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Blanchon P, Chutcharavan P. Meltwater Pulse 1a drowned fringing reefs around Tahiti 15 000 years ago. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230918. [PMID: 38094270 PMCID: PMC10716648 DOI: 10.1098/rsos.230918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 11/21/2023] [Indexed: 12/21/2023]
Abstract
Reconstruction of postglacial sea-level rise using reef cores recovered from Tahiti during IODP Expedition 310 showed that the first major acceleration, known as Meltwater Pulse 1a (MWP-1a), was a 12-22 m rise in 340 years starting at 14.65 ka BP. Although it was reported that the pulse did not drown Tahitian reefs, the subsequent discovery of a fringing reef at the base of several cores implies that its timing, magnitude and impact require revision. Here, we report facies and paleodepth data from this reef, revise sea level, and revisit reef response. We find its reef crest is dominated by surf-adapted corals to a depth of 2.5 m and show that it retreated upslope over an approximately 1000-year interval from 16 ka. Reef development then apparently ceased at 15 ka at -106 m and remained absent for approximately 600 years, before resuming at 14.4 ka further upslope at -93 m. This absence is consistent with reef drowning and requires that MWP-1a had a smaller magnitude of 13.8 ± 1.3 m, and may have started 300 years earlier than previously reported. It confirms MWP-1a was a global event, drowning reefs on Tahiti as well as those in other oceans.
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Affiliation(s)
- Paul Blanchon
- Reef Geoscience Group, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Peter Chutcharavan
- Department of Earth and Environmental Sciences, University of Minnesota Twin Cities, Minneapolis, USA
- Department of Geoscience, University of Wisconsin Madison, Madison, WI, USA
- Department of Geological Sciences, University of Florida, Gainesville, USA
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Prehistoric human migration between Sundaland and South Asia was driven by sea-level rise. Commun Biol 2023; 6:150. [PMID: 36739308 PMCID: PMC9899273 DOI: 10.1038/s42003-023-04510-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 01/20/2023] [Indexed: 02/06/2023] Open
Abstract
Rapid sea-level rise between the Last Glacial Maximum (LGM) and the mid-Holocene transformed the Southeast Asian coastal landscape, but the impact on human demography remains unclear. Here, we create a paleogeographic map, focusing on sea-level changes during the period spanning the LGM to the present-day and infer the human population history in Southeast and South Asia using 763 high-coverage whole-genome sequencing datasets from 59 ethnic groups. We show that sea-level rise, in particular meltwater pulses 1 A (MWP1A, ~14,500-14,000 years ago) and 1B (MWP1B, ~11,500-11,000 years ago), reduced land area by over 50% since the LGM, resulting in segregation of local human populations. Following periods of rapid sea-level rises, population pressure drove the migration of Malaysian Negritos into South Asia. Integrated paleogeographic and population genomic analysis demonstrates the earliest documented instance of forced human migration driven by sea-level rise.
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Cheng H, Edwards RL, Southon J, Matsumoto K, Feinberg JM, Sinha A, Zhou W, Li H, Li X, Xu Y, Chen S, Tan M, Wang Q, Wang Y, Ning Y. Atmospheric
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C changes during the last glacial period from Hulu Cave. Science 2018; 362:1293-1297. [DOI: 10.1126/science.aau0747] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 11/02/2018] [Indexed: 11/02/2022]
Affiliation(s)
- Hai Cheng
- Institute of Global Environmental Change, Xi’an Jiaotong University, China
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN, USA
| | | | - John Southon
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Katsumi Matsumoto
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Joshua M. Feinberg
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN, USA
- Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN, USA
| | - Ashish Sinha
- Department of Earth Science, California State University Dominguez Hills, Carson, CA, USA
| | - Weijian Zhou
- Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China
| | - Hanying Li
- Institute of Global Environmental Change, Xi’an Jiaotong University, China
| | - Xianglei Li
- Institute of Global Environmental Change, Xi’an Jiaotong University, China
| | - Yao Xu
- Institute of Global Environmental Change, Xi’an Jiaotong University, China
| | - Shitao Chen
- College of Geography Science, Nanjing Normal University, Nanjing, China
| | - Ming Tan
- Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Quan Wang
- College of Geography Science, Nanjing Normal University, Nanjing, China
| | - Yongjin Wang
- College of Geography Science, Nanjing Normal University, Nanjing, China
| | - Youfeng Ning
- Institute of Global Environmental Change, Xi’an Jiaotong University, China
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Yokoyama Y, Esat TM, Thompson WG, Thomas AL, Webster JM, Miyairi Y, Sawada C, Aze T, Matsuzaki H, Okuno J, Fallon S, Braga JC, Humblet M, Iryu Y, Potts DC, Fujita K, Suzuki A, Kan H. Rapid glaciation and a two-step sea level plunge into the Last Glacial Maximum. Nature 2018; 559:603-607. [PMID: 30046076 DOI: 10.1038/s41586-018-0335-4] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/05/2018] [Indexed: 11/09/2022]
Abstract
The approximately 10,000-year-long Last Glacial Maximum, before the termination of the last ice age, was the coldest period in Earth's recent climate history1. Relative to the Holocene epoch, atmospheric carbon dioxide was about 100 parts per million lower and tropical sea surface temperatures were about 3 to 5 degrees Celsius lower2,3. The Last Glacial Maximum began when global mean sea level (GMSL) abruptly dropped by about 40 metres around 31,000 years ago4 and was followed by about 10,000 years of rapid deglaciation into the Holocene1. The masses of the melting polar ice sheets and the change in ocean volume, and hence in GMSL, are primary constraints for climate models constructed to describe the transition between the Last Glacial Maximum and the Holocene, and future changes; but the rate, timing and magnitude of this transition remain uncertain. Here we show that sea level at the shelf edge of the Great Barrier Reef dropped by around 20 metres between 21,900 and 20,500 years ago, to -118 metres relative to the modern level. Our findings are based on recovered and radiometrically dated fossil corals and coralline algae assemblages, and represent relative sea level at the Great Barrier Reef, rather than GMSL. Subsequently, relative sea level rose at a rate of about 3.5 millimetres per year for around 4,000 years. The rise is consistent with the warming previously observed at 19,000 years ago1,5, but we now show that it occurred just after the 20-metre drop in relative sea level and the related increase in global ice volumes. The detailed structure of our record is robust because the Great Barrier Reef is remote from former ice sheets and tectonic activity. Relative sea level can be influenced by Earth's response to regional changes in ice and water loadings and may differ greatly from GMSL. Consequently, we used glacio-isostatic models to derive GMSL, and find that the Last Glacial Maximum culminated 20,500 years ago in a GMSL low of about -125 to -130 metres.
