Petrographic analysis was conducted on a suite of 34 samples, chosen as representatives of the variety of calcite veins observed in basement cores from Sites 897 and 899. The list of samples studied is given in Table 1, along with a brief petrographic description based on the discussion in the text. Before sectioning, thin-section billets were impregnated with blue-dyed epoxy to make existing porosity more visible. Standard petrographic examination was performed using several optical microscopes. Cathodoluminescence imaging was performed using a Premier American Technologies Luminoscope (model ELM-3R) mounted on a Leitz brand Ortholux microscope. Operating voltage and current were set at 10 kV and 0.4 mA, respectively.
A subset of the petrographic samples described herein was subsequently used for isotopic and trace-elemental analysis, using photographic maps of features noted during petrographic and cathodoluminescence examination. The analyses that were performed are detailed in Table 1, and the results and interpretations of this chemical study are presented in an accompanying paper by Milliken and Morgan (this volume).