Transcript: Ken Macdonald stbd observer
Macdonald/ Boyle/ Heintz;
LAUNCH POINT: 18º 08.30' S, 113º 20.5' W
Lava Lake 18 08-18 18S first dive in area.
Did two 360º spins for mag calibration at depth 1000m, 2683m, on bottom, in age 3-3.5 pillows at target 1
0935 130º, 2680m, stopping for rock sample 1 in age 3-3.5 pillow lavas.
0942 225º, 2685m; underway again, age 3 pillow lavas; underway to target 2
0944 225º, 2683m age 3 lobates and pillows, perhaps lobates are a bit older.
0946 231º; 2695m; younger looking lobates here, age 2.5?, then onto talus of pillows and lobates; the talus is fresh
0948 turning right to follow along the wall which is producing this talus. Crossing two N-S fissures each ~1/2m wide.
1006 rock sample 4 top of ~ 6m high dead chimney.
1024 2696m just collected top of the active vent; put in bio box with sample 3b of inactive chimney, so this sample is #3; now leaving field of one active and many inactive hydrothermal sulfide vents; built on top of a high standing ridge of pillow lavas.
1027 226º heading to waypt 2; age 2.5 pillows and lobates, could even be age 2; talus
1029 224º; 2700m; transition to age 2 pillow lavas. Crossed 1m wide fissure trending N-S.
1031 221º, 2697m; N-S fissure 1/2m wide, age 2-2.5 pillow lavas and fresh talus.
1032 on top of dead hydrothermal ridge.
1035 at least a dozen dead hydrothermal sulfide chimneys atop this ridge. The ridge itself appears to be a lava lake remnant, perhaps a linear array of pillars?? A "hydrovolcanic" edifice?
1042 still on this hydrovolcanic edifice, heading off to waypt 4 now.
1048 another N-S 1/2m wide fissure (note; on tape I was turned around and said the fissures were E-W)
1055-1100; collected rock sample 6; heading to waypt 4
1102 156º; 2694m; bottom drops ~12m; part of a N-S horst; age 3 lobates
1115 old sulfide mound
1119 6 old dead sulfide chimneys
1120 220º; 2708m; fresh talus and pillows age 2.5
1136 198º 2700m; pillows on top of lobate lava, age 2.5
ll44-7 stop for sample 8 in age 2.5 pillows and lobate lava
1148 underway 090, 2698m it is 500m to target 7going up east wall.
1151 starting steep ascent of east wall, lots of fresh talus
1152 094º, 2684m; old lava lake remnant and bathtub rings within the debris going up east wall, talus is fresh. Two fissures, one 1m and one 1/2 wide on east side of a ~10m wide sliver of crust which is calving off the face of the east wall much like the slabs of ice that calve off the face of a glacier.
1153 age 3 lobates and pillows on bench within east wall, 2683m, 090º
1156 stopping at edge of 3m wide N-S fissure. Fresh talus, truncated pillow lavas in exposed face. Another 3 slivers of extrusive crust tipping in toward valley floor. There are also some intact pillow lavas along the edge of the fissure, perhaps lava drained into this fissure at some earlier time?
1209 090º very fresh angular fault talus
1216 2662m , turning to 180 to head to waypt 8 about 200 m before getting to waypt 7
1225 10m vertical drop to west (according to mesotech)
1233 1/2m wide N-S fissure in age 3 pillows; on mesotech, floor of fissure ~10m deep
1240 back in floor of valley sheet flows and a few lobates, age 2-2.5, a few short pillars only ~1-2m high.
1252-54 stopped for sample11 , nice drained out lava tube here
1255 mostly lobates age 3
1300 204º 2697m change from pillows back to lobates age 3
1306 2692m 207º contact with age 2 pillows, ascending flow front of elongate pillows, perhaps on the side of a pillow mound. Very little sediment, some glass.
1322 2691m rock sample 13 at top of pillow mound? must head back to surface even though we have lots of power left because of bad weather topside.
1419-25 doing two 360s for magnetometer calibration.