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Affiliation(s)
- Yusuke Yokoyama
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan. .,Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Tokyo, Japan. .,Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan.
| | - Tezer M Esat
- Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, Australia.,Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory, Australia
| | | | | | - Jody M Webster
- University of Sydney, Sydney, New South Wales, Australia
| | - Yosuke Miyairi
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
| | - Chikako Sawada
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
| | - Takahiro Aze
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
| | | | | | - Stewart Fallon
- Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, Australia
| | | | | | | | - Donald C Potts
- University of California Santa Cruz, Santa Cruz, CA, USA
| | | | - Atsushi Suzuki
- Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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Jorry SJ, Camoin GF, Jouet G, Roy PL, Vella C, Courgeon S, Prat S, Fontanier C, Paumard V, Boulle J, Caline B, Borgomano J. Modern sediments and Pleistocene reefs from isolated carbonate platforms (Iles Eparses, SW Indian Ocean): A preliminary study. ACTA OECOLOGICA 2016. [DOI: 10.1016/j.actao.2015.10.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
The half-life of (234)U has been measured using a novel approach. In this method, a uranium material was chemically purified from its thorium decay product at a well-known time. The ingrowth of the (230)Th daughter product in the material was followed by measuring the accumulated (230)Th daughter product relative to its parent (234)U nuclide using inductively coupled plasma mass spectrometry. Then, the (234)U decay constant and the respective half-life could be calculated using the radioactive decay equations based on the n((230)Th)/n((234)U) amount ratio. The obtained (234)U half-life is 244 900 ± 670 years (k = 1), which is in good agreement with the previously reported results in the literature with comparable uncertainty. The main advantages of the proposed method are that it does not require the assumption of secular equilibrium between (234)U and (238)U. Moreover, the calculation is independent from the (238)U half-life value and its uncertainty. The suggested methodology can also be applied for the remeasurement of the half-lives of several other long-lived radionuclides.
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Affiliation(s)
- Zsolt Varga
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany
| | - Adrian Nicholl
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany
| | - Maria Wallenius
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany
| | - Klaus Mayer
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany
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Moseley GE, Edwards RL, Wendt KA, Cheng H, Dublyansky Y, Lu Y, Boch R, Spötl C. Reconciliation of the Devils Hole climate record with orbital forcing. Science 2016; 351:165-8. [PMID: 26744404 DOI: 10.1126/science.aad4132] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The driving force behind Quaternary glacial-interglacial cycles and much associated climate change is widely considered to be orbital forcing. However, previous versions of the iconic Devils Hole (Nevada) subaqueous calcite record exhibit shifts to interglacial values ~10,000 years before orbitally forced ice age terminations, and interglacial durations ~10,000 years longer than other estimates. Our measurements from Devils Hole 2 replicate virtually all aspects of the past 204,000 years of earlier records, except for the timing during terminations, and they lower the age of the record near Termination II by ~8000 years, removing both ~10,000-year anomalies. The shift to interglacial values now broadly coincides with the rise in boreal summer insolation, the marine termination, and the rise in atmospheric CO2, which is consistent with mechanisms ultimately tied to orbital forcing.
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Affiliation(s)
- Gina E Moseley
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - R Lawrence Edwards
- Department of Earth Sciences, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, USA
| | - Kathleen A Wendt
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria. Department of Earth Sciences, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, USA
| | - Hai Cheng
- Department of Earth Sciences, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, USA. Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yuri Dublyansky
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Yanbin Lu
- Department of Earth Sciences, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, USA
| | - Ronny Boch
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Christoph Spötl
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
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Clark PU, Shakun JD, Baker PA, Bartlein PJ, Brewer S, Brook E, Carlson AE, Cheng H, Kaufman DS, Liu Z, Marchitto TM, Mix AC, Morrill C, Otto-Bliesner BL, Pahnke K, Russell JM, Whitlock C, Adkins JF, Blois JL, Clark J, Colman SM, Curry WB, Flower BP, He F, Johnson TC, Lynch-Stieglitz J, Markgraf V, McManus J, Mitrovica JX, Moreno PI, Williams JW. Global climate evolution during the last deglaciation. Proc Natl Acad Sci U S A 2012; 109:E1134-42. [PMID: 22331892 PMCID: PMC3358890 DOI: 10.1073/pnas.1116619109] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Deciphering the evolution of global climate from the end of the Last Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents an outstanding opportunity for understanding the transient response of Earth's climate system to external and internal forcings. During this interval of global warming, the decay of ice sheets caused global mean sea level to rise by approximately 80 m; terrestrial and marine ecosystems experienced large disturbances and range shifts; perturbations to the carbon cycle resulted in a net release of the greenhouse gases CO(2) and CH(4) to the atmosphere; and changes in atmosphere and ocean circulation affected the global distribution and fluxes of water and heat. Here we summarize a major effort by the paleoclimate research community to characterize these changes through the development of well-dated, high-resolution records of the deep and intermediate ocean as well as surface climate. Our synthesis indicates that the superposition of two modes explains much of the variability in regional and global climate during the last deglaciation, with a strong association between the first mode and variations in greenhouse gases, and between the second mode and variations in the Atlantic meridional overturning circulation.
