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  1. Article ; Online: Author Correction

    Paul S. Wilcox / Charlotte Honiat / Martin Trüssel / R. Lawrence Edwards / Christoph Spötl

    Communications Earth & Environment, Vol 3, Iss 1, Pp 1-

    Exceptional warmth and climate instability occurred in the European Alps during the last interglacial period

    2022  Volume 6

    Keywords Geology ; QE1-996.5 ; Environmental sciences ; GE1-350
    Language English
    Publishing date 2022-04-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: A 350,000-year history of groundwater recharge in the southern Great Basin, USA

    Tracie R. Jackson / Simon D. Steidle / Kathleen A. Wendt / Yuri Dublyansky / R. Lawrence Edwards / Christoph Spötl

    Communications Earth & Environment, Vol 4, Iss 1, Pp 1-

    2023  Volume 10

    Abstract: Water-table changes in the southern Great Basin, USA, over the last 350,000 years are 3–4 times as sensitive to recharge changes during drier interglacial than wetter glacial conditions, according to modelling of groundwater flow model informed by paleo- ... ...

    Abstract Water-table changes in the southern Great Basin, USA, over the last 350,000 years are 3–4 times as sensitive to recharge changes during drier interglacial than wetter glacial conditions, according to modelling of groundwater flow model informed by paleo-water-level data.
    Keywords Geology ; QE1-996.5 ; Environmental sciences ; GE1-350
    Language English
    Publishing date 2023-03-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Effects of Ice Freeze-Thaw Processes on U Isotope Compositions in Saline Lakes and Their Potential Environmental Implications

    Pu Zhang / Chenyang Cao / Xiangzhong Li / Xuezheng Pei / Chi Chen / Lihua Liang / Youfeng Ning / Liangcheng Tan / R. Lawrence Edwards

    Frontiers in Earth Science, Vol

    2021  Volume 9

    Abstract: The dissolved uranium (U) content in the water column of saline lakes varies little between ice-free seasons throughout the whole water column. Such uniformity allows for the potential absolute dating and/or paleohydrologic interpretations of lake ... ...

    Abstract The dissolved uranium (U) content in the water column of saline lakes varies little between ice-free seasons throughout the whole water column. Such uniformity allows for the potential absolute dating and/or paleohydrologic interpretations of lake sediments and biogenic shell materials using U isotopes. Before using these methods in cold regions, however, it is necessary to evaluate the effects that ice freeze-thaw processes have on the distribution of U isotopes in saline lake waters, and to determine the amount of variation in U isotopic values when such processes occur. In this paper, we collected ice and dissolved water samples from six lakes with variable salinity in February 2021. Five groundwater and three water samples from rivers into Qinghai Lake were sampled in November 2020. The sampled water was analyzed for dissolved concentrations of 238U and the activity ratio of 234U/238U ([234U/238U]AR). The results show that the 238U concentration of ice samples was less than that of the underlying water. The [234U/238U]AR of ice in the five saline lakes was similar to that of the underlying water with less than a 10‰ variation, suggesting no observable fractionation between ice and dissolved water. Thus, the ice freeze-thaw processes have almost no effect on the uranium content and [234U/238U]AR of the sampled saline lakes, which were characterized by a limited recharge volume from surface runoff, groundwater, and ice volume, namely the close saline lake in arid alpine background. The results from the indoor freeze-thaw experiments also showed that the U isotopic composition of Qinghai Lake waters and ice were similar with the 238U concentration of the ice was about 40% of that of the dissolved lake water, supporting the data obtained from natural saline lakes. The above results provide important insights into whether it is feasible to use U isotopes for absolute dating and/or paleohydrologic analysis of lake sediments or biogenic shell materials. In addition, the results are important for evaluating the [234U/238U]AR and uranium concentrations in seawater when there exists a process of melting polar ice, and for determining the initial delta 234U variations needed for dating of coral and other fossil materials.
    Keywords U isotopes ; saline lakes ; freeze-thaw processes ; Qinghai region ; Qaidam basin ; Science ; Q
    Subject code 550
    Language English
    Publishing date 2021-12-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Millennial and orbital scale variability of the South American Monsoon during the penultimate glacial period

