气候变化领域集成服务门户(CCPortal): 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

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DOI	10.5194/cp-15-253-2019
	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
	Cartier R.; Sylvestre F.; Paillès C.; Sonzogni C.; Couapel M.; Alexandre A.; Mazur J.-C.; Brisset E.; Miramont C.; Guiter F.
发表日期	2019
ISSN	18149324
起始页码	253
结束页码	263
卷号	15 期号:1
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).
语种	英语
scopus关键词	altitude; climate variation; diatom; oxygen isotope; Alpes Maritimes; Alps; France; Lake Petit; Mediterranean Region; Provence-Alpes-Cote d'Azur; Bacillariophyta
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146856
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
推荐引用方式 GB/T 7714	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],2019,15(1).
APA	Cartier R..,Sylvestre F..,Paillès C..,Sonzogni C..,Couapel M..,...&Guiter F..(2019).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.Climate of the Past,15(1).
MLA	Cartier R.,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".Climate of the Past 15.1(2019).