Alvin Dive 3353, 13 Feb. 1999
Bruce Strickrott (pilot in training), R. Batiza (port obs.), and Blee Williams (stbd obs./ pilot instructor)
R. Batiza Transcript

Summary: Dive 3353 was to the southern part of the middle area, north of the OSC connecting this segment to the hump segment to the south. The goal was to investigate the possible southern boundary of the lava lake, and the boundary between inferred (from sidescan) fissured flows to the south and unfissured pillow mounds to the north. On descent, transponders F and G were heard, but on the bottom, there was no transponder navigation. The track was reconstructed from a combination of DR and surface tracking with the Noctronics (?) range and bearing system. The general stratigraphy observed throughout the dive consisted of sheet flows overlain by lobate pillows, overlain by bulbous pillows. This stratigraphy was observed on a small scale in areas of diverse flow morphology, and also on a larger scale of several kilometers. However, contacts were often unclear and lacking in any perceptible sediment age difference.
The dive began in sheet flows with diverse morphology, lobates and pillows, and progressed to a region dominated by lobates and collapse structures (with pillars), with only occasional pillows. The collapses in some cases had straight walls suggesting a component of fissuring in the collapse. Rare lineated sheet flow was observed in this southern region. The northern area is dominated by pillows overlying lobates and there is less fissuring in this area. this area has abundant signs of previously active hydrothermal activity, including dead sulfide chimneys and mounds. A ~30m wide and 6-7m deep crater occurs near the shallowest point of the dive, and may be related to subsidence within a small, apparently monogenetic edifice of lobates capped by pillows. The pillows may represent slightly later deposits, erupted sporadically during periods of inflation of the lobate flows.

 

Abbreviations:

 