    Stephen J. Burns / Lisa Kanner Welsh / Nick Scroxton / Hai Cheng / R. Lawrence Edwards

    Scientific Reports, Vol 9, Iss 1, Pp 1-

    2019  Volume 5

    Abstract: Abstract The presence of large, rapid climate oscillations is the most prominent feature of the Earth’s last glacial period. These oscillations are observed throughout the Northern Hemisphere and into the Southern Hemisphere tropics. Whether similar ... ...

    Abstract Abstract The presence of large, rapid climate oscillations is the most prominent feature of the Earth’s last glacial period. These oscillations are observed throughout the Northern Hemisphere and into the Southern Hemisphere tropics. Whether similar oscillations are typical of prior glacial periods, however, has not been well established. Here, we present results of a study of the South American Summer Monsoon system that covers nearly the entire penultimate glacial period, from 195 to 135 ky BP. We use a well-dated, high-resolution (~50 y) time series of oxygen isotopes to show that the precession of the earth’s orbit is the primary control on monsoon intensity. After removing the precession signal we observe millennial oscillations that are very similar in amplitude and structure to the Dansgaard/Oeschger cycles of the last interglacial and that match well a synthetic reconstruction of millennial variability. Time series analyses shows that the most prominent of the observed cycles occur at considerably longer frequency (~3500 y) that the Dansgaard/Oeschger cycles from Marine Isotope Stages 2–4.
    Keywords Medicine ; R ; Science ; Q
    Subject code 550
    Language English
    Publishing date 2019-02-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Antiphase response of the Indonesian–Australian monsoon to millennial-scale events of the last glacial period

    Nick Scroxton / Michael K. Gagan / Linda K. Ayliffe / Wahyoe S. Hantoro / John C. Hellstrom / Hai Cheng / R. Lawrence Edwards / Jian-xin Zhao / Bambang W. Suwargadi / Hamdi Rifai

    Scientific Reports, Vol 12, Iss 1, Pp 1-

    2022  Volume 12

    Abstract: Abstract Antiphase behaviour of monsoon systems in alternate hemispheres is well established at yearly and orbital scales in response to alternating sensible heating of continental landmasses. At intermediate timescales without a sensible heating ... ...

    Abstract Abstract Antiphase behaviour of monsoon systems in alternate hemispheres is well established at yearly and orbital scales in response to alternating sensible heating of continental landmasses. At intermediate timescales without a sensible heating mechanism both in-phase and antiphase behaviours of northern and southern hemisphere monsoon systems are recorded at different places and timescales. At present, there is no continuous, high resolution, precisely dated record of millennial-scale variability of the Indonesian–Australian monsoon during the last glacial period with which to test theories of paleomonsoon behaviour. Here, we present an extension of the Liang Luar, Flores, speleothem δ18O record of past changes in southern hemisphere summer monsoon intensity back to 55.7 kyr BP. Negative δ18O excursions (stronger monsoon) occur during Heinrich events whereas positive excursions (weaker monsoon) occur during Dansgaard-Oeschger interstadials—a first order antiphase relationship with northern hemisphere summer monsoon records. An association of negative δ18O excursions with speleothem growth phases in Liang Luar suggests that these stronger monsoons are related to higher rainfall amounts. However, the response to millennial-scale variability is inconsistent, including a particularly weak response to Heinrich event 3. We suggest that additional drivers such as underlying orbital-scale variability and drip hydrology influence the δ18O response.
    Keywords Medicine ; R ; Science ; Q
    Subject code 550
    Language English
    Publishing date 2022-11-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Asian monsoon intensity coupled to Antarctic climate during Dansgaard–Oeschger 8 and Heinrich 4 glacial intervals

    Yi-Jia Liang / Shi-Tao Chen / Yong-Jin Wang / Kan Zhao / Shao-Hua Yang / Zhen-Jun Wang / Yu-Zheng Huang / Hai Cheng / R. Lawrence Edwards

    Communications Earth & Environment, Vol 3, Iss 1, Pp 1-

    2022  Volume 9

    Abstract: Decadal to centennial variations in the intensity of the Asian summer monsoon were coupled with Antarctic temperatures during the Dansgaard–Oeschger 8 and Heinrich 4 intervals, according to a speleothem oxygen isotope record from Yongxing Cave, China. ...

