Alvin Dive 3354
14 February, 1999

Port Observer: John Sinton
With Scott White and Pilot Steve Faluotico

Launch Position

Time Depth Hdg
~0755 Alvin in the water
0830 Setting up to do maggie spins in water column; 1 deg/sec, spinning counter clockwise.
0841 Finished spinning
0932 2679 171 Bottom is folded sheet flows; with large lumps or piles of folded sheet flow material sticking up through sediment cover which is quite extensive, especially over flatter sheet flow area
0950 2682 Sample #1; X=5122, Y=7343. Folded sheet flow. Getting ready to move off toward WP2.
0953 2680 266 Moving off toward WP2
0954 2678 269 Moving upslope in mainly sheet flow, with some more lobate lavas around. Lava appears to have flowed down the slope from the NNW. There are extensive pockets of sediment with some mounds of lava sticking up through them.
0956 2676 267 Sheet flows are locally jumbled. There are some collapses 1-1.5 m deep. Overall relief on the flow is up to several meters.
0958 2670 269 Quite a bit of relief on the flow, most of which appears to be constructional. Mounds several meters high are mainly sheet flow lava.
0959 2666 267 Climbing up a small wall that has talus on it; the wall strikes about 020. Although this wall could be constructional it is hard to tell.
1001 2661 266 Sheet flow is getting broken up here making the relief up to 3-4 m. Some of this relief looks like it could be tectonic with some cracks running through here, but there are no clearly defined faults.
1002 2659 269 Some linear cracks beginning to appear, striking about 015. Lava is locally broken up. Some cracks strike almost due north. Some cracks are up to 3-4 m across and can see down the same 3-4 meters before they become floored by broken lava. Slope is flattening out in sheet flow.
1004 2655 232 Altitude is 2-3 m off bottom. Getting flatter. Cracks running through sheet flow. Some cracks run about 195. Some cracks lead into pits that are several meters deep.
1006 2652 233 Moving along a contact between sheet flows and lobate lavas that are transitional to pillow lavas, but not heavily budded. Looks like sheet flows are on top of the lobate and pillow lavas. Large fissure runs through the lavas here.
1011 2649 Attempting to sample pillow/lobate lava. Not quite on the top of the ridge. Slope up to west.
1015 2644 249 In pillow lava with a few buds, locally lobate. Just finished taking sample #2: bud from pillow. Very large crab here. About to go over an open fissure about 2 m wide, with broken pillows on the walls. Then another fissure striking about 010.
1017 1644 238 Pillow lava with a significant number of fissures, about one every 15 meters or so. Some fissures are open by only 15-20 cm whereas others are 1-2 m across. There are no real faults here.
1018 2642 Pillows are nicely striated here. Lots of fissures.
1019 2639 237 Large fault down to west. It is at least 8-10 m deep and a small graben is at least 4 m across. Structure strikes about 165. Slope is getting quite gentle, as we appear to be near the top of this hill.
1020 2641 236 Bottom getting deeper in front of us. Have come off of a fault with the bottom dropping about 8 m below us. The bottom as it sloped away from us appeared to be mainly constructional just before we lost it. Did not see obvious sign of faulting here. The bottom below is mainly lobate lava
1021 2651 234 Not seeing any real scarp, just lobate and pillow lavas that are pretty much in tact.
1022 2650 234 Bottom rises up to stbd to a constructional mound of striated pillows sloping down to the left.
1027 2649 Going over a deep crack striking about 175 that is about 1 m wide but very deep. It cuts this mound which appears to be constructional. Pillow are 1-2 m in diameter; some buds; some pillows are elongate downslope. Slope is up to NW.
1024 2646 205 Running parallel to a large fissure here, which cuts pillow lavas. Its strike varies from about 200 to 210.
1026 2647 202 Rocks are quite chewed up here with some very deep cracks and slices. Some cracks are deeper than sight, probably >10 m. There are some sheet flows here but it is mainly lobate and pillow lavas. As we begin to swing back to the right a large drop off over a fault scarp comes into view. We were right at the edge of a large scarp.
