www.pages-igbp.org Understanding sea level: Ways forward from the past Vol 17 No 2 June 2009 Editors: Mark Siddall, William G. Thompson, Claire Waelbroeck and Louise Newman ne w s Are tropical corals the key to understanding past changes in polar ice volume? What role do they have to play in helping us better understand the future? This issue of PAGES news highlights current research that aims to address these and other questions on past changes in sea level, and the implications for predictions of future sea level rise.
50 Announcements 06 07 Jul 2009 Corvallis, USA PAGES 1 st Young Scientists Meeting: Retrospective Views on Our Planet's Future 08 11 Jul 2009 Corvallis, USA PAGES 3 rd Open Science Meeting: Retrospective Views on Our Planet's Future 24 27 Aug 2009 Mytilene, Greece 2 nd Past Interglacials (PIGS) Workshop 21 25 Sep 2009 Woods Hole, USA Understanding future sea level rise: The challenges of dating past interglacials 02 05 Nov 2009 Hyres-les-Palmiers, France 1 st ADOM workshop: High-mid latitude northern atmospheric circulation changes during the last climate cycle PAGES Calendar 2009 Nominations for the PAGES SSC News from other SSCs EGU Medals Inside PAGES PAGES YSM & OSM update Polar Paleoscience addendum PAGES news Next issue of PAGES news Tales from the...eld? PAGES news
PAGES News Editorial Editorial: Past ice sheet dynamics and sea levelplacing the future in context MARK SIDDALL 1 WILLIA M G. THO M P S ON 2 AND CLAIRE WAELBROE C K 3 1 Department of Earth Sciences, University of Bristol, UK; firstname.lastname@example.org 2 Department of Geology and Geophyiscs, Woods Hole Oceanographic Institution, USA; 3 Laboratory of Climate and Environmental Sciences, Pierre-Simon Laplace Institute, Atomic Energy Commissariat, National Centre of Scientic Research, Gif-sur-Yvette, France. PAGES news New questions for paleodata are driven by the limitations of the modern-only approach Lessons for the future from paleoarchives Figure 1: Changes in elevation over the Greenland Ice Sheet between 2003 and 2006 from the ICESat elevation satellite. Thickening is shown in white and thinning is shown in blue while gray indicates no change. Care must be taken in considering the implications of this imagechanges in height do not necessarily translate to changes in mass because ice can melt, lose trapped air and refreeze in a denser conguration. The observation of a large, opaque object is inevitably dicult and indirect. Furthermore, the short duration of such observations places limits on the weight one can place on these observations. Paleo sea level and ice sheet reconstructions can help plug some of these gaps. Credit: NASA/Goddard Space Flight Center Scientic Visualization Studio. The Next Generation Blue Marble data is courtesy of Reto Stockli (NASA/GSFC).
Science Highlights: Paleo Sea Level Recent Antarctic and Greenland ice-mass uxes from satellite observations and their signicance JONA T HAN BA M BER Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, UK; email@example.com Understanding contemporary ice sheet behavior is crucial for estimating future trends but the useful satellite observation period of ~20 years is too short. Paleodata, especially from the Holocene, have the potential to help us interpret the contemporary observations. Figure 1: Estimates of the mass balance of the West (WA) and East (EA) Antarctic ice sheets (gigatonnes per year, Gt/a) from a variety of observations and authors. The width of the bars indicates the time period for the estimate and the thickness represents the uncertainty. Zwally et al., (2005) is estimated from satellite radar altimetry. Helsen et al., (2008) is a reassessment of radar altimetry data using a rn compaction model driven by climate model data. (Rignot et al.,, 2008) is from mass budget estimates combining velocity and thickness data with modeled snowfall. Chen et al., 2006, Ramillien et al., 2006, Velicogna and Wahr, 2006 are from gravity measurements from GRACE (Gravity Recovery and Climate Experiment). PAGES news Note For more information on the PALSEA Work ing Group please visit www.climate.unibe. ch/~siddall/working_group.html References Alley, R.B., Clark, P.U., Huybrechts, P. and Joughin, I., 2005: Ice-sheet and sea-level changes, Science 310 : 456-460. Fleming, K., Johnston, P., Zwartz, D., Yokoyama, Y., Lambeck, K. and Chappell, J., 1998: Rening the eustatic sea-level curve since the Last Glacial Maximum using farand intermediate-eld sites, Earth and Planetary Science Letters 163 (1-4): 327-342. DOI:10.1016/S0012-821X(98)00198-8 (). Gregory, J.M., Lowe, J.A. and Tett, S.B.T., 2006: Simulated global-mean sea-level changes over the last half-millennium, Journal of Cli matology 19 (18): 4576-4591. IPCC, 2007: Summary for Policymakers. In: Solomon, S. et al., (Eds), Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergov ernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, USA. PALSEA, 2009: The sea-level conundrum case studies from paleoarchives, Journal of Quaternary Science in press. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
PAGES News Science Highlights: Paleo Sea Level Figure 2: Surface topography ( gray ) and surface-ice velocities (m/a) ( colored ) for the West (WAIS) and East (EAIS) Antarctic Ice Sheet, indicating the locations of the ice streams and outlet glaciers along the margins of the ice sheet. Pine Island Glacier (PIG) and Thwaites Glacier (TWG) are responsible for the majority of the mass loss in the Amundsen Sea Sector (ASS) of West Antarctica (Rignot and others, 2008). Also shown are the Ross and Filchner Ronne Ice Shelves (FRIS). Figure 3: Landsat TM image of Jakabshavn Isbrae from 1996 showing the oating tongue and calving positions and velocities at various dates during the period of speed-up of the glacier, which is the largest (by discharge volume) in Greenland (Joughin et al., 2004). Figure courtesy K. Steen.
