Journal: Quaternary Science Reviews

Abbreviation

Quat. Sci. Rev.

Publisher

Pergamon

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ISSN

0277-3791

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Publications 1 - 8 of 8
  • Downscaling Last Glacial Maximum climate over southern Africa
    Item type: Journal Article
    Engelbrecht, Francois A.; Marean, Curtis W.; Cowling, Richard M.; et al. (2019)
    Quaternary Science Reviews
  • "Glacial geomorphology and chronology of deglaciation, South Georgia, sub-Antarctic" - Reply
    Item type: Journal Article
    Bentley, M. J.; Evans, D. J. A.; Fogwill, C. J.; et al. (2007)
    Quaternary Science Reviews
  • Corrigendum to "Revised quaternary glacial succession and post-LGM recession, southern Wind River Range, Wyoming, USA" (vol 192, pg 168, 2018)
    Item type: Other Journal Item
    Dahms, Dennis; Egli, Markus; Fabel, Derek; et al. (2019)
    Quaternary Science Reviews
  • Early Holocene thinning and final demise of the Scandinavian Ice Sheet across the main drainage divide of southern Norway
    Item type: Journal Article
    Romundset, Anders; Akçar, Naki; Fredin, Ola; et al. (2023)
    Quaternary Science Reviews
    The thinning and final decay of the Scandinavian Ice Sheet in the Gudbrandsdalen area in central southern Norway is described, based on (1) cosmogenic 10Be surface exposure dating of 25 glacially transported boulders, (2) radiocarbon dating of plant remains in the basal strata in four lakes and (3) mapping of large ice-dammed lakes that formed at different elevations and at different times during the last deglacation. We complement the new chronology with previously published 10Be-ages from the same region. The dated samples are spread from mountain summits 1800 m a.s.l. to the valley floor at 250 m a.s.l. Our results suggest that the ice sheet surface remained well above 1800 m a.s.l. in northern Gudbrandsdalen throughout the Younger Dryas. During the Early Holocene the ice sheet thinned rapidly, at rates estimated to 1.7–5.8 m yr−1. The final phase of deglaciation involved formation of large ice-dammed lakes, most notably the Store Dølasjø which was formed after 10.4 ka BP and finally drained around 10.0 ka BP. The ice-marginal landforms that characterize the mountain region of northern Gudbrandsdalen, i.e., moraine ridges, lateral meltwater channels, as well as deposits and shorelines from ice-dammed lakes, thus collectively originate from a period of rapid ice sheet downwasting over ca. 1600 years.
  • Distal tephras along the SE European margin date powerful explosive eruptions from the Elbrus volcanic center (Greater Caucasus)
    Item type: Journal Article
    Ponomareva, Vera; Portnyagin, Maxim; Danišík, Martin; et al. (2023)
    Quaternary Science Reviews
    Knowledge of temporal patterns of past explosive eruptions is necessary to understand possible future eruptive behavior. However, volcanic records based on geological reconstructions remain incomplete. This inference is true not only for remote and sparsely populated areas like the Aleutian or Kurile-Kamchatka arcs, but also for Europe, where past large explosive events are continuously recognized in the geological record. Here we report the first age and geochemical data on the violent middle to late Pleistocene explosive eruptions from the Elbrus volcanic center (Greater Caucasus), which towers over the densely populated regions in southern Russia and Georgia. We attribute six disparate ash deposits found in the terrestrial and marine sediments along the SE European margin to the Elbrus volcanic center based on major and trace element compositions of individual shards of volcanic glass and radiogenic Sr-Nd-Pb isotope compositions of bulk tephra. We suggest that these deposits represent products of five different eruptions that were dispersed over distances of more than 150–560 km from their source. Three of four eruptions are dated at 522 ± 36, 258 ± 13, and 84.6 ± 7.4 ka by a combined zircon U–Th–Pb and (U–Th)/He approach. One sample revealed an overdispersed spectrum of single crystal (U–Th)/He dates with an average of 176 ± 40 ka. Zircon characteristics and statistical deconvolution of the geochronology data suggest that this sample contains zircon crystals from two different eruptions tentatively dated at 156.5 ± 7.7 ka and 222.8 ± 13 ka. These eruption ages represent the first recognition of a suite of large pumiceous eruptions from the Elbrus volcanic center postdating the previously known explosive activity, documented by ∼800 ka old welded tuffs. These data also provide the first geochemical and geochronological characterization of both proximal and distal Elbrus tephra glasses and contribute to the global tephra database, permitting the identification of Elbrus tephras in distal terrestrial and marine paleoenvironmental archives and hence their use as paleoclimate and archaeological markers. We consider the significance of the identified tephras for paleoenvironmental research and show their potential for tephrochronological studies in the East European Plain and adjacent areas.
  • Last glacial maximum cooling of 9 °C in continental Europe from a 40 kyr-long noble gas paleothermometry record
    Item type: Journal Article
    Bekaert, David V.; Blard, P.H.; Raoult, Yann; et al. (2023)