TIME DEPTH HEADING COMMENTS
0850 Alvin in water
0911 500 WP 1 bears 065°, 260m
0921 830 Started mag and commenced logging
0924 995 Start mag 360°turn, CC (to port), 1°/sec
0953 143 1790 good fix x=1847, y=-3130, WP 1, 090°, 200 m; both EC frame counters at 002
1017 2429 water depth is 2660, consistent with previous posits. no nav.
1024 2637 020 A=31.9; dropped weights.
1036 2660 bottom in sight, heavy sed w/some rocks poking through. A=8m
1039 2660 A-9m, videos on, EC on, CTFM on, mesotech on, neutral trim.
nav fix @1039- 200m on 130 to WP-1.
1045 2667 A-2m, flat sheet flow with some flow folds, disrupted crust , and mini tumuli poking above level surface, sed thickness ~1-3 cm (?). Looks like 3 on Macdonald scale, but deceptive because the SF is so flat.
1046 2667 340 stopped sampling. CTFM shows wall about 350m on 330° and contact ahead also.
1049 2667 sampling. flash on HH doesn't work. EC frame is 021. EC flash later found to have been off also- turned on later.
1052 2666 (340) Blee saw holothurian fecal pattern in sed. u/w to search for better sample station (didn't go more than 5m).
1058 2667 332 sample 3353-1.5" long sheet flow fragment. Sample in BP 5a, Digital frames 1 and 2; location is 170m west of WP-1 based on previous nav fixes (during descent) using trans. F and G.
1105 2665 333 A-2m; flat sheet flow with local disruptions of only 1-0.5m at most.
1107 2667 (330) cracks in sheet flow.
1108 2667 333 folded SF, local relief of 1-2m. White sea whip (with little flowers on it- 1.5m tall.
1110 2668 slightly up hill? folded and JSF, brittle star. more seawhips -pretty common. Sed at least 2 on McDonald scale.
1111 2668 334 still JSF, sed age 2. Contact on CTFM (550 yd scale) still a wall to the left, also on right. Contacts in between look patchy. On 150 yd. scale, patchy contacts ahead.
1112 2669 (on auto) big L flows, contact was abrupt with relative ages unclear. no fissures yet. Lobates have clearly flowed over JSF here. Bruce sees a lot of pillows up ahead.
1113 2670 334 L. nice collapses in lobates. Also P, with buds. in distance. no more JSF
1114 2669 S- ~1 kt or less. Started moving at 1105- actually S is more like 1/2 to 1/3 kt., so we have gone maybe 150m so far. maybe 200m at most.
1115 2669 Big P mounds, look younger on Macdonald scale (1.5), but maybe just because more local relief. Clearly erupted onto lobates- can see underlying L covered with pillow/bud complexes.
1117 2668 351 stopped to get sample of P. Stratigraphy so far is SF overlain by L, overlain by P.
1118 2668 353 P here are 1-2m across, many buds.
1123 2668 sample 3353-2. P bud, digital photos 3, 4, and 5, BP 1a. location 175-200m from landing site on 330°.
1127 2668 004 will try to head 270 once u/w.
1129 2666 301 A-2m- trying to get west to find fissure to follow northward. CTFM shows wall up ahead. Now H=270, wall on CTFM is ~250m away. (could be west wall- 2650m contour).
1131 2666 269 A-2m. CTFM- wall ahead, 200-225m range. still no fissures. in collapsed L. Collapse pit.
1134 2672 268 L gave way to a small collapse feature, now a larger collapse with many pillars- some are very cylindrical (as opposed to irregular in x-section). (Just discovered that flash on EC not firing- turned it on at frame 112).
1136 2673 328 stopped sampling.
1138 2674 digital frames 6,7, and 8 are presampling shots of pillar.
@1140 collected sample 3353-3, pillar piece (from top) in BP 1b, digital frames 9, 10 and 11 are of sample.
1147 2672 342 try to go 000°, bottom of collapse is rubble with sediment (age ~2). Pillars, are 0.5-1m and collapse is only 1-3m deep.
1149 2671 345 coming to 000°, A=7m. Many pillars. Seem to due south of WP-3, will try to head for it.- huge pillar 5-6 m at base.
1150 2669 001 coming out of collapse pit. on to L. Collapse pit boundary is crenulated and very irregular.
1151 2669 001 moving at 0.3 to 0.5 kt gently up slope. sed age is 1 or slightly older. Looks younger, but maybe because lobates, not SF. Many collapsed L, seawhips and rattail.
1153 2669 001 moving slowly uphill on lobate pillows, age 1-1.5. CTFM shows
patchy outcrop on 150 yd scale. EC (stbd)=142.
1154 2668 002 Now on P that seem to have erupted on lobates, still visible below. Some are badly broken up by fissures, partly obscured by rubble itself- looks like in situ talus on level surface. some P are tubular but less than 2-3 long., mostly bulbous with many buds.
1157 2669 002 uphill at about 1/2 kt or less. (Blee says 0.3 kt). still on P, age 1-1.5, many buds.
1159 2668 356 looking for sample site.
1200 2669 333 stopped sampling. CTFM shows wall at ~40m range- strong contact.
1213 2669 334 P bud collected at 1210. BP 3a, digital photos 12 and 13. sample 3353-4. small piece.
1214 2668 000 u/w from sample site.
1215 2667 003 very nice P, 2-3m size, many buds. Age 1 or perhaps more, but still shiny glass. tiny limpets on P? CTFM on 150yd range shows contacts ahead. Also on 330, ~150m range is wall- (probably NOT west wall).
1217 2667 sed here is not white- more tan or pinkish with HT contribution.
1219 2664 001 uphill ahead. P, mostly bulbous.
1220 2662 001 SF on stbd side, P on port. 20 cm fissure, quite deep, N-S trend and goes "under" pillows and disappears. Fissures are in lobates.
1222 2659 001 stopped to change video tapes. On L, with fissures
1224 2657 A=5m, L w/fissures. trend is 010, meanders. Back on smooth SF, but small patch, mostly L.
1225 2658 002 A-2m, changed tapes, CTFM on 500yd scale- no contacts. On 150 yd scale, wall to left (330), patchy ahead. Bruce sees large fissure ahead.also small N-S fissures on port side. Now wrinkled SF with lobate on top. Pillows also- age relationships of P and L are unclear, but lobate is clearly in top of SF. 1m wide fissure on port side- trends 010. 1m deep- walls have truncated pillows. Back into P only- big and bulbous.
1228 2657 002 2m wide fissure on port. trends 010.
1229 2656 10m deep fissure directly below Alvin. 12-14m deep.
1231 2655 000 fissure ended in some P. Mostly L now, with small amounts of P.
