complete successions of Albian to Santonian marine, terrigenous, clastic rocks; and (3) relatively thin (
faunal changes within these cores with local modern radiolarian distributions in surface sediments to determine how climatic changes over the last 500 ka may have affected oceanographic conditions and sea surface temperatures in this region. We utilise preliminary sea surface temperature (SST) determinations using the modern analogue technique (MAT) and a modern dataset of 31 core-top assemblages. For the coastal region represented by MD97-2121, the last deglaciation (15-10 ka BP) was characterised by progressive warming from 15°C to 17°C and decreasing biosiliceous accumulation. The interaction of the subtropical East Cape Current and subantarctic waters jetting northward through Mernoo Gap may have promoted biosiliceous productivity in this near-coastal region in glacial times. There is little evidence from radiolarians for cooling of surface waters during the intervals correlated with the Antarctic Cold Reversal or Younger Dryas. However, a warming pulse is identified close to the termination of the Younger Dryas, c. 11.5-10 ka. Peak warmth of 17°C at 9-4.5 ka is associated with the Holocene Climatic Optimum. For the oceanic regions represented by ODP 1123 and 1124, MAT estimates are coarse, reflecting a lack of close analogues to the assemblages at these sites in the local core-top dataset. Nevertheless, glacial-interglacial cycles are well-defined with SSTs falling to 14°C in glacials and rising to 17°C in interglacials – similar to the modern seasonal range. POSTER THE GREENHOUSE BEHIND THE LAB: WHAT KAIKOURA’S LIMESTONE TELLS US ABOUT THE CONSEQUENCES <strong>OF</strong> GLOBAL WARMING C.J. Hollis 1 ,C.P.Strong 1 ,G.J.Wilson 1 , G.R. Dickens 2 &M.Nicolo 2 1 GNS Science, PO Box 30 368, Lower Hutt 2 Dept of Earth Sciences, Rice University, Houston, TX 77005, USA (c.hollis*gns.cri.nz) Muzzle Group strata exposed in a narrow gully behind the University of Canterbury <strong>Kaikoura</strong> Field Station record deposition at the southern margin of the Marlborough sub-basin under a greenhouse climate between 70 and 50 million years ago. Upper Cretaceous micritic limestone of the Mead Hill Formation is unconformably overlain by a 7 m thick interval of Paleocene-Eocene Teredo Limestone, consisting of highly bioturbated glauconitic sandstone. This basal member of the Amuri Limestone is overlain by >20 m of lower Eocene Lower Marl, which consists of alternating beds of marl and micritic limestone. Correlation with similar successions in middle and northern Clarence River valley (Hollis et al. <strong>2005</strong>a, b) indicate that lithofacies changes reflect climatically induced variation in ocean circulation, oceanic productivity and terrigenous sediment supply across a bathyal carbonate ramp. While Paleocene erosion, glaucony, and condensed sedimentation occurred in proximal settings (<strong>Kaikoura</strong>, mid-Clarence valley), a thick succession of biosiliceous sediment was deposited in distal settings (northern Clarence valley). This implies vigorous ocean circulation and enhanced coastal upwelling during a period of relatively cool climatic conditions. Early Eocene deposition of thick marl-rich sedimentary successions throughout the sub-basin suggests sluggish circulation and reduced upwelling during a period of warm climatic conditions. Distinctive marl-dominated intervals that can be correlated across the sub-basin represent episodes of extreme warming, notably the Initial Eocene Thermal Maximum (55 Ma) and the Early Eocene Climatic Optimum (53-50 Ma). These intervals are characterised by light carbon isotope signatures, short-lived occurrences of warm-water calcareous nannoplankton, planktic foraminifera and radiolarians, and acmes of some warm-water taxa. A significant increase in terrigenous flux suggests that the extreme warmth caused increased precipitation and weathering in the terrestrial hinterland. These results are consistent with general circulation models for Eocene greenhouse conditions (560 ppm CO2) that place New Zealand within a transition zone between a warm, subtropical, oligotrophic gyre to the north and a cool, eutrophic, cyclonic gyre to the south. Within this regime, additional warming is predicted to cause southward expansion of the subtropical gyre and increase precipitation over the New Zealand landmass. Hollis, C.J.; Dickens, G.R.; Field, B.D.; Jones, C.J.; Strong, C.P. <strong>2005</strong>: The Paleocene-Eocene transition at Mead Stream, New Zealand: a southern Pacific record of early Cenozoic global change. Palaeogeography, Palaeoclimatology, Palaeoecology 215: 313-343. Hollis, C.J.; Field, B.D.; Jones, C.M.; Strong, C.P.; Wilson, G.J.; Dickens, G.R. <strong>2005</strong> (in press): Biostratigraphy and carbon isotope stratigraphy of uppermost Cretaceous-lower Cenozoic in middle Clarence valley, New Zealand. Journal of the Royal Society of New Zealand 35 (3): 39p. ORAL 50 th <strong>Kaikoura</strong>05 -37- <strong>Kaikoura</strong> <strong>2005</strong>
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