Alvin Dive 3347 - Feb. 6, 1999

Transcript of Bill Ryan (Port Observer)
This is based on real-time audio recordings of port hole observations and subsequently modified and richly supplemented by a review of all of the videotape.


10:06 2717 261 Landed on the bottom. At last the stirred-up sediment cloud clears. The terrain around is heavily sedimented pillow lavas with depressions between the pillow heads completely covered in mud, and the spaces between the protrusions are all interconnected. Age 3.0 of Ken Macdonald.
10:07 2716 290 Underway to Way Point 2. Elongated pillow lavas are everywhere.
10:08 2714 286 Briefly stopped to set clock for display on video cameras. Could not make it precise. The settings were left with the display showing a time about 30 seconds earlier than the time logged in the computer. [These notes are all in computer time that registers with the subs navigation].
10:09 2715 286 Massive elongated pillow lavas trend downslope in the east direction. All pockets between pillows are joined by sediment. Pillows are studded with intact, yet long, delicate and fragile-looking digits.
10:11 2709 286 Climbing a slope over elongated pillows (what will subsequently be called tubes) with a 6-1 (length-diameter) aspect ratio all trending down the apparent slope. No visible tectonic disruption. Gorgonian coral.
10:12 2704 286 Continuing to climb the slope with elongated pillows and lava tubes trending down slope.
10:13 2700 288 Elongated pillows.
10:14 2696 296 Bulbous tall pillows with striations, cooling cracks and a few with open trap doors in crest. Coiled pillow heads are typically bent over in the downslope direction.
10:16 2685 294 Terrain is dominated by hummocky pillow lavas, heavily sedimented, 90-100% sediment cover.
10:17 2680 294 Another Gorgonian stalked coral in a terrain of pillow tubes, some tubes up to 10 meters in length and set on the landscape among a few detached pillow heads.
10:18 2674 295 Long pillow tubes erupting everywhere from this slope
10:19 2669 296 Crossing a 3m deep fissure running approx. N-S and cut through the pillow lavas in a slight zig-zag pattern as if finding the place of least resistance.
10:20 2671 296 After descending a small 2m step we continue up the constructional volcanic slope through more pillow lavas, observing some broken and scattered digits. Pillows still dominantly elongated. A 3 meter long tube has extruded from a pillow stump.
10:21 2666 295 Stopping for Rock Sample Station 1. Heavy sediment cover indicates a substrate of at least Age 2.5. Sediment is distinctly brown to umber in color suggesting an important and perhaps dominant component of hydrothermal products.
10:30 2664 291 Back underway and climbing through terrain of elongated pillows and tubes, we have not yet observed any lobate lava morphologies.
10:32 2661 292 Tiny shrimp with a red stripe behind its head swimming in the water. Crossing a small west-facing escarpment and then approaching first lobates of the dive with a small 1m diameter collapse pit in their roof. The roof rock of several of the lobate flows here is cracked into tabular slabs but mostly it is uncollapsed.
10:34 2660 294 The steepness of the slope we are climbing has substantially decreased and we observed more collapse roofs of lobate type lavas. Some signs of scattered angular talus.
10:35 2661 292 Bottom falling away into a 6 meter deep fissure, talus on its floor, bedrock layering seen in wall facing us and consisting of round truncated pillow shafts (trunks) and lens-like cross-sections of lobate flows.
10:36 2658 294 Looking over the edge of a west-facing cliff down 7-8 meters onto a floor strewn with talus. Horizontally bedded lavas are exposed in this wall with thicknesses on the <1m scale. Suspect that this cliff is a eastwardmost bounding fault of the east wall of the rift valley ahead.
10:37 2657 296 Heavily sedimented lava terrain, although the thickness of the cover on the talus is less than that observed on the intact lavas. The talus is estimated as age 1.5 compared to age 2.5 for the intact lavas.
1038 2658 296 The floor is 8 meters below us on the altimeter. The down-looking low-light-level SIT camera reveals pillows elongated to the east. Bottom coming up as the sub continues in the NW direction. Pillows below are distinctly elongated.
10:39 2653 297 Arriving at the top of another west-facing escarpment. The wall is vertical and one can not see to its base. As the sub drives at a level depth ahead into the water column, the altimeter climbs to 15.7 meters. When bottom below comes into view it continues to shallow. When I looked back at the scarp, it seemed that the lavas at the very top had dripped down the cliff. The starboard observer, when queried, replied that he had the same impression.
10:41 2656 271 As the bottom continues to climbs upward it reveals a surface of pillows and lobates. It is the east-dipping constructional slope of the top of a sliver of crust that has down-dropped along the wall we have just passed over. The pillows on this surface look a little shattered and loose.
