Cambridge Arctic Shelf Programme, Department of Earth Sciences, Downing Street, Cambridge CB2 3EQ, UK.
Facies and depositional processes in an Upper Jurassic to Lower Cretaceous pelagic sedimentary sequence, Antarctica
Version of Record online: 14 JUN 2006
Volume 40, Issue 2, pages 331–349, April 1993
How to Cite
WHITHAM, A. G. (1993), Facies and depositional processes in an Upper Jurassic to Lower Cretaceous pelagic sedimentary sequence, Antarctica. Sedimentology, 40: 331–349. doi: 10.1111/j.1365-3091.1993.tb01767.x
- Issue online: 14 JUN 2006
- Version of Record online: 14 JUN 2006
- Manuscript received 14 November 1990; revision received 30 December 1992
The Nordenskjöld Formation (?Oxfordian-Berriasian age) is exposed on the east coast of the Antarctic Peninsula, where it consists of interbedded ash layers and biosiliceous mudstones which accumulated under anaerobic to dysaerobic bottom waters. The mudstones were deposited by pelagic settling and the ash layers by pelagic settling from suspension or as fallout from subaerial eruption columns. The lower part of the succession accumulated in a basinal setting under anaerobic bottom waters and is characterized by parallel bedding. Mudstones deposited in this setting preserve abundant zooplankton faecel pellets. Compaction of these pellets has given rise to a bedding parallel fissility. The upper part of the succession accumulated under dysaerobic bottom waters in a slope setting. The sequence is wavy bedded and contains abundant evidence of post-depositional sediment instability and resedimentation, much of which was caused by tectonic activity. Discrete slide masses are absent from the slope sequence and it appears that slope processes were dominated by creep. Examination of the mudstones shows that as levels of dissolved oxygen in bottom waters increase, pelleted mudstones give way to structureless mudstones before visible bioturbation is noted.