High-altitude varve records of abrupt environmental changes and mining activity over the last 4000 years in the Western French Alps (Lake Bramant, Grandes Rousses Massif)

Guyard, Hervé; Chapron, Emmanuel; St‐Onge, Guillaume; Anselmetti, Flavio S.; Arnaud, Fabien; Magand, Olivier; Francus, Pierre; Mélières, Marie-Antoinette

doi:10.1016/j.quascirev.2007.07.007

Cited by 171 publications

(135 citation statements)

References 56 publications

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“…This interpretation is supported by high log(Cr inc /Cr coh ) values that correspond with distinct organic-rich layers. It is also supported by several previous studies showing Cr inc /Cr coh as a potential proxy for organic matter variations in organic-rich lacustrine sediments (Guyard et al 2007;Jouve et al 2013). …”

Section: Xrf Data Interpretationsupporting

confidence: 85%

Holocene paleohydrological reconstruction of Lake Strzeszyńskie (western Poland) and its implications for the central European climatic transition zone

et al. 2017

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Western Poland is located in the central European climatic transition zone, which separates the mild and humid Atlantic climate of Western Europe and the East European continental climate. This region is sensitive to lateral shifts of the European climate zones and is particularly suitable for reconstructing Holocene climate variability. This paper presents detailed analyses of the sedimentary record from Lake Strzeszyńskie since the Late Pleistocene. These include smear-slide and thin-section observations, X-ray fluorescence core scanning, magnetic susceptibility measurements, pollen analyses, and radiocarbon dating. The sediment record reveals three distinct sedimentary units consisting of: (1) an alternation of sand layers and laminated silt and clay deposits accumulated prior to 14,600 cal yr BP; (2) faintly laminated calcareous sediments intercalated with organic matter-rich layers deposited between 14,600 and 10,200 cal yr BP; and (3) massive calcareous mud deposited after 10,200 cal yr BP. The Holocene period is marked by nine phases of organicrich sedimentation and enhanced Fe deposition, which occurred at ca. 10.1, 9.3, 6.4-6.1, 5.5-5.1, 4.7-4.5, 2.7-2.4, 1.3-1.2, 0.8-0.6, 0.4-0.2 kyr cal BP. These phases are associated with high lake levels and correspond with wet periods recognized in several other records from Poland and central Europe. These phases partly coincide with North Atlantic cold periods, which may suggest that high lake levels are triggered by an ocean-continent linking mechanism.

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Section: Xrf Data Interpretationsupporting

confidence: 85%

Holocene paleohydrological reconstruction of Lake Strzeszyńskie (western Poland) and its implications for the central European climatic transition zone

et al. 2017

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“…Similar observations have been made in lakes and peat profiles in Europe (e.g. Hettwer et al 2003;Koinig et al 2003;Shotyk et al 2005;Guyard et al 2007) and other South American countries like Peru or Bolivia (Abbott and Wolfe 2003;Cooke et al 2007Cooke et al , 2008.…”

Section: Anthropogenic Impact and Further Vegetation Changessupporting

confidence: 82%

“…PC1 reduces all the allochthonous minerogenic input parameters hitherto frequently used in other studies, such as the conservative lithogenic metal Ti (Shotyk et al 2001;Haberzettl et al 2005Haberzettl et al , 2006Haberzettl et al , 2007Haberzettl et al , 2008 or Rb (Guyard et al 2007), to one proxy. Hence, increases in that proxy represent an increase in runoff or eolian supply.…”

Section: Methodsmentioning

confidence: 99%

“…The incoherent/coherent (inc/coh) ratio may be used as an estimate of sediment organic content (Guyard et al 2007;Rolland et al 2008). This explains the opposite pattern of this ratio to PC1.…”

Section: Methodsmentioning

confidence: 99%

“…Distinct Pb anomalies were attributed to long range transport of atmospheric Pb contamination from Pb mining and smelting during Roman times in Europe (Hettwer et al 2003;Shotyk et al 2005;Guyard et al 2007). The same studies show an even more distinct Pb peak related to the introduction of aerosols from leaded gasoline combustion or coal burning (Koinig et al 2003;Shotyk et al 2005).…”

