3. Bolboforma biostratigraphy from Hatton-Rockall Basin (North Atlantic)1

Dorothee Spiegler2


Although they are fossils of uncertain origin, bolboforms are the best calcareous microfossil group for Neogene biostratigraphy in the North Atlantic.

Fifty-two Bolboforma species were observed at the Hatton-Rockall Basin in Ocean Drilling Program Holes 982A (26 samples) and 982B (301 samples) and in Deep Sea Drilling Project Hole 116 (71 samples). The sequence investigated spans the interval from lower Miocene to upper Pliocene. Fourteen zones/subzones were identified and correlated with the calcareous nannoplankton zones, the planktonic foraminifer biostratigraphy, and the time (Ma). The last occurrence of the genus Bolboforma can be dated to 2.84 Ma.

Different Bolboforma specimens of middle Miocene age, observed in upper Miocene and upper middle Miocene sediments at Site 982, document redeposition of sediment from the Rockall Bank into the Hatton-Rockall Basin during the latest middle Miocene and late Miocene.

1Raymo, M.E., Jansen, E., Blum, P., and Herbert, T.D. (Eds.), 1999. Proc. ODP, Sci. Results, 162: College Station, TX (Ocean Drilling Program).
2GEOMAR Forschungszentrum für Marine Geowissenschaften an der Christian-Albrechts Universität, Wischhofstrasse 1-3, Gebäude 4, D-24148 Kiel, Federal Republic of Germany. dspiegler@geomar.de

Date of initial receipt: 16 September 1997
Date of acceptance: 2 March 1998
Ms 162SR-013