    Abstract Decadal to centennial variations in the intensity of the Asian summer monsoon were coupled with Antarctic temperatures during the Dansgaard–Oeschger 8 and Heinrich 4 intervals, according to a speleothem oxygen isotope record from Yongxing Cave, China.
    Keywords Geology ; QE1-996.5 ; Environmental sciences ; GE1-350
    Language English
    Publishing date 2022-11-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Hydroclimate variability in the Caribbean during North Atlantic Heinrich cooling events (H8 and H9)

    Yassine Ait Brahim / Matthew C. Peros / André E. Viau / Mercedes Liedtke / Jesús M. Pajón / Julio Valdes / Xianglei Li / R. Lawrence Edwards / Eduard G. Reinhardt / Frank Oliva

    Scientific Reports, Vol 12, Iss 1, Pp 1-

    2022  Volume 12

    Abstract: Abstract We present a speleothem record from western Cuba, spanning the period 98.7–84.9 ka BP. Our record shows two distinctive periods of high δ18O corresponding to dry and/or cold periods during 85–87.6 and 90.2–93.1 ka BP, synchronous with Heinrich ... ...

    Abstract Abstract We present a speleothem record from western Cuba, spanning the period 98.7–84.9 ka BP. Our record shows two distinctive periods of high δ18O corresponding to dry and/or cold periods during 85–87.6 and 90.2–93.1 ka BP, synchronous with Heinrich events 8 and 9 (H8 and H9). Hence, we provide the first proxy evidence of the local Caribbean climate response to H8 and H9. Interestingly, H8 is more pronounced compared to H9, which may be a local response to lower temperatures in the North Atlantic resulting in a weak AMOC and reduced deep water formation, therefore a stronger south shift of the ITCZ. Our data complement existing speleothem records from western Cuba which, collectively, provide a nearly continuous paleoclimate time-series spanning the last 100 ka BP, indicating a consistent response to millennial-scale events as dry and/or cooler conditions. The comparison with regional paleoclimate records reveals an anti-phased relationship with South America, caused by the southern movements of the ITCZ during millennial-scale events which lead to dry conditions in the Caribbean and a stronger South American Monsoon System.
    Keywords Medicine ; R ; Science ; Q
    Subject code 550
    Language English
    Publishing date 2022-12-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Rapid northern hemisphere ice sheet melting during the penultimate deglaciation

    Heather M. Stoll / Isabel Cacho / Edward Gasson / Jakub Sliwinski / Oliver Kost / Ana Moreno / Miguel Iglesias / Judit Torner / Carlos Perez-Mejias / Negar Haghipour / Hai Cheng / R. Lawrence Edwards

    Nature Communications, Vol 13, Iss 1, Pp 1-

    2022  Volume 16

    Abstract: Stalagmites from NW Iberia record the rapid demise of large ice sheets during the penultimate deglaciation, and reveal decadal-scale feedbacks between warming and ice melting. ...

