Calcareous nannofossil assemblage changes and stable isotope data from Maastrichtian to Selandian in the Akveren Formation, Western Black Sea, Turkey

Maastrichtian - Selandian Planktonic Foraminifera Biostratigraphy and Palaeoecological Interpretation of Akveren Formation in Bartin Area (Western Black Sea, Turkey)

“…Increasing abundance of Morozovella taxa which lived in low nutrition waters, indicates mesotrophicoligotrophic and warmer environmental conditions in the Selandian. Kaya-Özer (2014) suggested similar environmental conditions in the Paleocene based on δ 13 C values.…”

“…can be interpreted as the presence of oligotrophic and warmer environmental conditions in this study (Table 1-2, Figure 6-7). Kaya-Özer (2014) investigated nanofossil assemblages, carbon and oxygen stable isotope data in this stratigraphic section and suggested that environmental conditions changed from eutrophic to oligotrophic during the Maastrichtian. Diversification of planktonic foraminifera species indicate the same environmental conditions in this study.…”

“…The temperature in the Late Cretaceous from Cenomanian to Maastrichtian was higher than today as determined by stable isotope studies and global climate models (Huber et al, 1995(Huber et al, , 2002Clarke and Jenkyns, 1999;DeConto et al, 1999;Wilson and Norris, 2001;Norris et al, 2002;Wilson et al, 2002;Bice et al, 2006;Forster et al, 2007;Bornemann et al, 2008;Friedrich et al, 2008;Shirazi et al, 2013;Kaya-Özer, 2014).…”

Vesiculation in the dinoflagellate cyst Cannosphaeropsis franciscana Damassa, 1979 across the K/Pg boundary (Vancouver Island, Canada) with implications for spiniferate gonyaulacacean taxonomy and ecophenotypy

“…The latest Maastrichtian is also characterized by a period of general stability in the calcareous dinoflagellate cyst assemblages from other oceanic localities such as DSDP sites 356 and 357 in the western South Atlantic (Thierstein, 1981;Hildebrand-Habel et al, 1999;Hildebraiid-Habel and Willems, 2000). The most characteristic change among these assemblages is elevated relative abundances of Cervisiella operculata beginning in the latest Maastrichtian (e.g., Thierstein, 1981;Hildebrand-Habel et al, 1999;Hildebraiid-Habel and Willems, 2000;Egger et al, 2009) and peaking above the K/Pg boundary as has been observed beyond the Pacific from the U.S. Gulf Coast (Jiang and Gartner, 1986), Haiti (Keller et al, 2001), Argentina (Scasso et al, 2005;del Río et al, 2011;Guerra et al, 2021), Spain (Romein, 1977;Lamolda et al, 2005Lamolda et al, , 2016, France (Peybernés et al, 1996;Rodríguez-Tovar et al, 2010), Austria (Egger et al, 2009;, Turkey (Kaya Ozer, 2014;Karabeyoğlu et al, 2019), Israel (Eshet et al, 1992), Egypt (e.g., Faris and Farouk, 2012;Kasem et al, 2017;Khozyem et al, 2019), Iraq (Kharajiany et al, 2019(Kharajiany et al, , 2020Al-Qayim et al, 2020), Iran (e.g., Parandavar et al, 2013;Asgharian Rostami et al, 2018;Mahanipour et al, 2021), equatorial Atlantic (Perch-Nielsen, 1977, South Atlantic (Hildebrand-Habel et al, 1999;Hildebraiid-Habel and Willems, 2000;…”

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“…The cause of unstable environmental conditions coincides with the tectonic and volcanic activity in the region that induced dramatic change in nannoplankton assemblage linked to the subduction event in the İzmir-Ankara Zone. of this species across the K-Pg suggests it is an opportunistic species, and it has been interpreted as indicating a high-stress environment (TANTAWY, 2003;AGUADO et al, 2005;KAYA-OZER, 2014). Acmes of Thoracosphaera operculata Bramlette & Martini, 1964 may correlate with episodes of increased environmental stress, higher atmospheric CO 2 contents, fluctuations in marine salinity and pH, and/or significant warming over a short period of time, such as the conditions that followed the K-Pg boundary event (LAMOLDA et al, 2005).…”