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Drysdale R, Couchoud I, Zanchetta G, Isola I, Regattieri E, Hellstrom J, Govin A, Tzedakis PC, Ireland T, Corrick E, Greig A, Wong H, Piccini L, Holden P, Woodhead J. Magnesium in subaqueous speleothems as a potential palaeotemperature proxy. Nat Commun 2020; 11:5027. [PMID: 33024094 PMCID: PMC7538886 DOI: 10.1038/s41467-020-18083-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 08/01/2020] [Indexed: 11/09/2022] Open
Abstract
Few palaeoclimate archives beyond the polar regions preserve continuous and datable palaeotemperature proxy time series over multiple glacial-interglacial cycles. This hampers efforts to develop a more coherent picture of global patterns of past temperatures. Here we show that Mg concentrations in a subaqueous speleothem from an Italian cave track regional sea-surface temperatures over the last 350,000 years. The Mg shows higher values during warm climate intervals and converse patterns during cold climate stages. In contrast to previous studies, this implicates temperature, not rainfall, as the principal driver of Mg variability. The depositional setting of the speleothem gives rise to Mg partition coefficients that are more temperature dependent than other calcites, enabling the effect of temperature change on Mg partitioning to greatly exceed the effects of changes in source-water Mg/Ca. Subaqueous speleothems from similar deep-cave environments should be capable of providing palaeotemperature information over multiple glacial-interglacial cycles. Few palaeoclimate archives beyond the polar regions preserve continuous and datable paleotemperature proxy time series over multiple glacial-interglacial cycles. Here, the authors show that Mg concentrations in a subaqueous speleothem from an Italian cave track regional sea-surface temperatures over the last 350,000 years.
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Affiliation(s)
- Russell Drysdale
- School of Geography, The University of Melbourne, Parkville, 3010, VIC, Australia. .,Laboratoire EDYTEM, UMR CNRS 5204, Université Savoie Mont Blanc, 73376, Le Bourget-du-Lac cedex, France.
| | - Isabelle Couchoud
- School of Geography, The University of Melbourne, Parkville, 3010, VIC, Australia.,Laboratoire EDYTEM, UMR CNRS 5204, Université Savoie Mont Blanc, 73376, Le Bourget-du-Lac cedex, France
| | - Giovanni Zanchetta
- Dipartimento di Scienze delle Terra and CIRSEC, University of Pisa, 56126, Pisa, Italy
| | - Ilaria Isola
- Istituto Nazionale di Geofisica e Vulcanologia, 56126, Pisa, Italy
| | - Eleonora Regattieri
- Istituto di Geoscienze e Georisorse, IGG-CNR, Via Moruzzi 1, 56126, Pisa, Italy
| | - John Hellstrom
- School of Earth Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia
| | - Aline Govin
- LSCE-IPSL (CEA-CNRS-UVSQ), Paris-Saclay University, 91190, Gif-sur Yvette, France
| | - Polychronis C Tzedakis
- Environmental Change Research Centre, Department of Geography, University College London, London, WC1E 6BT, UK
| | - Trevor Ireland
- Research School of Earth Sciences, The Australian National University, Canberra, 2600, ACT, Australia
| | - Ellen Corrick
- School of Geography, The University of Melbourne, Parkville, 3010, VIC, Australia
| | - Alan Greig
- School of Earth Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia
| | - Henri Wong
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2234, Australia
| | - Leonardo Piccini
- Dipartimento di Scienze delle Terra, Universita degli Studi di Firenze, Via la Pira 4, 50121, Firenze, Italy
| | - Peter Holden
- Research School of Earth Sciences, The Australian National University, Canberra, 2600, ACT, Australia
| | - Jon Woodhead
- School of Earth Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia
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Climate during the Last Glacial Maximum in the Northern Sawatch Range, Colorado, USA. QUATERNARY 2019. [DOI: 10.3390/quat2040036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Temperature-index modeling is used to determine the magnitude of temperature depression in the northern Sawatch Range required to maintain steady-state mass balances of six reconstructed glaciers at their extent during the local Last Glacial Maximum (LLGM), dated at ~21 ka. Assuming no significant differences in precipitation compared to modern values, mean annual temperatures in the region were on average 8.8 + 0.5/– 0.8 °C cooler than they are today. Allowing for modest (± 10 cm) increases or decreases in precipitation, required temperature depressions only differ by ±0.2 °C. Temperature depression in the northern Sawatch Range is consistent, although slightly greater, with those determined in other ranges in Colorado using similar approaches. The estimates presented here are, however, substantially less than those suggested by several downscaled simulations of global Last Glacial Maximum (LGM) climate, that might be due to the need for improved calibration of such downscaled simulations, or the models from which they are derived. Our estimates of LGM temperature depression are considerably greater than that previously determined in the study area and those in two other ranges in Colorado derived using different methodologies, the latter being most likely responsible for the discrepancies.
