Alvin Dive 3356

Ken Macdonald (S-O)/ Eric Bergmanis (P-O)/ Matt Heintz (Pilot)
Launch: 18 12.85' S, 113 20.50' W; x=6250 y=13200
Transponder origin: 18° 20' S 113° 24' W

Note: two 360 spins for magnetometer calibration done at 1500-1900m depth

Transcript follows:
0939 on bottom in age 4 pillow lavas on east flank of ridge about 1600m east of the axis of the trough floor.
0940 heading 245 depth+alt.= 2663m, age 3-3.5 pillow lavas.
0942-45 rock sample 1, 2713m in age 3 pillow lavas.
0948 2747m heading 245, age 3 pillow lavas, more outcrop than where we first landed; but not much glassiness evident.
heading 243, 2737m, two 1m wide fissures, some minor dip slip on both. Trending N-S thru age 3 pillows. Some minor volcanic draping of outward facing scarps occurs here.
2730m, heading 241; Another 1m wide N-S fissure that is fresh, truncated pillow lavas; now we see small exposure of age 2.5 folded sheet lavas atop the pillows, then back to age 3 pillows in only ~10m.
2722m, several small outcrops of sheet flows age 2.5 atop pillows of age 3.
1m wide N-S fissure cutting thru age 3 pillow lavas.
Another 1/2m wide N-S fissure, pillows have more glassy buds here.
0959 2696m heading 240, another 1/2m wide N-S fissure not much sediment in the bottom so like the others we have seen, I think there are active tectonic fissures.
2683m, heading 241, pillows appear to have more buds here, pillows are both elongate and bulbous in shape.
Two 1m wide N-S fissures. Might be a little dip slip displacement.
1005 depth 2686, alt. 15m, flying high now, crossed a N-S scarp which is about 15m high, facing west
lows and lobates, some recent fissures cutting through age 4 sediment covered lavas; fissures are only ~10cm wide; the apparent increase to age 4 might really just be a transition from mostly pillows to mostly lobated lavas.
2694m, Stopped for rock sample 2.
transition back to bulbous pillows with buds, climbing flank of pillow mound which could be seen on the DSL 120 side scan sonar records. Here we are about 100m past target 2.
1023 2684m, changing course from ~245 to ~130; two 1/4m wide N-S fissures. In Age 3 pillows.
1026 122, 2687m, age 3 pillows.
ñ37 2722m, stopping for rock sample 3 in age 3 bulbous pillow lavas. Some glassy buds. Perhaps age is more like 2.5?
1037 2712m, alt. 13m; heading off to waypt 4 ~245.
2717m, heading 248 , age 2.5 pillows, about 50% sediment cover but glassy buds on pillows.
2715m, Local outcrop of folded sheet flows only a few m across then back to pillows, all of age 2.5. Flow direction is East.
2709m, 245, back to age 4, but may actually be a transition to lobates and flat sheet flows?
2707m, 245, Folded sheet flows, age 2.5-3
shrimp, fish. Age 3 pillow lavas.
Age 4, now uphill and back to pillows lavas age 2.5-3; seems like every time there is a flat place we have sediment covered lobates and sheets, and where it is uphill, we have age 2.5-3 pillows.
2695m, heading 253, 1m wide N-S fissure, truncated pillow lavas and very little sediment in fissure, so it is tectonically active a probably very recent.
2695m, 253, old collapse pit with bathtub rings and 1-2m high pillars. Pillars are vertical which suggests no significant tilting of crustal blocks here on top of east wall. Age 3 lobates and sheets. Back to age 3 pillows. 1/2m wide N-S fissure.
Two 10 cm wide active fissure which cuts around the pillow edges. Age 2.5-3 pillows.
2688m, 248, age 2.5 pillows.
2677m, age 2.5 pillows.
Bottom is flattening, on bench, 2675m, rock sample 4.
heading 249, heading up pillow slope, flow direction generally east
1/2m wide N-S fissure cutting age 3 pillows.
250, 2566m, heading up pillow slope of age 3
pillow lavas, fewer buds and a bit more sediment.
