Several methods of marking cores have been used, including paint, grease 

 pencil, engraving tools, soldering iron, and waterproof felt-tip markers. Paint 

 and grease pencils do not generally provide permanent markings as they deterio- 

 rate during later handling and storage; engraving or soldering tools are satis- 

 factory, but their use is time consuming and the marks are not always legible. 

 However, these means are sometimes useful for supplementary markings which will 

 remain if the primary marks are lost. The use of waterproof felt-tip markers 

 is the fastest and most permanent way for primary marking of core liners. 

 However, since all markers are not permanent or indelible, the selected marker 

 should be tested for withstanding wetness and handling. 



3. Core Sampling . 



Sediment samples can be removed from a core either by drilling holes in the 

 core container or by splitting the core lengthwise and removing samples from 

 one of the halves. A power drill fitted with a 1.5- to 2-inch hole saw can be 

 used to make holes in the liner. Samples can then be removed with a spoon and 

 the hole closed by replacing the cutout disk and sealing with duct or plastic 

 electrical tape. Since some core liners are opaque and clear plastic liners 

 often become semiopaque due to abrasion and mud coatings, the spacing of the 

 sample holes is generally arbitrary. To assure that samples are representative 

 of the sequence of lithologies in the cores, spacing of about 1 foot (30 centi- 

 meters) is recommended. 



Splitting the cores along the longitudinal axis is the preferred means of 

 processing the core as it allows direct observation of the vertical sedimentary 

 sequence in the core as well as detailed logging of lithologies, sedimentary 

 structures, bedding, and other important features. Samples removed from a 

 split-core half that is logged in detail generally need not be as numerous, and 

 St the same time may be more representative than "blind samples" taken through 

 access holes in the liner where no logging is done. 



A satisfactory technique of splitting cores for all types of core liners 

 is described by Meisburger, Williams, and Prins (1980)'*, and is summarized in 

 Appendix A. In practice, it is desirable that half of the split core be used 

 for sampling and the other half be preserved as an archive. The archive half 

 should be sealed in plastic sleeving and stored on core racks for future study 

 or sampling. Careful handling is necessary because much of the strength of 

 the liner is lost after splitting and the container easily twists or breaks if 

 not adequately supported. 



4. Core Logging . 



The core log consists of a visual description of each sedimentary unit 

 recovered in the core. Cores are generally logged on a form containing a 

 vertical column on which the various sedimentary intervals are plotted with 

 a description of each unit entered opposite the pertinent interval (Fig. 3). 

 If possible, each core should be split for logging. If this is not feasible, 

 then representative cores should be selected on the basis of sample data and 



'^MEISBURGER, E.P., WILLIAMS, S.J., and PRINS, D.A., "An Apparatus for Cutting 

 Core Liners," Jouvnal of Sedimentary Petrology , Vol. 50, No. 2, June 1980, 

 pp. 641-642. 



