CARBONATE CEMENTATION IN DEEP-OCEAN SEDIMENTS

Recently the writers tested approximately 60 ft (18 m) of core obtained in water depths of about 9,800 ft (3,000 m) in the Labrador Basin. The geologic setting included typical abyssal conditions as well as levee deposits. For the purposes of this analysis, only the results of laboratory vane shear and identification tests were considered. In addition to common classification tests, carbonate contents, which are related to the magnitude of the cementation strength, were determined using the acid-neutralization technique. Values of c/p in which c equals the measured shear strength determined with a laboratory vane shear device, and p equals the effective vertical stress computed from measured bulk densities were computed at various depths for each core and plotted versus plasticity index for three cores. The data from this study lie well above the Skempton curve. Two possible reasons for this are cementation and overconsolidation. For cores C-1 and C-2 overconsolidation was considered unlikely; however, core C-3 was obtained from an area of levee deposits where overconsolidation due to erosion was possible. Further evidence for overconsolidation in core C-3 was the presence of 2 ft of sand and gravel in the top 3 ft of the core. For cores C-1 and C-2 where overconsolidation was unlikely carbonate cementation may be the cause of the high c/p values. To investigate this possibility a method proposed by Morgenstern was used.

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  • Accession Number: 00262272
  • Record Type: Publication
  • Report/Paper Numbers: Proc. Paper 10421
  • Files: TRIS
  • Created Date: Oct 22 1974 12:00AM