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n-Alkane evidence for the onset of wetter conditions in the Sierra Nevada, California (USA) at the mid-late Holocene transition, ~3.0ka
- Source :
-
Quaternary Research . Jan2013, Vol. 79 Issue 1, p14-23. 10p. - Publication Year :
- 2013
-
Abstract
- Abstract: n-Alkane biomarker distributions in sediments from Swamp Lake (SL), in the central Sierra Nevada of California (USA), provide evidence for an increase in mean lake level ~3000yr ago, in conjunction with widespread climatic change inferred from marine and continental records in the eastern North Pacific region. Length distributions of n-alkane chains in modern plants growing at SL were determined and compared to sedimentary distributions in a core spanning the last 13ka. As a group, submerged and floating aquatic plants contained high proportions of short chain lengths (< nC25) compared to emergent, riparian and upland terrestrial species, for which chain lengths > nC27 were dominant. Changes in the sedimentary n-alkane distribution over time were driven by variable inputs from plant sources in response to changing lake level, sedimentation and plant community composition. A shift toward shorter chain lengths (nC21, nC23) occurred between 3.1 and 2.9ka and is best explained by an increase in the abundance of aquatic plants and the availability of shallow-water habitat in response to rising lake level. The late Holocene expansion of SL following a dry mid-Holocene is consistent with previous evidence for increased effective moisture and the onset of wetter conditions in the Sierra Nevada between 4.0 and 3.0ka. [Copyright &y& Elsevier]
- Subjects :
- *ALKANES
*HOLOCENE Epoch
*BIOMARKERS
*CLIMATE change
*SEDIMENTS
Subjects
Details
- Language :
- English
- ISSN :
- 00335894
- Volume :
- 79
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Quaternary Research
- Publication Type :
- Academic Journal
- Accession number :
- 84481415
- Full Text :
- https://doi.org/10.1016/j.yqres.2012.09.004