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Affiliation(s)
- Peter U. Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Jeremy D. Shakun
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138
| | - Paul A. Baker
- Division of Earth and Ocean Sciences, Duke University, Durham, NC 27708
| | | | - Simon Brewer
- Department of Geography, University of Utah, Salt Lake City, UT 84112
| | - Ed Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Anders E. Carlson
- Department of Geoscience, University of Wisconsin, Madison, WI 53706
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
| | - Hai Cheng
- Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an 710049, China
- Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
| | - Darrell S. Kaufman
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011
| | - Zhengyu Liu
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
- Laboratory for Ocean-Atmosphere Studies, School of Physics, Peking University, Beijing 100871, China
| | - Thomas M. Marchitto
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309
| | - Alan C. Mix
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Carrie Morrill
- National Oceanic and Atmospheric Administration National Climatic Data Center, Boulder, CO 80305
| | - Bette L. Otto-Bliesner
- Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307
| | - Katharina Pahnke
- Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96822
| | - James M. Russell
- Department of Geological Sciences, Brown University, Providence, RI 02912
| | - Cathy Whitlock
- Department of Earth Sciences, Montana State University, Bozeman, MT 97403
| | - Jess F. Adkins
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - Jessica L. Blois
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
- Department of Geography, University of Wisconsin, Madison, WI 53706
| | - Jorie Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Steven M. Colman
- Large Lakes Observatory and Department Geological Sciences, University of Minnesota, Duluth, MN 55812
| | - William B. Curry
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Ben P. Flower
- College of Marine Science, University of South Florida, St. Petersburg, FL 33701
| | - Feng He
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
| | - Thomas C. Johnson
- Large Lakes Observatory and Department Geological Sciences, University of Minnesota, Duluth, MN 55812
| | - Jean Lynch-Stieglitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332
| | - Vera Markgraf
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011
| | - Jerry McManus
- Lamont-Doherty Earth Observatory, Palisades, NY 10964; and
| | - Jerry X. Mitrovica
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138
| | - Patricio I. Moreno
- Institute of Ecology and Biodiversity and Department of Ecological Sciences, Universidad de Chile, Santiago 1058, Chile
| | - John W. Williams
- Department of Geography, University of Wisconsin, Madison, WI 53706
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Deschamps P, Durand N, Bard E, Hamelin B, Camoin G, Thomas AL, Henderson GM, Okuno J, Yokoyama Y. Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago. Nature 2012; 483:559-64. [PMID: 22460900 DOI: 10.1038/nature10902] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 01/26/2012] [Indexed: 11/09/2022]
Abstract
Past sea-level records provide invaluable information about the response of ice sheets to climate forcing. Some such records suggest that the last deglaciation was punctuated by a dramatic period of sea-level rise, of about 20 metres, in less than 500 years. Controversy about the amplitude and timing of this meltwater pulse (MWP-1A) has, however, led to uncertainty about the source of the melt water and its temporal and causal relationships with the abrupt climate changes of the deglaciation. Here we show that MWP-1A started no earlier than 14,650 years ago and ended before 14,310 years ago, making it coeval with the Bølling warming. Our results, based on corals drilled offshore from Tahiti during Integrated Ocean Drilling Project Expedition 310, reveal that the increase in sea level at Tahiti was between 12 and 22 metres, with a most probable value between 14 and 18 metres, establishing a significant meltwater contribution from the Southern Hemisphere. This implies that the rate of eustatic sea-level rise exceeded 40 millimetres per year during MWP-1A.
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Affiliation(s)
- Pierre Deschamps
- CEREGE, UMR Aix-Marseille Université - CNRS - IRD - College de France, Technopole de l'Arbois, BP 80, 13545 Aix-en-Provence Cedex 4, France.
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Abstract
Excavations at the Mesa site in arctic Alaska provide evidence for a Paleoindian occupation of Beringia, the region adjacent to the Bering Strait. Eleven carbon-14 dates on hearths associated with Paleoindian projectile points place humans at the site between 9,730 and 11,660 radiocarbon years before present (years B.P.). The presence of Paleoindians in Beringia at these times challenges the notion that Paleoindian cultures arose exclusively in mid-continental North America. The age span of Paleoindians at the Mesa site overlaps with dates from two other cultural complexes in interior Alaska. A hiatus in the record of human occupation occurs between 10,300 and 11,000 years B.P. Late Glacial climatic fluctuations may have made northern Alaska temporarily unfavorable for humans and spurred their southward dispersal.
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Raynal O, Bouchette F, Certain R, Sabatier P, Lofi J, Seranne M, Dezileau L, Briqueu L, Ferrer P, Courp T. Holocene evolution of a Languedocian lagoonal environment controlled by inherited coastal morphology (northern Gulf of Lions, France). ACTA ACUST UNITED AC 2010. [DOI: 10.2113/gssgfbull.181.2.211] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Abstract
The Maguelone shore extends along the northern coast of the Gulf of Lions margin, West of the Rhône delta and East of some high gradient coastal streams that have been providing most of the clastic sediments to the Gulf of Lions margin since the early Miocene. This 10 km wide area comprises an onshore small coastal watershed (15 km long) in low-lying carbonate hills, kilometer wide marshes, sandy beach and shoreface featuring local low sedimentation. Deposit architecture in such a coastal zone records dynamics of incised valley fill under the influence of rivers and wave/current hydrodynamics in a microtidal environment during an eustatic cycle.
A detailed analysis of about 250 km of very high resolution seismic profiles, tens of cores and outcrops data revealed the evolution of the Maguelone coastal system from Late-Quaternary to present-day. It highlighted also dominant denudation processes in the upstream catchments associated to the formation of incised valley seaward during Quaternary. Combination of this inherited morphology together with hydrodynamics controlled the lagoonal environment evolution since the last transgression. In particular, the Maguelone shore is characterized by the formation of built-over-rias lagoonal systems and records an evolution from partially protected lagoon to isolated lagoon environment. These two stages of lagoon evolution correspond to distinct deposit environments. Correlation of fauna contents with deposit geometry improves lagoonal environment models.
