Extremely diverse dinoflagellate cyst and acritarch assemblages were recovered in the upper middle Eocene to Oligocene in Ocean Drilling Program Hole 913B, off of northeast Greenland. These assemblages enable a subdivision of the sequence into: middle Eocene from 581.42 to 560.68 mbsf; middle to upper Eocene from 550.90 to 510.89 mbsf; upper Eocene from 505.15 to 464.27 mbsf; ?upper Eocene to Oligocene from 462.68 to 427.45 mbsf, an interval with few dinocysts; and Oligocene from 425.98 to 424.49 mbsf. Relative abundance peaks of Deflandrea spp. and Phthanoperidinium spp. occur through the section. Two peaks in these genera coincide with the diatom- and radiolarian-rich biosiliceous oozes between 464 and 500 mbsf. These peaks may be interpreted as possibly reflecting high paleoproductivity events, and they are used to infer at least two other possible episodes of high paleoproductivity centered around 540 and 570 mbsf (middle to upper Eocene) in sediments wherein primary biosilica has been mostly removed or altered by diagenesis.
Date of initial receipt: 30 June 1995
Date of acceptance: 30 December 1995
Return to Contents of Leg 151
Return to Contents of Scientific Results