Figure F35. A. Photograph of hand specimen of moderately altered gabbro (interval 209-1275B-5R-1, 135–145 cm). B. In this part of Hole 1275B titanite (ti) is a common accessory phase. In thin section a photomicrograph shows that titanite forms rims along the margins of hematite (h) and borders against secondary plagioclase with acicular amphibole (arrow). Quartz (q) with amphibole needles is present in the lower right corner (Sample 209-1275B-5R-1, 134–137 cm) (cross-polarized light: blue filter; field of view = 1.4 mm; image 1275B_004). C. The X-ray diffractogram of Sample 209-1275B-5R-1, 134–137 cm, is dominated by peaks of plagioclase and amphibole. Minor peaks diagnostic of titanite confirm the petrographic observation that it is an abundant phase in the upper gabbro/diabase sequence of Hole 1275B.

Figure F35. A. Photograph of hand specimen of moderately altered gabbro (interval 209-1275B-5R-1, 135–145 cm). B. In this part of Hole 1275B titanite (ti) is a common accessory phase. In thin section a photomicrograph shows that titanite forms rims along the margins of hematite (h) and borders against secondary plagioclase with acicular amphibole (arrow). Quartz (q) with amphibole needles is present in the lower right corner (Sample 209-1275B-5R-1, 134–137 cm) (cross-polarized light: blue filter; field of view = 1.4 mm; image 1275B_004). C. The X-ray diffractogram of Sample 209-1275B-5R-1, 134–137 cm, is dominated by peaks of plagioclase and amphibole. Minor peaks diagnostic of titanite confirm the petrographic observation that it is an abundant phase in the upper gabbro/diabase sequence of Hole 1275B.