1059 2659m, 247, more outcrop, age 2.5 pillows, lots of glassy buds; crossed two 1/4m wide N-S fissures which are draped by pillow lavas.
1100 ~2m high inward or west-facing scarp, then a ~10m high outward or east facing fault scarp exposing truncated pillow lavas, some possible pillow lava draping at the top. 2654m at top. Then lots of fault talus
1101 2640m another outward or east facing fault scarp, ~20m high, fresh talus, fault breccia, truncated pillows and lobate lavas. Then 1/2m wide N-S active fissure.
pillow lava near top of east wall. Some volcanic draping of this outward facing scarp.
ñ18 2635m, 045, at waypt 4 at top of east wall, looking for rock sample 5 in age 2.5-3 bulbous pillow lavas.
1118 age 2.5 pillows, 2630m heading W, 10cm wide N-S fissure.
age 3 pillows, more sediment, heading to waypt 5
269, 2635m, near edge of east bounding wall of axial trough, several 10cm wide N-S fissures cutting through mixture of lobates and pillows. Local collapses too.
2634m, 286
2m drop off to west, edge of old collapse lava lake, 2m high pillar with glassy selvidges. Sheet flows and lobates.
1125, 2636m, alt. 5m, age 2 sheet flows and lobates in an area of local collapse.
1132 2678m, 285, came out over the west facing fault scarp of the east wall, ~40m high, landing in age 2 pillow lavas. Lots of fresh glassy buds. Stopping for sample.
1138 2679m got rock sample 6. In age 2 pillows.
1139 in axial trough floor, age 2 lobates.
1140 age 2 pillow lavas.
1141 2679m, 285, 2m wide N-S fissure, cuts through age 2 pillow lavas.
1146, 5-10 m east facing scarp, then a west facing scarp or edge of lava lake, age 2 lobates. There are two small horsts here, one partly draped by lava.
2685m; old sulfide chimneys on sediment covered sheet flow. Hit one so Matt spinning around to see what it was.
1151 2676m, 257, 2m wide N-S fissure cutting thru lobates and sheet lavas.
1152 another 10 cm wide N-S fissure, age 2.5 pillow lavas.
1153 at base of east facing fault scarp, fresh talus, truncated lobate flows in wall. Rather than climbing the west wall, we turn to ~050 to cross floor again, heading to waypt 6
Wall consisted of a number of narrow fault slivers calving off the main scarp, tipping toward the valley floor.
1155 fresh talus, no sediment at base of west wall.
1157-1203 stopped for rock sample 7, top of fault sliver or horst. Then head NE to #6.
1207 Old sulfide chimneys in age 3 sheet lava terrain
1208 fresh unsedimented talus , talus becomes finer and better sorted at base of west-facing fault scarp. 5m high. At top of scarp, it is draped by a lobate lava which has broken off and fallen to the base of the scarp.
1210 collapse in age 2.5 sheets and lobates. 1-2m high lava pillars.
age 2 sheet lavas, 2680m, talus of collapsed lava lake, stopping to get rock sample from the edge of this lava lake, out my porthole is a 1m wide by ~5m tall lava pillar, a beauty! Lots of larval crabs in water. Some sediment on the bathtub rings of the pillar, so collapse is not that recent. Rock sample 8
1217 2677m, 060, underway again, heading over edge of 2-3m deep collapsed lava lake. Age 2 sheets and lobates all broken up into plates.
2674m, into another collapse region
10-15m scarp stepping down to east.
2686m, 060, 1/2m wide N-S fissure in age 2 pillows.
1221 another collapse area, coming up pillowed flow front or fault scarp, crossing 1/2m wide N-S fissure. Age 2 pillows, could be as young as 1.5.
2677m, yes age 1.5 pillows
1/2m wide N-S fissure in age 1.5 pillows.
1225 2679m fresh talus, climbing west facing scarp,
2675m, 060, lava lake remnant on top of scarp, several 1-2m high lava pillars, age 1.5 in collapsed lava lake.
ñ31 rock sample 9 in lava lake area.
1231 229, 2679m, fresh talus and lava lake debris,
1232 old sulfide chimney beneath us in this collapsed lava lake or possible lava channel? A few pillow lavas here now.