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Affiliation(s)
- Olivier Raynal
- Geosciences-m, Université Montpellier II/CNRS, cc 60, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Tel.: +33 4 67 14 42 93.
| | - Frédéric Bouchette
- Geosciences-m, Université Montpellier II/CNRS, cc 60, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Tel.: +33 4 67 14 42 93.
- Institut de Mathématiques et de Modélisation de Montpellier, Université Montpellier II/CNRS, cc 51, Place Eugène Bataillon, 34095 Montpellier cedex, France
| | - Raphaël Certain
- IMAGES, Université de Perpignan, 52 av. de Villeneuve, 66860 Perpignan cedex, France
| | - Pierre Sabatier
- Geosciences-m, Université Montpellier II/CNRS, cc 60, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Tel.: +33 4 67 14 42 93.
| | - Johanna Lofi
- Geosciences-m, Université Montpellier II/CNRS, cc 60, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Tel.: +33 4 67 14 42 93.
| | - Michel Seranne
- Geosciences-m, Université Montpellier II/CNRS, cc 60, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Tel.: +33 4 67 14 42 93.
| | - Laurent Dezileau
- Geosciences-m, Université Montpellier II/CNRS, cc 60, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Tel.: +33 4 67 14 42 93.
| | - Louis Briqueu
- Geosciences-m, Université Montpellier II/CNRS, cc 60, Place Eugène Bataillon, 34095 Montpellier cedex 5, France. Tel.: +33 4 67 14 42 93.
| | - Pierre Ferrer
- IMAGES, Université de Perpignan, 52 av. de Villeneuve, 66860 Perpignan cedex, France
| | - Thierry Courp
- IMAGES, Université de Perpignan, 52 av. de Villeneuve, 66860 Perpignan cedex, France
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Dorale JA, Onac BP, Fornós JJ, Ginés J, Ginés A, Tuccimei P, Peate DW. Sea-Level Highstand 81,000 Years Ago in Mallorca. Science 2010; 327:860-3. [DOI: 10.1126/science.1181725] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Jeffrey A. Dorale
- Department of Geoscience, University of Iowa, 121 Trowbridge Hall, Iowa City, IA 52242, USA
| | - Bogdan P. Onac
- Department of Geology, University of South Florida, 4202 East Fowler Avenue, SCA 528, Tampa, FL 33620, USA; and Department of Geology, Babes-Bolyai University, Emil Racovita Institute of Speleology Cluj, Romania
| | - Joan J. Fornós
- Departament de Ciències de la Terra, Universitat de les Illes Balears, Carretera Valldemossa km 7.5, Palma de Mallorca, 07122, Spain
| | - Joaquin Ginés
- Departament de Ciències de la Terra, Universitat de les Illes Balears, Carretera Valldemossa km 7.5, Palma de Mallorca, 07122, Spain
| | - Angel Ginés
- Departament de Ciències de la Terra, Universitat de les Illes Balears, Carretera Valldemossa km 7.5, Palma de Mallorca, 07122, Spain
| | - Paola Tuccimei
- Dipartimento di Scienze Geologiche, Università di Roma III, Largo St. Leonardo Murialdo, 1, 00146 Roma, Italy
| | - David W. Peate
- Department of Geoscience, University of Iowa, 121 Trowbridge Hall, Iowa City, IA 52242, USA
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Bard E, Hamelin B, Delanghe-Sabatier D. Deglacial meltwater pulse 1B and Younger Dryas sea levels revisited with boreholes at Tahiti. Science 2010; 327:1235-7. [PMID: 20075212 DOI: 10.1126/science.1180557] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Reconstructing sea-level changes during the last deglaciation provides a way of understanding the ice dynamics that can perturb large continental ice sheets. The resolution of the few sea-level records covering the critical time interval between 14,000 and 9,000 calendar years before the present is still insufficient to draw conclusions about sea-level changes associated with the Younger Dryas cold event and the meltwater pulse 1B (MWP-1B). We used the uranium-thorium method to date shallow-living corals from three new cores drilled onshore in the Tahiti barrier reef. No significant discontinuity can be detected in the sea-level rise during the MWP-1B period. The new Tahiti sea-level record shows that the sea-level rise slowed down during the Younger Dryas before accelerating again during the Holocene.
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Affiliation(s)
- Edouard Bard
- Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), UMR 6635 CNRS, University Aix-Marseille, Institut de Recherche pour le Développement, Collège de France, Europôle de l'Arbois, BP 80, F-13545 Aix-en-Provence Cedex 4, France.
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14
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Clark PU, Dyke AS, Shakun JD, Carlson AE, Clark J, Wohlfarth B, Mitrovica JX, Hostetler SW, McCabe AM. The Last Glacial Maximum. Science 2009; 325:710-4. [PMID: 19661421 DOI: 10.1126/science.1172873] [Citation(s) in RCA: 687] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level approximately 14.5 ka.
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Affiliation(s)
- Peter U Clark
- Department of Geosciences, Oregon State University, Corvallis, OR 97331, USA.
