DOI: 10.1016/j.quascirev.2016.07.020
Scopus记录号: 2-s2.0-84979085314
论文题名: Plant-wax D/H ratios in the southern European Alps record multiple aspects of climate variability
作者: Wirth S.B. ; Sessions A.L.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 148 起始页码: 176
结束页码: 191
语种: 英语
英文关键词: Holocene
; Lake sediments
; Mediterranean sea
; Moisture source
; Plant-wax D/H ratio
; Southern European Alps
; Temperature
; Vegetation
; Westerlies
; Younger Dryas
Scopus关键词: Catchments
; Isotopes
; Lakes
; Moisture
; Sensitivity analysis
; Temperature
; Vegetation
; D/h ratios
; European Alps
; Holocenes
; Lake sediments
; Mediterranean sea
; Moisture sources
; Westerlies
; Younger Dryas
; Climate change
; altitude
; catchment
; climate variation
; evapotranspiration
; Holocene
; isotopic composition
; lacustrine deposit
; leaf
; moisture content
; precipitation assessment
; proxy climate record
; temperature profile
; wax
; Younger Dryas
; Alps
; Italy
; Mediterranean Sea
; Southern Europe
英文摘要: We present a Younger Dryas–Holocene record of the hydrogen isotopic composition of sedimentary plant waxes (δDwax) from the southern European Alps (Lake Ghirla, N-Italy) to investigate its sensitivity to climatic forcing variations in this mid-latitude region (45°N). A modern altitudinal transect of δD values of river water and leaf waxes in the Lake Ghirla catchment is used to test present-day climate sensitivity of δDwax. While we find that altitudinal effects on δDwax are minor at our study site, temperature, precipitation amount, and evapotranspiration all appear to influence δDwax to varying extents. In the lake-sediment record, δDwax values vary between −134 and −180‰ over the past 13 kyr. The long-term Holocene pattern of δDwax parallels the trend of decreasing temperature and is thus likely forced by the decline of northern hemisphere summer insolation. Shorter-term fluctuations, in contrast, may reflect both temperature and moisture-source changes. During the cool Younger Dryas and Little Ice Age (LIA) periods we observe unexpectedly high δDwax values relative to those before and after. We suggest that a change towards a more D-enriched moisture source is required during these intervals. In fact, a shift from northern N-Atlantic to southern N-Atlantic/western Mediterranean Sea sources would be consistent with a southward migration of the Westerlies with climate cooling. Prominent δDwax fluctuations in the early and middle Holocene are negative and potentially associated with temperature declines. In the late Holocene (<4 kyr BP), excursions are partly positive (as for the LIA) suggesting a stronger influence of moisture-source changes on δDwax variation. In addition to isotopic fractionations of the hydrological cycle, changes in vegetation composition, in the length of the growing season, and in snowfall amount provide additional potential sources of variability, although we cannot yet quantitatively assess these in the paleo-record. We conclude that while our δDwax record from the Alps does contain climatic information, it is a complicated record that would require additional constraints to be robustly interpreted. This also has important implications for other water-isotope-based proxy records of precipitation and hydro-climate from this region, such as cave speleothems. © 2016 资助项目: We thank all helpers in the field, M. Fujak and N. Dubois for
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59491
Appears in Collections: 过去全球变化的重建
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作者单位: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States
Recommended Citation:
Wirth S.B.,Sessions A.L.. Plant-wax D/H ratios in the southern European Alps record multiple aspects of climate variability[J]. Quaternary Science Reviews,2016-01-01,148