Physical properties of sediment core CRP-2A

• Main Author: Niessen, Frank
• Format: Dataset
• Language: English
• Published: PANGAEA 1999
• Subjects: 14.2 km at 096° true from Cape Roberts; Cape Roberts Project; Core wireline system; CRP; CRP-2; CRP-2A; CWS; Density; wet bulk; DEPTH; sediment/rock; Multi-Sensor Core Logger 17; GEOTEK; off Cape Roberts; Ross Sea; Antarctica; Porosity; Sampling/drilling from ice; Susceptibility; Velocity; compressional wave; Cape Roberts; Roberts Cape; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.55713; https://doi.org/10.1594/PANGAEA.55713

In this paper the relationship between whole-core compressional wave velocities and gamma-ray attenuation porosities of sediments cored at CRP-2/2A is examined, and compared with results from CRP-1, CRP-2/2A core-plug samples, and global models for velocity/porosity relationships of marine sediments. The high degree of data scatter observed in the velocity/porosity relationship of CRP-1 core is even larger in CRP-2/2A core. The general pattern of the velocity/porosity relationship is similar in CRP-2/2A whole core and core plug measurements. Despite scatter, all data indicate a strong primary dependence of velocity on porosity. This relationship appears to be independent of lithology except for sections with zero porosity and porosity >0.6, which are attributed to large lonestones and lapillistones, respectively. Core velocity/porosity patterns of CRP-1 and CRP-2/2A are very similar for sediments from the same age interval (19-23 Ma), both characterized by relatively low velocities (mostly between 2 and 3 km s-1) compared to porosity (0.1 - 0.4). Within this range of porosity, core velocities increase significantly up to more than 4 km s-1 below ca 440 mbsf. The change in the velocity/porosity relationship as a function of core depth is attributed to down-core increase in intergrain coupling enhanced by carbonate cementation. This is confirmed by a positive correlation of carbonate content with velocities higher or lower than empirically predicted from porosity. After removing first-order compaction control from the whole-core porosity record, no significant control by clay content can be identified (R = 0.3). This is different to the results for core from CRP-1 (R = 0.6) which is not cemented.