Export productivity and carbonate accumulation in the Pacific Basin at the transition from a greenhouse to icehouse climate (late Eocene to early Oligocene)

Elizabeth Griffith, Michael Calhoun, Ellen Thomas, Kristen Averyt, Andrea Erhardt, Timothy Bralower, Mitch Lyle, Annette Olivarez-Lyle, Adina Paytan

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The late Eocene through earliest Oligocene (40-32 Ma) spans a major transition from greenhouse to icehouse climate, with net cooling and expansion of Antarctic glaciation shortly after the Eocene/Oligocene (E/O) boundary. We investigated the response of the oceanic biosphere to these changes by reconstructing barite and CaCO3 accumulation rates in sediments from the equatorial and North Pacific Ocean. These data allow us to evaluate temporal and geographical variability in export production and CaCO3 preservation. Barite accumulation rates were on average higher in the warmer late Eocene than in the colder early Oligocene, but cool periods within the Eocene were characterized by peaks in both barite and CaCO3 accumulation in the equatorial region. We infer that climatic changes not only affected deep ocean ventilation and chemistry, but also had profound effects on surface water characteristics influencing export productivity. The ratio of CaCO3 to barite accumulation rates, representing the ratio of particulate inorganic C accumulation to Corg export, increased dramatically at the E/O boundary. This suggests that long-term drawdown of atmospheric CO2 due to organic carbon deposition to the seafloor decreased, potentially offsetting decreasing pCO2 levels and associated cooling. The relatively larger increase in CaCO3 accumulation compared to export production at the E/O suggests that the permanent deepening of the calcite compensation depth (CCD) at that time stems primarily from changes in deep water chemistry and not from increased carbonate production.

Original languageEnglish (US)
Article numberPA3212
JournalPaleoceanography
Volume25
Issue number3
DOIs
StatePublished - Sep 1 2010

Fingerprint

barite
Oligocene
Eocene
accumulation rate
carbonate
productivity
climate
basin
cooling
drawdown
water chemistry
biosphere
ventilation
glaciation
calcite
seafloor
deep water
organic carbon
surface water
climate change

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Palaeontology

Cite this

Griffith, Elizabeth ; Calhoun, Michael ; Thomas, Ellen ; Averyt, Kristen ; Erhardt, Andrea ; Bralower, Timothy ; Lyle, Mitch ; Olivarez-Lyle, Annette ; Paytan, Adina. / Export productivity and carbonate accumulation in the Pacific Basin at the transition from a greenhouse to icehouse climate (late Eocene to early Oligocene). In: Paleoceanography. 2010 ; Vol. 25, No. 3.
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Export productivity and carbonate accumulation in the Pacific Basin at the transition from a greenhouse to icehouse climate (late Eocene to early Oligocene). / Griffith, Elizabeth; Calhoun, Michael; Thomas, Ellen; Averyt, Kristen; Erhardt, Andrea; Bralower, Timothy; Lyle, Mitch; Olivarez-Lyle, Annette; Paytan, Adina.

In: Paleoceanography, Vol. 25, No. 3, PA3212, 01.09.2010.

Research output: Contribution to journalArticle

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T1 - Export productivity and carbonate accumulation in the Pacific Basin at the transition from a greenhouse to icehouse climate (late Eocene to early Oligocene)

AU - Griffith, Elizabeth

AU - Calhoun, Michael

AU - Thomas, Ellen

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