1029 2653 238 Descending a fault scarp that is about 10-12 m high. At this depth we are still 7-8 m off bottom. Bottom appears to be lobate lavas with some folded sheets.
1037 2657 Sample #3. Sheet flow, transitional to lobate lava. Lave here is in place although it is cut by cracks and fissures. Going to head off toward WP2 at a heading of 237.
1038 2656 238 Starting to move from some sheet flow into collapsed lobate lavas with bathtub rings in the collapses. There is a lot of colored (hydrothermal) sediment here and also some broken shells. Maybe some very small pillars <1 m high.
1040 2655 239 Very rugged terrain, now mainly in sheet flow. Maybe some fissures striking about 175.
1042 2660 237 Still in sheet flow with some flat lobate surfaces in it. Lot of yellow sediment and staining here. Collapsed lobate lavas have bathtub rings; collapses are only about 0.5 m deep. Some linear cracks could be tectonic but hard to tell.
Large drop off. Maybe spaghetti worms on scarp ?? talus
176 Broken pillows
1044 2666 203 Coming down a large drop off and have turned parallel to it; it strikes between 175 and 205. There are appear to be a lot of white biology on the scarp, maybe spaghetti worms. The scarp is mainly composed of truncated pillow lavas. Bottom is still about 9 m below, so the scarp is about 15 m high.
1044 2670 209 Parallel to scarp. Wall consists of broken pillows and lobate lavas. Lots of hydrothermal staining on scarp and in talus. Continuing to descend.
1047 2686 236 Still 6-7 m above bottom. There are several pillars here. Lots of talus. One pillar is 7 m high. There also are some extinct hydrothermal chimneys here.
1053 2687 238 Sample #4: top of pillar, 7-m high. Lots of dead chimneys around us. Extinct hydrothermal field here.
1055 2688 254 Top of some 7-8 m-high extinct chimneys. We are well off the bottom. We are right at the foot of the fault scarp we came over.
1056 Small hydrothermal mound here. The pillars and chimneys are in a slot at the foot of the scarp. The bottom comes up again to the SW. Sediment and staining all along both walls. Slot or notch is 15-20 m across and at least 9 m deep.
1057 2679 239 Climbing back up next wall to SW. Top is at 2675 m. Top consists of lobate lavas. Several anemones here.
1100 2672 239 Intensely broken and up and faulted pillow lavas and some lobate lavas.
1101 2668 234 9 m off bottom. Crossed another drop off
1102 2667 Bottom about 5 m below us. Some sheet lavas here. Another step down about 4 m then back up onto a ledge of broken pillows, then back down again. Some blocks appear to be tilted but this is not very clear. Very rugged bottom here.
1103 2662 236 Fairly flat lobate lavas; still some hydrothermal staining. These lavas are relatively untectonized. Coming over an open fissure about 4 m wide and 4 m deep. Then back to a very flat area, probably sheet flows covered by sediment. There are a few fissures but not too many. Can definitely see that we are here in a relatively flat sheet flow that is lineated; lineations suggest flow is from west to east. Then to a drop off of about 4-5 m in the sheet flow. In the wall can see that sheet flows overlie lobate lavas.
1106 2672 238 About 500 m from WP2. Mixed lobate and sheet flows that are not too damaged.
1107 2674 239 Another drop off in front of us, which is about 15 m wide that, is about 7-8 m deep. This gives way to another area of relatively flat lobate lavas.
1109 2674 237 Here seeing some collapsed features with bathtub rings. One very deep fissure strikes about 255 and is about 4 m wide and at least 8-9 m deep. Seeing a lot of collapse of a meter or less with bathtub rings all around.
1111 2673 236 Fairly flat ground, mostly lobate and sheet lavas. Heavily sedimented.
