DOI: 10.5194/cp-15-253-2019
Scopus记录号: 2-s2.0-85061337130
论文题名: Diatom-oxygen isotope record from high-altitude Lake Petit (2200 m a.s.l.) in the Mediterranean Alps: Shedding light on a climatic pulse at 4.2 ka
作者: Cartier R. ; Sylvestre F. ; Paillès C. ; Sonzogni C. ; Couapel M. ; Alexandre A. ; Mazur J.-C. ; Brisset E. ; Miramont C. ; Guiter F.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2019
卷: 15, 期: 1 起始页码: 253
结束页码: 263
语种: 英语
Scopus关键词: Bacillariophyta
英文摘要: In the Mediterranean area, the 4.2 ka BP event is recorded with contrasting expressions between regions. In the southern Alps, the high-altitude Lake Petit (Mercantour Massif, France; 2200 m a.s.l.) offers pollen and diatom-rich sediments covering the last 4800 years. A multi-proxy analysis recently revealed a detrital pulse around 4200 cal BP due to increasing erosion in the lake catchment. The involvement of a rapid climate change leading to increasing runoff and soil erosion was proposed. Here, in order to clarify this hypothesis, we measured the oxygen isotope composition of diatom silica frustules (δ 18 O diatom ) from the same sedimentary core. Diatoms were analysed by laser fluorination isotope ratio mass spectrometry after an inert gas flow dehydration. We additionally enhanced the accuracy of the age-depth model using the Bacon R package. The δ 18 O diatom record allows us to identify a 500-year time lapse, from 4400 to 3900 cal BP, where δ 18 O diatom reached its highest values (> 31). δ 18 O diatom was about 3 ‰ higher than the modern values and the shifts at 4400 and 3900 cal BP were of similar amplitude as the seasonal δ 18 O diatom shifts occurring today. This period of high δ 18 O diatom values can be explained by the intensification of 18O-enriched Mediterranean precipitation events feeding the lake during the ice-free season. This agrees with other records from the southern Alps suggesting runoff intensification around 4200 cal BP. Possible changes in other climatic parameters may have played a concomitant role, including a decrease in the contribution of 18 Odepleted Atlantic winter precipitation to the lake water due to snow deficit. Data recording the 4.2 ka BP event in the northwestern Mediterranean area are still sparse. In the Lake Petit watershed, the 4.2 ka BP event translated into a change in precipitation regime from 4400 to 3900 cal BP. This record contributes to the recent efforts to characterize and investigate the geographical extent of the 4.2 ka BP event in the Mediterranean area. © 2019 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/122245
Appears in Collections: 气候变化事实与影响
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作者单位: Aix-Marseille University, CNRS, IRD, Collège de France, INRA, CEREGE, Europôle de l'Arbois, Aix-en-Provence, 13545, France; Aix-Marseille University, CNRS, IRD, Avignon University, IMBE, Europôle de l'Arbois, Aix-en-Provence, 13545, France; IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Tarragona, Spain; Àrea de Prehistòria, Universitat Rovira i Virgili, Tarragona, Spain; Lund University, Department of Geology, Lund, Sweden
Recommended Citation:
Cartier R.,Sylvestre F.,Paillès C.,et al. Diatom-oxygen isotope record from high-altitude Lake Petit (2200 m a.s.l.) in the Mediterranean Alps: Shedding light on a climatic pulse at 4.2 ka[J]. Climate of the Past,2019-01-01,15(1)