An evaluation of 14C age relationships between co-occurring foraminifera, alkenones, and total organic carbon in continental margin sediments
Schneider, Ralph R.
Hayes, John M.
Eglinton, Timothy I.
MetadataShow full item record
Radiocarbon age relationships between co-occurring planktic foraminifera, alkenones and total organic carbon in sediments from the continental margins of Southern Chile, Northwest Africa and the South China Sea were compared with published results from the Namibian margin. Age relationships between the sediment components are site-specific and relatively constant over time. Similar to the Namibian slope, where alkenones have been reported to be 1000 to 4500 years older than co-occurring foraminifera, alkenones were significantly (~1000 yrs) older than co-occurring foraminifera in the Chilean margin sediments. In contrast, alkenones and foraminifera were of similar age (within 2σ error or better) in the NW African and South China Sea sediments. Total-organic-matter and alkenone ages were similar off Namibia (age difference TOC-alkenones: 200-700 years), Chile (100-450 years), and NW Africa (360-770 years), suggesting minor contributions of pre-aged terrigenous material. In the South China Sea total organic carbon is significantly (2000-3000 yrs) older due to greater inputs of pre-aged terrigenous material. Age offsets between alkenones and planktic foraminifera are attributed to lateral advection of organic matter. Physical characteristics of the depositional setting, such as sea-floor morphology, shelf width, and sediment composition, may control the age of co-occurring 2 sediment components. In particular, offsets between alkenones and foraminifera appear to be greatest in deposition centers in morphologic depressions. Aging of organic matter is promoted by transport. Age offsets are correlated with organic richness, suggesting that formation of organic aggregate is a key process.
Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 20 (2005): PA1016, doi:10.1029/2004PA001103.
Showing items related by title, author, creator and subject.
Ancient DNA derived from alkenone-biosynthesizing haptophytes and other algae in Holocene sediments from the Black Sea Coolen, Marco J. L.; Boere, Arjan C.; Abbas, Ben; Baas, Marianne; Wakeham, Stuart G.; Sinninghe Damste, Jaap S. (American Geophysical Union, 2006-02-18)Holocene sea surface temperatures (SST) of the Black Sea have been reconstructed using sedimentary C37 unsaturated alkenones assumed to be derived from the coccolithophorid haptophyte Emiliania huxleyi, whose fossil ...
Alkenone distribution in Lake Van sediment over the last 270 ka : influence of temperature and haptophyte species composition Randlett, Marie-Eve; Coolen, Marco J. L.; Stockhecke, Mona; Pickarski, Nadine; Litt, Thomas; Balkema, Cherel; Kwiecien, Ola; Tomonaga, Yama; Wehrli, Bernhard; Schubert, Carsten J. (Elsevier, 2014-07-29)Fossil long-chain alkenones have been used for several decades to reconstruct past ocean surface water temperatures and gained recent interest as a paleotemperature proxy for continental lake settings. However, factors ...
A radiocarbon-based assessment of the preservation characteristics of crenarchaeol and alkenones from continental margin sediments Mollenhauer, Gesine; Eglinton, Timothy I.; Hopmans, Ellen C.; Sinninghe Damste, Jaap S. (2008-01-22)Crenarchaeotal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids and alkenones are two types of biomarkers derived from planktonic marine micro-organisms which are used for reconstruction of sea-surface temperatures. ...