A multiple stable isotope record of Late Quaternary limnological changes and chironomid paleoecology from northeastern Iceland

作者：Wooller Matthew^*; Wang Yiming; Axford Yarrow

来源：Journal of Paleolimnology, 2008, 40(1): 63-77.

DOI：10.1007/s10933-007-9144-8

• chironomids
• stable isotopes
• carbon
• nitrogen
• oxygen
• hydrogen

We present results from multiple stable isotope analyses (delta(18)O of chironomid larval head capsules, chironomid adult thoraxes and other insect remains and delta D, delta(13)C, delta(15)N of total organic matter-TOM) of a lake sediment core (04-SVID-03) taken from Stora Vidarvatn in northeastern Iceland to reconstruct past environmental, limnological and delta(18)O of past lake water changes during the Holocene. Core 04-SVID-03 represents a similar to 12,000 cal. yrs BP to present record. Large magnitude changes in delta(18)O occurred during the Holocene at the site. Downcore shifts in delta(18)O of chironomids did not correlate with measurements of the delta(13)C and delta(15)N of chironomid head capsules, implying that the delta(18)O changes were not primarily driven by changes in chironomid diet during the Holocene. The delta D of TOM provided a proxy of relative lake-water delta D changes at the site and also showed large magnitude changes during the record. This approach was supported by analyses of a modern training set where delta D(TOM) analyses were conducted using surface sediments from a suite of freshwater lakes over a large latitudinal gradient. The magnitude of changes in both the delta(18)O and delta D and the relatively negative delta(18)O values throughout much of the core suggest that the proxies represent more paleoenvironmental information than solely temperature. Additional possible influences on lake-water isotopic composition are discussed, including changes in the seasonality of precipitation, in the patterns of air masses supplying precipitation to Iceland and in the dominant mode of the North Atlantic Oscillation.

• 出版日期2008-7