A number of shore-based sample preparation procedures and analyses were performed on selected core and are included in this volume. The following sections are a summary of techniques employed.
Approximately 50 g of core was crushed for geochemical analysis. All saw-cut or drilled surfaces of the core were first removed by diamond polishing. Polished samples were broken into 100-mm3 chips with weathered surfaces removed. Chips were cleaned three to four times in an ultrasonic bath of distilled water and dried at 110°C. Cleaned chips were powdered in a ceramic (Al2O3) SPEX shatterbox. For each sample, the ceramic inner liner was first cleaned with quartz sand, rinsed, and dried. The inner liner was then precontaminated by powdering approximately equal parts quartz sand and sample, totaling 25 g, rinsed, and dried. A total of 25 g of sample was finally pulverized to a fine powder.
Sample powders were analyzed by XRF for major and minor elements (Si, Ti, Al, Fe, Mn, Mg, Ca, K, and P) and selected trace elements (V, Cr, Ni, Cu, Zn, Sr, and Zr) using glass discs at the GEUS laboratory in Copenhagen. Sodium was determined by atomic absorption, and the ferrous iron content determined by titration. Details of the GEUS standard analytical procedures are provided in Sørensen (1975) and Kystol and Larsen (1999). Representative data are presented in the individual site chapters. All analytical results are given in "Appendix A."
Mineral compositions were determined in polished thin sections using the University of California, Davis, Cameca SX-50 electron microprobe operating at an acceleration voltage of 15 kV and a beam current of 10 nA. All phases were analyzed with a ~1-mm-diameter beam and counting time of 10 s using natural mineral standardizations. Data tables are presented in "Appendix B."
All thin sections were point-counted postcruise using an automated Swift stage mounted to an Olympus petrographic microscope. A total of 2000 points were accumulated for each thin section at a spacing of 0.02 mm x 0.5 mm and 25x–50x magnification. Tabulation of these results is provided in "Appendix C."
The procedures for the onshore studies were identical to the shipboard studies (see "Shipboard Scientific Procedures"), with the exception that the measurements were determined using a 2G super-conducting quantum interference device magnetometer and a 2G automatic, three-axis AF demagnetizer.