Science Highlights: Paleo Sea Level U-series dating of fossil coral reefs: Consensus and controversy MOR T EN B ANDER S EN 1 C.D GALLUP 2 D SC HOLZ 3 C.H. ST IRLIN G 4 AND W.G. THO M P S ON 5 1 Department of Earth Sciences, University of Bristol, UK; 2 Department of Geological Sciences, University of Minnesota Duluth, USA; 3 School of Geographical Sciences, University of Bristol, UK; 4 Department of Chemistry, University of Otago, New Zealand; 5 Department of Geology and Geophysics, Woods Hole Oceanographic Institution, USA; firstname.lastname@example.org New developments in U-series coral dating are sparking a healthy debate over how best to interpret coral ages from older fossil coral reefs, reinvigorating research in sea level changes during previous interglacial periods, and fostering a new appreciation of the challenges ahead. Identifying reliable coral ages Seawater 234 U/ 238 U References Bamber, J.L., Alley R.B. and Joughin I., 2007: Rapid response of modern day ice sheets to external forcing, Earth and Planatary Science Letters 257 : 1-13. Bindschadler, R., 2006: The environment and evolution of the West Ant arctic ice sheet: setting the stage, Philosophical Transactions of the Royal Society A: Mathematical Physical and Engineering Sci ences 364 (1844): 1583-1605. Huybrechts, P. and de Wolde, J., 1999: The dynamic response of the Greenland and Antarctic ice sheets to multiple-century climatic warming, Journal of Climate 12 (8): 2169-2188. Joughin, I., Abdalati W. and Fahnestock, M., 2004: Large uctuations in speed on Greenland's Jakobshavn Isbrae glacier, Nature 432 (7017): 608-610. Shepherd, A. and Wingham, D., 2007: Recent sea-level contributions of the Antarctic and Greenland ice sheets, Science 315 (5818): 1529-1532. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
55 PAGES News Science Highlights: Paleo Sea Level Error estimation and modeldependent sensitivities Figure 1: U/Th activity ratio diagram illustrating the major processes aecting U-series dating of older corals. The blue arc represents the range of closed-system isotopic compositions expected for corals that are approx. 65 to 165 ka and have evolved from a modern seawater uranium isotope composition. Each point along this arc cor responds to a unique U/Th age. The large black circle is the expected isotopic composition of a coral that is 105 ka old. The adsorption/loss of decay-produced 234 Th and 230 Th from/to the surrounding carbonate matrix will produce a range of compositions in the direction of the red arrows. U or Th gain or loss will produce a range of compositions in the direction of the black arrows. The open blue circles are isotopic compositions of a suite of corals collected from the MIS 5c terrace on Barbados, West Indies, which should all be near 105 ka in age. The changes in isotopic composition due to these processes are a signicant source of age error. Stratigraphic context Standardizing age and error conventions
Science Highlights: Paleo Sea Level References Andersen, M.B., Stirling, C.H., Potter, E.-K., Halliday, A.N., Blake, S.G., McCulloch, M.T., Ayling, B.F. and O'Leary, M. 2008: High-preci sion U-series measurements of more than 500,000 year old fossil corals, Earth and Planetary Science Letters 265 : 229-245. Gallup, C.D., Edwards, R.L. and Johnson, R.G. 1994: The timing of high sea levels over the past 200,000 years, Science 263 : 796-800. Potter, E.-K., Esat, T.M., Schellmann, G., Radtke, U., Lambeck, K. and McCulloch, M.T. 2004: Suborbital-period sea-level oscillations during marine isotope substages 5a and 5c, Earth and Planetary Science Letters 225 (1-2): 191-204. Scholz, D. and Mangini, A. 2007: How precise are U-series coral ages? Geochimica et Cosmochimica Acta 71 : 1935-1948. Thompson, W.G., Spiegelman, M.W., Goldstein, S.L. and Speed, R.C. 2003: An open-system model for the U-series age determina tions of fossil corals, Earth and Planetary Science Letters 210 : 365-381. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html Using models to inform the eld community: Far-eld sea level data applications GLENN A. MILNE Department of Earth Sciences, University of Ottawa, Canada; email@example.com Far-eld sea level data contain information on past global ice volume and the source distribution of meltwater pulses. To extract this information in an accurate and eective manner requires site selection that is informed by model output. Inferring past global ice volume Figure 1: Output for a large suite of model runs based on a single ice model and 162 Earth viscosity models. Results are shown for the Last Glacial Maximum (LGM; 21 cal ka BP). White contours indicate where the (mean) predicted sea level is equal to (mean) eustatic sea level. Black contours indicate where these values deviate by 3 m (deviations > 3 m are masked by the light-gray shading). Colored contours show standard deviation of the predictions due to changes in Earth viscosity structure. Values of low standard deviation (blue colors) indicate where model predic tions are insensitive to variations in Earth viscosity structure. Optimal localities for measuring sea level to estimate past ice volume are where the predicted sea level is close to the eustatic value (i.e., near the white contour) and the standard deviation is low (i.e., blue colors). Three locations where LGM sea levels have been measured are shown: Barbados (Ba), Bonaparte Gulf (Bo) and Sunda Shelf (Su). See Milne and Mitrovica (2008) for more details.
PAGES News Science Highlights: Paleo Sea Level Inferring distribution of rapid ice mass loss during meltwater pulses Summary References Clark, J.A., Farrell, W.E. and Peltier, W.R., 1978: Global changes in post glacial sea level: a numerical calculation, Quaternary Research 9 : 265. Clark, P.U., Mitrovica, J.X., Milne, G.A. and Tamisiea, M., 2002: Sea-level ngerprinting as a direct test for the source of global meltwater pulse 1A, Science 295 : 2438. Farrell, W.E. and Clark, J.A., 1976: On postglacial sea-level, Geophysical Journal of the Royal Astronomical Society 46 : 647. Fleming, K., Johnston, P., Zwartz, D., Yokoyama, Y., Lambeck, K. and Chappell, J., 1998: Rening the eustatic sea-level curve since the Last Glacial Maximum using farand intermediate-eld sites, Earth and Planetary Science Letters 163 (1-4): 327-342. Milne, G.A. and Mitrovica, J.X., 2008: Searching for eustasy in deglacial sea-level histories, Quaternary Science Reviews 27 : 2292-2302. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html Figure 2: Sea level predicted at 6 sites (color-coded) for 7 distinct melt source scenarios (x-axis). Each line shows the sea level rise predicted at a given location for the 7 source scenarios considered. This information can be used to choose sites that would be eective in better constraining the melt-source distribution of meltwater pulse IA. Good sites for discriminating between dierent scenarios are those that exhibit a large dierence in predicted rise compared to other sites. For example, precise data from the Argentine Shelf would provide a powerful test of an Antarctic source scenario. Note, the predicted rise has been divided by the model eustatic value so that the results can be applied to ngerprint any rapid melt event regardless of magnitude. For example, an event of ice volume loss equivalent to 10 m eustatic rise would result in a sea level rise of ~8 m (i.e., ~80% of the eustatic value) at the Argentine Shelf for an Antarctic source. See Clark et al. (2002) for more details.
Science Highlights: Paleo Sea Level PLIOMAX: Pliocene maximum sea level project MAUREEN E RAY M O 1 P HEAR T Y 2 R. DE CON T O 3 M. O LEARY 4 H.J. DO WS E TT 5 M.M. ROBIN S ON 5 AND J.X. MI T ROVI C A 6 1 Department of Earth Sciences, Boston University, Massachusetts, USA; firstname.lastname@example.org 2 Bald Head Island Conservancy and Department of Environmental Studies, University of North Carolina, USA; 3 Department of Geosciences, University of Massachusetts-Amherst, USA; 4 Department of Environmental and Geographical Sciences, Manchester Metropolitan University, UK; 5 U.S. Geological Survey, Reston Virginia, USA; 6 Department of Physics, University of Toronto, Canada Accurate estimates of mid-Pliocene sea levels are necessary if we are to better constrain Greenland and Antarctic ice sheet stability in a warmer world. The mid-Pliocene warm period Figure 1: Ice-volume record for the Plio-Pleistocene using the LR04 benthic 18 O stack and timescale (Lisiecki and Raymo, 2005). Geomagnetic reversal stratigraphy is shown above the x-axis. PLIOMAX will target three super-interglacial events, G17, K1 and KM3 (orange bars) that are well constrained by magnetoand biostratigraphy. Oxygen isotope inferred sea level changes, assuming no temperature, salinity, diagenetic, or vital eect overprints are shown on the scale on the right.
