ARTICLE IN PRESS UNCORRECTED PROOF Calcareous dino£agellate associations and Maastrichtian^Tertiary climatic change in a high-latitude core (ODP Hole 689B, Maud Rise, Weddell Sea) 1 2 3 Tania Hildebrand-Habel a;b; Ã , Michael Streng b 4 a Department of Geology, University of Oslo, P.O.Box 1047 Blindern, 0316 Oslo, Norway b Geological Department, University of Bremen, P.O.Box 330440, 28334 Bremen, Germany 5 6 Received 12 October 2001; accepted 23 April 2003 7 8 Abstract 9 10 The distribution of calcareous dinoflagellates has been analysed for the Maastrichtian^Miocene interval of Ocean 11 Drilling Project Hole 689B (Maud Rise, Weddell Sea). The investigation thus represents a primary evaluation of the 12 long-term evolution in high-latitude calcareous dinoflagellate assemblages during the transition from a relatively 13 warm Late Cretaceous to a cold Neogene climate. Major assemblage changes during this interval occurred in 14 characteristic steps: (1) an increase in relative abundance of tangentially structured species ^ particularly 15 Operculodinella operculata ^ at the Cretaceous/Tertiary boundary; (2) a diversity decrease and several first and last 16 appearances across the Middle^Late Eocene boundary, possibly attributed to increased climate cooling; (3) a diversity 17 decrease associated with the dominance of Calciodinellum levantinum in the late Early Oligocene; (4) the reappearance 18 and dominance of Pirumella edgarii in the Early Miocene, probably reflecting a warming trend; (5) monogeneric 19 assemblages dominated by Caracomia spp. denoting strong Middle Miocene cooling. The results not only extend the 20 biogeographic ranges of many taxa into the Antarctic region, but also indicate that the evolution of high-latitude 21 calcareous dinoflagellate assemblages parallels the changing environmental conditions in the course of the Cenozoic 22 climate transition. Therefore, calcareous dinoflagellates contribute to our understanding of the biotic effects 23 associated with palaeoenvironmental changes and might possess the potential for reconstructing past conditions. The 24 flora in the core includes one new taxon: Caracomia arctica forma spinosa Hildebrand-Habel and Streng, forma nov. 25 Additionally, two new combinations are proposed: Fuettererella deflandrei (Kamptner, 1956) Hildebrand-Habel and 26 Streng, comb. nov. and Fuettererella flora (Fu « tterer, 1990) Hildebrand-Habel and Streng, comb. nov. 27 ß 2003 Published by Elsevier Science B.V. 28 29 Keywords: calcareous dino£agellates; Cretaceous; Tertiary; climate change; high latitudes 30 31 1. Introduction 32 Dino£agellates are generally unicellular algae 33 that live in most aquatic environments. As part 34 of their life-cycle, some dino£agellates produce 35 ‘dinosporin’ cysts that may be fossilised (so-called 1 0031-0182 / 03 / $ ^ see front matter ß 2003 Published by Elsevier Science B.V. 2 doi:10.1016/S0031-0182(03)00470-X * Corresponding author. Fax: +47-22854215. E-mail address: hiha@geologi.uio.no (T. Hildebrand-Habel). 4 3 2 1 Palaeogeography, Palaeoclimatology, Palaeoecology 3155 (2003) 1^29 www.elsevier.com/locate/palaeo