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Journal ArticleDOI

Deglaciation in the central Pyrenees during the Pleistocene–Holocene transition: Timing and geomorphological significance

TL;DR: In this article, the authors used cosmic-ray exposure (CRE) dating to study deglaciation in a sector of the southern-central Pyrenees (the Panticosa massif and the upper Gallego and Ossau valleys).
About: This article is published in Quaternary Science Reviews.The article was published on 2017-04-15. It has received 63 citations till now. The article focuses on the topics: Deglaciation & Rock glacier.
Citations
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Journal ArticleDOI
TL;DR: This article investigated the magnitude and timing of climate variability during the Little Ice Age (LIA) in the mountains of the Iberian Peninsula, based on a wide range of natural records (including from glacial, periglacial, and lacustrine/peatland areas; fluvial/alluvial deposits; speleothems; and tree rings), historical documents, and early instrument data.

115 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarize the current knowledge on the spatial and temporal patterns of glacial activity in the Iberian mountains during the Late Quaternary and present-day.

69 citations

Journal ArticleDOI
TL;DR: A review of current understanding of deglaciation in North, Central and South America from the Last Glacial Maximum to the beginning of the Holocene can be found in this article.

64 citations


Cites background from "Deglaciation in the central Pyrenee..."

  • ...If altered boulders or boulders with prior radiation exposure are sampled, the statistic only increases the error (Palacios, 2017)....

    [...]

  • ...Knowledge of the activity of these glaciers has increased enormously in recent years (Palacios, 2017)....

    [...]

References
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Journal ArticleDOI
TL;DR: In this paper, the authors present theoretical estimates of the production rates of isotopes of He, Ne and Ar based on available cross-section data, and discuss the implications of these parameters for single and multiple nuclide studies in terms of the erosion models considered.

2,322 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the cosmic ray flux increases at higher altitude as air pressure and the shielding effect of the atmosphere decrease, and that altitude-dependent scaling factors are required to compensate for this effect in calculating cosmic ray exposure ages.
Abstract: The cosmic ray flux increases at higher altitude as air pressure and the shielding effect of the atmosphere decrease. Altitude-dependent scaling factors are required to compensate for this effect in calculating cosmic ray exposure ages. Scaling factors in current use assume a uniform relationship between altitude and atmospheric pressure over the Earth's surface. This masks regional differences in mean annual pressure and spatial variation in cosmogenic isotope production rates. Outside Antarctica, air pressures over land depart from the standard atmosphere by ±4.4 hPa (1σ) near sea level, corresponding to offsets of ±3–4% in isotope production rates. Greater offsets occur in regions of persistent high and low pressure such as Siberia and Iceland, where conventional scaling factors predict production rates in error by ±10%. The largest deviations occur over Antarctica where ground level pressures are 20–40 hPa lower than the standard atmosphere at all altitudes. Isotope production rates in Antarctica are therefore 25–30% higher than values calculated by scaling Northern Hemisphere production rates with conventional scaling factors. Exposure ages of old Antarctic surfaces, especially those based on cosmogenic radionuclides at levels close to saturation, may be millions of years younger than published estimates.

2,034 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a single complete and straightforward method that reflects currently accepted practices and is consistent with existing production rate calibration measurements, which is intended to enable geoscientists, who wish to use cosmogenic-nuclide exposure age or erosion rate measurements in their work, to calculate exposure ages and erosion rates; compare previously published exposure ages on a common basis; and evaluate the sensitivity of their results to differences between published production rate scaling schemes.

1,708 citations

Book ChapterDOI
TL;DR: In this paper, the authors present revised maps of North American deglaciation at 500-year and finer resolution, which represent an updating of a series prepared nearly two decades ago for the INQUA 1987 Congress.
Abstract: Publisher Summary This chapter reviews that the Late Wisconsinan North American ice sheet complex consisted of three major ice sheets: (1) the Laurentide Ice Sheet, which was centred on the Canadian Shield, but also expanded across the Interior Plains to the west and south, (2) the Cordilleran Ice Sheet, which inundated the western mountain belt between the northernmost co-terminus United States and Beringia, and (3) the Innuitian Ice Sheet, which covered most of the Canadian Arctic Archipelago north of about 7°N latitude. The ice cover over Newfoundland and the Maritime Provinces of Canada is usually referred to as the Appalachian Ice Complex, because ice flowed out from local centres rather than from the Canadian Shield. All of the peripheral ice sheets were confluent at the Last Glacial Maximum (LGM) with the Laurentide Ice Sheet, and the Greenland Ice Sheet was confluent with the Innuitian Ice Sheet. The nucleus of this complex, the Laurentide, comprised three major sectors, the Labrador Sector, the Keewatin Sector, and the Baffin Sector, named for areas of inception mid probable areas of outflow at LGM and located respectively east, west and north of Hudson Bay. The chapter presents revised maps of North American deglaciation at 500-year and finer resolution. These maps represent an updating of a series prepared nearly two decades ago for the INQUA 1987 Congress.

920 citations

Journal ArticleDOI
TL;DR: In this article, an aliquot of highly enriched 10 Be master solution was serially diluted with increasing well-known masses of 9 Be and the specific activity was measured by means of accurate liquid scintillation counting (LSC).
Abstract: The importance of 10 Be in different applications of accelerator mass spectrometry (AMS) is well-known. In this context the half-life of 10 Be has a crucial impact, and an accurate and precise determination of the half-life is a prerequisite for many of the applications of 10 Be in cosmic-ray and earth science research. Recently, the value of the 10 Be half-life has been the centre of much debate. In order to overcome uncertainties inherent in previous determinations, we introduced a new method of high accuracy and precision. An aliquot of our highly enriched 10 Be master solution was serially diluted with increasing well-known masses of 9 Be. We then determined the initial 10 Be concentration by least square fit to the series of measurements of the resultant 10 Be/ 9 Be ratio. In order to minimize uncertainties because of mass bias which plague other low-energy mass spectrometric methods, we used for the first time Heavy-Ion Elastic Recoil Detection (HI-ERD) for the determination of the 10 Be/ 9 Be isotopic ratios, a technique which does not suffer from difficult to control mass fractionation. The specific activity of the master solution was measured by means of accurate liquid scintillation counting (LSC). The resultant combination of the 10 Be concentration and activity yields a 10 Be half-life of T 1/2 = 1.388 ± 0.018 (1 s, 1.30%) Ma. In a parallel but independent study (Chmeleff et al. [11] ), found a value of 1.386 ± 0.016 (1.15%) Ma. Our recommended weighted mean and mean standard error for the new value for 10 Be half-life based on these two independent measurements is 1.387 ± 0.012 (0.87%) Ma.

797 citations