PAGES News Science Highlights: Paleo Sea Level Modeling Pliocene ice sheets Summary Figure 2: Ice elevations (grounded) and ice thickness (oating) in meters, for present day ( A ) and during a Pliocene interglacial ( B ) as simulated by an ice sheet-shelf model (Pollard and DeConto, 2009). The model is driven by a parameterized climatology and oceanic sub-ice melt rates derived from deep-sea core isotope records (Lisiecki and Raymo, 2005) and local insolation. The loss of ice in B is equivalent to ~7 m of sea level rise, far less than that required to account for some Pliocene sea level estimates. References Chandler, M., Rind, D. and Thompson, R., 1994: Joint investigations of the Middle Pliocene climate II: GISS GCM Northern Hemisphere results, Global Planetary Change 9 : 197. Dowsett, H.J., 2007: The PRISM Palaeoclimate Reconstruction and Pliocene Sea-Surface Temperature. In: M. Williams, et al. (Eds) Deep-time perspectives on climate change: marrying the signal from computer models and biological proxies The Micropalae ontological Society Special Publications, The Geological Society of London. Haywood, A.M. and Valdes, P.J., 2004: Modelling Middle Pliocene warmth: contribution of atmosphere, oceans and cryosphere, Earth Planetary Science Letters 218 : 363. Lisiecki, L.E. and Raymo, M.E., 2005: A Pliocene-Pleistocene stack of 57 globally distributed benthic 18 O records, Paleoceanography 20 : PA1003, doi:10.1029/2004PA001071. Pollard, D. and DeConto, R.M., 2009: Modeling West Antarctic Ice Sheet growth and collapse through the last 5 million years, Nature 458 : 329-332. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
Science Highlights: Paleo Sea Level The dimensions of the Greenland Ice Sheet since the Last Glacial Maximum MEREDI T H A. KELLY 1 AND AN T ONY J. LON G 2 1 Department of Earth Sciences, Dartmouth College, Hanover, USA; Meredith.A.Kelly@Dartmouth.edu 2 Department of Geography, Durham University, UK The Greenland Ice Sheet survived the warming of the last deglaciation but nonetheless has experienced signicant changes in size since the Last Glacial Maximum, thus contributing to global sea level change. The Greenland Ice Sheet during the LGM and last deglaciation Figure 1: Map of Greenland showing the modern ice sheet extent and locations discussed in the text. Geographical divisions are generally following the Geological Survey of Denmark and Greenland (Dawes and Glendal, 2007). Also shown is Kjoveland, the location of the photo in Figure 2.
PAGES News Science Highlights: Paleo Sea Level Late glacial & early Holocene ice sheet readvances and stand-stills The Greenland Ice Sheet during the Holocene References Bennike, O. and Bjrck, S., 2002: Chronology of the last deglaciation of Greenland, Journal of Quaternary Science 17 : 211-219. Hall, B.L., Baroni, C., Denton, G.H., Kelly, M.A. and Lowell, T.V., 2008a: Relative sea-level Change, Kjove Land, Scoresby Sund, East Greenland: Implications for seasonality in late-glacial time, Qua ternary Science Reviews 27 : 2283-2291. Kelly, M.A., Lowell, T.V., Hall, B.L., Schaefer, J.M., Goehring, B.M., Alley, R.B. and Denton, G.H., 2008: A 10 Be chronology of late-glacial and Holocene mountain glaciation in the Scoresby Sund region, east Greenland: Implications for seasonality during late-glacial time, Quaternary Science Reviews 27 : 2273-2282. Long, A.J., Roberts, D.H., Simpson, M.J.R., Dawson, S., Milne, G.A. and Huybrechts, P., 2008: Late Weichselian relative sea-level changes and ice sheet history in southeast Greenland, Earth and Planetary Science Letters 272 : 8-18. Roberts D.H., Long, A.J., Schnabel, C., Freeman, S. and Simpson, M.J.R., 2008: The deglacial history of the southeast sector of the Green land Ice Sheet during the Last Glacial Maximum, Quaternary Sci ence Reviews 27 : 1505-1516. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html Figure 2: Milne Land stage (left lateral) moraines deposited by a Greenland Ice Sheet outlet glacier prior to or during the Younger Dryas in the Scoresby Sund region of Central East Greenland. View to the east over Kjoveland.
Science Highlights: Paleo Sea Level Extending the uranium-series dating of fossil coral reefs back to marine isotope stage 15 CLAUDINE H. ST IRLIN G 1 AND MOR T EN B ANDER S EN 2 1 Department of Chemistry, University of Otago, New Zealand; email@example.com 2 Department of Earth Sciences, University of Bristol, UK. Recent advances in U-series isotopic analysis allow absolutely dated records of past sea level change to be extended back through the last 600 ka, and oer decadalto millennial-scale resolution for the last 400 ka. Gearing up towards a highprecision chronometer Figure 1: A ) Typical representation of U-series observations for fossil coral reefs, whereby 234 U/ 238 U is plotted against 230 Th/ 238 U and contoured in units of U-series age (near vertical lines). 234 U/ 238 U is reformulated into 234 U-notation as the permil deviation away from radioactive equilibrium, and 230 Th/ 238 U is reformulated into the activity ratio [ 230 Th/ 238 U] act (e.g., Edwards et al., 2003). For fossil corals, the U-series chronometer is based on the radioactive decay of 234 U (half-life = 245 ka) and radioactive in-growth of 230 Th (half-life = 76 ka) toward radioactive equilibrium with 238 U. The initial 234 U = 147 contour (red line) gives the closed-system evolution path for a coral, assuming a 234 U composition of 147 (identical to present-day seawater) and no 230 Th at the time the coral formed, and no postdepositional loss/gain of 238 U, 234 U and 230 Th other than by radioactive decay. A living coral would plot at position (a), whereas older 125 ka and 225 ka fossil corals would plot at positions (b) and (c) respectively, as shown by the three data points (green squares). The three data points (measured with identical levels of precision) also demonstrate that the resolution of the U-series chronometer decreases with increasing sample age as the separation between isochrons (orange lines) decreases. If the U-series system becomes open at any time, the isotopic composition of the coral will move away from the closed-system curve and will follow a new decay path, assuming the system remains closed afterward. B ) Compilation of published U-series observations pre-dating the last glacial cycle from reef complexes in Barbados (circles) and Henderson Island (squares) displayed as 234 U versus [ 230 Th/ 238 U] act The initial 234 U = 147 contour denoting the closed-system evolution path for a coral is shown for reference (red line). The majority of data plot above this curve due to open-system exchange of the U-series isotopes during diagenetic alteration and therefore yield unreliable U-series ages. The error bars are 2.
PAGES News Science Highlights: Paleo Sea Level 5 Figure 2: A compilation of sea level and climate records for MIS 9: Summer solar insolation predictions for latitude 65 N ( red line ), which according to the Milankovitch theory of climate change (Milankovitch, 1941), drive Qua ternary glacial-interglacial climate variability; LR04 deep-sea sediment 18 O record ( blue line ; Lisiecki and Raymo, 2005), which comprises a stack of 57 globally distributed deep-sea 18 O records, and provides a combined signal of deep-ocean temperature and global sea level for the past 5.3 Ma. The Pliocene-Pleistocene section of the record has been assigned a chronology based on orbital tuning to Milankovitch insolation predictions; D for the EPICA deep ice core from Dome C, Antarctica ( black line ; EPICA, 2004), which provides a proxy record of local air temperature for the past 740 ka. The chronology for the EPICA record has been derived using ice ow modeling, constrained by radiometric control points based upon Milankovitch orbital forcing theory; high-resolution global sea level recon structions derived from the 18 O signatures of two independent Red Sea sediment cores (dark and light green lines ; Siddall et al., 2003). The 18 O records were translated into global sea level using a complex hydraulic model for the exchange of water between the Red Sea and the open ocean. A chronology was assigned to the Red Sea records based on a combination of radiometric control points and synchronization with orbitally-tuned Antarctic ice core records; relative sea level observations based on the height-U-series age relationships of fossil corals sampled from Henderson Islands MIS 9 reef complexes but uncorrected for lithospheric exural uplift and glacio-hydro-isostasy, are shown by the horizontal bars. Conventional U-series ages assessed as reliable on the basis of macroscopic and isotopic screening criteria are denoted by the black bars (Stirling et al., 2001); open-system U-series ages for other reef complexes that have been corrected for U-series isotopic shifts caused by diagenetic alteration using the open-system U-series model of Thompson et al. (2003) are represented by the gray bars ; U-series observations for speleothems from the Bahamas ( purple ) constrain the timing of the MIS 8/9 glacial-interglacial transition (Homann et al., 2007); Bahamian aragonitic slope sediments ( orange ) suggest an early onset for the initiation of MIS 9 (Henderson et al., 2006), which is contrary to the coral reef observations.
