Figure 3. Representative thin section photographs of Group 1, 2, and 3 samples showing textural and mineralogical differences primarily related to various degrees of alteration. See text and Table 2 for description of the respective minicores. A. Interval 163-990A-12R-2, 75-77 cm. B. Interval 163-990A-13R-3, 31-33 cm. C. Interval 163-990A-9R-2, 5-7 cm.