    Abstract Stalagmites from NW Iberia record the rapid demise of large ice sheets during the penultimate deglaciation, and reveal decadal-scale feedbacks between warming and ice melting.
    Keywords Science ; Q
    Language English
    Publishing date 2022-07-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: A Novel Tracer Technique to Quantify the Lithogenic Input Flux of Trace Elements to Qinghai Lake

    Pu Zhang / Xuezheng Pei / Chenyang Cao / Chi Chen / Ziqin Gong / Xuerou Li / Jingya Pang / Lihua Liang / Xiangzhong Li / Youfeng Ning / R.Lawrence Edwards

    Frontiers in Earth Science, Vol

    2022  Volume 10

    Abstract: Thorium (Th) isotopes were applied to quantify the contributions of lithogenic inputs to the Qinghai Lake (QHH). Concentrations of dissolved 232Th and 230Th were measured in 59 water samples collected from Qinghai Lake and its exogenous recharge rivers. ... ...

    Abstract Thorium (Th) isotopes were applied to quantify the contributions of lithogenic inputs to the Qinghai Lake (QHH). Concentrations of dissolved 232Th and 230Th were measured in 59 water samples collected from Qinghai Lake and its exogenous recharge rivers. There are significant differences in the concentration of 232Th of the sampled water in QHH that confirm the input of variable lithogenic material sources. The 230Th concentrations were used to calculate a scavenging residence time for Th, which was then applied to calculate the flux of dissolved 232Th by matching the measured concentrations of dissolved 232Th. Then the 232Th content of lithogenic material was used with the solubility of Th from the preliminary particle data from the Qinghai–Qaidam district. When using a Th solubility from particles of 1%, the fluxes of lithogenic material range from 0.03 to 25.25 g/m2/yr in the surface water, consistent with the flux results of settled particles from the previous study. When a large number of exogenous recharge rivers are mixed into the northwest basin of Qinghai Lake, the 232Th content and lithogenic flux of the lake water are mainly influenced by the type and content of the particles in the Buha and Shaliu rivers. Conversely, in south basin with limited recharging rivers, the 232Th content of the lake water away from the estuary is mainly influenced by atmospheric dust. Furthermore, based on the 230Th normalization method (combining with 232Th and τTh), the Buha and Shaliu rivers located in the northwest basin contribute about 90% of the detrital flux to the lake. The lithogenic flux in the southeast lake is dominated by dust flux with a value of ∼0.109 g/m2/yr, while the higher lithogenic flux at the bottom of the lake was likely generated by accumulated sinking particulate matter and resuspension of bottom sediments in September. This study confirms the utility of long-lived Th isotopes to quantify lithogenic inputs based on the Th content of the dissolved lake water and also supply deposition resolution ...
    Keywords 232Th content ; 230Th normalization technique ; lithogenic flux ; dust flux ; Qinghai Lake ; Science ; Q
    Subject code 550
    Language English
    Publishing date 2022-04-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Millennial-scale glacial climate variability in Southeastern Alaska follows Dansgaard-Oeschger cyclicity

    Paul S. Wilcox / Jeffrey A. Dorale / James F. Baichtal / Christoph Spötl / Sarah J. Fowell / R. Lawrence Edwards / Johanna L. Kovarik

    Scientific Reports, Vol 9, Iss 1, Pp 1-

    2019  Volume 8

    Abstract: Abstract A stalagmite from Prince of Wales Island grew episodically between ~75,000 and ~11,100 yr BP; interrupted by seven hiatuses. Hiatuses most likely correspond to permafrost development and a temperature drop of up to 5 °C from modern conditions. ... ...

    Abstract Abstract A stalagmite from Prince of Wales Island grew episodically between ~75,000 and ~11,100 yr BP; interrupted by seven hiatuses. Hiatuses most likely correspond to permafrost development and a temperature drop of up to 5 °C from modern conditions. Intervals of calcite deposition place tight constraints on the timing of mild climatic episodes in Alaska during the last glacial period, when permafrost was absent, allowing water infiltration into the karst system. These periods of calcite deposition are synchronous, within dating uncertainties, with Greenland Interstadials 1, 10, 11, 12c, 14b-14e, 16.1a, 17.2, and 20c.
    Keywords Medicine ; R ; Science ; Q
    Language English
    Publishing date 2019-05-01T00:00:00Z
    Publisher Nature Publishing Group
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