LATE TRIASSIC (LATE NORIAN-RHAETIAN) RADIOLARIANS FROM THE ANTALYA NAPPES, CENTRAL TAURIDES, SOUTHERN TURKEY

The Hocaköy section measured from the Alakirçay Nappe (middle nappe) of the Antalya Nappes contain rich radiolarian fauna ranging from late Norian (Late Triassic) to middle-late Cenomanian (mid Cretaceous). At the basal part of the section, the Late Triassic (late Norian-Rhaetian) Gökdere Formation is characterized by gray to beige cherty limestone at the base and pinkish red chert- gray to beige limestone alternation at the top, with moderately to well-preserved radiolarians in the red chert beds. The overlying Jurassic - Middle Cretaceous Hocaköy Radiolarite is mainly represented by chert-mudstone alternations with some limestone interlayers. Radiolarians of the Gökdere Formation can be well correlated with that of the fauna from the Mino Terrane, central Japan and the fauna from the Queen Charlotte Islands, British Columbia, Canada. Four radiolarian zones from central Japan are recognized in the fauna obtained from Gökdere Formation such as “Praemesosaturnalis multidentatus Lowest Occurrence Zone (TR8A)” (late Norian), “Praemesosaturnalis pseudokahleri Lowest Occurrence Zone (TR8B)” (late Norian), ? “ Skirt F lowest Occurrence Zone (TR8C)” (late Norian-Rhaetian) and partly “Haeckelicyrtium breviora Taxon Range Zone (TR8D)” (Rhaetian). In comparison with the Queen Charlotte fauna, the two zones “Betraccium deweveri Zone” (late Norian) and “Proparvicingula moniliformis Zone” (early Rhaetian) are also encountered in the Gökdere Formation. Radiolarians of the uppermost part of the Gökdere Formation indicate that “Globolaxtorum tozeri Zone” defined in Queen Charlotte Islands corresponding to the late Rhaetian, is not present in the section. Five new taxa, Capnuchosphaera okayi, Bistarkum rhaeticum, Praemesosaturnalis heilongjiangensis aksekiensis, P. nobleae, Veghicyclia sanfilippoae were determined within the late Norian-Rhaetian radiolarian fauna of the Gökdere Formation in Hocaköy section.  &nbsp

The Arkot Dağ Mélange Central Turkey: evidences for the geodynamic evolution of the Intra-Pontide suture zone.

The geological setting of Turkey can be described as an assemblage of continental terranes separated by ophiolite-bearing suture zones that mark the areas where the PaleoTethyan and NeoTehyan oceanic basins were destroyed. In northern Turkey, one of the most important suture zones is represented by the Intra-Pontide one consisting of an east-west trending belt of deformed and/or metamorphic units located at the boundary between the Istanbul-Zonguldak terrane to the north and the Sakarya terrane to the south. These units can be regarded as issued from the Intra-Pontide domain, whose geodynamic history is still a matter of debate. Along the Akpinar-Araç-Bayramoren geotraverse, located in central Turkey, an ophiolite-bearing mélange, known as the Arkot Dağ Mélange, is well-exposed along the Intra-Pontide suture zone. The Arkot Dağ Mélange can be described as an Upper Santonian chaotic sedimentary deposit consisting of an up to 1000-m-thick succession of slide-blocks of different sizes and lithologies enclosed in a sedimentary matrix consisting of shales, coarse-grained arenites, pebbly mudstones and pebbly sandstones. The slide-blocks, from a few meters to hectometers in size, are represented by metamorphic rocks (mainly micaschists and gneisses), by ophiolites (peridotites, gabbros, IAT and BAB basalts and cherts) and by sedimentary rocks (cherts, neritic and pelagic limestone, marly limestone and ophiolite-bearing turbidites). The youngest age among the slide- blocks has been provided by the ophiolite-bearing turbidites where a late Coniacian nannofossil assemblage has been found. The cherts have provided a wide range of ages from the Middle Triassic to Late Cretaceous, whereas the fossils found in the limestone indicate Late Jurassic to Early Cretaceous ages. The matrix of the Arkot Dağ Mélange, even if unaffected by metamorphism, shows deformations represented by multiple meters-thick cataclastic shear zones at the boundaries of the mélange slices or inside them. According to its features, the source area of the Arkot Dağ Mélange was most likely a stack of continental and oceanic thrust sheets emplaced in the Late Cretaceous onto a continental margin. The data collected from the different slide-blocks suggest that the Intra-Pontide domain was characterised by an oceanic basin that opened at the latest in the Early Jurassic. The opening of the Intra-Pontide oceanic basin was followed by the development of a subduction zone with a subsequent opening of suprasubduction oceanic basin in the Middle Jurassic – Early Cretaceous. The convergence in this suprasubduction oceanic basin started at the Early/Late Cretaceous boundary by an obduction process, whereas its final closure can be regarded as Late Paleocene

