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Alegret, Ortiz & Kaminski (eds.), 2012. Ninth International Workshop on Agglutinated Foraminifera, Abstract Volume References: McNeil, D.H. 1997. New foraminifera from the Upper Cretaceous and Cenozoic of the Beaufort– Mackenzie Basin of Arctic Canada. Cushman Foundation Special Publication 35, 1–95. Podobina, V. M. 2000. Upper Cretaceous foraminifera and biostratigraphy of Western Siberia. Tomsk, “NTL” Press, 388 pp.+80 pls. [in Russian]. Setoyama, E., Kaminski, M.A. & Tyszka, J. 2011a. Late Cretaceous Agglutinated Foraminifera and Implications for the Biostratigraphy and Palaeobiogeography of the southwestern Barents Sea. In: (Kaminski, M.A. & Filipescu, S., eds), Proceedings of the Eighth International Workshop on Agglutinated Foraminifera. Grzybowski Foundation Special Publication 16, 251–309. Setoyama, E., Kaminski, M.A. & Tyszka, J. 2011b. The Late Cretaceous–Early Paleocene palaeobathymetric trends in the southwestern Barents Sea–Palaeoenvironmental implications of benthic foraminiferal assemblage analysis. Palaeogeography, Palaeoclimatology, Palaeoecology, 307, 44–58. 87
Alegret, Ortiz & Kaminski (eds.), 2012. Ninth International Workshop on Agglutinated Foraminifera, Abstract Volume Morphogroup analysis of Late Cretaceous–Paleogene agglutinated foraminifera from Indian Harbor M-52 well, Labrador Sea Eiichi SETOYAMA 1 , Michael A. KAMINSKI 2 and Jarosław TYSZKA 1 1 Polish Academy of Sciences, Institute of Geological Sciences, Cracow Research Centre, BioGeoLab, Senacka 1,31-002 Kraków, Poland. 2 Earth Sciences Department, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Saudi Arabia. e-mail: ndsetoya@cyf-kr.edu.pl The Late Cretaceous foraminiferal assemblages of Indian Harbor M-52 well drilled in the Hopedale Basin in the Labrador Sea were previously investigated by Gradstein and Berggren (1981), Kuhnt et al. (1989) and Gradstein et al. (1994). Classical deep-water agglutinated foraminiferal (DWAF) biofacies, namely the flysch-type fauna (Gradstein and Berggren, 1981) and the high-latitude slope assemblages (Kuhnt et al., 1989), were defined, in part, based on the Late Cretaceous assemblages from the well. The quantitative data of the assemblages were, however, not published in the original studies, and the description of the assemblages given was qualitative due to the large number of wells examined. This study investigates a different set of samples from the Upper Cretaceous–Paleogene sequence recovered by M-52 well from the one analysed previously with the main objective of a semiquantitative palaeoenvironmental analysis of the foraminiferal assemblages using morphogroup analysis. The foraminiferal assemblages are consistently dominated by DWAF, and highly diversified. Calcareous benthic and planktic foraminifera are often rare, while the former being more common than the latter. The calcareous specimens are invariably etched indicating early diagenetic dissolution. The interval, which was previously estimated as Maastrichtian, is now regarded as the early–middle Campanian (10,750–10,660 feet) based on the concurrence of Caudammina gigantea and Uvigerinammina jankoi. The age of the overlying sequence up to 10,480 feet is estimated to be late Campanian to Maastrichtian, corresponding to the Caudammina gigantea zone of Geroch and Nowak (1984). A mesotrophic, well-oxygenated environment with bottom currents was inferred from the presence of all morphogroups, the consistent dominance of tubular forms (M1) and the common occurrence of infaunal forms (M4). The relatively high diversity and the dominance of DWAF, especially tubular forms, indicate a possibly lower–middle bathyal setting for the Alexis and Markland formations. The frequent occurrence of Reticulophragmium, Budashevaella and streprospiral forms in the Cartwright Formation, which are characteristic of “Foraminiferal Biofacies 3” in the Eocene outer neritic–upper bathyal facies in the Barents Sea (Nagy et al., 2000), together with a general decreasing trend in diversity and the relative abundance of M1, indicate regional shallowing which may well be related to the Selandian– earliest Thanetian regression suggested by Dickie et al. (2011), or the sediments in the samples are derived from cavings. The interval between 10,750 and 10,690 feet is thought to belong to the Valanginian– Albian volcanic Alexis Formation. The foraminiferal assemblages are, however, dominated by Late Cretaceous DWAF, and this suggests that this sequence may belong to either the Markland Formation or the transitional unit between the Bjarni and Markland formations described by Dickie et al. (2011). 88
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