1112 2673 238 Beautiful field of 1-m pillars and some small hydrothermal chimneys. There also are some much larger ones. This leads into a very extensive field of extinct chimneys, some of which are quite large.
1116 2666 Some huge chimneys here, at least 10 m high.
2662 At top of one large chimney. Altimeter shows that this is 15 m high. Lots of mushroom-shaped sponges (?) attached to chimney.
1119 2672 244 Descending; altimeter shows bottom is 20 m below. We are entering the inner ditch. The large hydrothermal field is on the eastern wall of the inner ditch.
1121 2694 242 Can see bottom only in the SIT camera and it appears to be mainly pillows and lobate lavas, mostly lobate. Coming into view out porthole. Floor is not heavily faulted; lavas are more or less in tact.
1127 2694 274 Just finished taking Sample #5: piece of lobate crust from floor of inner ditch. Fissures run essentially N-S or maybe 005. Some of these are up to 5-6 m wide and a similar depth. Some hydrothermal sediment here. More fissures coming into view so here we are seeing fairly chopped up seafloor with lots of blocks going up and down.
1129 2692 263
1132 2684 273 Changing videotapes. There is a wall out in front of us with a lot of talus on it ­ probably the beginning of the west wall.
1136 2679 244 Getting under way again. Stepping up onto a small shelf and then continuing up. Some minor hydrothermal staining here.
1136 2672 242 Continuing to step up over lobate lavas. Some shelves in the scarps. Locally some well-budded pillows.
1137 2667 240 Mixed talus and broken lobate and pillow lavas.
1144 2650 Sample #6. Lobate lava, near top of western wall. Turning to WP 3.
1149 2670 138 Altimeter indicates bottom is 34 m below us.
1152 2695 138 Bottom is 8-9 m below showing talus in the SIT cam. Lot of staining on the talus. We are coming back up the eastern wall of the inner ditch.
1154 2692 139 Climbing up a west-facing scarp. All talus below us.
1155 2673 136 Just above talus ramp and seeing broken lobate lavas in the scarp. Just coming to top of scarp which is at least 20 m high.
1157 2665 137 Moving out over relatively flat area of lobate lavas with lots of sediment on them.
1158 2667 Have hydrothermal chimneys on stbd side. Seeing some relatively unbroken, elongate pillows flowing down to SE.
1159 2665 137 Just coming over a ~4 m wide open fissure at least 8-10 m deep. Then back into pillows and lobates and then another large, deep fissure that might have some throw, down to east but not much. This one is about 4 m across. It is very deep.
1201 2671 137 Moving across pillow lavas that flowed in an easterly direction. Pillows with buds and a few cracks. Some are transitional to lobate.
1202 2671 136 Just moved out over a large slot. It is 8-12 m deep with broken lavas in it. Then back into relatively unbroken lobate and pillow.
1203 2674 134 Seeing talus in a wall in front of us. Stepping up. Lava in upper part is relatively fluid, mostly lobate. This scarp is down to west, having come up at least 5 m. Lots of hydrothermal staining. Top is at 2666 m.
1205 2665 136 Good lobate lavas below us, with some collapse and fissures cutting them. Some lobates are hollow. Lots of sediment.
1207 2662 137 Pillows and lobate lavas here, broken into horst and graben structure. Then a very deep drop off in front of us.
1208 2663 Bottom is quite a ways below us. There is field of extinct hydrothermal chimneys below us.
1212 2669 176 Settling down to take a sample. Must be out on the bench area of the graben.
1219 2668 139 Sample #7. Floor of graben. Step down in front of us with a depth of 8-10 m.
1220 2673 151 Bottom well below us. Some spires visible in SIT cam, maybe chimneys (?).
1221 2677 141 Fairly flat lobate lavas here, relatively unbroken, but there is another drop off in front which comes back up, i.e. small graben structure that is about 3-4 m deep.
1223 2672 149 Climbing up a scarp covered with talus, then up over the top onto fairly flat lobate surface. Top is at 2673-2674.