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15
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Jorry SJ, Droxler AW, Mallarino G, Dickens GR, Bentley SJ, Beaufort L, Peterson LC, Opdyke BN. Bundled turbidite deposition in the central Pandora Trough (Gulf of Papua) since Last Glacial Maximum: Linking sediment nature and accumulation to sea level fluctuations at millennial timescale. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2006jf000649] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Crockett JS, Nittrouer CA, Ogston AS, Naar DF, Donahue BT. Morphology and filling of incised submarine valleys on the continental shelf near the mouth of the Fly River, Gulf of Papua. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2006jf000674] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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18
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Hughen KA. Chapter Five Radiocarbon Dating of Deep-Sea Sediments. DEVELOPMENTS IN MARINE GEOLOGY 2007. [DOI: 10.1016/s1572-5480(07)01010-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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19
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20
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Cai Y, Warren B, Peng Z, Zhang Z. Effect of dead carbon on the14C dating of the speleothem. CHINESE SCIENCE BULLETIN-CHINESE 2005. [DOI: 10.1007/bf03183684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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Siddall M, Rohling EJ, Almogi-Labin A, Hemleben C, Meischner D, Schmelzer I, Smeed DA. Sea-level fluctuations during the last glacial cycle. Nature 2003; 423:853-8. [PMID: 12815427 DOI: 10.1038/nature01690] [Citation(s) in RCA: 1202] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2003] [Accepted: 04/24/2003] [Indexed: 11/09/2022]
Abstract
The last glacial cycle was characterized by substantial millennial-scale climate fluctuations, but the extent of any associated changes in global sea level (or, equivalently, ice volume) remains elusive. Highstands of sea level can be reconstructed from dated fossil coral reef terraces, and these data are complemented by a compilation of global sea-level estimates based on deep-sea oxygen isotope ratios at millennial-scale resolution or higher. Records based on oxygen isotopes, however, contain uncertainties in the range of +/-30 m, or +/-1 degrees C in deep sea temperature. Here we analyse oxygen isotope records from Red Sea sediment cores to reconstruct the history of water residence times in the Red Sea. We then use a hydraulic model of the water exchange between the Red Sea and the world ocean to derive the sill depth-and hence global sea level-over the past 470,000 years (470 kyr). Our reconstruction is accurate to within +/-12 m, and gives a centennial-scale resolution from 70 to 25 kyr before present. We find that sea-level changes of up to 35 m, at rates of up to 2 cm yr(-1), occurred, coincident with abrupt changes in climate.
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Affiliation(s)
- M Siddall
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, UK.
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22
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Weaver AJ, Saenko OA, Clark PU, Mitrovica JX. Meltwater pulse 1A from Antarctica as a trigger of the Bølling-Allerød warm interval. Science 2003; 299:1709-13. [PMID: 12637739 DOI: 10.1126/science.1081002] [Citation(s) in RCA: 429] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Meltwater pulse 1A (mwp-1A) was a prominent feature of the last deglaciation, which led to a sea-level rise of approximately 20 meters in less than 500 years. Concurrent with mwp-1A was the onset of the Bølling-Allerød interstadial event (14,600 years before the present), which marked the termination of the last glacial period. Previous studies have been unable to reconcile a warm Northern Hemisphere with mwp-1A originating from the Laurentide or Fennoscandian ice sheets. With the use of a climate model of intermediate complexity, we demonstrate that with mwp-1A originating from the Antarctic Ice Sheet, consistent with recent sea-level fingerprinting inferences, the strength of North Atlantic Deep Water (NADW) formation increases, thereby warming the North Atlantic region and providing an explanation for the onset of the Bølling-Allerød warm interval. The established mode of active NADW formation is then able to respond to subsequent freshwater forcing from the Laurentide and Fennoscandian ice sheets, setting the stage for the Younger Dryas cold period.
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Affiliation(s)
- Andrew J Weaver
- School of Earth and Ocean Sciences, University of Victoria, Post Office Box 3055, Victoria, British Columbia V8W 3P6, Canada.
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23
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Jull AJT, Burr GS, Beck JW, Donahue DJ, Biddulph D, Hatheway AL, Lange TE, McHargue LR. Accelerator mass spectrometry at Arizona: geochronology of the climate record and connections with the ocean. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2003; 69:3-19. [PMID: 12860086 DOI: 10.1016/s0265-931x(03)00083-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
There are many diverse uses of accelerator mass spectrometry (AMS). Carbon-14 studies at our laboratory include much research related to paleoclimate, both with 14C as a tracer of past changes in environmental conditions as observed in corals, marine sediments and many terrestrial records. Terrestrial records such as forest fires can also show the influence of oceanic oscillations, whether they are short-term such as ENSO, or on the millennial time scale. In tracer applications, we have developed the use of 129I as well as 14C as tracers for nuclear pollution studies around radioactive waste dump sites, in collaboration with IAEA. We discuss some applications carried out in Tucson for several of these fields and hope to give some idea of the breadth of these studies.
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Affiliation(s)
- A J T Jull
- NSF Arizona AMS Laboratory, University of Arizona, 1118 East Fourth St., Tucson, AZ 85721, USA.
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24
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Adkins JF, McIntyre K, Schrag DP. The salinity, temperature, and delta18O of the glacial deep ocean. Science 2002; 298:1769-73. [PMID: 12459585 DOI: 10.1126/science.1076252] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We use pore fluid measurements of the chloride concentration and the oxygen isotopic composition from Ocean Drilling Program cores to reconstruct salinity and temperature of the deep ocean during the Last Glacial Maximum (LGM). Our data show that the temperatures of the deep Pacific, Southern, and Atlantic oceans during the LGM were relatively homogeneous and within error of the freezing point of seawater at the ocean's surface. Our chloride data show that the glacial stratification was dominated by salinity variations, in contrast with the modern ocean, for which temperature plays a primary role. During the LGM the Southern Ocean contained the saltiest water in the deep ocean. This reversal of the modern salinity contrast between the North and South Atlantic implies that the freshwater budget at the poles must have been quite different. A strict conversion of mean salinity at the LGM to equivalent sea-level change yields a value in excess of 140 meters. However, the storage of fresh water in ice shelves and/or groundwater reserves implies that glacial salinity is a poor predictor of mean sea level.
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Affiliation(s)
- Jess F Adkins
- MS 100-23, Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
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25
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Adkins J. Paleoclimate. Dating--vive la différence. Science 2001; 294:1844-5. [PMID: 11729292 DOI: 10.1126/science.1067544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- J Adkins
- California Institute of Technology, Pasadena, CA 91125, USA.
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26
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Affiliation(s)
- E Bard
- Centre Européen de Recherche et d'Enseignement en Géosciences de l'Environnement, CNRS-Université d'Aix-Marseille III, UMR-6635, Europole de l'Arbois, 13545 Aix-en-Provence cedex 4, France.
