In order to evaluate X-ray imaging efficacy for observation and description of sedimentary structures in consolidated sedimentary rocks with a computed tomography (CT) scanner, X-ray images obtained during the Ocean Drilling Program Leg 210 cruise and X-ray CT images obtained during postcruise study are compared with split surface digital images of the correlative half-core.
Sedimentary structures are clearly to faintly recognized with X-ray images, implying that sedimentary rocks (sandstone, siltstone, and shale) retain density contrasts despite decreases in porosity caused by compaction. X-ray imaging is efficient for observing partial sedimentary and postsedimentation structures. However, carbonate rocks tend to be unsuitable for X-ray imaging and observation because whole-core cementation often masks density contrasts, rendering homogeneous sedimentary structures. Overlap of high-angle structures often prevents clear two-dimensional imaging.
X-ray CT scanning is a powerful tool that can image structures in sedimentary rock core samples before they are split. Constructing an efficient X-ray CT imaging methodology to be used during the time constraining the core description process is required.
1Shirai, M., Nishimura, M., and Yasuda, H., 2007. Data report: descriptive evaluation of consolidated sedimentary rock structures with X-ray imaging: examples from Site 1276 core samples. In Tucholke, B.E., Sibuet, J.-C., and Klaus, A. (Eds.), Proc. ODP, Sci. Results, 210: College Station, TX (Ocean Drilling Program), 1–21. doi:10.2973/ odp.proc.sr.210.111.2007
2Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo, 164-8639, Japan. email@example.com
3Marine Works Japan, Yokohama Institute of Marine Science, JAMSTEC, 3172-25 Showa-cho, Kanazawa-ku, Yokohama, 236-0042, Japan.
4Center for Advanced Marine Core Research, Kochi University, B200 Monobe, Nankoku, Kochi, 783-8502, Japan.
Initial receipt: 16 February 2006
Acceptance: 26 July 2006
Web publication: 11 May 2007