10:42 2649 292 Crossing an escarpment (fault?) with the bottom falling away to 15 m below us on the altimeter. Talus is abundant in the distal view below.
10:43 2648 305 Reach the far side and cross a heavily sedimented terrain of age 2.5 cut by narrow (<1m wide) fissures perpendicular to sub's track. Landscape is dominated by pillow lavas. This is apparently the top of another down-dropped (?) sliver. Then further along track the pillow lavas transition into lobate flows. The lobates look stratigraphically younger by an observed onlapping against the pillows.
10:44 2651 303 As the sub flies at a near constant depth the floor below once again shallows to reveal more thin fissures in these lobate flows and some angular slab-like talus (loose roof rock ?). The terrain has the distinct impression of less sediment than before and is assigned age 1.5.
10:45 2651 304 Lobate flows predominate
10:46 2647 305 Cross another escarpment, this one 12 meters high on the altimeter . The smooth lobate extends right to the rim where it is truncated by the presumed fault that created this relief. Another slope faces us at a distance of 50 yards on the CTFM sonar monitor. We slowly motor down and ahead with the bottom out of sight below us. Looking back I see a bench on the west-facing wall that we crossed with the same lobate terrain of the rim of the fissure. It looks like evidence of a thin slice dropped into the large fissure.
10:50 2649 305 While the sub has motored ahead and descended 2 meters, the floor below has ascended to come into view at an altitude of 4 meters. It is an east-dipping surface of sedimented lobate flows and some scattered tabular talus. We cross a fissure in this surface, this one about 5 m deep whose floor is littered with angular (blocky) talus. Much less sediment on the talus down in the crack than on the rims of the fissure. Among the tabular fragments are the broken trunks and heads of pillows presumably detached and fallen from some nearby escarpment.
10:51 2654 302 Talus and broken pillows come into view suggesting a cliff facing us from ahead.
10:53 2645 270 Looking now directly at this cliff in front of us. According to the dive map it appears to be the west wall of the rift valley. The base of the cliff is littered with talus as we climb and look down. As we slowly climb, we view outcrops of pillows in what appear to be beds or layers more or less horizontal in extent in the cliff face. Looking into the truncated strata one sees the radial cracking of the pillow trunks and tubes more or less circular in cross-section. The altimeter in the stern of the sub shows 13 meters to the top of the talus ramp as the manipulator arm picks at the lava from the outcrop at the wall. We stop to take a sample of this pillow lava at what we judge from our limited perspective to be the top of the wall. Rock sampling station 2.
10:57 2646 252 Backing off the cliff and turning around to motor NE to Way Point 3. Begin to gradually descend looking ahead into water.
11:00 2648 081 Having dropped only 2 meters we are still up in the water column at an altitude of 5 m and out of sight of the lavas below us..
11:01 2654 082 Bottom comes into view ahead of us at last. We see cracked pillows with the walls of the 5-10 cm. wide cracks stained white, presumably by hydrothermal fluids. The staining is not on the sediment right at the lip of the crack suggesting that the escaping fluids coated the walls of the cracks prior to the accumulation of the present sediment covering. Some angular talus lies scattered on these pillows, probably derived from the nearby west wall of the valley.
11:02 2654 081 Heading east we climb a small escarpment with truncated pillow lava bedrock exposed in the wall facing us. This ridge turned out to be the north tip of a spur (north plunging crustal sliver?) as the bottom falls away on its other side.
11:03 2652 79 Pillow lavas and lobate morphologies on the floor below us as we cruise briefly at an altitude of 6 to 7 meters.
11:04 2656 080 Cross a narrow <1m wide fissure with talus on its floor. Climbing a talus slop, consisting mostly of truncated pillows.
11:05 2651 080 Up and over a ridge with about 4 meters of relief, heavily sedimented (age 2.5) and consisting of pillows and lobates.
11:06 2651 080 Crossing N-S fissures in the lobated lava flows.
11:07 2652 079 Crossing two more small fissures in these lobates as the seabed deepens in one meter steps with each fissure. Outcrop of thin layers visible in the observable wall of the fissures. In the outcrop the layers are capped by pillows and lobates right at the level of the seabed beyond the fissure.
11:08 2649 081 Stopping sub to investigate this outcrop. At close inspection the thin layers are the filling of 1 and 2 meter diameter giant tubes whose own enclosing wall (skin) is clearly visible and less than ~10 cm. thick. The tubes are not perfectly round in cross section, but one is squashed vertically and the other a few meters adjacent to it horizontally. The tubes have interbedded pillow lavas between them and below them a mass of pillow lavas is seen in round cross-sections.The truncated pillows are but 40-60 cm. in diameter and many smaller than that. The top of the tubes lies just 20-30 cm. below the seafloor in the wall having been capped by the surface lobate lavas. One of these surficial lobates appears to spill a 30 cm. long tongue down the exposed face of the fissure, but this could possibly be an illusion.