Science Highlights: Paleo Sea Level Ice sheet retreat and sea level rise during the last deglaciation PE T ER U CLARK Department of Geosciences, Oregon State University, Corvallis, USA; firstname.lastname@example.org The terrestrial record of deglaciation provides important constraints on the relative contribution of individual ice sheets to global sea level rise, thus improving our ability to estimate sea level sensitivity to climate change. Sea level records pre-dating the last glacial cycle References Andersen, M.B., Stirling, C.H., Potter, E.K., Halliday, A.N., Blake, S.G., Mc Culloch, M.T., Ayling, B.F. and O'Leary, M., 2008: High-precision U-series measurements of more than 500,000 year old fossil cor als, Earth and Planetary Science Letters 265 : 229-245. Edwards, R.L., Cutler, K.B., Cheng, H. and Gallup, C.D., 2003: Geochemi cal Evidence for Quaternary Sea-level Changes. In: Turekian, K.K. and Holland, H.D. (Eds) Treatise on Geochemistry Elsevier, 6.13 : 343-364. Goldstein, S.J. and Stirling, C.H., 2003: Techniques for measuring ura nium-series nuclides: 1992-2002. In: Bourdon, B. et al., (Eds) Reviews in Mineralogy and Geochemistry Geochemical Society, 52 : 23-57. Stirling, C.H., Esat, T.M., Lambeck, K., McCulloch, M.T., Blake, S.G., Lee, D.-C. and Halliday, A.N., 2001: Orbital forcing of the Marine Iso tope Stage 9 interglacial, Science 291 : 290-293. Thompson, W.G. and Goldstein, S.L., 2005: Open-system coral ages reveal persistent suborbital sea-level cycles, Science 308 : 401404. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
PAGES News Science Highlights: Paleo Sea Level Figure 1: A ) The last deglaciation relative sea level record (RSL) reconstructed from geomorphic and biological indicators at sites far from the former large ice sheets and compared to the retreat of the Laurentide Ice Sheet (LIS; black line) (Dyke, 2004). Symbols are coded to individual sites as follows: Green lines are Bonaparte Gulf calibrated 14 C ages (Yokoyama et al., 2000) showing age and depth uncertainty, Gray diamonds are U/Th ages on Barbados corals from core RGF-9 (Bard et al., 1993; Peltier and Fairbanks, 2006). Sunda Shelf calibrated 14 C ages are shown as pink lines (non-mangrove organics), light blue lines (mangrove remains, not in situ), and dark blue lines (mangrove remains in situ) (Hanebuth et al., 2000), Orange triangles are U/Th ages on corals from New Guinea (Edwards et al., 1993; Cutler et al., 2003), Light green triangles are U/Th ages on corals from Tahiti (Bard et al., 1996). B ) Detail of sea level history and LIS deglaciation between 21.5 ka and 16.8 ka, using same symbols as in A). Also shown are Barbados corals from core RGF-15 (red squares), including the species Montastrea annularis (Peltier and Fairbanks, 2006). C ) Detail of sea level history and LIS deglaciation between 19 ka and 14.5 ka using same symbols as in A). Also shown is the CaCO 3 component of ice-rafted debris, showing a peak at the time of Heinrich event 1 (H1; Bond et al., 1999). D ) Detail of sea level history and LIS deglaciation between 15 ka and 13 ka using same symbols as in A). The Barbados coral samples from cores RGF-9 and RGF-12 are identied. Montastrea annu laris
Science Highlights: Paleo Sea Level A new chronology of sea level highstands for the penultimate interglacial ANDREA DU TT ON 1 F. AN T ONIOLI 2 AND E BARD 3 1 Research School of Earth Sciences, Australian National University, Canberra; email@example.com 2 Italian National Agency for New Technologies, Energy and Environment, Rome, Italy; 3 European Center for Research and Teaching of Geosci ences and the Environment, National Center of Scientic Research and Aix-Marseille University, College de France, Aix-en-Provence, France A suite of submerged Italian speleothems constrain the timing of sea level highstands across the entirety of marine isotope stage 7 (~190-245 ka) indicating that sea level highstands were broadly in phase with insolation forcing. Figure 1: Sea level curves shown for MIS 7, derived using three dierent methods: ( a ) model (Bintanja et al., 2008) driven by benthic oxygen isotope ( 18 O) stack, ( b ) reconstruction of Red Sea seawater 18 O (Siddall et al., 2003), ( c ) open system U-Th ages of corals (Thompson and Goldstein, 2005). Shading indicates periods of time that sea level rose above -20 m (dashed lines), the approx. depth of Argentarola Cave stalagmites. Note dierences in the number of highstands predicted to exceed -20 m and the dierence in elevation predicted for MIS 7.3 in particular. Figure modied from Dutton et al., 2009. References Bassett, S.E., Milne, G.A., Mitrovica, J.X. and Clark, P.U., 2005: Ice sheet and solid earth inuences on far-eld sea level histories, Science 309 : 925-928. Clark, P.U., Mitrovica, J.X., Milne, G.A. and Tamisiea, M., 2002: Sea level ngerprinting as a direct test for the source of global meltwater pulse IA, Science 295 : 2438-2441. Clark, P.U., McCabe, A.M., Mix, A.C. and Weaver, A.J., 2004: The 19-kyr B.P. meltwater pulse and its global implications, Science 304 : 1141-1144. Dyke, A.S., 2004: An outline of North American Deglaciation with em phasis on central and northern Canada, In: Ehlers, J. and Gibbard, P.L. (Eds), Quaternary Glaciations: Extent and Chronology Elsevier, 373-424. Milne, G.A. and Mitrovica, J.X., 2008: Searching for eustasy in deglacial sea level histories, Quaternary Science Reviews 27 : 2292-2302. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
PAGES News Science Highlights: Paleo Sea Level Figure 2: Comparison of Argentarola submerged stalagmite data (Agentarola stalagmite N, E, and I: ASN, ASE, ASI) with other relative sea level records across MIS 7. Speleothem U-Th data represent growth periods and should be above the sea level curve, whereas coral data should be just below the curve; Solid lines connecting these U-Th ages represent periods of uninterrupted growth. Error bars for samples next to hiatuses are shown as dashed lines Peak MIS 7.5 coral data were assumed to sit at modern sea level (Thompson and Goldstein, 2005). The remainder of the Barbados coral elevations are calculated assuming constant uplift rates, which introduces some error into the elevation estimates. Gray data points are heavily altered corals ( 234 U initial > 330); blue data points in circle are beach cobbles. Closed-system ages are shown for corals with 234 U inital within 2 of seawater. TIII = Termination III. Figure modied from Dutton et al., 2009.
