Observers: John Sinton (transcript) and Cindy Van Dover (transcript)
Pilot: Robert Williams
Launch: 18° 36.36'S; 113° 23.74'W
Objectives: Work south from Animal Farm, exploring axis. Watch for evidence of different eruptive episodes/features. Test "musset pot" and search for suitable "bio-dive" site.
Summary: This dive traversed the axis at least four
times. All lavas on this dive are extremely glassy and all areas
visited had at least a thin coating of sediment. The eastern flank
is dominated by lobate lavas with some pillows, locally with abundant
buds. The axial region typically contains collapsed lobate lavas
with a variety of sheet flows lying in the collapsed areas. For
much of the dive there is a tendency for asymmetric collapse,
mostly down to the west with sheet flows primarily flowing westward.
Most collapsed areas are relatively small, less than a few meters
deep although one area near 18° 37.65'S, 113° 24.25'W
is 12 m deeper than the surrounding lobate surface. An extensive
area of sheet flows is present on the western flank between about
18°37.5'S and 18°38.4'S. The heaviest sediment cover observed
was on the east flank near 18° 37.4'S. Contacts between various
lava morphologies, e.g. between lobate and sheet lavas, were extremely
common although it is unclear which of these, if any, represent
boundaries between the products of different eruptive events.
Some lobate, and or pillow lavas on the east flank may be an older
Diffuse hydrothermal venting was found at two sites - Animal Farm near 18°36.48'S, 113° 23.95'S, and an area about 570m along strike to the SW near 18° 36.78'S, 113° 24.09'W. Alvin window temperature indicates an approximately 0.4°C anomaly at the latter site. The part of the Animal Farm site visited during this dive appears to be less active with less vital animal communities present than in in 1993 when this site was visited during NAUDUR dive 12. Animal Farm may be evolving into Pet Cemetary. Approximately 4.5 km of track was covered during this dive and ten samples collected, of which one was biological and the other nine, primarily lava fragments, some of which had attached biota.
Sample # Latitude (°S) Longitude (°W) 1 18° 36.39 113° 23.78 2 18° 36.45 113° 23.96 3 18° 36.45 113° 23.96 4 18° 36.66 113° 24.04 5 18° 37.06 113° 24.06 6 18° 37.49 113° 24.14 7 18° 37.74 113° 24.40 8 18° 38.52 113° 24.40 9 18° 38.77 113° 24.53 10 18° 38.90 113° 24.55