuf Kağan; Yağmurlu, Fuzuli; Us, Muhammed Sami

  Widespread Maastrichtian siliciclastics and carbonates cropping out in the Haymana (S Ankara) and Nallihan (NW Ankara) districts in the northwest and central Anatolia basins include rich Orbitoides occurrences. Microborings in the Orbitoides tests are interesting to notify. In this study, the details of their morphologic structures were investigated. Microborings were analyzed in more than 650 equatorial thin sections of the Orbitoides tests and 100 hard rock thin sections. The abundance of microborings increases in the siliciclastics towards the Cretaceous/Palaeogene boundary (K/Pg). They were identified as Maeandropolydora osmaneliensis Nielsen and Görmüs, Maeandropolydora isp. Curvichnus semorbis Nielsen, Oichnus simplex Bromley, Oichnus isp. Maeandropolydora osmaneliensis Nielsen and Görmüs. Maeandropolydora isp., semicircular to circular microborings of Curvichnus semorbis Nielsen and Oichnus simplex Bromley are related to parasitic life modes. Irregular wider unidentified microborings are hermit type life mode tunnels. Abundance of the microborings might be related to shallower siliciclastic environmental conditions such as feeding and suitable Eh-pH, test shape, and easy entrance to the test for parasites. Smaller benthic foraminifera are seen in both microspheric and megalospheric Orbitoides tests as parasites. In conclusion, occurrences of microborings and encrustations are associated with parasitism by appearances of Maeandropolydora osmaneliensis Nielsen and Görmüs, Curvichnus semorbis Nielsen and Oichnus simplex Bromley and commensally attachment by microalgae.

  AtıfScopus10·OpenAlex8

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