THE CASE FOR THE GLOBAL STRATOTYPE SECTION AND POINT(GSSP) FOR THE BASE OF THE NORIAN STAGE

The Norian Stage is the longest stage in the Phanerozoic, and some members of the boundary working group have been evaluating suitable Carnian-Norian boundary sections for roughly two decades. This has identified two possible candidate boundary sections, at Black Bear Ridge (British Columbia, Canada) and Pizzo Mondello (Sicily, Italy). After a formal voting procedure within the working group, ending on the 26th July, 2021, the Pizzo Mondello section was selected as the global stratotype section and point for the base of the Norian. We evaluated the global correlation potential of the two proposed primary markers, the conodont Metapolygnathus parvus and the ‘flat-clam’ Halobia austriaca. Secondary markers were also evaluated around these boundary datums for correlation potential, and the veracity of the proposed sections for GSSP status. Data and arguments for the proposed sections and datums are presented here. Through a two-stage process of option elimination in voting, conforming with ICS guidelines, the working group decided by 60% majority to propose that the first occurrence datum of Halobia austriaca in the Pizzo Mondello section at the base of bed FNP135A should become the ‘golden spike’ for the base of the Norian. A secondary biotic marker for this boundary is the first occurrence of Primatella (Carnepigondolella) gulloae, in sample NA43, ca. 0 m below FNP135A, and the FA of Dimorphites noricus (sample NA42.1) ca. 3.5 m above bed FNP135 (indicating the first subzone of the Jandianus Zone). The best physical secondary marker is the magnetozone PM5n with the proposed boundary ca.40% through the thickness of PM5n. Strengths of the chosen datum are: 1) it also maintains historical priority for ammonoid zonations, which had placed the base Norian near to this level in Europe, North America and probably NE Asia; 2) Halobia austriaca is widely distributed in all paleolatitudes and is a long-established taxon

LATE LADINIAN (MIDDLE TRIASSIC) SPUMELLARIA (RADIOLARIA) FROM THE DINARIDES OF BOSNIA AND HERZEGOVINA

A limestone sample from southern Bosnia and Herzegovina near Fojnica town yielded extremely abundant and well-preserved radiolarians. The radiolarians are late Ladinian in age and clearly indicate the Spongoserrula fluegeli Subzone of Muelleritortis cochleata Zone based on the index forms and associated fauna. A highly diverse spumellarian fauna is described from this sample. Within the defined spumellarian fauna, five genera (Ligulatubus, Tubospongopallium, Hexacatoma, Octostella and Discofulmen) seventeen species (Dumitricasphaera galeata, D. trialata, Spongostylus bosniensis, Spongopallium crassum, Ligulatubus yaoi, Tubospongopallium gracile, T. kozuri, T. tornatum, Archaeospongoprunum globosum, Veghicyclia cruciforma, V. krystyni, Hexacatoma elegantissima, H. nobleae, Octostella pulchra, Pentaspongodiscus similediscus, Discofulmen dumitricai, D. ishidai) are new

MIDDLE CARNIAN (LATE TRIASSIC) NASSELLARIA (RADIOLARIA) OF KÖSEYAHYA NAPPE FROM EASTERN TAURIDES, EASTERN TURKEY

Abundant, very diverse, and well-preserved Nassellarian fauna has been obtained from cherty/clayey limestone levels at the basal part of the Köseyahya nappe east of the town of Elbistan, Eastern Taurides. A comparison with the radiolarian faunas of Austria, Japan and Turkey allows us to assign a middle Carnian age to this radiolarian fauna from the Elbistan region. This fauna contains Nassellaria that are typical for this time interval. Moreover, it contains Tetraporobrachia haeckeli Kozur & Mostler which is an index fossil that gives the name to the zone established by Kozur & Mostler. As a result of the taxonomic study of the Nassellarian fauna, thirty-nine taxa among which nine new species (Goestlingella tueysuezi, Haeckelicyrtium planum, Hinedorcus koeseyahyaensis, Katroma ? ornata, K. ? proba, K. ? tunoglui, Syringocapsa firma, S. nuda, Sanfilippoella carterae) and twelve taxa remained in open nomenclature are described and figured in this study.

