ISSN 0145-8752, Moscow University Geology Bulletin, 2016, Vol. 71, No. 3, pp. 217–233. © Allerton Press, Inc., 2016. Original Russian Text © V.N. Benyamovskiy, L.F. Kopaevich, 2016, published in Vestnik Moskovskogo Universiteta, Seriya 4: Geologiya, 2016, No. 00000, pp. 00000–00000. The Alan-Kyr Coniacian–Campanian Section (Crimean Mountains): Biostratigraphy and Paleobiogeography Aspects V. N. Benyamovskiya and L. F. Kopaevichb aGeological Institute, Russian Academy of Sciences, Pyzhevsky per. 7, Moscow, 119017 Russia bDepartment of Geology, Moscow State University, Moscow, 119991 Russia e-mail: [email protected] Received December 8, 2015 Abstract⎯This investigation continues the study of the Alan-Kyr reference section (Central Crimea, Belogorsk Region). The zoned age difference in the stratigraphic scheme of the Upper Cretaceous in the Eastern European Platform is considered according to benthic and planktonic foraminifers, as well as radio- larians in the Alan-Kyr section. This fact can be explained based on the suggestion that stratigraphically important taxa could have appeared in Crimea several million years earlier than on the platform, where they could migrate under the great global eustatic transgression in the Early Campanian. We also considered the influence of paleobiogeographic conditions on the taxonomic composition of the zoned foraminifer com- plexes, both benthic and planktonic. Keywords: benthic and planktonic foraminifers, radiolarians, biostratigraphy, paleobiogeography, Alan-Kyr section, Crimea Mountain center, and Coniacian–Campanian DOI: 10.3103/S0145875216030042 INTRODUCTION material makes it possible to consider the important stratigraphy issues related to these two genera. This investigation continues the study of the Alan- Despite the high interest in Bolivinoides and Sten- Kyr Coniacian–Campanian section, which is located sioeina in the biostratigraphy of the Upper Santonian– near the Lechebnoe Settlement in the Belogorsk Maastrichtian, the thorough paleontological mono- Region of the Crimean Mountains (Fig. 1). The major graphic study of these genera remains at the level of the data on this section that were studied in the previous early 1960s in Russia, after the publication of the well- paper are as follows (Bragina et al., 2015). First, new known summarized data on the Upper Cretaceous biostratons (at the level of layers) were identified for the Mangyshlak (Vasilenko, 1961). first time in radiolarians and foraminifers. Secondly, biostratigraphic units identified by radiolarians and The investigation of Alan-Kyr Bolivinoides and planktonic foraminifers were traced in the adjacent Ak- Stensioeina populations by three-dimensional scan- Kaya section (Korchagin et al., 2012). Thirdly, Crimea ning microscopy (CamScan and Tescan 2300) with a was the subject for the first time of a comparison of BSE detector at high magnification made it possible to biostratigraphic units identified not only on the basis carry out a thorough and detailed morphological anal- of radiolarians and planktonic foraminifers, but also ysis of the sculptural features of the shell structure and first identified layers with benthic foraminifer com- shell porosity and to find their place in a systematic plexes. Some of the earlier results require further inter- row (Figs. 2, 3). Our investigations were based on the pretation and additional study. previous studies of the morphology and systematics of the genera (Vasilenko, 1961; Barr, 1966, 1967, 1970; Hiltermann, 1963; Koch, 1977; Petters, 1977; Geor- RESEARCH METHODS gescu et al., 2011). The data on the paleontology and biostratigraphy of Bolivinoides and Stensioeina. Two lower complexes New data on the development of benthic foraminifers in the Alan-Kyr section are of Bolivinoides Cushman, 1927 characterized by species of the Bolivinoides and Sten- V.P. Vasilenko (1961), who was the leading Russian sioeina genera with a better preservation relative to expert on the study of Late Cretaceous foraminifers, those in well-known sections of the Eastern European suggested that Upper Santonian B. strigillatus (Chap- Platform (EEP) and Mangyshlak (Fig. 2). The obtained man) with a rounded shape was an ancestral form to 217 218 @Разрез Алан-кыр на окраине пос. Лечебное Core Samples Layers 5 (13-2-18) (13-2-17) 12-5-15(13-2-16) Sea of Azov 12-5-14(13-2-15) 12-5-13 (13-2-14) (13-2-13) 12-5-12(13-2-12) CRIMEA 1 MOSCOW UNIVERSITYGEOLOGY BULL 12-5-11(13-2-11) BENYAMOVSKIY, KOPAEVICH BENYAMOVSKIY, 4 12-5-10 2 Belogorsk Feodosia 12-5-9(13-2-10) Simferopol (13-2-9) 12-5-8 3 Bakhchisaray 12-5-7 12-5-6 4 12-5-5 20 m 3 12-5-4(13-2-8) 12-5-3(13-2-8, 13-2-6) Black Sea 12-5-2 5 (13-2-5) 16 @Карасеевка (13-2-4) 6 White Cliff @Мал. Карасеевка (13-2-3) 12 2 7 ETIN Vol.71 No.3 2016 (13-2-2) Lechebnoe Settl. Belogorsk (13-2-1) 