Section: Anthropogenic Impact and Further Vegetation Changesmentioning

confidence: 99%

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High-resolution studies on vegetation succession, hydrological variations, anthropogenic impact and genesis of a subrecent lake in southern Ecuador

Brunschön

Haberzettl

Behling

2010

Veget Hist Archaeobot

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A lake sediment record from Laguna Campana at 2,488 m a.s.l. in the eastern Ecuadorian Andes allows the reconstruction of local environmental conditions over the past *500 years. A high-resolution multi-proxy approach using pollen, spore, charcoal and XRF analyses provides information about lake genesis, hydrological variations and the development of the surrounding vegetation. Results suggest that Laguna Campana originated from a landslide, which are naturally common and anthropogenically promoted in the study area. Human activities, e.g. deforestation or slash and burn cultivation, impacted the local vegetation development and biodiversity during the recorded period. After a first dense layer of pioneer grasses developed on open soil around the small lake, successional stages of secondary upper mountain rainforest forest mainly composed of Alnus and Weinmannia were observed. The record shows no signs of dense forest regeneration but rather open vegetation with trees and a grassy understory. Especially since ca. A.D. 1980, the proportion of forest in the area was reduced, most probably by fire use for pastures, cultivation and wood extraction. Hydrological variability was derived from differences in minerogenic input and variations in Botryococcus braunii and Sphagnum occurrence. After wettest conditions at the study site, probably triggering the landslide, humid conditions persisted until a time of drier conditions between A.D. 1900 and 1960. A subsequent return to wetter conditions was observed over the last decades. XRF analyses suggest an increase in deposition of atmospherically derived lead since the formation of the lake.

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Choosing optimal exposure times for XRF core‐scanning: Suggestions based on the analysis of geological reference materials

Huang

Löwemark

Chang

et al. 2016

Geochem Geophys Geosyst

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X‐ray fluorescence (XRF) core‐scanning is a fast and nondestructive technique to assess elemental variations of unprocessed sediments. However, although the exposure time of XRF‐scanning directly affects the scanning counts and total measurement time, only a few studies have considered the influence of exposure time during the scan. How to select an optimal exposure time to achieve reliable results and reduce the total measurement time is an important issue. To address this question, six geological reference materials from the Geological Survey of Japan (JLK‐1, JMS‐1, JMS‐2, JSD‐1, JSD‐2, and JSD‐3) were scanned by the Itrax‐XRF core scanner using the Mo‐ and the Cr‐tube with different exposure times to allow a comparison of scanning counts with absolute concentrations. The regression lines and correlation coefficients of elements that are generally used in paleoenvironmental studies were examined for the different exposure times and X‐ray tubes. The results show that for those elements with relatively high concentrations or high detectability, the correlation coefficients are higher than 0.90 for all exposure times. In contrast, for the low detectability or low concentration elements, the correlation coefficients are relatively low, and improve little with increased exposure time. Therefore, we suggest that the influence of different exposure times is insignificant for the accuracy of the measurements. Thus, caution must be taken when interpreting the results of elements with low detectability, even when the exposure times are long and scanning counts are reasonably high.

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High-altitude varve records of abrupt environmental changes and mining activity over the last 4000 years in the Western French Alps (Lake Bramant, Grandes Rousses Massif)

Cited by 171 publications

References 56 publications

Holocene paleohydrological reconstruction of Lake Strzeszyńskie (western Poland) and its implications for the central European climatic transition zone

Holocene paleohydrological reconstruction of Lake Strzeszyńskie (western Poland) and its implications for the central European climatic transition zone

High-resolution studies on vegetation succession, hydrological variations, anthropogenic impact and genesis of a subrecent lake in southern Ecuador

Choosing optimal exposure times for XRF core‐scanning: Suggestions based on the analysis of geological reference materials

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