    Quaternary Science Reviews
    The Last Glacial Maximum (LGM; ∼26–18 kyr ago) is a time interval of great climatic interest characterized by substantial global cooling driven by radiative forcings and feedbacks associated with orbital changes, lower atmospheric CO2, and large ice sheets. However, reliable proxies of continental paleotemperatures are scarce and often qualitative, which has limited our understanding of the spatial structure of past climate changes. Here, we present a quantitative noble gas temperature (NGT) record of the last ∼40 kyr from the Albian aquifer in Eastern Paris Basin (France, ∼48°N). Our NGT data indicate that the mean annual surface temperature was ∼5 °C during the Marine Isotope Stage 3 (MIS3; ∼40–30 kyr ago), before cooling to ∼2 °C during the LGM, and warming to ∼11 °C in the Holocene, which closely matches modern ground surface temperatures in Eastern France. Combined with water stable isotope analyses, NGT data indicate δD/NGT and δ18O/NGT transfer functions of +1.6 ± 0.4‰/°C and +0.18 ± 0.04‰/°C, respectively. Our noble-gas derived LGM cooling of ∼9 °C (relative to the Holocene) is consistent with previous studies of noble gas paleothermometry in European groundwaters but larger than the low-to-mid latitude estimate of 5.8 ± 0.6 °C derived from a compilation of noble gas records, which supports the notion that continental LGM cooling was more extreme at higher latitudes. While an LGM cooling of ∼9 °C in Eastern France appears compatible with recent data assimilation studies, this value is greater than most estimates from current-generation climate model simulations of the LGM. Comparing our estimate for the temperature in Eastern France during MIS3 (6.4 ± 0.5 °C) with GCM outputs presents a promising avenue to further evaluate climate model simulations and constrain European climate evolution over the last glacial cycle.
  • Evidence for Late-Mesolithic agriculture?
    Item type: Journal Article
    Tinner, Willy; Nielsen, Ebbe H.; Lotter, André F. (2008)
    Quaternary Science Reviews
  • The Southern Ocean during the ice ages: A review of the Antarctic surface isolation hypothesis, with comparison to the North Pacific
    Item type: Review Article
    Sigman, Daniel M.; Fripiat, François; Studer, Anja S.; et al. (2021)
    Quaternary Science Reviews
    The Southern Ocean is widely recognized as a potential cause of the lower atmospheric concentration of CO2 during ice ages, but the mechanism is debated. Focusing on the Southern Ocean surface, we review biogeochemical paleoproxy data and carbon cycle concepts that together favor the view that both the Antarctic and Subantarctic Zones (AZ and SAZ) of the Southern Ocean played roles in lowering ice age CO2 levels. In the SAZ, the data indicate dust-driven iron fertilization of phytoplankton growth during peak ice age conditions. In the ice age AZ, the area-normalized exchange of water between the surface and subsurface appears to have been reduced, a state that we summarize as “isolation” of the AZ surface. Under most scenarios, this change would have stemmed the leak of biologically stored CO2 that occurs in the AZ today. SAZ iron fertilization during the last ice age fits with our understanding of ocean processes as gleaned from modern field studies and experiments; indeed, this hypothesis was proposed prior to evidentiary support. In contrast, AZ surface isolation is neither intuitive nor spontaneously generated in climate model simulations of the last ice age. In a more prospective component of this review, the suggested causes for AZ surface isolation are considered in light of the subarctic North Pacific (SNP), where the paleoproxies of productivity and nutrient consumption indicate similar upper ocean biogeochemical changes over glacial cycles, although with different timings at deglaciation. Among the proposed initiators of glacial AZ surface isolation, a single mechanism is sought that can explain the changes in both the AZ and the SNP. The analysis favors a weakening and/or equatorward shift in the upwelling associated with the westerly winds, occurring in both hemispheres. This view is controversial, especially for the SNP, where there is evidence of enhanced upper water column ventilation during the last ice age. We offer an interpretation that may explain key aspects of the AZ and SNP observations. In both regions, with a weakening in westerly wind-driven upwelling, nutrients may have been “mined out” of the upper water column, possibly accompanied by a poleward “slumping” of isopycnals. In the AZ, this would have encouraged declines in both the nutrient content and the formation rate of new deep water, each of which would have contributed to the lowering of atmospheric CO2. Through several effects, the reduction in AZ upwelling may have invigorated the upwelling of deep water into the low latitude pycnocline, roughly maintaining the pycnocline’s supply of water and nutrients so as to (1) support the high productivity of the glacial SAZ and (2) balance the removal of water from the pycnocline by the formation of Glacial North Atlantic Intermediate Water. The proposed return route from the deep ocean to the surface resembles that of Broecker’s (1991) “global ocean conveyor,” but applying to the ice age as opposed to the modern ocean.
Publications 1 - 8 of 8