1225 2670 149 Lobate lavas have given way to sheet lavas here. Lots of fish. Still some lobate lavas around. Some small fissures here but a larger drop off in front of us.
1226 2669 149 Crossed a 5m-wide open fissure. Back up onto relatively flat lavas, probably sheet lava. Can see some talus in front of us as we step up over a west-facing scarp.
1228 2656 141 Climbing up progressively over a series of horsts and grabens that generally are rising up to the east. Lavas are mainly lobate at the tops but there also are some pillows that can be several meters in size. Quite a bit of hydrothermal staining on these rock.
1232 2648 144 Have come up a couple of steps and here have nice pillow lavas that are quite bulbous that appear to have flowed from west to east. Bottom descends in front of us but these lavas appear to have flowed down this slope which goes down to the east. Bottom continues to deepen in front of us. This slope is at least partially constructional. Lavas definitely flowed down this slope.
1233 2653 141 Evidence for lavas draping a slope here.
1239 Attempting to sample pillow flow that drapes slopes (faults?).
1245 2653 Sample #8. Pillow flow in graben.
1247 Turning to WP 5, which is about 600 m away at a bearing of 242.
1249 2646 240 Moving out over pillow flow that is rather heavily budded here. Some pillows are elongate from west to east. Then we move out over a west-facing drop off. These pillows are thus definitely faulted. There is a very deep (~14 m) open fissure cutting these pillows.
1251 2649 Back into pillow lava on the other side.
1254 2662 243 Fairly high off bottom here, which descends as we go west. Bottom is about 12 m below us.
1256 2668 243 Bottom still more than 10 m below us.
1259 2679 243 Can see fairly flat flows below us in SIT cam; these appear to be folded sheet flows.
1300 2675 241 Coming back up a large drop off. Crossed some talus. Here have cracked up sheet flows (but they aren't laughing).
1302 2676 242 Lots of staining and some very small (<1 m) chimneys present here. Some are about 0.5 m high with a diameter of no more than about 15 cm. There also are some much larger ones, several meters high. We turn left to 178 which is parallel to the crack that has chimneys in it.
1304 2676 241 About 200 m from WP5. Moving across some broken lobate lavas here. Some talus also present. Quite broken up terrain.
1306 2673 245 Seeing some very flat sheet flows here which we will sample. Probably just east of the inner ditch proper.
1311 2674 Sample #9. Piece of sheet lava. Also some lobate lava here.
1312 2669 244 Crossed a broken up area and now seeing more lobate lavas with a lot of sediment.
1314 2672 242 Very nice pillar field here, mainly about 3 m high, some are less. Bathtub rings all around us as we descend into this area. Pan and tilt camera is history.
1315 2676 Still in pillar field. Pillars appear to be vertical, i.e. not tilted. Floor is mainly broken pillar debris.
1322 2671 Sample #10. Pillar top. As we move off, we are seeing a number of hydrothermal chimneys. Some of them are at least 10 m high with things growing on it. Top is at 2670. There is another, even bigger one, behind it. Can see pillow lavas on the floor, but just barely.
1325 2666 252 Crossed a collapse zone with pillars and hydrothermal deposits and then into a fairly flat area of lobate lavas. There is a drop off in front of us, that probably is the descent into the inner ditch. As we descend we see some sheet flows right on the surface; just below those are some bulbous pillows and then can't see the rest. The collapse zone of sample #10 is about 50 m back to our east (just outside the main steps into the inner ditch). Big hydrothermal structure below me. Dead!
1327 2670 160 Turned to run almost parallel to the scarp bounding the east side of the inner ditch. The scarp heading is closer to N-S.
1328 2677 238 Beginning to see some pillars, no more than a couple of meters high, with bathtub rings on them. Many dead hydrothermal chimneys here. As we move on the chimneys are all around us.
1330 2681 223 Following a depression that here appears to be mainly sheet lava. Have come out of the hydrothermal area. Still getting a little deeper. Still some pillar structure and bathtub rings.