8 04812 km Not exposed 4 1 0 Fig. 1. (а) The Alan-Kyr section; (b) its position in the Crimean Mountains. (1) Limestone, (2) limestone with flint nodules, (3) siliceous limestone and marlstone, (4) siliceous limestone and marlstone with flint interlayers, (5) clay limestone and marl- stone, (6) clay, (7) flint concretions. THE ALAN-KYR CONIACIAN–CAMPANIAN SECTION 219 3 30 mk 30 mk 100 mk 1 30 mk 2 4 6 100 mk 7 100 mk 8 100 mk 5 100 mk 9 100 mk 30 mk 30 mk 10 11 12 100 mk 13 100 mk 100 mk 14 15 30 mk 18 16 100 mk 17 100 mk 100 mk Fig. 2. Stensioeina and Bolivinoides in the Alan-Kyr section: (1–3) Stensioeina exsculpta (Reuss): (1) dorsal side, Alan-Kyr sample 12-5-2 (3); (2) ventral side, Alan-Kyr sample 12-5-3 (7); (3) profile, Alan-Kyr sample 12-5-3 (8). (4–6) Stensioeina gracilis (Brotzen): (4) dorsal side, Alan-Kyr sample 12-5-2 (4); (5) ventral side, Alan-Kyr sample 12-5-3 (9); (6) profile, Alan-Kyr sample 12-5-2 (5); (7–9) Stensioeina perfecta Koch: (7) dorsal side, Alan-Kyr sample 12-5-3 (12); (8) ventral side, Alan-Kyr sam- ple 12-5-3 (13); (9) profile, Alan-Kyr sample 12-5-3 (14); (10, 11) Stensioeina pommerana Brotzen: (10) dorsal side, Alan-Kyr sample 12–5-8 (5); (11) ventral side, Alan-Kyr sample 12-5-8 (6); (12) Bolivinoides strigillatus (Chapman): general appearance, Alan-Kyr sample 12-5-2 (7 and 8); (13–15) Bolivinoides strigillatus (Chapman)–Bolivinoides сulvirensis Barr: (13) general appearance, Alan-Kyr sample 12-5-5(1); (14) side appearance, Alan-Kyr sample 12-5-2 (7); (15) general appearance, Alan-Kyr sample 12-5-5(1); (16–18) Bolivinoides сf. сulvirensis Barr: (16, 17) general appearance, Alan-Kyr samples 13-2-6 and 13-2-7 (1); (18) side appearance, Alan-Kyr sample 13-5-7 (2). MOSCOW UNIVERSITY GEOLOGY BULLETIN Vol. 71 No. 3 2016 220 B. strigillatus (Chapman) B. culvirensis Barr B. decoratus (Jones) Alan-Kyr section 6b 6a (Kuepper, 1963); Upper Santonian, Australia (Barr, 1966); 87 1b Upper Campanian, µ 100 µm 100 µm 100 µm 200 m Southern 100 µm Alan-Kyr, Alan-Kyr, England Alan-Kyr, Alan-Kyr, Alan-Kyr, Alan-Kyr, sample 13-2-7 sample 12-5-2 sample 12-5-5 sample 12-5-2 sample 13-2-6 sample 13-2-7 B. stritgillatus(Chapman) – B. culvirensis Barr B. cf. culvirensis Barr MOSCOW UNIVERSITYGEOLOGY BULL (Koch, 1977); KOPAEVICH BENYAMOVSKIY, Lower B. culvirensis Barr, 1966–1967 Campanian, (Lower Campanian of Southern England) FRG 1a 1b 3b 1b 17b (Barr, 17a 1966); (Akimets, 1961); Upper Belarus, Santonian, 8 3a Upper Campanian Southern 1a 2 1a Topotype Topotypes England, 9 Holotype topotypes ETIN Vol.71 No.3 2016 After (Hiltermann, 1963): B. stritgillatus-B. decoratus; 8c 7c After (Barr, 1966) (Vasilenko, 1961); and (Georgesku et al., 2011) 8a Mangyshlak, B. culvirensis 2 3 (Vasilenko,1961); Upper Santonian 789 Mangyshlak, 7a (FRG, Hannover, Lower Campanian) Upper Campanian Fig. 3. The three Bolivinoides species that are most important in terms of stratigraphy: B. strigillatus (Chapman), B. culvirensis Barr, and B. decoratus (Jones), playing a great role in the phylogeny and zonal stratigraphy of the Upper Santonian–Upper Campanian in different regions. The place of the studied Alan-Kyr Bolivinoides representatives in the taxonomy of these three Bolivinoides. THE ALAN-KYR CONIACIAN–CAMPANIAN SECTION 221 the Campanian species of B. decoratus (Jones) with a species of the new genus Elongateporeia based on the wedge-shaped shell. In 1963, H. Hiltermann, who was pore elongation on the surface of the chamber wall. the greatest Western European micropaleontologist, However, according to our investigation data, Bolivi- summed the research data of the taxonomy and phy- noides culvirensis in the Bolivinoides collection from logeny experts from different countries on Bolivinoides the Alan-Kyr section contains both elongated and oval and also made the conclusion that B. strigillatus was a dotted pores; thus, it can be referred to the genus predecessor of a phylogenetic branch of B. decorates; Bolivinoides (Fig. 4D). he noted that B. strigillatus was also an ancestor of Stratigraphic importance of Bolivinoides. It should Bolivinoides austinianus Cushman. The Campanian be noted that Bolivinoides species are markers in the branch of Bolivinoides characterized by a narrow zoned scales by benthic foraminifers of the Upper wedge-shaped shell originated from this species (Hil- Santonian–Maastrichtian part of the Upper Creta- termann, 1963). ceous in different regions of the Earth, in particular, in F. Barr (Barr, 1966, 1967) made a revision of Boliv- Western Europe; in England (Barr, 1966, 1967; inoides and described a new form, viz., Bolivinoides Swiecicki, 1980; Bailey et al., 1983; Wilkonson, 2000; culvirensis Barr, 1967, which took an intermediate Hampton et al., 2007), Belgium, the Netherlands, position between B. strigillatus (Chapman) and B.