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Preliminary investigation of n-alkanes and alkenones in East Greenland lacustrine sediment: Implications for possible Holocene climate reconstructions

Mergenthal, Zachary L.
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342716929

Abstract Details

2012, MS, University of Cincinnati, Arts and Sciences: Geology.
This study reports a reconstruction of Holocene lacustrine paleotemperatures and paleovegetation for the Scoresby Sund region 70.5¿¿¿¿ north latitude in east Greenland using long- chain alkenones and n-alkanes. Long-chain alkenones (LCAs) are biomarkers, which are produced by haptophyte algae that can provide information on regional paleoclimate conditions. C37 LCAs were analyzed using the alkenone unsaturation index, Uk37, along with published lacustrine alkenone temperature calibrations. LCAs were identified in only 1 lake (Snoopy Lake) out of 4 lakes that were examined within Scoresby Sund. At Snoopy Lake, the coldest temperature of the Holocene was measured at 9,700 YBP while the warmest temperature was measured at 7,300 YBP, corresponding with the mid-Holocene climate optimum. Late Holocene warming indicated by the Snoopy Lake Uk37 record is inconsistent with other temperature records from Greenland. We suspect this difference in Uk37 predicted temperatures is related to extrinsic factors that modify the haptophyte Uk37 proxy rather than warmer than expected absolute temperatures in eastern Greenland. Terrestrial leaf wax lipids, n-alkanes, were also analyzed in order to infer changes in vegetation caused by changes in climate. Increasing concentration of long-chain n-alkane values indicate rapid expansion of terrestrial plants 8,000 years before present, followed by decreasing abundance towards present. This vegetation pattern is consistent with other regional records of the Holocene Thermal Maximum and the Little Ice Age. The similarities between our temperature reconstruction for the Early Holocene and other records suggest that something fundamental changed during the latter part of the Holocene effecting the alkenone unsaturation. Future work needs to characterize extrinsic factors that modify Uk37 proxies and methods to identify when reconstructed temperatures are biased.
Thomas Lowell, PhD (Committee Chair)
Aaron Diefendorf, PhD (Committee Member)
Warren Huff, PhD (Committee Member)
63 p.
Geology
Holocene; Paleoclimate; Greenland; Long-chain Alkenone; Biomarkers; n-alkane;

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Citations

  • Mergenthal, Z. L. (2012). Preliminary investigation of n-alkanes and alkenones in East Greenland lacustrine sediment: Implications for possible Holocene climate reconstructions [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342716929

    APA Style (7th edition)

  • Mergenthal, Zachary. Preliminary investigation of n-alkanes and alkenones in East Greenland lacustrine sediment: Implications for possible Holocene climate reconstructions. 2012. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342716929.

    MLA Style (8th edition)

  • Mergenthal, Zachary. "Preliminary investigation of n-alkanes and alkenones in East Greenland lacustrine sediment: Implications for possible Holocene climate reconstructions." Master's thesis, University of Cincinnati, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342716929

    Chicago Manual of Style (17th edition)

ucin1342716929
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© 2012, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.