11:10 2647 145 As the sub turns to further inspect this wall another cross-section of a giant tube appears that is only about 3/4 filled with the thin (1-2 cm. thick) horizontal (sheet-like) flows and the upper 1/4 of the cross-section of the tube is a void. It looks like an incompletely filled sewer pipe. Then another one of the giant tubes in cross-section comes into view filled with some thin bedded flows that have run through it and are themselves submerged under a layer of welded talus that looks like roof rock perhaps collapsed further upstream into the tube and transported by the topmost thin flow to the site of this cross-section. This tube is about 1.5 m in diameter and also lies only one or two pillow thicknesses below the present seafloor at the top of the wall.
11:12 2645 082 Underway on the original eastward course from this brief deviation as the cliff ahead is scaled. Lots of pillow rubble below at the foot of the exposure. Clearly this wall is bedrock outcrop produced by some significant vertical displacement of the seafloor.
11:14 2649 083 Cross a 14m deep fissure or down-dropped sliver(in a relative sense). The rims of this depression pillow lavas. Talus is very faint in the SIT camera that looks into the trough. This cleft (?) appears to run N-S up the rift valley.
11:18 2663 081 Lobates now dominate the substrate. A fissure right ahead of us gives an excellent opportunity to look again at a vertical cross-section into the valley floor and two more giant tubes are exposed, one whose interior is completely filled with welded (?) talus and the other about 7/8th filled with very thin (1-2cm thick) slightly wrinkled flows with a void on top, The skin of the tube is now very visible to both observers, is about 5-10 cm. thick and forms the circumference of the tube. It is not smooth and circular, but squashed and indented and even folded. The top of the tube lies just below a single lobate belonging the rim of the fissure wall.
11:19 2661 080 Stop to sample this surficial lobate flow of zero-age directly overlying one of the giant tubes. Rock sample 3 is from the intact lobate rook broken from the cross-section exposure. This lobate is lens-shaped in outcrop and empty. Its skin (roof) was only about 5cm thick.
11:22 2661 122 Sample in the basket and ready to get underway.
11:23 2660 105 The sediment cover on the lobated seabed is heavy, about Age 2.0. The floor of the valley here is a mixture of predominate lobates with subordinate pillows.
11:24 2660 080 We are back on course and proceeding towards the east wall of the rift. The substrate is mixture of lobates and pillows with approximately 80 to 90% sediment cover. The pillows become more rare and lobates become the main lava morphology.
11:25 2660 080 With the sub now driving down a gentle incline the pillows appear and soon become elongated and trend lengthwise in the downslope direction eastward. It looks like more sediment cover on the this pillowed surface (Age 2.5) than the lobates we had just crossed, but I can not be sure about this. All interstices are interconnected with sediment, and glassy buds are still omnipresent.
11:26 2662 081 We are driving across an apparently "old (?)" terrain of pillows and elongated pillows and tubes. No more lobates.
11:27 2665 059 Then we begin our turn to head back across the rift valley to the west wall. The pillow lava terrain is populated with a few tall sea pens (?).
11:28 2661 310 Slowing to re-climb the gentle slope that we had just descended before the turn and see tubes oriented in flow direction towards us. Pillows and tubes of age 2.5 to 3.0. 100% sediment film everywhere.
11:29 2662 292 Steady on course and now encountering lobates as the floor flattens out momentarily.
11:30 2662 290 Large collapse pit in the lobate flow ahead. Looking down into the trap door opened by the roof collapse I can see the thin (1-2cm thick) sheet-like flows outcrop in the wall of this hole. They are not bathtub rings, but the lava which has flowed horizontally through the conduit into which we are looking and suggest that it is one of the giant tubes (sewer pipes) that we had observed only in outcrop cross-section. The fallen tabular roof rock lies scattered on these thin flows and in the distance I can clearly see frozen tongues of lobate lava pouring back into the hole from the surface surrounding the hole and dripping down for 20-40 cm. from the rim. This scene definitely looks like a view down into one of the giant tubes that had recently seen in cross-section in the wall of the large fissures on the previous track across the valley floor. A 5m wide N-S trending fissure appears just after this collapse pit whose floor is 4m below the sub.. The terrain then transitions back into pillow lavas from the lobates and the pillows become the dominate morphology.
11:32 2662 293 Pillow lavas and tubes cut by a narrow fissure where the floor steps down a meter or so towards the west.
11:33 2655 291 Another fissure cutting the pillow lavas and another step down to the west. At the next step the floor ahead of the fault dips gently back towards us and is covered by elongated pillows and tubes flowing at us (to the east).