1333 2680 195 About 4 m above bottom, nearly parallel to structures here which trend closer to 200. Broken sheet and lobate lava here.
1334 2680 199 Following fissures in broken up lobate lavas in inner ditch.
1337 2679 193 Seeing lots of yellow hydrothermal sediment and some small chimneys ­ all dead. Lavas are broken, flat lobate lavas with cracks parallel to our heading. Some very large hydrothermal structures around.
1339 2675 193 Now have chimneys all around us. Seem to be in a huge chimney field (both the field and the chimneys are huge). Spires sticking up all around us. Bottom is 9 m below us as we fly near the tops of some of the chimneys. As we go on the chimneys are every where we look and the sediment completely covers the older lava surfaces. Nothing but yellow dirt and dead chimneys.
1342 2680 205 Still in field of chimneys and sediment. Very few lavas exposed. Appear to be following a lineament that is a fissure or possibly a collapse zone. The chimneys are strongly aligned along it.
1344 2678 186 Running along a scarp on the left side with broken pillow and lobate lavas. On stbd side are chimneys. Port side wall contains cross sections of some very thick lavas that thin to south but are still about 1 m thick.
1346 2669 189 Still in chimney row running parallel to fault scarp.
1348 2667 145 About 8-9 meters above bottom.
1350 2672 178 Bottom has gotten deeper and here we have pillow lavas below us as we seem to have come out of the hydrothermal field. Pillows are bulbous and not very fractured.
1351 2678 176 Following fissures and cracks. No hydrothermal stuff here, just pillows and lobate lavas. Then we came over a couple of chimneys and I can see talus on the port side as we come into a more tectonized area.
1357 2672 101 Leaving the inner ditch where it ends to the south and beginning to move over an area that seems to deepen on our stbd side.
1358 2674 107 Moving out over a scarp that is west facing, about 12 m high. Top is lobate lavas. Steps down again and then back up to a flat area, probably rather flat lobate lavas.
1400 2671 110 Lobates and pillow lavas here. A number of fractures through here but none of them are very deep or wide. They run generally N-S
1402 2670 109 Sedimented pillow and lobate lavas. Maybe some tiny chimneys about 0.5 m high below us. Large fault scarp in front of us dropping off to east. Scarp trends about 015. Drops vertically
1404 2675 106 Comes back up on other side of fault and on the east side we have wrinkled sheet flows. These give way to lobate lavas which have quite a bit of hydrothermal sediment around.
1407 2672 110 11 m above bottom. Crossing a fairly deep area, presumably near the eastern wall of the graben.
1408 2673 110 Come to a wall of talus in front of us. Some staining and yellow sediment in the talus slope.
1409 2667 110 Have come over a ledge of talus with no in tact rock at all present. Then begin to see some healthier lobate lava.
1411 2661 110 Moving up a talus slope with no rocks in place. Talus consists of meter size blocks and locally bigger. Some of it is stained.
1413 2646 108 Still have all talus here, but beginning to see some broken, nearly in place lobate and pillow lavas here.
1415 2640 110 Seeing a small bench in the wall where there are pillow and lobate lavas.
1418 2641 Attempting to sample from ledge.
1425 2641 Sample #11. Came up talus ramp, then into broken outcrop, and here sampled from sort of flat ledge in the wall, that consists of mostly lobate lava with some pillows.
1427 2636 Moving away from sample site across ledge.
1428 2636 Bottom is 10 m below us here. Must be a little slot on the east side of this ledge. Starting to see some wall to ESE.
1430 2631 112 Deep slots are present here with broken lavas ahead of us. Near break in slope near top of west wall.
1431 2630 127 Slope decreases as we come out over top of scarp. Mostly pillows and lobates.
1434 2632 Top of next step up (top of scarp). Sample #12.
1451 Finished sampling; weights away, beginning ascent..

PAU