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Lu H, Liu W, Yang H, Wang H, Liu Z, Leng Q, Sun Y, Zhou W, An Z. 800-kyr land temperature variations modulated by vegetation changes on Chinese Loess Plateau. Nat Commun 2019; 10:1958. [PMID: 31036861 PMCID: PMC6488643 DOI: 10.1038/s41467-019-09978-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 04/05/2019] [Indexed: 11/10/2022] Open
Abstract
The complicity of long-term land surface temperature (LST) changes has been under investigated and less understood, hindering our understanding of the history and mechanism of terrestrial climate change. Here, we report the longest (800 thousand years) LSTs based on distributions of soil fossil bacterial glycerol dialkyl glycerol tetraethers preserved in well-dated loess-paleosol sequences at the center of the Chinese Loess Plateau. We have found a previously-unrecognized increasing early and prolonged warming pattern toward the northwestern plateau at the onset of the past seven deglaciations, corresponding to the decrease in vegetation coverage, suggesting underlying surface vegetation or lack of has played an important role in regulating LSTs, superimposed on the fundamental global glacial–interglacial changes. Our results support that LSTs in semi-humid and semi-arid regions with little vegetation will be more sensitive to the anticipated global temperature rise, while improving vegetation coverage would reduce LSTs and thus ecological impacts. Modern observation indicates that vegetation cover could modulate land surface temperatures substantially. Here the authors demonstrate that such vegetation feedbacks could be clearly identified in the Chinese Loess Plateau land surface temperature records during past cool periods when vegetation cover was reduced.
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Affiliation(s)
- Hongxuan Lu
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710061, Xi'an, China.,CAS Center for Excellence in Quaternary Science and Global Change, 710061, Xi'an, China
| | - Weiguo Liu
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710061, Xi'an, China. .,CAS Center for Excellence in Quaternary Science and Global Change, 710061, Xi'an, China.
| | - Hong Yang
- Laboratory for Terrestrial Environments, Department of Science and Technology, College of Arts and Sciences, Bryant University, Smithfield, RI, 02917, USA.