1233 2656 001 more bulbous P on L, fissure ~3m away on port side, 3-4m wide, headed 005 to 010.
1233 2658 001 crossing fissure, just ended in rubble. fissure is full of rubble.
1234 2660 001 Blee sees intact P on stbd, I have pillow rubble. Talus on my side 10-50 cm size)- Blee sees bacteria mats.
1237 2658 359 no drainback into fissure- looks tectonic. P. w/buds.
1239 2658 357 on L now and wrinkled sheet flow. and smooth SF, also JSF, Blee sees flow channel.
1241 2661 lineated SF flow channel with levee on Blee's side and also possibly a levee on port side. stopped to sample.
1242 2661 sample 3353-5. sheet flow piece. BP 5b. - no digital photos.
1252 2660 003 u/w from sample site. CTFM shows very straight wall on 150 yd scale (015- trend). now on JSF
1254 2657 003 end first side of tape. Blee sees big hole on stbd. side. Collapsed L.
1255 2657 003 big wall on CTFM 150 yd scale (010 scale to left). near west wall? (probably not)
1256 2656 001 on L, large collapse or fissure to port. far wall is 6-7m away- deep and linear. Collapse on video. Pillars in view now. It is a collapse. Big pillars- very deep collapse, 10-15m deep. Branching pillars, 4-5m high. collapse is linear N-S.
1259 2655 pillars on SIT camera.
1300 2656 003 pillars on SIT- nice views.
1301 2657 (003) going along the wall we can see on CTFM. more pillars and collapse.
1302 2657 002 collapse. CTFM shows lineated fabric on 150 yd scale, slightly oblique to track (010). A=10m
1306 2661 036 stopped to sample at bottom of collapse.
1310 2666 100 sample 3353-6. digital photo 14 and 15 of sample. Big sheet flow, in BP 8.
yellowish bacteria in cracks.
1311 2666 098
1319 2661 y/w/ from sample site to go 270 up wall. Fine grained talus at sides of collapse pit. Try to get thickness measurements of lava lake.
1322 2656 284 P at top
1324 2655 285 over little horst or remnant in collapse.
1327 2650 028 coming around to 010 to head for WP-5 (crater)- decided that west wall was not here at all. just multiple collapses parallel to 010. These look like a combination of collapses and fissures.
1330 2649 010 A-5m, below are P with buds. sed age ~1
1331 2650 012 lobates now. fix from surface is 500m on 010 to WP-5. P now- downhill tubes, but short.
1332 2650 (000) fissures N-S in P along our track. Looks like down hill tubes, with L now.
1333 2650 009 L now, gently uphill, occasional small P with buds. anemonies.
1333 2649 N-S 20 cm fissure in P, with much rubble. also fissure on stbd side. in L. Edifice, if anything is L, not P- is this young P mounds?
1334 2649 012 P on top of L A=5m, depth is 2753. Blee sees sed SF, L on port, with P. age 1-1.5.
1336 2650 012 on L with bulbous P, with many buds. Slope ahead and to the right., P now, no more L and few fissures.
1337 2650 009 slope on P.
1338 2649 010 P upslope, anemonies. large bulbous pillows with buds.
1341 2641 009 leveling off- P. going up slope. N-S fissure on port side.
1344 2640 010 A-3m. back on P, after 5m dip in topo- this is local relief on P.
no downslope tubes, just mounds of bulbous pillows.
1346 2640 012 CTFM shows lineated contacts trending 020 on 150 yd scale. P.1-2m in size. short tubular sections. More yellow bacteria in cracks. here some longer tubes.
1349 2632 010 P. HT bacteria deposits., fissures in P. gentle slope up to crater.
1351 2627 passing over sulfides. dead mounds and fallen chimneys, HT sediment., on L
1352 2627
1353 2627 010 large deposits of dead sulfides. now onto P again. d=2626.
1354 2626 009 6m wide fissure, 6m deep- truncated P in sides. trend is 015 or 020 (CTFM and visual estimate).
1356 2626 012 fissure on SIT- on P. more fissures on stbd side. P on port. A=3m.
1401 2638 fix from surface- 100m north to crater. A-2m. now on L w/buds. still uphill. lots of HT sediment, HT bacteria. anemone.
1404 2636 012 HT bacteria. on L, SF on stbd. heavily sed. with HT sed.
1405 2635 L, with cracks and thin fissures.
1406 2633 c/c 290 roughly circular contact on CTFM, range 120m. surface also says crater bears 296 from us.
1407 2632 L and P with buds.
1409 2630 295 P. pile with tubes across track (flowing downslope from N)
1412 2628 c/c330 CTFM on 150 yd scale- contacts, patchy.
1414 2625 336 toward crater. A-6-7m, P and tubes.
1417 2626 335
1418 2627 000 c/c 000, P, A-5-6m.
1420 2634 005 on L here, now mostly P with buds. headed toward CTFM contact.
1421 2638 006 A-4-5m, P with buds. CTFM contact at 30m ahead. upslope ahead. large inflated P. no fissures.
1424 2636 002 changing videos. L here.
1429 2638 106 stopped sampling at edge of crater. Crater is ~30m across and maybe 8m deep with talus and benches on one side- lobates on bench.
1447 2637 sample 3353-7, folded sheet flow. digital stills 16 and 17. BP -7.
1453 2635 153 turning to look at crater
1454 2635 153 collapsed L. at lip of crater. talus in walls.
1459 2635 308 going to center of crater to look at bottom.- rubble, with maybe intact P.
1501 2640 073 sides are mostly talus. Small ledges and benches w/P on them.
1502 2638 055 rubble and fissure, north of crater
1506 2635 003 on L., now SF, small collapse with BTR. now L again.
1507 2636 004 L, rattail. now onto P that are erupted onto L. Bruce sees P ahead.
1508 2638 002 P. SIT on.
1509 2640 002 P. and L. L. with animals on them.
1510 2644 004 large P., uphill on stbd side. downhill on port. P. with buds. animals. sed age is greater than 1.
1512 2642 003 more P and L Pillows on top.
1513 2650 021 try to get a last sample before surfacing.
1520 2652 096 sample 3353-8, pillow bud, digital photo 18,and 19. BP 4. also holothurian in bio box. also tried to collect a tunicate, but it drifted away when brushed by arm.
1521 2640 dropped weights, EC-565 (stbd).

 

Sample Locations
Sample	Time	Depth*Latitude (S)Longitude (W)
3353-1	1105	2667	18°21.70'	113°22.91
3353-2	1123	2668	21.62'	22.98'
3353-3	1138	2674	21.62'	23.04'
3353-4	1213	2669	21.49'	23.05'
3353-5	1242	2661	21.33'	23.03'
3353-6	1310	2666	21.27'	23.00'
3353-7	1447	2637	20.87'	23.05'
3353-8	1520	2652	20.52'	23.09'
				
*- all depths are Alvin pressure depths- these are ~25-30m shallower than Seabeam depths.