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Beck JW, Richards DA, Edwards RL, Silverman BW, Smart PL, Donahue DJ, Hererra-Osterheld S, Burr GS, Calsoyas L, Jull AJ, Biddulph D. Extremely Large Variations of Atmospheric 14C Concentration During the Last Glacial Period. Science 2001; 292:2453-8. [PMID: 11349137 DOI: 10.1126/science.1056649] [Citation(s) in RCA: 275] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A long record of atmospheric 14C concentration, from 45 to 11 thousand years ago (ka), was obtained from a stalagmite with thermal-ionization mass-spectrometric 230Th and accelerator mass-spectrometric 14C measurements. This record reveals highly elevated Delta14C between 45 and 33 ka, portions of which may correlate with peaks in cosmogenic 36Cl and 10Be isotopes observed in polar ice cores. Superimposed on this broad peak of Delta14C are several rapid excursions, the largest of which occurs between 44.3 and 43.3 ka. Between 26 and 11 ka, atmospheric Delta14C decreased from approximately 700 to approximately 100 per mil, modulated by numerous minor excursions. Carbon cycle models suggest that the major features of this record cannot be produced with solar or terrestrial magnetic field modulation alone but also require substantial fluctuations in the carbon cycle.
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Affiliation(s)
- J W Beck
- NSF-Arizona Accelerator Mass Spectrometry Facility, Department of Physics, University of Arizona, Tucson, AZ 85721, USA.
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28
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Abstract
Sea level change during the Quaternary is primarily a consequence of the cyclic growth and decay of ice sheets, resulting in a complex spatial and temporal pattern. Observations of this variability provide constraints on the timing, rates, and magnitudes of the changes in ice mass during a glacial cycle, as well as more limited information on the distribution of ice between the major ice sheets at any time. Observations of glacially induced sea level changes also provide information on the response of the mantle to surface loading on time scales of 10(3) to 10(5) years. Regional analyses indicate that the earth-response function is depth dependent as well as spatially variable. Comprehensive models of sea level change enable the migration of coastlines to be predicted during glacial cycles, including the anthropologically important period from about 60,000 to 20,000 years ago.
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Affiliation(s)
- K Lambeck
- Research School of Earth Sciences, The Australian National University, Canberra 0200, Australia
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29
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Wang Y, Wu J, Wu J, Mu X, Xu H, Chen J. Correlation between high-resolution climate records from a Nanjing stalagmite and GRIP ice core during the last glaciation. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/bf02906881] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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Hughen KA, Southon JR, Lehman SJ, Overpeck JT. Synchronous radiocarbon and climate shifts during the last deglaciation. Science 2000; 290:1951-5. [PMID: 11110659 DOI: 10.1126/science.290.5498.1951] [Citation(s) in RCA: 324] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Radiocarbon data from the Cariaco Basin provide calibration of the carbon-14 time scale across the period of deglaciation (15,000 to 10, 000 years ago) with resolution available previously only from Holocene tree rings. Reconstructed changes in atmospheric carbon-14 are larger than previously thought, with the largest change occurring simultaneously with the sudden climatic cooling of the Younger Dryas event. Carbon-14 and published beryllium-10 data together suggest that concurrent climate and carbon-14 changes were predominantly the result of abrupt shifts in deep ocean ventilation.
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Affiliation(s)
- K A Hughen
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
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31
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Abstract
During the Last Glacial Maximum, ice sheets covered large areas in northern latitudes and global temperatures were significantly lower than today. But few direct estimates exist of the volume of the ice sheets, or the timing and rates of change during their advance and retreat. Here we analyse four distinct sediment facies in the shallow, tectonically stable Bonaparte Gulf, Australia--each of which is characteristic of a distinct range in sea level--to estimate the maximum volume of land-based ice during the last glaciation and the timing of the initial melting phase. We use faunal assemblages and preservation status of the sediments to distinguish open marine, shallow marine, marginal marine and brackish conditions, and estimate the timing and the mass of the ice sheets using radiocarbon dating and glacio-hydro-isostatic modelling. Our results indicate that from at least 22,000 to 19,000 (calendar) years before present, land-based ice volume was at its maximum, exceeding today's grounded ice sheets by 52.5 x 10(6) km. A rapid decrease in ice volume by about 10% within a few hundred years terminated the Last Glacial Maximum at 19,000 +/- 250 years.
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32
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Old radiocarbon ages in the southwest Pacific Ocean during the last glacial period and deglaciation. Nature 2000; 405:555-9. [PMID: 10850711 DOI: 10.1038/35014581] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Marine radiocarbon (14C) dates are widely used for dating oceanic events and as tracers of ocean circulation, essential components for understanding ocean-climate interactions. Past ocean ventilation rates have been determined by the difference between radiocarbon ages of deep-water and surface-water reservoirs, but the apparent age of surface waters (currently approximately 400 years in the tropics and approximately 1,200 years in Antarctic waters) might not be constant through time, as has been assumed in radiocarbon chronologies and palaeoclimate studies. Here we present independent estimates of surface-water and deep-water reservoir ages in the New Zealand region since the last glacial period, using volcanic ejecta (tephras) deposited in both marine and terrestrial sediments as stratigraphic markers. Compared to present-day values, surface-reservoir ages from 11,900 14C years ago were twice as large (800 years) and during glacial times were five times as large (2,000 years), contradicting the assumption of constant surface age. Furthermore, the ages of glacial deep-water reservoirs were much older (3,000-5,000 years). The increase in surface-to-deep water age differences in the glacial Southern Ocean suggests that there was decreased ocean ventilation during this period.
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33
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Hanebuth T, Stattegger K, Grootes PM. Rapid flooding of the sunda shelf: A late-glacial sea-level record. Science 2000; 288:1033-5. [PMID: 10807570 DOI: 10.1126/science.288.5468.1033] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The increase in sea level from the last glacial maximum has been derived from a siliciclastic system on the tectonically stable Sunda Shelf in Southeast Asia. The time from 21 to 14 thousand calendar years before the present has been poorly covered in other records. The record generally confirms sea-level reconstructions from coral reefs. The rise of sea level during meltwater pulse 1A was as much as 16 meters within 300 years (14.6 to 14.3 thousand years ago).