| | - Huanye Wang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710061, Xi'an, China.,CAS Center for Excellence in Quaternary Science and Global Change, 710061, Xi'an, China
| | - Zhonghui Liu
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| | - Qin Leng
- Laboratory for Terrestrial Environments, Department of Science and Technology, College of Arts and Sciences, Bryant University, Smithfield, RI, 02917, USA
| | - Youbin Sun
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710061, Xi'an, China.,CAS Center for Excellence in Quaternary Science and Global Change, 710061, Xi'an, China
| | - Weijian Zhou
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710061, Xi'an, China.,CAS Center for Excellence in Quaternary Science and Global Change, 710061, Xi'an, China
| | - Zhisheng An
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710061, Xi'an, China.,CAS Center for Excellence in Quaternary Science and Global Change, 710061, Xi'an, China
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Timing of the Brunhes-Matuyama transition constrained by U-series disequilibrium. Sci Rep 2019; 9:6039. [PMID: 30988519 PMCID: PMC6465598 DOI: 10.1038/s41598-019-42567-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/03/2019] [Indexed: 12/02/2022] Open
Abstract
U-series disequilibrium measurements carried out on thermogenic travertine samples from a 12.6 m-long core and a 10 m-thick section from southeastern Morocco yielded finite ages ranging from 500 ka to the present-day, as well as two clusters determined to be older than 500 ka. The calculation of initial 234U/238U activity ratios in all samples younger than 500 ka shows high, reasonably constant values, with an average of 5.172 ± 0.520 (one standard deviation). Assuming that this value prevailed for periods older than 500 ka, we derived ages of up to approximately 1.2 Ma using the initial 234U excess decay. Our results indicate that the two older clusters have ages of 776 ± 14 ka for samples from between 8 and 10.1 m and 1173 ± 22 ka for deeper samples respectively. The palaeomagnetic record of the core shows normal polarity inclinations from the surface to around 9 m followed by reverse polarity inclination and antipodal declinations. The inversion is attributed to the Brunhes-Matuyama transition. 234U excess ages for the interval corresponding to the part of the core where the polarity inversion occurred are in the range of 735 ± 51 to 794 ± 54 ka, with an arithmetic mean value of 776 ± 14 ka for the B-M transition. This age is in good agreement with that determined previously using other dating methods.
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Speleothem Paleoclimatology for the Caribbean, Central America, and North America. QUATERNARY 2019. [DOI: 10.3390/quat2010005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Speleothem oxygen isotope records from the Caribbean, Central, and North America reveal climatic controls that include orbital variation, deglacial forcing related to ocean circulation and ice sheet retreat, and the influence of local and remote sea surface temperature variations. Here, we review these records and the global climate teleconnections they suggest following the recent publication of the Speleothem Isotopes Synthesis and Analysis (SISAL) database. We find that low-latitude records generally reflect changes in precipitation, whereas higher latitude records are sensitive to temperature and moisture source variability. Tropical records suggest precipitation variability is forced by orbital precession and North Atlantic Ocean circulation driven changes in atmospheric convection on long timescales, and tropical sea surface temperature variations on short timescales. On millennial timescales, precipitation seasonality in southwestern North America is related to North Atlantic climate variability. Great Basin speleothem records are closely linked with changes in Northern Hemisphere summer insolation. Although speleothems have revealed these critical global climate teleconnections, the paucity of continuous records precludes our ability to investigate climate drivers from the whole of Central and North America for the Pleistocene through modern. This underscores the need to improve spatial and temporal coverage of speleothem records across this climatically variable region.
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Wendt KA, Dublyansky YV, Moseley GE, Edwards RL, Cheng H, Spötl C. Moisture availability in the southwest United States over the last three glacial-interglacial cycles. SCIENCE ADVANCES 2018; 4:eaau1375. [PMID: 30397648 PMCID: PMC6200359 DOI: 10.1126/sciadv.aau1375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 09/20/2018] [Indexed: 06/08/2023]
Abstract
The projected long-term drying of the southwest (SW) United States in response to climate warming raises a sobering alarm for this already water-limited region, yet the climatic controls on moisture availability over longer time scales remain a topic of debate. Here, we present a 350,000-year record of past water table fluctuations in Devils Hole 2 cave that are driven by variations in recharge amount to the local groundwater flow system. Because of the unprecedented length and precision of our record, we can observe variations in regional moisture availability over the last three glacial-interglacial cycles at a millennial-scale resolution. The timing of past water table rises and falls (>9 m in amplitude) closely coincides with the expansion and reduction of Northern Hemisphere ice volume, which in turn influences the position and intensity of westerly winter storms on orbital time scales. Superimposed on this long-term trend are millennial-scale highstands recorded during the last glaciation that coincide with North Atlantic Heinrich events. Earlier millennial-scale highstands provide the first evidence of multiple short-lived wet periods in the SW United States linked to coeval cooling intervals in the North Atlantic during marine isotope stages 6 and 8. The Devils Hole 2 water table record is currently the longest independently dated paleomoisture record in the SW United States and thus provides a critical testbed to examine the controls on regional moisture availability over larger time scales.