11:35 2650 291 We cross a 3m deep fissure perpendicular to our track whose facing wall has exposed the bedrock of the valley floor consisting of the cross-sections of pillows and lobates. Here the pillows lie above the lobates and are topped by the pillows that make up the surface of the valley floor in our immediate vicinity.
11:36 2648 289 Pass next over the top of a west-facing escarpment and look out into water. The altimeter reads 8 meters and then 12 meters as the sub separates from the cliff. Suddenly the bottom comes into view. It is the 2m wide top of a slab that has detached from the cliff and is leaning out into the valley ahead of us. As the sub passes over this slab, the altimeter climbs to 14 meters . Almost immediately we run into a facing cliff and have to rise up over it.
11:38 2652 291 Next we cross two more N-S oriented fissures, each with a small step down to the west and each exposing bedrock outcrop in its facing wall. Then over a vertical cliff 7 m high with very little talus at its base. The cliff turns out to be the west facing wall of a wide fissure as we pass across it and onto a flat floor of lobate lava. Small collapse pits are present in some of the lobates. Then on to a thin fissure that cuts N-S through the lobates.
11:40 2656 291. As we continue to motor to the west wall the lobates pass abruptly to jumbled sheet flows. The apparent sediment cover on the sheet flows is much reduced, perhaps age 1.5 compared to age 2.0 as the minimum for the adjacent lobate. The jumbled sheet flows only last a minute or two of the transect.
11:41 2655 293 As the floor shallows the jumbled sheet flows terminate as abruptly as they appeared and onlap against older more heavily sediment pillows. These pillows are cracked and the walls of the cracks are stained white from presumed hydrothermal exhalations. We cross over a fissure as the floor valley below steps up one meter and then another narrow fissure at a second upward step. The steps are surfaced with pillow lava that has been cut and offset by the tectonics that opened the fissures and offset the relief of the valley floor.
11:43 2654 293 Many heavily-sedimented pillows cut by white-stained cracks. We reach Way Point 4 near the base of the west wall in a pillowed terrain and turn clockwise to head back across the valley floor to once again visit its east side. No talus here.
11:44 2657 034 With the turn mostly completed we cross two fissures separated by a 1 m high horst with the floor everywhere made of heavily sedimented pillows cut by the tectonics. Most of the pillows display white coated cracks that dissect the bulbous heads.
11:45 2655 068 The hydrothermal staining is pervasive in cracked pillows and in the edges of collapse roof rock of the lobate flows that now begin to surround us.
11:47 2656 067 Soon we reach the belt of jumbled sheet flows recently passed on the previous transect towards the west wall. Much less sediment on them than on the flows to each side. The age of these jumbled sheet flows is age 1.5 compared to the age of 2.0 to 2.5 for the adjacent pillow lava terrain. (Is this the young lava that John Sinton suspects to have poured south through the rift valley?).
11:48 2658 067 We transect across the jumbled sheet flows and back on to older lobates (age of 2.0 ) cut by thin white-stained cracks.
11:49 2659 068 We now fly over a 3m wide fissure with talus in its floor . The altimeter shows it to be 3-4 m deep. Terrain cut by the fissure is both pillow and lobate in morphology.
11:50 2658 067 Head directly into a west- facing wall. It consists of bedrock outcrop (truncated pillows and lobates) with lobated lava clearly dripping from the topmost layer of the modern seafloor down the uppermost face of the wall. The starboard observer concurs. These lobates are age 2.0.
11:52. 2656 124. With the sub momentarily turned SE we climb this wall for a height of 4 meters to its top and pass on to large broken lobates cut by thin fissures.
11:54 2652 064 It is time to climb up in the water to get a transponder fix.
11:56 2647 068 As we start to descend from this perch above the bottom, the SIT camera shows the floor below to be pillow lavas cut by N-S trending fissures . We encounter another west-facing cliff and ascend it. Pillows outcrop in its wall..
11:58 2649 068 As we crest the cliff lobates are present as the top most strata superimposed on pillows exposed in the wall. This seems to be a recurring relationship of lobates as the stratigraphically highest morphology in the succession of lava flows in the valley floor locale. The lobates pass along-track into pillows and tubes as the sub heads down a gentle east-dipping slope. The tubes reach a 10:1 aspect ratio (l:d) and the lava has clearly flowed eastward along this seabed.
12:00 2654 069 As we cross a 4 meter deep and wide N-S fissure we run straight on into its facing wall of outcropping pillow lavas. We then pass over a fissure on to a heavily sedimented terrain of elongated pillow and tubes (age 2.5) cut by thin N-S fissures.