1234 1/4 m wide fissure in pillow lavas of age 2.
1237 age 1.5 lobates, big eruptive? fissure on stbd side, ~2m wide. Yellow sulfide staining. Just came out of a large collapse area, a possible eruptive fissure. 2683m.
two dead sulfide chimney.
2687m, 336, age 1.5 lobate lavas and pillows.
2687m, stopping for rock sample 10 in age 1.5 pillow lavas
1247 underway again 333, 2687m,
1248 age 1.5 pillow lavas, flow direction seems to be S; 1/2m wide N-S fissure.
1249 lobate lavas age 2
1251 at base of west wall, lots of fresh talus.
1252 stopped for rock sample 11 on top of the first fault sliver within the west wall. This fault sliver is like a domino tipping toward the valley floor. 2660m
1258 underway again 090, 2683m, age 1.5 pillow lavas
1259 two 1-2m wide fissures, now a flat sheet flow, fractured in many directions and apparently tilted ~5 dipping west. Age 1.5
1300-06 rock sample12, folded curtain sheet flow of age 1.5, 2677m,
2678m, 101, two 1/2m wide fissure with some draping or drainback in age 1.5 folded sheet flows. Yellow sediments.
1 1/2 m wide eruptive? Fissure trending N-S,
2682 m, 100, climbing west facing scarp of the axial trough east wall, lots of fresh unsedimented talus.
2868m, 100, fault breccia, yellow hydrothermal sediment, some massive lava in the exposed section, minor columnar jointing.
Nice lava lake remnant and 1-2m high pillar preserved in wall. Stop here to look for rock sample 13. 2659m three other 2m high pillars further off.
2657m, underway 100 again, on a local bench within east wall here. More lava pillars ~2m high.
2655m, looking down at nice example of a linear pillar, ie, a long one. Note that all of these pillars on this bench in the east wall are vertical and we have seen at least half a dozen, this suggests no tilting within the east wall.
Several dead sulfide chimneys, 1m across by >5m high, some Matt can see that the base is a lava pillar with bathtub rings and higher up a sulfide chimney, ie, a ìhydrovolcanic construct.î
2649m more old pillars and chimneys, speculating that these start with a black smoker in the floor which gets engulfed by and eruption forming a lava pillar, then the smoker continues after the eruption causing the chimney to enclose the pillar.
More lava lake remnants and sulfide chimneys with many stalked crinoids.
1327 2643m, more dead chimneys and hybrid pillars/chimneys in age 2.5 pillows and talus.
1328 3-4m wide N-S fissure bounding a fault sliver. At main step in east wall now, sheet flows and massive flows seen. The wall is vertical.
1329, 2639m getting rock sample 14 right at edge atop the east wall.
1333 moving slightly, 2637m heading 124. Getting rock sample 15 near the edge of the scarp that is the east wall, you can see a narrow ledge or selvidge jutting out 1/2m about 5 m below us in this vertical wall.
1337 underway east again, age 2.5 folded sheet flows, 5m wide N-S fissure
1338 sediment covered lobates and sheet flows. Age 3?
1342 on top of east wall, 2635m, heading north on age 3 sheets.
1344 collapse then a big pillow, all age 3, then more collapses lineated N-S
1345 hairline fissures and more collapses. Region is about 50-100m long, seeing some 1m high lava pillars supporting old lava lake remnants. The pillars are vertical! No tilting.
1347 folded sheet lava age 2.5, lots of sediment but they are also glassy.
1348 age 3 pillows
1350 more collapses and narrow n-s fissures.
1359-1405 stopped for rock sample 16 2639m
1406 heading N, Macdonald driving sub while Matt pees.
1408 age 2.5 folded sheet lavas 2639m
collapse in age 32.5 folded sheet flows.
jumbled sheet flows, age 2.5
a few pillows age 3
1415 back to folded sheet flows age 2.5 still heading N
1418 fissures are linking these collapses together about 10-20m east of the edge of the east wall making me think that a fault sliver is about to calve off of this fault face.
1424 just sampled rock 17 in age 2.5 sheet lavas.
1432 end of dive.