Alkenone sea-surface temperatures and carbon burial at site 846 (Eastern Equatorial Pacific Ocean) : the last 1.3 M.Y. Public Deposited

http://ir.library.oregonstate.edu/concern/defaults/2b88qd93s

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • We analyzed the unsaturation ratio (U k/37 ) of long-chain ketones—a molecular sea-surface temperature (SST) indicator—concentrations of carbonate and organic carbon in sediments from Site 846 in the eastern equatorial Pacific Ocean. Based on an isotopic age model for the composite depth section of 0-46 m below seafloor and on estimates of sediment density, accumulation rates of these biogenic compounds were calculated. Our combined temperature and biogenic flux record traces conditions at the origin of the South Equatorial Current over the last 1.3 m.y. S STs have fluctuated considerably over the interval studied. A long trend of gradual decrease from 24°C at 1.3 Ma ends between 500 and 400 Ka, when lowest values of 19°C were reached. Since this time, the temperature data indicate a warming trend to the Holocene modulated by high-amplitude variation (19° to 27°C). The inversion of the trend between 400 and 500 Ka coincides with maximal accumulation rates of carbonate, which since then have decreased. In contrast, organic carbon accumulation since then has increased in variability and in absolute values. On shorter time scales, the records show a strong link to the global climatic background. Since 1.3 Ma, carbonate (0.2-3 g/cm² k.y.¯¹) and organic carbon accumulation rates (2-30 mg/cm² k.y¯¹) were consistently high (more than twice their modern values and those of interglacials) during glacial maxima in the benthic isotope record, when temperatures were low. However, cross-spectral analyses with the δ¹⁸O record suggest that variation in organic carbon flux is not linked directly to variations in SST. Temperature maxima in our record led interglacial events by 7 k.y. in the 100-k.y. eccentricity cycle and by 5 k.y. in the 41-k.y. obliquity cycle. In contrast, maxima in organic carbon accumulation lag behind glacial maxima and low temperatures by 14 k.y. in the eccentricity cycle. On glacial/interglacial time scales, a prominent influence on SST—but not on organic carbon burial—at Site 846 appears to be the advection of cold water into the South Equatorial Current.
Resource Type
Date Available
Date Issued
Citation
  • Emeis, K.-C., H. Doose, A.C. Mix, and D. Schulz-Bull (1995) Alkenone sea-surface temperatures and carbon burial at Site 846 (Eastern Equatorial Pacific): the last 1.3 M.Y <http://www.coas.oregonstate.edu/facultypages/mix/Emeis_etal_ODP138_uk37.pdf >. In: Pisias, N.G., L. Mayer, T. Janecek, A. Palmer-Julson, T.H. van Andel (eds.), /Proceedings of the Ocean Drilling Program, Scientific Results,/ 138, College Station, TX (Ocean Drilling Program), 605-614.
Series
Rights Statement
Publisher
Language
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Linda Kathman(linda.kathman@oregonstate.edu) on 2009-12-17T21:15:38Z (GMT) No. of bitstreams: 1 EmeisEtAl1995_Leg138_AlkenoneSeaSurfaceTemps.pdf: 2596555 bytes, checksum: feb10e7c86991be3bebd576f460ca6ee (MD5)
  • description.provenance : Submitted by Mary Phan (mpscanner@gmail.com) on 2009-12-17T19:15:05Z No. of bitstreams: 1 EmeisEtAl1995_Leg138_AlkenoneSeaSurfaceTemps.pdf: 2596555 bytes, checksum: feb10e7c86991be3bebd576f460ca6ee (MD5)
  • description.provenance : Made available in DSpace on 2009-12-17T21:15:38Z (GMT). No. of bitstreams: 1 EmeisEtAl1995_Leg138_AlkenoneSeaSurfaceTemps.pdf: 2596555 bytes, checksum: feb10e7c86991be3bebd576f460ca6ee (MD5) Previous issue date: 1995

Relationships

In Administrative Set:
Last modified: 07/25/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items