12:03 2652 051 Pillows are the dominate morphology . Reaching way point 5 near the base of east wall of the rift valley.
12:04 2646 051 As we come upon scattered angular talus (presumably shed from the east wall that we see dead ahead in the CTFM sonar, we turn back to the NW to re-cross the valley once again.
12:05 2645 297 Step down a few small 1m-relief and presumably faulted(?) blocks surfaced with pillow lava with lots of digits still attached.
12:07 2643 299 Soon we descend a 5-meter high west-facing cliff with a tall thin Gorgonian coral attached to its crest. Lots of talus at the base as seen in the down-looking SIT camera.



12:27 2648 086 The present terrain on the valley floor is now dominated by lobate lava flows of age 2.0.
12:28 2656 085 On a very smooth floor of little relief we pass into wavy sheet flows cracked apart and with the walls of the cracks stained white by hydrothermal fluids. (Is this white a preserved anhydrite coating?)
12:29 2655 083 Flat and wavy sheet flows with sparse lobates. Age 1.5 followed by:
12:30 2653 085 Jumbled sheet flows and cracked lobates and a narrow N-S fissure.
12:31 2654 086 and then more wavy and cracked sheet flows .
12:32 2653 086 Then a large 1-2m wide fissure . The altimeter reads 5 m as it is crossed and the bottom drops out of visual sight. The SIT camera reveals talus on the floor of this fissure that looks much fresher than the surface split by the fissure.
12:33 2653 084 A collapse pit in the lobate lavas. All the broken edges of the roof rock in its interior are stained white.
12:34 2655 087 Pillows and lobates.
12:35 2655 086 Talus appears at the base of a small west-facing escarpment. We realize that his is the east wall as we climb up it.
12:36 2653 082 Still climbing as we observe sections of exposed bedrock appearing in windows through the talus.
12:37 2644 302 Nine meters higher we turn back to the NW while still on the wall. Altimeter reaches 14 meters showing the cliff to be very steep above the valley floor.
12:39 2649 293 As the sub descends the wall the SIT camera show talus at its base passing outward to hummocky pillows that cast large shadows.
12:40 2654 282 Back on the bottom of the valley, stopping at Rock Sample station 4 to sample a pillow bud from this pillowed terrain of age 2.5.
12:44 2653 300 Underway as pillow lavas pass laterally into what seems like slightly younger lobates of Age 2.0.
12:46 2651 297 Cross a 5m deep N-S fissure with talus on its floor and white hydrothermal staining on its walls. Lobated lavas cap its east rim. They too are cracked and their cracks are also stained white. These lobates now seem clearly younger than the pillow lavas near the base of the east wall as judged by less sediment cover and more glassy surfaces. Soon we ruin into a 5 meter high east facing wall (presumably of this fissure) with lobates on its west rim. Signs of layered sheet flow in the face of this wall beneath the surficial lobate flows. These thinly layered and horizontally bedded strata which extended with continuity to out of sight do not look like bath tube rings, but veritable bedrock outcrop.
12:49 2653 298 Back onto the valley floor comprised of lobate terrain populated with a few upright pillows.
12:50 2653 298 The lobates now pass into what appears to be relatively younger (age 1.5) folded sheet flows with some spiral eddies (whorls) around a pillow sticking up out of the flows like an island.
12:51 2652 299 Cross a fissure cutting jumbled sheet flows with white stained walls. Talus abundant. The CTFM sonar indicates that we are directly approaching the west wall of the valley. The sub begins to ascend the wall. As it climbs up the talus ramp into bedded outcrop, the altimeter reaches 11 meters. The wall is near vertical.
12:53 2640 071 Turn to head back to the east wall. Looking out into water and beginning the descent. The SIT camera shows a steep (>45 degree) talus ramp at the base of the west wall.
12:55 070 071 Arriving back on the valley floor. A fissure N-S cuts the wrinkly sheet flow. Its cracked surfaces as well as the wall of the fissure are all stained white by presumed hydrothermal fluids.
12:56 2646 070 Stop and begin to descend onto the substate from a relatively high altitude for Rock Sample 5 to break off a piece of folded sheet flow with very glassy surfaces. Age 1.5.
13:06 2653 344 Finishing sampling and getting back underway.
13:07 2652 083 Continue across these regionally-flat wavy sheet flows with some broken upper surfaces.
13:08 2651 052 The sheet flows rather abruptly pass into what looks like relatively older (age 2.0) lobate flows of quite low relief.
13:09 2652 056 A few pillows appear within the lobates.
13:10 2649 054 Cross a wide 2m deep crack or cleft with rubble at the base of its west side and younger looking sheet flows on its central floor. They are wavy sheet flows.
13:12 2652 055 Stop for what turns out to be an aborted sampling effort.
