At Site 1098 we recovered diatom oozes to diatom bearing mud. Deposition was by pelagic settling of diatom blooms and by gravity flows from the steep margins of the basin. Three prominent silt or sand turbidites occur between 23 and 40 mbsf. Laminae are diatom oozes of different species composition. Microfossil preservation is excellent, and this site will provide an unparalleled record of Antarctic Holocene paleoproductivity.
Cores provide an extremely high resolution record of variation in geomagnetic field direction.
The approach to basement is marked by a greater increase in density coincident with the lithologic change to terrigenous silt and sand at around 42 mbsf. Natural gamma levels may show some cyclicity on the order of 10 m while generally increasing downhole. The sulfate reduction zone lies between 20 and 30 mbsf. Organic matter decay has surprisingly little effect on interstitial water chemistry above the sulfate reduction zone. We speculate that the tightly encased Chaetoceros spores, the majority of diatoms in Palmer Deep, render organic material unavailable for bacterial consumption until dissolution breaches the external casing.