The Fabric of Consolidating Clayey Sediment Column, ODP Site 697
Abstract
Consolidation of sediment is the main cause of porosity reduction with depth in the upper 1000 m of the sediment column. The consolidation of high-porosity sediment is mostly mechanical: the weight of the overlying sediment drives the rearrangement of individual particles and groups of sedimentary particles and domains. The mechanics of particle reorientation may be understood best through an examination of the sediment microfabric. A clay- rich sediment section 318 m thick, recovered during ODP Leg 113 from the South Orkney Microcontinental Margin, Site 697 in the Weddell Sea, was examined by transmission electron microscopy of ultrathin sections. Reorientation of randomly arranged particles of this fine-grained, high-porosity (70% - 75%) sediment occurs very gradually: porosity decreases to only about 50% at a depth of 318 m, because of the very fine-grained nature of the imparts a very low permeability even at porosities of 50%. Keywords: Sediment transport; Sediments; Pore pressure; Clay.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1990
- Accession Number
- ADA227641
Entities
People
- F. R. Rack
- P. J. Burkett
- R. H. Bennett
- W. R. Bryant
Organizations
- United States Naval Research Laboratory