13:15 2652 056 Wavy sheet flows with a few lobates. Then more wavy sheet flows. Valley floor is very flat here.
13:16 2652 055 Some smooth sheet floor (like a "billiard table") . Unable to sample find an opportunity to get the claw into in order to break off a piece.
13:23 2651 003 Aborting this effort and continuing NE to the bounding wall of the valley. Quickly arrive at the angular talus shed from this wall.
13:24 2647 054 Climbing the steep wall. Altimeter at 7 meters as we look from an arms length at the cliff face. Still over a talus ramp below us.
13:26 2642 314 Reach top of a ledge covered by pillow lavas and turn to the NW for yet another crossing of the valley.
13:27 2652 315 Look down at wavy sheet flows that have flooded the valley below us and onlap onto the talus shed from this east wall.
13:28 2655 316. Stop to sample these sheet flows at the valley edge as Rock Sample 6. They are both wavy and jumbled with Age 1.5 and are considerably younger than the nearby pillow flow above us and at the top of the wall.
13:30 2657 315 Underway over lobate flows.
13:31 2657 314 Cross a couple of small N-S fissures whose walls are stained white.
13:32 2654 316 Then over a gentle swell of a meter or two where the flows turn back from sheets to lobates, pillows and elongate pillows. Then having crossed to the other side of this small elevation we pass back into smooth sheet flows and the occasional lobate.
13:33 2653 315 Cracked lobates and another narrow N-S fissure with hydrothermal (?) staining.
13:34 2653 316 A deep fissure with talus at base of its walls and partly flooded with young jumbled sheet flows (age 1.0).
13:36 2651 314 A 5-6 meter deep fissure floored by what looks like the same young jumbled sheet flows as in the previous fissure.
13:37 2649 318 Across this second fissure and onto very smooth sheet flow, and wavy sheet flows with a small collapse indicated by broken and sagged roof rock.
13:38 2646 315 Arriving once again onto the talus ramp of the west wall of the valley. This talus is angular with lots of pillow fragments.
13:39 2641 338 Ascending up the talus ramp and up the sheer face of the wall. Altimeter reads 9 meters.
13:40 2629 049 At top of the climb we turn back to the NE . The down-looking SIT camera shows the talus ramp far below with lots of pillow rubble on it.
13:42 2633 049 Motoring down the west wall.
13:44 2643 063 Lobated lavas on the valley floor from an altitude of 8 m in the SIT camera and seen overlapping onto the talus, but some talus has also scattered out on to the top of these lobates.
13:45 2650 063 Back on valley floor. Lobates are quite glassy here and some wavy sheet flows appear in addition. Terrain is Age 1.5. Cross a 1m wide and very deep N-S fissure cut into the wavy sheet flows. Then soon after another fissure <1 m wide but deep. Can't see the bottom of either this one or the previous one. The altimeter momentarily registers 10m.
13:46 2650 060 Wavy sheet flows of the valley floor with some lobates on these sheet flows. A clear inter-fingering of contemporary sheet and lobate flows, some of the sheets wavy, others very smooth. The smooth "billiard table" ones are cracked and the polygon-shaped roof rock is slightly tilted into small, sagged depressions 20-40 cm. deep in their center below the local valley floor.
13:47 2652 060 Smooth low relief lobates cracked and stained white on the walls of the cracks.
13:48 2653 063 Wavy sheet flows and even hackly sheet flows, becoming jumbled sheet flows. Youngest terrain observed so far. Maybe Age 1.0. Crossing a 3m deep N-S trending fissure in the valley floor\ cut into the wavy sheet flows. Hydrothermal (?) staining on its uppermost walls.
13:49 2652 062 Valley floor remains quite flat and is covered by wavy and smooth sheet flows.
13:50 2653 059 Striated sheet flow and some very low-relief smooth lobate flows. Then more wavy sheet flow. All of the same age and grading one into the other. Hydrothermal white staining everywhere in thin cracks with spaghetti worms blown around by Alvin's thrusters followed almost immediately by talus from the approaching east wall.
13:51 2653 061 Arriving at the east wall and climbing the narrow talus ramp to then vertically ascend the cliff face.
13:53 2637 064 Altimeter registers 13 meters as we look directly at the face of this wall high above the top of the talus ramp. Pillows visible in the outcrop.
13:54 2646 071 Climbing up a massive unit of the bedrock exposure covered in streaks by fine pebble to sand size talus and some large blocks precariously perched on narrow ledges. More talus on these narrow ledges and then climbing up along additional outcrop. The valley wall is itself fissured into vertical cracks and looks like it could peel off with the slightest nudge.
