Reliability of core sampling of soft bottom sediment—an in situ study
Article first published online: 14 JUN 2006
Volume 32, Issue 4, pages 605–612, August 1985
How to Cite
BLOMQVIST, S. (1985), Reliability of core sampling of soft bottom sediment—an in situ study. Sedimentology, 32: 605–612. doi: 10.1111/j.1365-3091.1985.tb00474.x
- Issue published online: 14 JUN 2006
- Article first published online: 14 JUN 2006
- (Manuscript received 21 September 1984; revision received 18 November 1984)
The performances of four light-weight, open sampling devices intended for use in soft sediments, the Axelsson-Håkanson gravity corer, the Kajak gravity corer, the Jenkin bottom sampler and the Ekman grab (box corer), were examined in situ by direct observation, measurement and photographic documentation by a SCUBA diver. Restrictions on the reliability of the sediment samples obtained with these devices and sediment coring instruments in general are evaluated.
Separate studies of core shortening show: (1) a positive linear relationship between sediment penetration depth at which shortening of cores starts and coring tube inner diameter, (2) a tube size related shift of curve pattern in the regressions of the core shortening versus sediment depth, and (3) a negative non-linear relationship of shortening intensity versus increasing coring tube inner diameter. These findings show the great risk, when sampling soft sediments, of obtaining a sample quantitatively unrepresentative of the in situ stratification. An accurate correction factor for the degree of core shortening requires a knowledge of: (1) the sediment depth at which core shortening commences, and (2) the curve describing the relationship of shortening to depth of penetration.