Science Highlights: Paleo Sea Level Figure 3: Sea level and climate reconstructions during MIS 7. Sea level highstands at Argentarola denoted by vertical gray bars. ( a ) Obliquity, and ( b ) summer insolation curves at 65 N (JJA) (maxima shown by dotted lines in MIS 7) and 70 S (DJF) (Laskar, 1990), ( c ) Iberian Margin benthic carbon isotope ( 13 C) data (Martrat et al., 2007) highlights the unusual nature of MIS 7.3, ( d ) benthic 18 O stack (Lisiecki and Raymo, 2005: black) and benthic 18 O from the Iberian Margin (Martrat et al., 2007: blue), ( e ) sea level reconstructions (Siddall et al., 2003; Bintanja et al., 2008: dashed and solid orange lines, respectively), ( f ) compiled Antarctic ice core CO 2 (Lthi et al., 2008), ( g ) EPICA Dome C temperature change (Jouzel et al., 2007). TII and TIII = Terminations. Data sources as follows:  Henderson et al., 2006;  Robinson et al., 2002;  Gallup et al., 1994;  Edwards et al., 1997;  Thompson and Goldstein, 2005;  Andersen, 2006;  Sptl et al., 2008;  Dutton et al., 2009. Figure modied from Dutton et al., 2009. Tempo of global deglaciation during the early Holocene: A sea level perspective SHI-YON G YU, Y .-X. LI AND T. E TRNQVI ST Department of Earth and Environmental Sciences, Tulane University, New Orleans, USA; firstname.lastname@example.org High-resolution early Holocene sea level records are essential to aid predictions of future sea level change. However, our current understanding about the nonlinear response of sea level to rapid climate changes during this critical time interval is still in its infancy. Acknowledgements We would like to thank T. Esat, K. Lambeck and M. McCulloch for their contributions to the work discussed here, and also J. Desmarchelier, L. Kin sley and G. Mortimer for analytical assistance. Data Information Data are available in online supplemental ma terial associated with Dutton et al. (2009) Na ture Geoscience at http://dx.doi.org/10.1038/ NGEO470 References Antonioli, F., Bard, E., Potter, E.-K., Silenzi, S. and Improta, S., 2004: 215ka History of sea level oscillations from marine and continental layers in Argentarola cave speleothems (Italy), Global and Plan etary Change 43 : 57-78. Bard, E., Antonioli, F. and Silenzi, S., 2002: Sea level during the penulti mate interglacial period based on a submerged stalagmite from Argentarola Cave (Italy), Earth and Planetary Science Letters 196 : 135-146. Dutton, A., Bard, E., Antonioli, F., Esat, T.M., Lambeck, K. and Mc Culloch, M.T., 2009: The phasing and amplitude of climate and sea level during the penultimate interglacial, Nature Geoscience doi:10.1038/NGEO470. Lea, D.W., Martin, P.A., Pak, D.K. and Spero, H.J., 2002: Reconstructing a 350 ky history of sea level using planktonic Mg/Ca and oxygen isotope records from a Cocos Ridge core, Quaternary Science Re views 21 : 283-293. Siddall, M., Rohling, E.J., Almogi-Labin, A., Hemleben, C., Meischner, D., Schmelzer, I. and Smeed, D.A., 2003: Sea level uctuations dur ing the last glacial cycle, Nature 423 : 853-858. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
PAGES News Science Highlights: Paleo Sea Level Figure 1: Comparison of Holocene relative sea level (RSL; height of sea level relative to the present-day datum) records from near-eld ( purple ; Yu et al., 2007), intermediate-eld ( green ; Trnqvist et al., 2006; plus unpublished data), and far-eld ( red ; Horton et al., 2005); Blue plot shows rate of sea level rise from the decay of the Laurentide Ice Sheet (LIS; Carlson et al., 2008). Vertical blue bar highlights the period of sea level rise dominated by the ice-volume component; yellow bar highlights a rapid sea level rise event centered on 7.6 cal ka BP in the Baltic Sea record. Conventional wisdom and current knowledge gap High-resolution (centennial) sea level records: A key to the future
Science Highlights: Paleo Sea Level Figure 2: A ) A sedimentary sequence including a paleosol (fossil soil) that caps the Pleistocene substrate, basal peat and lagoonal mud from the Mississippi Delta. Note the sharp contact (arrow) between the ~2 cm thick peat layer and the overlying lagoonal mud, which represents an abrupt sea level rise at ca. 8.2 cal ka BP. B ) Stratigraphic signature of the abrupt sea level rise at ca. 8.2 cal ka BP at Bayou Sale, Mississippi Delta (Trnqvist et al., 2004). The occurrence of Rangia cuneata a brackish water clam characteristic of estuarine and lagoonal environments, is also shown. Coastal vegetation evidence for sea level changes associated with Heinrich Events CA T ALINA GONZLEZ AND LYDIE M. DUPON T MARUM Centre for Marine Environmental Sciences, Geosciences Department, University of Bremen, Germany; email@example.com A Cariaco Basin pollen record shows the development of tropical salt marshes during marine isotope stage 3 and suggests that millennial sea level changes during the periods encompassing Heinrich Events followed Antarctic climate variability. References Carlson, A.E., Legrande, A.N., Oppo, D.W., Came, R.E., Schmidt, G.A., Anslow, F.S., Licciardi, J.M. and Obbink, E.A., 2008: Rapid early Holocene deglaciation of the Laurentide ice sheet, Nature Geosci ence 1 : 620-624. Kendall, R.A., Mitrovica, J.X., Milne, G.A., Trnqvist, T.E. and Li, Y., 2008: The sea level ngerprint of the 8.2 ka climate event, Geology 36 : 423-426. Trnqvist, T.E., Bick, S.J., Gonzalez, J.L., van der Borg, K. and de Jong, A.F.M., 2004: Tracking the sea level signature of the 8.2 ka cool ing event: New constraints from the Mississippi Delta, Geophysi cal Research Letters 31 : L23309. Trnqvist, T.E., Bick, S.J., van der Borg, K. and de Jong, A.F.M., 2006: How stable is the Mississippi Delta? Geology 34 : 697-700. Yu, S.-Y., Berglund, B.E., Sandgren, P. and Lambeck, K., 2007: Evidence for a rapid sea level rise 7600 yr ago, Geology 35 : 891-894. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
PAGES News Science Highlights: Paleo Sea Level Figure 1: Left main ecological preferences of 3 salt marsh taxa. Right schematic representation of salt marsh community dynamics in a changing sea level environment according to the Cariaco Basin pollen record (Gonzlez and Dupont, 2009). Thicker black lines indicate areas of soil hypersalinity. SL 1 to SL4 denote dierent sea levels reconstructed from the pollen record and correspond with phases indicated in Fig. 2. a ) Establishment of salt marshes when arid conditions promote extensive hypersaline environments; b ) rapid sea level rise causes erosion; only pioneer species tolerate the change; c ) sea level rise decelerates, and accretion of sediments and autochthonous organic material takes place; more competitive species take advantage of favorable conditions; d ) sea level drops, sediment accumulation constrains the tidal inuence to the seaward edge. Tropical salt marsh response to millennial climate and sea level changes The pollen record Atriplex Salicornia