13:56 2635 071 Still climbing while looking directly at the sheer wall. Lots of tiny fissures in the wall (vertical joints) and outcrop exposure of truncated pillow lavas.
13:58 2624 013 . As we approach the top we see tongues of frozen lava that had partly dripped down into the void from the rim. We momentarily stop for more observations and then continue turning back to the NW to Way Point 16. The pillow lavas at the top of zero age are in the highest stratigraphic position and make up the modern rim floor with Age 2.5.
14:00 2626 345 Motoring out into the water column to begin long descent to the valley floor at the bottom of the cliff.
14:02 2634 312 The down-looking SIT camera shows talus below us on ledges and the talus containing many round pillow fragments. The ledge surfaces are the same pillow lava terrain just seen at the top,
14:04 2645 316 The altimeter registers 14 meters with rubble and talus barely made out by the SIT camera. As we continue powering down, it looks like the sheet flows of the valley floor overlap and cover the base of the talus ramp, though some large blocks have tumbled out onto the sheet lava surface.
14:06 2654 315 Back on the wavy sheet flows of the valley flow and stopping for Rock Sample 7. Hydrothermal stains are pervasive on all broken surfaces. The stain here is both white and rust colored. Lots of unknown floating creatures and shrimp in the water around us. Sampling the glassy wavy sheet flow.
14:11 2655 342 Underway from this sampling station and flying through a sea of floating spaghetti worms set free by the turbulence of the sub's thrusters or bow wave. The lava surface looks very young (Age 1.0). Lots of hydrothermal staining in thin cracks. As we head NW there is a huge tabular surface out the port-side viewport. It is a large sliver of the east wall that has fallen out onto the valley floor. Its top surface (former seafloor) dips 45 degrees down to the west. It takes on the appearance of an inward tilted block and the joint surface exposed on its eastward-dipping back (detached surface) is extraordinarily smooth.
14:14 2652 316 We next cross a very flat valley floor lava flow composed of smooth sheet flows cracked by thin millimeter wide fissures.


14:21 2656 314 The CTFM sonar shows us rapidly approaching the west wall having crossed the valley floor. Angular and tabular talus and broken pillow fragments with no sediment cover (a very fresh rock fall) are soon pervasive.
14:22 2647 314 Climbing the west wall talus slope and turning back to the NE and stopping to sort out a problem with a VCR.
14:31 2655 048 Problem solved, the VCR back on. We are now out on lobated lavas of the westernmost side of the valley floor.
14:32 2655 049 Moving across low relief smooth lobates lightly dusted with sediment (age 1.5).
14:33 2653 049 Cracked and stained wavy sheet flows and striated sheet flows.
14:34 2653 048 Passing into wavy sheet flows and a few lobate flows of perhaps the same eruption or near contemporaneous eruption. If anything, the lobates have the appearance of over-spilling onto the sheet flows rather than visa-versa. Cross a 3 meter deep fissure cut through the lobate flows. Some small steps (<1m) down of the seafloor as we proceed to the NE.
14:35 2652 048 We soon encounter wavy sheet flows and lobates, this time quite clearly flowing out on top of the sheet flows. Very little sediment dusting on these youngest flows.
14:36 2651 050 A fissure cuts a very flat sheet flow surface, then some blocky talus immediately followed by a 3m wide deep fissure. The altitude registers 6 m as we cross over this crack. Flat sheet flows pond in its floor and these sheet lavas are only very lightly dusted with sediment (Age 1.0). Hydrothermal white staining is everywhere in thin cracks in the lava.
14:38 2650 049 Further out beyond this fissure the locally flat and featureless valley floor is now a wavy sheet flow.
14:39 2653 048 Stop for Rock Sample 8 on this relatively young wavy sheet flow.
14:43 2652 048 Back underway to the NE to continue to cross the valley floor to its east side. Wavy sheet flows continue among rare lobates. The few lobates appear to have flowed out onto the sheet flows as judging from their contacts. Smooth sheet flow and some lobates transitional into a wavy sheet flow morphology.
14:45 2653 049 Angular talus and broken pillow lavas and massive blocks of basalt.
14:46 2652 049 Crossing a broken lava surface as if squeezed up in a thrust. Talus contains detached pillow heads. Lots of loosely scattered rubble among the shattered pillow heads and pillow trunks.
14:47 2651 046 More talus and allochthonous pillow heads. The view out the porthole presents a deep wide cleft below us. As we cross it the altimeter registers 19 meters. Approaching its east wall, one can see frozen lobate flows dripping down into the cleft from the flooded valley floor. The starboard observers concurs. The west-facing wall presents a cross-section of the valley floor in which we see layered outcrop. Passing over the top of this wall we look down to see it as both vertical in relief and sheer in smoothness. The outcrop is thinly (20-30 cm.) and massively (several meters) bedded strata with no sign of the round cross-sections of pillows..
