Siliceous microfossils in middle Eocene sediments of ODP Holes 120-748B and 120-749B ...

• Main Authors: Witkowski, Jakub, Bohaty, Steven M, McCartney, Kevin, Harwood, David M
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2012
• Subjects: Drilling/drill rig; Leg120; Joides Resolution; Ocean Drilling Program ODP; Southern Ocean
• Online Access: https://dx.doi.org/10.1594/pangaea.777114; https://doi.pangaea.de/10.1594/PANGAEA.777114

The Middle Eocene Climatic Optimum (MECO) is a major transient warming event that occurred at ~ 40 Ma and reversed a long-term cooling trend through the early and middle Eocene. We report the results of a high-resolution, quantitative study of siliceous microfossils at Ocean Drilling Program Sites 748 and 749 (Southern Kerguelen Plateau, Southern Ocean, ~ 58°S) across a ~ 1.4 myr interval spanning the MECO event. At both sites, a significant increase in biosiliceous sedimentation is associated with the MECO event. Rich siliceous planktonic microfossil assemblages in this interval are unusual in that they are dominated by ebridians, with radiolarians as a secondary major component. Silicoflagellates and diatoms comprise only a minor fraction of the assemblage, in contrast to siliceous microfossil assemblages that characterize modern Southern Ocean sediments. Based on our new siliceous microfossil records, we interpret two ~ 300 kyr periods of elevated nutrient availability in Southern Ocean surface waters ... : Supplement to: Witkowski, Jakub; Bohaty, Steven M; McCartney, Kevin; Harwood, David M (2012): Enhanced siliceous plankton productivity in response to middle Eocene warming at Southern Ocean ODP Sites 748 and 749. Palaeogeography, Palaeoclimatology, Palaeoecology, 326-328, 78-94 ...