Cherts rubanés à radiolaires du Dévonien du complexe de Karakaya, Turquie nord-occidentale : implications pour l’évolution de la Paléo-Téthys

Des cherts rubanés dévoniens à radiolaires ont été trouvés sous la forme d’olistolithes et de minces lames tectoniques (&lt;100 m), dans des grès et argiles considérablement déformés d’un complexe de subduction-accrétion triasique (Complexe de Karakaya supérieur) de Turquie nord-occidentale, le complexe de subduction-accrétion comporte aussi des blocs exotiques de calcaire du Carbonifère inférieur et du Permien supérieur. Il repose tectoniquement sur une série épaisse de métabasite et est recouvert en discordance par des roches sédimentaires d’âge Jurassique peu déformées, d’origine continentale à marine peu profonde. Les cherts dévoniens à radiolaires, de même que les descriptions plus récentes de cherts à radiolaires carbonifères et permiens du complexe de Karakaya suggèrent la subduction d’un océan Paléozoïque tardif, la Paléo-Téthys, le long de la marge méridionale des Pontides.Devonian radiolarian ribbon cherts are found as olistoliths and as a thin (&lt;100 m) tectonic slice in pervasively deformed sandstone and shale in a Triassic subduction-accretion complex (Upper Karakaya Complex) in Northwest Turkey. The subduction-accretion complex also comprises exotic blocks of Lower Carboniferous and Upper Permian limestone. It lies tectonically over a thick metabasite series and is unconformably overlain by little deformed continental to shallow marine sedimentary rocks of Jurassic age. The Devonian radiolarian cherts, along with the earlier descriptions of Carboniferous and Permian radiolarian cherts from the Karakaya Complex suggest the subduction of a Late Paleozoic ocean, the Paleo-Tethys, along the southern margin of the Pontides.</p

Thematic Section: Proceedings Of Interrad Xv

WoSScopu

Geochemistry, tectono-magmatic discrimination and radiolarian ages of basic extrusives within the Izmir-Ankara Suture Belt (NW Turkey): Time constraints for the neotethyan evolution

The Dagkuplu Melange in the Central Sakarya Valley represents the northernmost outcrops of the Izmir-Ankara Suture Belt in northwest Anatolia. In addition to blocks and slivers of serpentinite, gabbro, blueschist, neritic and pelagic limestones, it includes blocks of basic volcanic rocks associated with radiolarian cherts, pelagic carbonates and mudstones

Late Triassic to Early Jurassic radiolarian, conodont and ammonite assemblages from the Tavuscayiri block, Mersin Mélange, southern Turkey: Time constraints for the T/J boundary and sedimentary evolution of the southern margin of the northern Neotethys

Tekin, Kagan, Krystyn, Leopold, Okuyucu, Cengiz, Bedi, Yavuz, Sayit, Kaan (2020): Late Triassic to Early Jurassic radiolarian, conodont and ammonite assemblages from the Tavuscayiri block, Mersin Mélange, southern Turkey: Time constraints for the T/J boundary and sedimentary evolution of the southern margin of the northern Neotethys. Geodiversitas 42 (27): 493-537, DOI: 10.5252/geodiversitas2020v42a2

The Mississippian in the Central and Eastern Taurides (Turkey): constraints on the tectonic setting of the Tauride-Anatolide Platform

Data from the Mississippian tectono-stratigraphic units in the Tauride-Anatolide Platform, Central and Eastern Taurides, reveal that this region underwent incipient back-arc extension during the Variscan orogeny, but that rifting failed, leaving a basin floored with highly extended continental crust. The stratigraphy of several tectono-stratigraphic units, the Geyik Dagi, Aladag, and Bolkar Dagi Units were studied in detail in the Sultan Dagi and Hadim areas in the Central and Eastern Taurides. In the Sultan Dag area, the Geyik Dagi Unit contains shelf-type (shallow) marine clastics and carbonates of the Middle-Upper Mississippian Gokdere Member of the Harlak Formation, overlain by shales and basic volcanic/volcaniclastic rocks of the Kuz Member of the formation. The Mississippian age rocks in the Aladag Unit around Hadim are characterized by quartzarenites and carbonates of coastal to shallow shelf environment. The Bolkar Dagi Unit in the Hadim area includes inner shelf-type recrystallized limestones, dolomites and oolitic limestones. To the north of Konya, however, Middle Mississippian formations of the Bolkar Dagi Unit include metamorphosed olistostromal deposits with Silurian-Upper Devonian olistoliths, which were generated in an extensional basin with back-arc type bimodal volcanism. In the Cataloturan Nappe of the Bolkar Dagi Unit, in the Eastern Taurides, the Mississippian is represented by a basin/slope-toetype succession with an alternation of lithic tuffs, radiolarian cherts and pelagic limestones. It grades into Upper Mississippian shallow-marine carbonates. The data presented suggest the presence of a north-facing system with slope (Cataloturan) aborted rift basin (Konya-Bolkar Dagi) inner shelf (Hadim-Bolkar Dagi) coastal shelf (Hadim-Aladag) and shallow-shelf (Sultan Dagi-Geyik Dagi) along the northern margin of the Tauride-Anatolide Platform during the Mississippian