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Affiliation(s)
- T Hanebuth
- Institute of Geosciences, University of Kiel, Olshausenstrasse 40, 24 118 Kiel, Germany
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34
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Variations of Younger Dryas atmospheric radiocarbon explicable without ocean circulation changes. Nature 2000; 403:877-80. [PMID: 10706281 DOI: 10.1038/35002547] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The concentration of radiocarbon, 14C, in the atmosphere depends on its production rate by cosmic rays, and on the intensity of carbon exchange between the atmosphere and other reservoirs, for example the deep oceans. For the Holocene (the past approximately 11,500 years), it has been shown that fluctuations in atmospheric radiocarbon concentrations have been caused mostly by variations in the solar magnetic field. Recent progress in extending the radiocarbon record backwards in time has indicated especially high atmospheric radiocarbon concentrations in the Younger Dryas cold period, between 12,700 and 11,500 years before the present. These high concentrations have been interpreted as a result of a reduced exchange with the deep-ocean reservoir, caused by a drastic weakening of the deep-ocean ventilation. Here we present a high-resolution reconstruction of atmospheric radiocarbon concentrations, derived from annually laminated sediments of two Polish lakes, Lake Gosciaz and Lake Perespilno. These records indicate that the maximum in atmospheric radiocarbon concentrations in the early Younger Dryas was smaller than previously believed, and might have been caused by variations in solar activity. If so, there is no indication that the deep-ocean ventilation in the Younger Dryas was significantly different from today's.
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35
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Esat TM, McCulloch MT, Chappell J, Pillans B, Omura A. Rapid fluctuations in sea level recorded at huon peninsula during the penultimate deglaciation. Science 1999; 283:197-201. [PMID: 9880247 DOI: 10.1126/science.283.5399.197] [Citation(s) in RCA: 154] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
About 140,000 years ago, the breakup of large continental ice sheets initiated the Last Interglacial period. Sea level rose and peaked around 135,000 years ago about 14 meters below present levels. A record of Last Interglacial sea levels between 116,000 years to 136, 000 years ago is preserved at reef VII of the uplifted coral terraces of Huon Peninsula in Papua New Guinea. However, corals from a cave situated about 90 meters below the crest of reef VII are 130, 000 +/- 2000 years old and appear to have grown in conditions that were 6 degreesC cooler than those at present. These observations imply a drop in sea level of 60 to 80 meters. After 130,000 years, sea level began rising again in response to the major insolation maximum at 126,000 to 128,000 years ago. The early (about 140,000 years ago) start of the penultimate deglaciation, well before the peak in insolation, is consistent with the Devils Hole chronology.
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Affiliation(s)
- TM Esat
- T. M. Esat, M. T. McCulloch, J. Chappell, B. Pillans, Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia. A. Omura, Kanazawa University, Kanazawa, Ishikawa 920, Japan
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36
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Physical and biogeochemical responses to freshwater-induced thermohaline variability in a zonally averaged ocean model. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/gm112p0263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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37
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Mix AC, Lund DC, Pisias NG, Bodén P, Bornmalm L, Lyle M, Pike J. Rapid climate oscillations in the Northeast Pacific during the last deglaciation reflect Northern and Southern Hemisphere sources. MECHANISMS OF GLOBAL CLIMATE CHANGE AT MILLENNIAL TIME SCALES 1999. [DOI: 10.1029/gm112p0127] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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38
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Rubin CM, Lindvall SC, Rockwell TK. Evidence for large earthquakes in metropolitan los angeles. Science 1998; 281:398-402. [PMID: 9665880 DOI: 10.1126/science.281.5375.398] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Sierra Madre fault, along the southern flank of the San Gabriel Mountains in the Los Angeles region, has failed in magnitude 7.2 to 7.6 events at least twice in the past 15,000 years. Restoration of slip on the fault indicated a minimum of about 4.0 meters of slip from the most recent earthquake and suggests a total cumulative slip of about 10.5 meters for the past two prehistoric earthquakes. Large surface displacements and strong ground motions resulting from greater than magnitude 7 earthquakes within the Los Angeles region are not yet considered in most seismic hazard and risk assessments.
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Affiliation(s)
- CM Rubin
- C. M. Rubin, Department of Geology, Central Washington University, Ellensburg, WA 98926, USA. S. C. Lindvall, William Lettis and Associates, 27201 Tourney Road, Suite 201-B, Valencia, CA 91355, USA. T. K. Rockwell, Department of Geological Scie
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39
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Abstract
The history of the immigration of East Asians to America during the last glacial period remains controversial. In an attempt to add critical data to this problem, a large sample of whole teeth derived from Southeast Asian, Mongolian, Thule, Western Inuit, and pre-Inca (Huari) people was quantified (N = 4,507 teeth from 495 individuals; approximately 30 variables per tooth). Multivariate analysis helped establish that all Native Americans were likely derived from one ancient, extinct population that resided in the region of Mongolia (east Central Asia), and that Mongolians and Southeast Asians are two independent groups. A controversial and enigmatic Central Canadian Arctic "Thule culture Inuit" group on Southampton Island that survived until 1902 was identified as a relic, mainly Paleoeskimo Dorset community. Surprisingly, there was little, or no, indication of Dorset-to-Thule gene flow. Cumulatively, the data suggest that a small population of Paleoindian founders remained resident in Beringia, may have blocked further immigration, and were the antecedents to the Thule/Inuit. With the confluence of the Arctic and Pacific oceans at the breakup of Beringia, the resulting increased availability of marine animal food sources allowed this population to increase in size and expand throughout the eastern Arctic.
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Affiliation(s)
- E D Shields
- Department of Oral Biology, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.
