Biostratigraphy and magnetostratigraphy of the upper Tithonian–Berriasian of the Crimean Mountains

The calcareous nannofossils and magnetostratigraphic results from the Upper Tithonian–Berriasian of Feodosiya region (Eastern Crimea)

“…Recently, a team of European researches published independent bio-and magnetostratigraphic data and interpretation that they obtained in studying the Jacobi Zone of the Feodosiyan section (Bakhmutov et al 2018), which significantly differs from our outcomes made earlier (Arkadiev et al 2018;Guzhikov et al 2012;). Discussion of these contradictions along with presentation of new data on calcareous nannofossils is the purpose of this article.…”

“…The compiled Feodosiyan section comprises several independent sections (outcrops 2901, 2922-2924, 3112, 3113, 2456, 2927, 2920, and 2921) of the Dvuyakornaya Formation exposed as coastal cliffs at the Black Sea beach in the Feodosiisky Cape, Saint Ilya Cape, and in Dvuyakornaya Bay, at the southern edge of the Feodosiya town ( Fig. 1) (see Guzhikov et al 2012;Arkadiev et al 2018). The section represents calciturbidites, debrites and pelagic deposits from the deeper part of a distally steepened ramp (Guzhikov et al 2012;Baraboshkin et al 2016b) of about 400 m total thickness.…”

“…Guzhikov et al (2012) first provided a description of the compiled Upper Tithonian-Lower Berriasian section situated at the southern edge of the town of Feodosiya within the area of Dvuyakornaya Bay Saint Ilya Cape, and Feodosiisky Cape. Later, Arkadiev et al (2018) and Baraboshkin et al (2016a) detailed the structure of the section, summarized and analysed data on bio-and magnetostratigraphic stratification of the section, and provided zonal schemes on ammonites, calpionellids, foraminifera, ostracods, dinocysts, and trace fossils. The section covers an interval from the Upper Tithonian (Microcanthum and Andreaei ammonite Zones) to the Lower Berriasian (Jacobi Zone), where corresponding of the magnetic chrons from M20n to M17r inclusively were determined.…”

“…Therefore, the boundary between the Jurassic and Cretaceous was assumed by the authors to be the base of the Berriasella jacobi ammonite Zone but it has not been accurately positioned in the section. Higher levels of the Berriasian section (Occitanica and Boissieri Zones) were studied within the Zavodskaya Balka quarry in the Feodosiya area (Arkadiev et al 2015(Arkadiev et al , 2017(Arkadiev et al , 2018Savelieva et al 2017; Baraboshkin et al 2017Baraboshkin et al , 2019. There, on the basis of bio-and magnetostratigraphic data the boundary between the Berriasian and Valanginian was first justified.…”

Integrated stratigraphy of the Upper Barremian–Aptian sediments from the south-eastern Crimea

“…The Lower Cretaceous sediments of different intervals are studied in this area in varying degrees by different methods, including biostratigraphical, paleomagnetic, sedimentological and geochemical analyses. The main recent studies were focused on the Jurassic/Cretaceous transition (e.g., Arkadiev 2004Arkadiev , 2011Guzhikov et al 2012;Arkadiev et al 2018) and on the upper Berriasian to Valanginian sediments (Arkadiev 2007;Guzhikov et al 2014;Arkadiev et al 2017, a.o.). However, during the last half-century the Hauterivian to Aptian sediments of this area were rarely studied (e.g., Salman & Dobrovolskaya 1968;Baraboshkin 2016).…”