Figure F60. A. Site 1139 igneous rock compositions on the Na₂O + K₂O vs. SiO₂ classification diagram (Le Bas et al., 1986); alkalic and tholeiitic basalt fields are distinguished by the Macdonald-Katsura (1964) line. Note that there is one chemical analysis per igneous unit except for Units 5, 18, and 19 from which two, two, and four samples, respectively, were analyzed. The least-altered Unit 18 and 19 samples are marked in bold, and other samples from these units show considerable spread caused by alteration. B. Site 1139 mafic compositions compared to samples from Kerguelen Plateau Sites 1136, 1137, and 1138. The fields represent data from previous dredging and drilling on the southern and central Kerguelen Plateau (Sites 738, 747, 749, 750, and dredge locations reported by Weis et al., 1989). Data sources are Davies et al. (1989), Alibert (1991), Mehl et al. (1991), Salters et al. (1992), Storey et al. (1992), Mahoney et al. (1995), and this study.