Figure F14. Close-up photograph of interval 183-1141A-20R-1, 71-91 cm, showing the contact between basement Units 4 and 5. Note the altered glassy chill margins (arrows) at the contact and defining the 10-cm-thick pahoehoe lobe at the top of Unit 5. When the whole core is examined, it is apparent that the contact between Units 4 and 5 has 5-cm-scale topography, and the cut surface of the core obliquely intersects a pocket of Unit 4 lava filling a gap in the top of Unit 5.