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40
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Adkins JF, Cheng H, Boyle EA, Druffel ERM, Edwards RL. Deep-Sea coral evidence for rapid change in ventilation of the deep north atlantic 15,400 years Ago. Science 1998; 280:725-8. [PMID: 9563946 DOI: 10.1126/science.280.5364.725] [Citation(s) in RCA: 194] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Coupled radiocarbon and thorium-230 dates from benthic coral species reveal that the ventilation rate of the North Atlantic upper deep water varied greatly during the last deglaciation. Radiocarbon ages in several corals of the same age, 15.41 +/- 0.17 thousand years, and nearly the same depth, 1800 meters, in the western North Atlantic Ocean increased by as much as 670 years during the 30- to 160-year life spans of the samples. Cadmium/calcium ratios in one coral imply that the nutrient content of these deep waters also increased. Our data show that the deep ocean changed on decadal-centennial time scales during rapid changes in the surface ocean and the atmosphere.
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Affiliation(s)
- JF Adkins
- J. F. Adkins and E. A. Boyle, Department of Earth, Atmosphere and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. H. Cheng and R. L. Edwards, Department of Geology and Geophysics, University of Minnesota, Minne
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41
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Kitagawa H. Atmospheric radiocarbon calibration to 45,000 yr B.P.: late glacial fluctuations and cosmogenic isotope production. Science 1998; 279:1187-90. [PMID: 9469804 DOI: 10.1126/science.279.5354.1187] [Citation(s) in RCA: 316] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
More than 250 carbon-14 accelerator mass spectrometry dates of terrestrial macrofossils from annually laminated sediments from Lake Suigetsu (Japan) provide a first atmospheric calibration for almost the total range of the radiocarbon method (45,000 years before the present). The results confirm the (recently revised) floating German pine chronology and are consistent with data from European and marine varved sediments, and combined uranium-thorium and carbon-14 dating of corals up to the Last Glacial Maximum. The data during the Glacial show large fluctuations in the atmospheric carbon-14 content, related to changes in global environment and in cosmogenic isotope production.
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Affiliation(s)
- H Kitagawa
- H. Kitagawa, International Research Center for Japanese Studies, 3-2, Goryo Oeyama-cho, Nishikyo-ku, Kyoto, 610-1192 Japan. J. van der Plicht, Centre for Isotope Research, Nijenborgh 4, 9747AG Groningen, Netherlands
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42
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43
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Abrupt Climatic Changes Associated with the Arid Younger Dryas Interval in Africa. ACTA ACUST UNITED AC 1998. [DOI: 10.1007/978-94-017-1437-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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44
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Alley RB, Shuman CA, Meese DA, Gow AJ, Taylor KC, Cuffey KM, Fitzpatrick JJ, Grootes PM, Zielinski GA, Ram M, Spinelli G, Elder B. Visual-stratigraphic dating of the GISP2 ice core: Basis, reproducibility, and application. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/96jc03837] [Citation(s) in RCA: 178] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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Grootes PM, Stuiver M. Oxygen 18/16 variability in Greenland snow and ice with 10−3- to 105-year time resolution. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jc00880] [Citation(s) in RCA: 729] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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46
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Leuenberger MC. Modeling the signal transfer of sea water δ18O to the δ18O of atmospheric oxygen using a diagnostic box model for the terrestrial and marine biosphere. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jc00160] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Mayewski PA, Meeker LD, Twickler MS, Whitlow S, Yang Q, Lyons WB, Prentice M. Major features and forcing of high-latitude northern hemisphere atmospheric circulation using a 110,000-year-long glaciochemical series. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/96jc03365] [Citation(s) in RCA: 648] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yang Q, Mayewski PA, Twickler MS, Whitlow S. Major features of glaciochemistry over the last 110,000 years in the Greenland Ice Sheet Project 2 ice core. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jd00737] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Druffel ER. Geochemistry of corals: proxies of past ocean chemistry, ocean circulation, and climate. Proc Natl Acad Sci U S A 1997; 94:8354-61. [PMID: 11607745 PMCID: PMC33753 DOI: 10.1073/pnas.94.16.8354] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This paper presents a discussion of the status of the field of coral geochemistry as it relates to the recovery of past records of ocean chemistry, ocean circulation, and climate. The first part is a brief review of coral biology, density banding, and other important factors involved in understanding corals as proxies of environmental variables. The second part is a synthesis of the information available to date on extracting records of the carbon cycle and climate change. It is clear from these proxy records that decade time-scale variability of mixing processes in the oceans is a dominant signal. That Western and Eastern tropical Pacific El Niño-Southern Oscillation (ENSO) records differ is an important piece of the puzzle for understanding regional and global climate change. Input of anthropogenic CO2 to the oceans as observed by 13C and 14C isotopes in corals is partially obscured by natural variability. Nonetheless, the general trend over time toward lower delta18O values at numerous sites in the world's tropical oceans suggests a gradual warming and/or freshening of the surface ocean over the past century.
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Affiliation(s)
- E R Druffel
- Department of Earth System Science, University of California, Irvine, CA 92697, USA
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Plummer MA, Phillips FM, Fabryka-Martin J, Turin HJ, Wigand PE, Sharma P. Chlorine-36 in fossil rat urine: an archive of cosmogenic nuclide deposition during the past 40,000 years. Science 1997; 277:538-41. [PMID: 9227999 DOI: 10.1126/science.277.5325.538] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Knowledge of the production history of cosmogenic nuclides, which is needed for geological and archaeological dating, has been uncertain. Measurements of chlorine-36/chlorine (36Cl/Cl) ratios in fossil packrat middens from Nevada that are radiocarbon-dated between about 38 thousand years ago (ka) and the present showed that 36Cl/Cl ratios were higher by a factor of about 2 before approximately 11 ka. This raises the possibility that cosmogenic production rates just before the close of the Pleistocene were up to 50% higher than is suggested by carbon-14 calibration data. The discrepancy could be explained by addition of low-carbon-14 carbon dioxide to the atmosphere during that period, which would have depressed atmospheric radiocarbon activity. Alternatively, climatic effects on 36Cl deposition may have enhanced the 36Cl/Cl ratios.
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Affiliation(s)
- M A Plummer
- Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, NM 87801, USA
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