14:49 2634 049 Coming up a ramp of small fist-sized and black glassy sand onto widespread angular talus.
14:50 2622 054 We are now high above the bottom as we climb the steep east wall. It consists of layered pillow and lobate flows viewed in outcrop .
14:52 2611 132 As we reach the top of this east wall and stop on its capping pillow lavas, we find this high surface to be heavily covered in sediment and age 2.5. Rock Sample 9 is from this cap rock.
14:54 2610 127 It is time to leave our perch on the cliff. Altimeter registers 15 meters to the top of the talus ramp directly below us. The cliff face is near vertical >80 degrees).
14:56 2604 325 We now motor out into the water column to begin a power descent to the valley floor below. At 2614 m depth along the cliff face, the altitude is 19m. At 2620 m the altitude is 31m. We can see the wall fall off below us in the down-looking SIT camera. Talus lies far below.
14:59 2647 325 The bottom comes into view out the porthole as we land on the valley floor. Very glassy lobate flows of Age 1.5. The sediment film is rust colored. Only 30% sediment cover.
15:00 2654 323 Wavy sheet flows with occasional smooth lobate flows. N-S fissure cuts through these lobates.
15:02 2658 323 Folded and pleated sheet flows now pass into wavy and jumbled sheet flows all of Age 1.5 to possibly 1.0.
15:03 2656 321 We re-cross the large N-S axial cleft that has cut deeply through mostly lobate flows. These lobates seem to have flowed out onto the adjacent sheet flows. The altimeter registers 6 meters as we cross this large fissure. The flow morphology on the west side of this fissure is now dominantly lobate flows.
15:04 2654 322 Cracks in lobate flows are stained white on their broken faces. Lobates continue to dominate the local landscape.
15:06 2658 322 A fissure cuts across the lobates and through a rare pillow mound. A collapse pit lies directly in front of us in the lobates with pieces of the broken roof rock scattered on its floor.
15:07 2660 325 Another N-S trending fissure cutting through the lobate lava surface.
15:08 2659 323 It is time to stop for Rock Sample 10 located in a small pocket of wavy sheet flow amongst the lobates. This glassy flow looks quite fresh with an age of 1.0.
15:11 2659 092 Completing the sampling and starting to turn and move NW towards the west wall to finish this last crossing of the valley floor.
15:12 2649 286 Encounter talus shed from the west wall. It looks exceedingly fresh and may represent a recent rock fall. In this case the talus is all strewn out onto the lobate and wavy sheet flows that otherwise abut against the valley wall. Beginning to climb the talus ramp and the east-facing sheer wall.
15:13 2647 286 As we view the wall straight ahead of us, the altimeter registers 14 meters. We see a large sliver of this wall beginning to peal away as we peer into an open joint behind it, This sliver is actually leaning out in the direction of the valley floor. We climb up along the widening gap between it and the main wall only to discover that what we think is the main wall is another 1-2 meter wide (direction into the wall) and ten meter high sliver of the bedrock, very precariously standing nearly upright but clearly pealing away to the east from a vertical joint surface. Talus is present in the open joint that broaden upwards. The summit of each observed sliver is capped by heavily sedimented pillow lava of Age 2.5.
15:16 2621 285 More sheer bedrock of layered pillow lavas and truncated tubes in the exposed face of the west wall as we continue to climb. Occasionally there is scree running down narrow chutes that are shallow indentations (probably opening joints)in the wall. Glassy sand and small pea-sized gravel populate many of these chutes and accumulate in cones on ledges in a feature that looks like miniature alluvial fans except the slope is steeper. Then to our amazement the wall that we have been climbing is yet another 2-3 meter thick sliver (the third 0ne) partly peeled away from the vertical valley-wall along the valley-parallel joint surface. The on these near-vertical faces outcrop is now near 100 percent bedrock. comprised of layered pillows whose round and radially cracked cross-sections make the whole face look like a poka-dot covered cloth.
15:18 2608 286 Still climbing the near vertical face Scree become 100% and then disappears to expose more bedrock.
15:20 2597 283 The wall is now total outcrop
15:21 2591 349 At some 70 meters above the valley floor below we reach what we believe from our dive map to be the summit of the west wall. It is coated with old pillow lava heavily sedimented of age 2.5 to age 3.0. We stop to take a last sample, but the effort to position the sub is great and time runs out. While hanging here at the top of the cliff, the altimeter reads in excess of 20 m down into the opened joint below us.
15:00 2590 358 After much frustration and no success in sampling, the dive ends by releasing the ascent weights. Thank you Dudley Foster for a insightful and thrilling trip.