Evidence for differential degradation of alkenones under contrasting bottom water oxygen conditions: Implication for paleotemperature reconstruction

Journal Article · Mon Feb 01 04:00:00 EST 1999 · Geochimica et Cosmochimica Acta

DOI:https://doi.org/10.1016/S0016-7037(98)00283-X· OSTI ID:355666

Gong, C; Hollander, D J ^[1]

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1. Northwestern Univ., Evanston, IL (United States). Dept. of Geological Sciences

The successful reconstruction of sea surface temperatures using alkenone paleothermometry (U{sub 37}{sup k{prime}}) has relied on the premise that there is no significant differential degradation of alkenones with different states of unsaturation during diagenetic processes. To test this assumption, the authors conducted a comparative study of contemporary sediments in oxic and anoxic bottom waters from the Santa Monica Basin, offshore California. Long-chain alkenones were quantified and sea surface temperature were calculated using the calibrated U{sub 37}{sup k{prime}}-T relationship of Prahl et al. (1988). Results show that temperature record from the oxic sediments is higher by as much as 4 C compared to those from time-equivalent anoxic sediments as a result of differential degradation of long-chain unsaturated alkenones and bioturbation mixing in the oxic sediments. The differential degradation of C{sub 37:3} vs. C{sub 37:2} alone could account for up to 2.5 C difference between these two records. This finding has significant implication in the interpretation of paleo-sea surface temperature data using alkenone paleothermometry.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• OSTI ID: 355666
• Journal Information: Geochimica et Cosmochimica Acta, Journal Name: Geochimica et Cosmochimica Acta Journal Issue: 3-4 Vol. 63; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ACCURACY
AMBIENT TEMPERATURE
CALIFORNIA
COASTAL WATERS
DECOMPOSITION
HYDROCARBONS
PALEOCLIMATOLOGY
PALEOTEMPERATURE
SEAS