Science Highlights: Paleo Sea Level Figure 2: Comparison of the high-resolution palynological record from core MD03-2622 (Cariaco Basin) with sea level reconstructions from Red Sea marine sediment cores and Huon Peninsula (Papua New Guinea) fossil corals during HE 4 (Gonzlez and Dupont, 2009). Top to bottom: Reectance data from core MD03-2622 (Laj, 2004). Sea level data; dark blue line central Red Sea (Siddall et al., 2003; 2008), light blue line northern Red Sea (Arz et al., 2007), and dotted pink line Huon Peninsula (Thompson and Goldstein, 2006). Pollen % of Chenopodiaceae, Poaceae, and Cyperaceae indicating the directional alternation of salt marsh species during HE4. Dotted gray lines SL1 to SL4 denote dierent sea levels reconstructed from the Cariaco Basin pollen record, which correspond to phases explained in Figure 1. Comparison Conclusions Acknowledgements This work was supported by the Programme Alan the European Union Programme of High Level Scholarships for Latin America (Scholar ship E04D047330CO) and the Deutsche Aka demische Austausch Dienst (DAAD)-Colfuturo Program. Data will be available in PANGAEA (www.pangaea.de). References Adam, P., 2002: Saltmarshes in a time of change, Environmental Conser vation 29 : 39-61. Arz, H.W., Lamy, F., Ganopolski, A., Nowaczyk, N. and Ptzold, J., 2007: Dominant Northern Hemisphere climate control over millennialscale glacial sea-level variability, Quaternary Science Reviews 26 : 312. Gonzlez, C. and Dupont, L.M., 2009: Tropical salt marsh succession as sea-level indicator during Heinrich events, Quaternary Science Reviews 28 : doi: 10.1016/j.quascirev.2008.12.023. Siddall, M., Rohling E.J., Thompson, W.G. and Waelbroeck, C., 2008: Marine isotope stage 3 sea level uctuations: Data synthesis and new outlook, Reviews of Geophysics 46 : RG4003, doi: 10.1029/2007RG00226. Thompson, W.G. and Goldstein, S.L., 2006: A radiometric calibration of the SPECMAP timescale, Quaternary Science Reviews 25 : 32073215. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
PAGES News Science Highlights: Paleo Sea Level Ice sheet-climate interactions during the ice age cycle AYAKO ABE-OU C HI 1 AND BE TT E OTT O-BLIE S NER 2 1 University of Tokyo, Japan; firstname.lastname@example.org; 2 National Center for Atmospheric Research, Boulder, USA; email@example.com The impact of ice sheet size and geometry on both climate and the ice sheet itself is investigated with general circulation models. This information is used to simulate the observed change of ice sheet and sea level throughout the ice age cycle. Climate response to ice sheets Figure 1: A ) Mean annual 500-mb geopotential height (m) for the LGM simulation with ICE5G reconstruction; B ) Annual surface temperature dierence (C) for the LGM simulation with ICE5G reconstruction compared to a preindustrial simulation; C ) Annual surface temperature dierence (C) of LGM simulations with reduced ice sheet topography (black box) minus regular (ICE5G) LGM simulation; only dierences signicant at 95% are shown (Figure modied from Otto-Bliesner et al., 2006).
Science Highlights: Paleo Sea Level Ice sheet evolution under climate forcing References Abe-Ouchi, A., Segawa, S. and Saito, F., 2007: Climatic Conditions for modelling the Northern Hemisphere ice sheets throughout the ice age cycle, Climate of the Past 3 : 423-438. Braconnot, P. et al., 2007: Results of PMIP2 coupled simulations of the mid-Holocene and Last Glacial Maximum Part 1: experiments and large-scale features, Climate of the Past 3 : 261-277. Marshall, S.J., 2005: Recent advances in understanding ice sheet dynam ics, Earth and Planetary Science Letters 240 : 191-204. Otto-Bliesner, B.L, Brady, E.C., Clauzet, G., Tomas, R., Levis, S. and Kotha vala, Z., 2006: Last Glacial Maximum and Holocene Climate in CCSM3, Journal of Climate 19 : 2526-2544. Yamagishi, T., Abe-Ouchi, A., Saito, F., Segawa, T. and Nishimura, T., 2005: Re-evaluation of paleo-accumulation parameterization over Northern Hemisphere ice sheets during the ice age examined with a high-resolution AGCM and a 3-D ice-sheet model, Annals of Glaciology 42 : 433-440. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html Figure 2: Simulated N. Hemisphere ice sheet distribution at dierent time slices. Contour intervals are 250 m (thin lines) and 1000 m (thick lines, blue shading). The approx. volume of each ice sheet in terms of sea level contribution is a) m, b) m, c) m, d) m, e) m, f) m. Figure modied from Abe-Ouchi et al. (2007).
PAGES News ADOM Atmospheric circulation dynamics during the last glacial cycle: Observations and modeling Figure 2: Dust particles ltered from Antarctic ice (EPICA, Photo: J-R Petit) Figure 1: Satellite picture (SeaWifs) of an Asian dust event (Source: NASA, 2001). Program News DENI S-DIDIER ROU SS EAU 1 C. HA TT E 2 AND I. TE G EN 3 1 Lab. de Meteorologie Dynamique and CERES-ERTI, Paris, France; firstname.lastname@example.org 2 UMR CEA-CNRS-UVSQ, Gif-sur-Yvette, France; 3 Leibniz Institute for Tropospheric Research, Germany Note For more information on ADOM, please see www.pages-igbp.org/science/adom/ References Andersen, K.K. et al., 2006: The Greenland Ice Core Chronology 2005, 15-42 ka, Part 1: constructing the time scale, Quaternary Science Reviews 25 : 3246-3257. GRIP members, 1993: Climate instability during the last interglacial pe riod recorded in the GRIP ice core, Nature 364 : 203-207. Petit, J.R. et al., 1999: Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica, Nature 399 : 429-436. Porter, S.C. and An, Z.S., 1995: Correlation between climate events in the North Atlantic and China during the last glaciation, Nature 375 : 305-308. Rousseau, D.D., Sima, A., Antoine, P., Hatt, C., Lang, A. and Zoeller, L., 2007: Link between European and North Atlantic abrupt climatic changes over the last glaciation, Geophysical Research Letters 34 : doi:10.1029/2007GL031716. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html
Science Highlights: Polar Paleoscience Addendum Termination of the Medieval Warm Period: Linking subpolar and tropical N Atlantic circulation changes to ENSO AN T OON KUI J PER S 1 B .A. MAL MG REN 2 M.-S. SEIDENKRAN T Z 3 1 Geological Survey of Denmark and Greenland, Copenhagen, Denmark; email@example.com 2 Norrtlje, Sweden; 3 Department of Earth Sciences, University of Aarhus, Denmark Paleoceanographic evidence from the N Atlantic subpolar gyre and NE Caribbean indicates a major, longterm change in ocean-atmosphere circulation modes around AD 1230, indicating that the termination of the Medieval Warm Period prevailing circulation mode occurred prior to the Wolf Solar Minimum, apparently without an obvious external trigger. Medieval warming and Little Ice Age climate anomalies West Greenland Current changes and medieval cooling Figure 1: Map of the North Atlantic with location of gravity core 248-260-2 from Ameralik Fjord, SW Greenland and the NE Caribbean study of core PRP-07 (box core and piston core). Blue lines indicate cold Polar Water transport pathways (EGC = East Greenland Current, LC = Labrador Current); red lines and arrows show the main warm water transport pathways of the North and Equatorial Atlantic.
