Giant diatoms from the genus Ethmodiscus Castracane are a ubiquitous but relatively rare component of the warm-surface ocean plankton. Ethmodiscus oozes have been documented as occurring during the geological past; however, the debate over the mechanism of formation of these oozes is still unresolved. This report documents the nature and occurrence of early Pliocene Ethmodiscus ooze from Ocean Drilling Program Site 1010. The sediment fabric of the ooze interval has been analyzed using scanning electron microscopy, specifically backscattered electron imagery. This has shown that the sediment consists of an irregular alternation between laminae rich in Ethmodiscus fragments; mixed-sediment laminae comprising silt grains, clays, and nannofossils; and horizontal to subhorizontal burrows filled with nannofossil clay that is similar to sediment deposited above and below the diatom-rich interval. The short stratigraphic occurrence of Ethmodiscus ooze at Site 1010 precludes any substantial contribution to the debate over the mechanism of formation of these deep-sea oozes; it is suggested, however, that further studies should consider the concentration (and subsequent deposition) of these giant diatoms along convergent oceanic frontal zones.
1Lyle, M., Koizumi, I., Richter, C., and Moore, T.C., Jr. (Eds.), 2000. Proc. ODP, Sci. Results, 167 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/167_SR/167sr.htm>. [Cited YYYY-MM-DD]
2Department of Earth Sciences, University of Wales, Cardiff, P.O. Box 914, Cardiff, CF10 3YE, United Kingdom. pikej@cardiff.ac.uk
Date of
initial receipt: 23 November 1998
Date of acceptance: 17 June 1999
Ms 167SR-233