Karig, D. E. (1996): Uniaxial reconsolidation tests on porous sediments; mudstones from Site 897. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Whitmarsh, Robert B., Sawyer, Dale S., Klaus, Adam, Beslier, Marie-Odile, Collins, Eric S., Comas, Maria Carmen, Cornen, Guy, de Kaenel, Eric, Pinheiro, Luis de Menezes, Gervais, Elisabeth, Gibson, Ian L., Harry, Dennis L., Hobart, Michael A., Kanamatsu, Toshiya, Krawcyzk, Charlotte M., Liu, Li, Lofts, Jeremy C., Marsaglia, Kathleen M., Meyers, Philip A., Milkert, Doris, Milliken, Kitty L., Morgan, Julia K., Ramirez, Pedro, Seifert, Karl E., Shaw, Timothy J., Wilson, Chris, Yin, Chuan, Zhao, Xixi, Proceedings of the Ocean Drilling Program; scientific results, Iberia abyssal plain; covering Leg 149 of the cruises of the Drilling Vessel JOIDES Resolution; Balboa Harbor, Panama, to Lisbon, Portugal; sites 897-901, 10 March-25 May 1993, 149, 363-373, georefid:2007-088101

The porosity and yield stress of clay-rich marine sediments can be sensitive indicators of stress and stress history, if testing of these sediments is done carefully and the results are interpreted with an understanding of sediment mechanical behavior. Consolidation tests on a nannofossil clay from 619 mbsf in Hole 897D indicated a very low yield stress (about 1 MPa), but at a porosity that was also quite low with respect to that of the same sediment when it was disaggregated and consolidated from a slurry. Moreover, no evidence for cementation of the natural sediment was observed, despite its calcareous nature. The lower porosity of the natural sample was shown to result from the much slower geological rates of consolidation than the laboratory rates. The lower compressibility of the natural sample was attributed to "delayed consolidation" during the subsequent laboratory consolidation. Together with the downward increase in porosity and intense fracture/vein development observed at Site 897, the low yield stress indicates near-lithostatic pore pressures in the basal sediments over much of their history and probably at present. This condition would suggest that fluid is rising from below and probably moving laterally toward egress to the ocean at the ridge top. The source and hydrodynamic setting of this fluid are as yet inadequately explored.
West: -12.2847 East: -12.2847 North: 40.5019 South: 40.5019
Expedition: 149
Site: 149-897
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.149.234.1996 (c.f. for more detailed metadata)
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