PAGES News Northeast Caribbean SST since AD 800 Figure 2: A ) Variations in the strength of Irminger Sea Water (ISW) transport by the West Greenland Current based on benthic foraminiferal studies of a core from Ameralik Fjord, SW Greenland (Seidenkrantz et al., 2007). Note increased ISW transport during colder European (winter) climate of the Dark Ages and Little Ice Age. B ) Cold (winter) season (CS) and warm season (WS) SST variations over the southern Puerto Rico insular slope since AD 800 reconstructed for core PRP-07 by the Articial Neural Networks (ANN) method (Malmgren et al., 2001). RWP = Roman Warm Period, DA = (European) Dark Ages, MWP = Medieval Warm Period, LIA = Little Ice Age, MW = Modern Warming. Subpolar tropical and ENSO linkage References Bakke, J., Lie, ., Dahl, S.O., Nesje, A. and A.E. Bjune, 2008: Strength and spatial patterns of the Holocene wintertime westerlies in the NE Atlantic region, Global and Planetary Change 60 : 28-41. Broecker, W.S., 2001: Was the Medieval Warm Period global? Science 291 : 1497-1499. Malmgren, B.A., Winter, A. and D. Chen, 1998: El Nino-Southern Oscil lation and North Atlantic Oscillation control of climate in Puerto Rico, American Meteorological Society Notes and Correspondence October 1998: 2713-2717. Mohtadi, M., Romero, O.E., Kaiser, J. and D. Hebbeln, 2007: Cooling of the southern high latitudes during the Medieval Period and its eect on ENSO, Quaternary Science Reviews 26 (7-8): 1055-1066. Seidenkrantz, M.-S., Aagaard-Srensen, S., Sulsbrck, H., Kuijpers, A., Jensen, K.G. and Kunzendorf, H., 2007: Hydrography and climate of the last 4400 years in a SW Greenland ord: implications for Labrador Sea palaeoceanography, The Holocene 17 (3): 387401. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html Science Highlights: Polar Paleoscience Addendum
Reading the rst early Cenozoic central Arctic sediment record: A palynological view FRAN C E SC A SAN G IOR G I 1,2 A. SLUI JS 1 J. BARKE 1 AND H. BRINKHUI S 1 1 Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht University, Netherlands; firstname.lastname@example.org 2 Department of Marine Biogeochemistry and Toxicology, Royal Netherlands Institute for Sea Research, Texel, Netherlands Palynological analyses performed on long sedimentary records from the crest of the Lomonosov Ridge (Arctic Ocean) indicates that the Arctic developed from a warmer-than-expected, semi-isolated, shallow, freshwater dominated, eutrophic basin during the early Paleogene, to a sea-ice and iceberg dominated ocean during most of the Neogene. During the Eocene, the environmental changes were orbitally paced, with a biological response strongly aected by obliquity. Paleocene-Eocene Greenhouse and "hyperthermals" Figure 1: A ) Arctic Ocean map (modied from International Bathymetric Chart of the Arctic Ocean, Jakobsson et al., 2000), with indication of the Arctic sub-basins and ridges: AR, Alpha Ridge; FS, Fram Strait; GR, Gakkel Ridge; LR, Lomonosov Ridge; MR, Mendeleev Ridge; MB, Makarov Basin; NB, Nansen Basin; AB, Amundsen Basin; CA, Canada Basin. Star indicates the location of IODP 302 drilling on the LR; B ) Location of drilling within the early Eocene paleogeographical reconstruction of the Arctic Ocean (Brinkhuis et al., 2006) TO, Tethyan Ocean; P-AO, Proto-Atlantic Ocean; NS, North Sea; C ) ACEX age model (modied from Backman et al., 2008) with indication of the Lithologic Units (Lith. Unit) and sub-units (Expedition 302 Scientists, 2006). Pictures of the dinoagellate cysts Apectodinium augustum (1), Phthanoperidinium clithridium (3), Arcticacysta backmanii (4), A. moraniae (5) and the remains of Azolla (2) used as biostratigraphical markers are also shown. The palynological events considered in building the age model in the early Cenozoic are: Last Occurrence (LO) of A. augustum (F), LO of Azolla (E), Last Abundant Occurrence of P. clithridium (D) and the mid point of the Burdigalian stage where A. backmanii and A. moraniae occur (C). The oldest identied paleomagnetic chron datum (top of magnetochron C25n, Chron C25n), (G) deepest Berillium-10 samples (B) and top of the section (A) on which the age model is based are also shown. TD: Terminal Depth. Depth scale in meters composite depth (mcd). Science Highlights: Polar Paleoscience Addendum
PAGES News Apectodinium The Arctic "lake" phase: The Azolla event Azolla Azolla Azolla Azolla Azolla Azolla Azolla Azolla Azolla Azolla Azolla Azolla Azolla The rst sea ice in the midEocene and orbital modulation of environmental changes Hiatus at the greenhouseicehouse transition Figure 2: A ) Lithostratigraphic column showing the lithologic units and sub-units recognized in the ACEX section (Expedition 302 Scientists, 2006); B ) image of the core section showing the hiatus (wiggly red line); C ) Dinocyst events used to identify the location and duration of the hiatus, see text for full species names, LO = last occurrence, LAO = last abundant occurrence, FO = First Occurrence; D ) Selected palynological proxies and their environmental interpretation, hiatus = red dashed line, Asterisks = abundant occurrence of fungal spores (see text). Depth scale in meters composite depth (mcd). Science Highlights: Polar Paleoscience Addendum
Science Highlights: Open Section Phthanoperidinium clithridium Arcticacysta Arcticacysta backmanii A. moraniae Acknowledgements We thank the Netherlands Organisation for Sci entic Research (NWO) for funding, and the In tegrated Ocean Drilling Program for providing samples and data. Stefan Schouten, Jaap Sin ninghe Damst, ACEX co-chiefs Jan Backman and Kate Moran, and all the ACEX colleagues are thanked for the fruitful collaboration. References Backman J. et al., 2008: Age Model and Core-Seismic Integration for the Cenozoic ACEX Sediments from the Lomonosov Ridge, Pale oceanography 23 : PA1S03, doi:10.1029/2007PA001476 Brinkhuis, H. et al., 2006: Episodic fresh surface water in the Eocene Arc tic Ocean, Nature 441 : 606-609. Sangiorgi, F. et al., 2008a: A 26 million year gap in the central Arctic record at the Greenhouse-Icehouse transition: Looking for clues, Paleoceanography 23 : PA1S04, doi:10.1029/2007PA001477 Sangiorgi, F. et al., 2008b: Cyclicity in the middle Eocene cen tral Arctic Ocean sediment record: orbital forcing and en vironmental response, Paleoceanography 23 : PA1S08, doi:10.1029/2007PA001487 Sluijs A. et al., 2006: Subtropical Arctic Ocean temperatures during the Paleocene/Eocene thermal maximum, Nature 441 : 610-613. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html Potential imprint of changes in multidecadal climate variability on temperature reconstructions of the past millennium MI C HAEL SC HULZ AND MA TT HIA S PRAN G E MARUM Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Germany; email@example.com Model results suggest that the wider spread of individual Northern Hemisphere temperature reconstructions during cold phases of the last millennium may partly reect enhanced climate variability at multidecadal timescales. Figure 1: Surface air-temperature dierence (C) between cold and warm mode in the Northern Hemisphere.