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Affiliation(s)
- Kathleen A. Wendt
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Yuri V. Dublyansky
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - Gina E. Moseley
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
| | - R. Lawrence Edwards
- Department of Earth Sciences, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455, USA
| | - Hai Cheng
- Department of Earth Sciences, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455, USA
- Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an 710049, China
| | - Christoph Spötl
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
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7
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Arctic cryosphere and Milankovitch forcing of Great Basin paleoclimate. Sci Rep 2017; 7:12955. [PMID: 29021632 PMCID: PMC5636905 DOI: 10.1038/s41598-017-13279-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/19/2017] [Indexed: 11/28/2022] Open
Abstract
Although Great Basin paleoclimate history has been examined for more than a century, the orbital-scale paleoclimate forcings remain poorly understood. Here we show – by a detailed phasing analysis of a well-dated stalagmite δ18O time series – that Great Basin paleoclimate is linearly related to, but lagged, the 23,000 yr precession cycle in northern hemisphere summer insolation by an average of 3240 years (−900 to 6600 yr range) over the last two glacial cycles. We interpret these lags as indicating that Great Basin climate is sensitive to and indirectly forced by changes in the cryosphere, as evidenced by fast and strong linkages to global ice volume and Arctic paleoclimate indicators. Mid-latitude atmospheric circulation was likely impacted by a northward shifted storm track and higher pressure over the region arising from decreased sea ice and snow cover. Because anthropogenic warming is expected to reduce northern hemisphere snow and ice cover, continued increase in atmospheric greenhouse gases is likely to result in warming and drying over coming centuries that will amplify a warming trend that began ~2400 years ago.
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Moseley GE, Dublyansky YV, Edwards RL, Wendt KA, Pythoud M, Zhang P, Cheng H, Lu Y, Boch R, Spötl C. Response to Comments on "Reconciliation of the Devils Hole climate record with orbital forcing". Science 2016; 354:296. [PMID: 27846529 DOI: 10.1126/science.aaf8679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/21/2016] [Indexed: 11/02/2022]
Abstract
Winograd and Coplen question the thorium-230 distribution model proposed to explain the age bias observed with increasing depth during Termination II. We have evaluated both criticisms and find that all samples display virtually identical fabrics, argue that the modern setting is not analogous to the conditions during Termination II, and reiterate the robustness of our age models. Our conclusions remain unchanged.
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Affiliation(s)
- Gina E Moseley
- Institute of Geology, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria.
| | - Yuri V Dublyansky
- 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
| | - Mathieu Pythoud
- Department of Earth Sciences, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, USA
| | - Pu Zhang
- 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
| | - 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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9
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Winograd IJ. Comment on "Reconciliation of the Devils Hole climate record with orbital forcing". Science 2016; 354:296. [PMID: 27846527 DOI: 10.1126/science.aaf7718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 09/21/2016] [Indexed: 11/02/2022]
Abstract
Moseley et al (Reports, 8 January 2016, p. 165) postulate an increase in dissolved thorium isotope 230Th with depth below the water table as the explanation for the differing ages of Termination II. Flow of geothermal water through the Devils Hole caverns precludes this explanation. Deposition of younger secondary calcite into the initial porosity of the calcite comprising their cores is a plausible alternate explanation.
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10
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Coplen TB. Comment on "Reconciliation of the Devils Hole climate record with orbital forcing". Science 2016; 354:296. [PMID: 27846528 DOI: 10.1126/science.aaf8074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 09/21/2016] [Indexed: 11/03/2022]
Abstract
Moseley et al's (Reports, 8 January 2016, p. 165) preferred-Termination-II age is subjective, as evidenced by variation in their Termination-II ages of 2500 years per meter. Termination-II-age bias decreases to zero at ~1.5 meters below the present-day water table, if one assumes linear variation with core-sample height. Maintaining the required gradient of thorium isotope 230Th over 3.6 meters for 1000 years, much less 10,000 years, seems exceedingly unlikely.
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Affiliation(s)
- Tyler B Coplen
- U.S. Geological Survey, 431 National Center, Reston, VA 20192, USA
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