PAGES News Figure 2: Ratio between surface-temperature standard deviation during the cold and warm modes, respectively. Values larger than unity indicate enhanced temperature variability at multidecadal timescales in the cold mode. Ratios are only depicted if they dier signicantly ( = 0.01) from unity, taking the autocorrelation of the time series into account. References: Jansen, E. et al., 2007: Palaeoclimate. In: Solomon, S. et al. (Eds.) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cam bridge, United Kingdom and New York, NY, USA. Jongma, J.I., Prange, M., Renssen, H. and Schulz, M., 2007: Amplication of Holocene multicentennial climate forcing by mode transitions in North Atlantic overturning circulation, Geophysical Research Letters 34 : L15706, doi:15710.11029/12007GL030642 Mann, M.E., Zhang, Z., Hughes, M.K., Bradley, R.S., Miller, S.K., Ruther ford, S. and Ni, F., 2008: Proxy-based reconstructions of hemi spheric and global surface temperature variations over the past two millennia, Proceedings of the National Academy of Sciences 105 :13252-13257. Schulz, M., Prange, M. and Klocker, A., 2007: Low-frequency oscillations of the Atlantic Ocean meridional overturning circulation in a coupled climate model, Climate of the Past 3 : 97-107. Science Highlights: Open Section
Global monsoon in observations, simulations and geological records PAGES Global Monsoon Symposium Shanghai, China, 29-31 October 2008 PIN X IAN WAN G 1 BIN WAN G 2 AND T. KIE F ER 3 1 State Key Laboratory of Marine Geology, Tongji University, Shanghai, China; firstname.lastname@example.org 2 SOEST, University of Hawaii, Honolulu, USA; 3 PAGES International Project Oce, Bern, Switzerland Figure 1: The modern global monsoon precipitation (GMP) domain (outlined by the black curves) based on annual range (local summer minus winter mean) of precipitation normalized by annual mean precipitation (color shad ing). Red ( Blue ) line indicates the ITCZ position in Jan-Feb (July-Aug) estimated by maximum precipitation rate (B. Wang and Ding, 2008). Workshop Reports
PAGES News References deMenocal, P.B., Ortiz, J., Guilderson, T., Adkins, J., Sarnthein, M., Baker, L. and Yarusinski, M., 2000: Abrupt onset and termination of the African Humid Period: Rapid climate response to gradual insola tion forcing, Quaternary Science Reviews 19 : 347-361. Fleitmann, D., Burns, S.J., Mudelsee, M., Ne, U., Kramers, J., Mangini, A. and Matter, A., 2003: Holocene Forcing of the Indian Monsoon recorded in a stalagmite from Southern Oman, Science 300 : 1737-1739. Wang, B. and Ding, Q., 2006: Changes in global monsoon precipitation over the past 56 years, Geophysical Research Letters 33 : L06711. Wang, B. and Ding, Q., 2008: Global monsoon: Dominant mode of annual variation in the tropics, Dynamics of Atmospheres and Oceans 44 : 165-183. Wang, Y. et al., 2008: Millennialand orbital-scale changes in the East Asian monsoon over the past 224,000 years, Nature 451 : 10901093. For full references please consult: www.pages-igbp.org/products/newsletters/ref2009_2.html Figure 2: Global monsoon in the Holocene: The common trend in monsoon variations in the Northern Hemisphere. A ) South Asian monsoon: Stalagmite 18 O from Qunf Cave in Southern Oman (Fleitmann et al., 2003); B ) North African monsoon: Terrigenous detritus % from ODP 658, tropical Atlantic o Western Africa (deMenocal et al., 2000); C ) North American monsoon: Ti% in laminated deposits from the Cariaco Basin o Venezuela (Haug et al., 2001); D ) East Asian monsoon: Stalagmite 18 O from Dongge Cave, South China (Y. Wang et al., 2005). First international cave monitoring eld workshop Gibraltar, 26 February 1 March, 2009 DAVID MA TT EY 1 AND CHRI ST OPH SP T L 2 1 Department of Earth Sciences, Royal Holloway, University of London, UK; email@example.com 2 Institute for Geology and Paleontology, University of Innsbruck, Austria; firstname.lastname@example.org PAGES News Workshop Reports
Figure 1: Participants of the INTERDYNAMIC status seminar in Bremen. Integrated analysis of interglacial climate dynamics INTERDYNAMIC Status Seminar Bremen, Germany, 24-25 February 2009 MI C HAEL SC HULZ AND ANDR PAUL MARUM Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Germany; email@example.com Workshop Reports Figure 1: Workshop participants inside the rock of Gibraltar (St. Michaels Cave)
PAGES News Workshop Reports Compiling records of Holocene erosion and sediment transport LUCIFS Workshop Christchurch, New Zealand, 6-10 December 2008 NI C K PRE ST ON School of Geography, Environment and Earth Sciences, Victoria University of Wellington, New Zealand; Nick.Preston@vuw.ac.nz Figure 1: Participants of the LUCIFS general meeting
Workshop Reports Sustainable water and land management in semi-arid regions: Middle East and North Africa (MENA) Cairo, Egypt, 20-21 November 2008 ELENA XOPLAKI 1,2 AND FEKRI HA SS AN 3 1 Oeschger Centre for Climate Change Research and Institute of Geography, University of Bern, Switzerland; 2 Energy, Environment and Water Research Center, The Cyprus Institute, Nicosia, Cyprus; firstname.lastname@example.org; 3 Institute of Archaeology, University College London, UK; email@example.com Figure 1: Historical records from the MENA region. Left: Anales Palatinos. Right: View of the Nilometer (Luigi Mayer, R. Brown Historic Gallery, Pall Mall 1802).
PAGES News Workshop Reports Note Sections of this article were extracted from the IGBP Secretariat Press Release see www.igbp. net/page.php?pid=444 References World Bank, 2007: The World Bank Middle East and North Africa Region (MENA) Sustainable Development Sector Department (MNSSD) Regional Business Strategy to Address Climate Change. Available at: http://siteresources.worldbank.org/INTCLIMATECHANGE/ Resources/MENA_CC_Business_Strategy_Nov_2007_Revised. pdf RETROSPECTIVE VIEWS ON OUR PLANET'S FUTURE 8 11 July, Corvallis, USA UNABLE TO MAKE IT TO THE PAGES OSM? POST-CONFERENCE FIELD TRIPS AT PAGES 3 RD OPEN SCIENCE MEETING PAGES 3 rd Open Science Meeting www.pages-osm.org/ New on the PAGES bookshelf Alan M. Haywood, Harry, J. Dowsett and Paul J. Valdes Summary of contents: Ordering Information: http://rsta.royalsocietypublishing.org/site/issues/pliocene.xhtml Philosophical Transactions of the Royal Society The Pliocene: a vision of Earth in the late 21 st century?
Announcements Special Section: Understanding sea level: Ways forward from the past Science Highlights: J. Bamber M.B. Andersen, C.D. Gallup, D. Scholz, C.H. Stirling and W.G. Thompson G.A. Milne M.E. Raymo, P. Hearty, R. De Conto, M. OLeary, H.J. Dowsett, M.M. Robinson and J.X. Mitrovica M.A. Kelly and A.J. Long C.H. Stirling and M.B. Andersen P.U. Clark A. Dutton, F. Antonioli and E. Bard S.-Y. Yu, Y.-X. Li and T.E. Trnqvist C. Gonzlez and L.M. Dupont A. Abe-Ouchi and B. Otto-Bliesner Program News Science Highlights: Polar Paleoscience Addendum A. Kuijpers, B.A. Malmgren, M.-S. Seidenkrantz F. Sangiorgi, A. Sluijs, J. Barke and H. Brinkhuis Science Highlights: Open section M. Schulz and M. Prange Workshop Reports Impressum Editors: ISSN 1563-0803 Cover images: Acropora palmata Contents
PAGES (Past Global Changes) supports research aimed at
understanding the Earth's past environment in order to make
predictions for the future. We encourage international and
interdisciplinary collaborations and seek to promote the
involvement of scientists from developing countries in the
global paleo-community discourse.
PAGES scope of interest includes the physical climate
system, biogeochemical cycles, ecosystem processes,
biodiversity, and human dimensions, on different time
scales Pleistocene, Holocene, last millennium and the
Founded in 1991, PAGES is a core project of the
International Geosphere-Biosphere Programme (IGBP) and is
funded by the U.S. and Swiss National Science Foundations,
and the National Oceanic and Atmospheric Administration
It is overseen by a Scientific Steering Committee (SSC)
comprised of members chosen to be representative of the
major techniques, disciplines and geographic regions that
contribute to paleoscience.