Alvin Dive 3346 - February 5, 1999

Transcript from audio tape recording by Karl Grönvold.

Launch Point: 18° 49.00' S 113° 25.33' W

(x:1200 y: 1800 with net origin at 18° 41.00' S 113° 26.00' W)

Tape 1 Side A.

 

 

 

0926 - Depth is 2668 m - altitude 51 m.

0928 - Altitude 32 m depth 2694 m and we are 38 m from target. Bottom in sight.

0929 - Altitude 12 m depth 2714 m bottom in sight. Bottom seems to have a fairly thick sedimentary cover.

0930 - Altitude 5 m.

0937 - First sample went into the first forward box on port side: a little pillow bud. Sample 1 picked up at x 1195 y 1817 depth 2725. Went into box 1a. No digital camera shot but pan and tilt video recorded.

Still at way point 1 sitting next to a large pillow and pillows make the high points but are surrounded by lobate lava flows.

Starting to drive from way point 1. There appear to be pillow lavas standing up through lobate flows. Quite nice big pillows up to at least 2 meters in diameter. The sediment cover is quite thick and more or less continuous. Continue driving over mainly lobate flows. With sediment cover not only filling depressions but also surfaces.

Sediment cover seems to be thinner but could be the effect of the boat stirring up the sediment cover. The bottom is covered with lobates with plates of sheet lava probably about 5-10 m in diam. across. Moving into pure lobate flow with similar sediment cover.

These sheets within the lobate are clearly part of the lobate formation. Sediment cover similar.

0946 - Travelling from waypoint 1 to way point 2. Still lobate flow and individual lobes are quite large and some are fairly continuous. There are occasional pillows poking up through the lobate field. Now travelling through a small field of pillows. Coming into a pillow area. We are now in a pillow area with pillows over 2 m in diameter. Sedimentary

cover similar as before so when going from dominantly lobate to dominantly pillow did not affect the sediment thickness. Some very nice pillow with striations. So there was clearly a transition from lobate to a pillow flow. The sediment cover on the pillows is almost continuous: never less than 60% on the top of the pillows.

0948: (Instructions on video settings).

0950: Still travelling across a pillow flow. Very nice small buds sticking out of the

pillows and between them - otherwise the pillows are fairy large and equal in size.:plenty of nice little buds between the pillows. Sedimentary cover still very similar.

0952: Still travelling over the pillow lava: nice large pillows of uniform size with abundant small pillow buds. Sedimentary cover on top of the pillows well over 60%.

Looking for another sample collection site.

0954: Still travelling over the pillow lava.

0955: Trying to collect a sample. First one broke, trying again. Picked up a pillow bud (sample 2) that went into bin 1b. Location x 1347 y 1962 depth.

Continuing across the same pillow field, still with large pillow and similar sediment cover. Occasional pillow is broken and seems to have approximately 5 cm thick outer rim and then a separate core.

Still large pillows with abundant pillow buds. A small sheet with possibly thinner sediment cover.

0958: x 1445 y 2007 depth 2704.

0959: Traveling about 16 m/min: still in the coarse pillows with similar sediment cover. Travelling on more lobate lavas. Likely to have just passed a contact.

1001: Now clearly in lobate and folded sheet lava with some very nice folding. Going to settle and take a sample. The sediment thickness on this lobate flow is similar if not thicker than on the pillows. Sample location on folded sheet but large pillow are visible just in front of the window.

1005: Moving after a successful sample from the sheet flow. Traveling over lobate flow.

Some large lobes with similar sedimentary cover as before.

1015: Just picked up a sample 3 did not get a good fix. Good fix just after the sample location x 1550 y 2086 dept 2697.

Travelling over a folded sheet lava. wavelength between 0.5: 2 meters. Sediment cover similar as before.

Travelling over a channel and coming out of channel into pillows with similar sedimentation as before.

1017 - Pillow lava clearly a pillow flow.

1018 - Still pillow lava with similar size pillows.

Contact over to lobate lava. Sediment thickness may be greater than before. Seem to be close to pillow lobate contact. Going from pillows to lobes.

1018: In lobate lava. Well over 50% sediment cover on flat surfaces. Lobate lava: possibly sloping away. (Possibly contact as Rodey is seeing mainly pillows before getting into lobate.) . Sediment cover heavy - up to 90% on the flattest pieces.

Still on lobates - nice sheets in between the lobes, 20-40 m in diameter, usually cracked down the middle.

1021 - Good fix x 1646 y 2157 depth 2693. Travelling over fairly regular lobate lava with thick sediment.

1022 - Still travelling over similar lobate lava.

1024: Still over lobate lava with similar amount of sediment cover up to 90 %.

1025: Pillows sticking up through the lobate flow with similar sediment cover as the lobates. Back into lobates only with large lobes and little else between. Large pillow 2 x 10 meters sitting on top of the lobate flow and presumably coming up through it. No collapses have been observer so far. (Rodey was seeing some on his side.)

Lobates turning into sheets but still mainly lobate flow with occasional sheets. Lobes are large wavelength: with occasional ropy appearance.

1027: Here is a pit - here is a crack: a definite crack. There are pillows in it. Matt is seeing lot of biology mussels. Dead mussels mainly.

A long gap in tape.

1040: Just picked up a sample number 4. y 1909 x 2345 depth 2680 m.

1041: Travelling over fissured area. Ropy lava with over 70% sediment cover. Changing into sheet lava with collapses. Here is a bunch of fissures (collapses) one coming up showing layers of flow units each few centimeters thick. Another big fissure (collapse) with rubble on the bottom. Another collapse in a lobate flow. Lobate flow changing into sheets and back. With similar sediment thickness as before: possibly 80% covered on reasonably flat areas. Another big collapse coming up possibly 10 m vertical wall with thin sheet flow in the walls. Still in lobate lava.

1043 (voice 1033: must be wrong): A good fix x 1982 y 2388 depth 2676 m. Another a collapse: looks deep in the middle - looks tectonic. There are a lot of rifts/collapses here. Travelling over one that clearly looks tectonic.

1044: I have a feeling that we have just been traversing tectonic fissures ö not only collapses. There is a definite tectonic feeling about some of the collapses we are now crossing. A collapse with thin sheets in the walls. Another thin (narrow) again a feeling for a tectonic bottom. Travelling across lobate lava.

End of side A

Side B

1046: Travelling over lobate lava with an occasional pillow like structures. Hydrothermal staining coming up. Yellowish reddish staining in the cracks and seems to follow the cracks. No sign of water movement (simmering). A fair amount of geothermal but it looks dead - looks like an alteration that has been laying about some time. We have now come into pillows: yes, pillows. We have a crack did not get a good feeling for it.

Now in (coarse) large wavelength lobate lava.

1048: x 2091 y 2756 depth. Now in a broken up sheet flow. That was short: now we are lobate lava.

A large gap in tape. (Missed out a dead hydrothermal chimney at 1050.)

More biology than usual but I can see no simmering.

1053 - Now travelling inside a collapse. We are on lobate lava. Have feeling of less sediment on top of this but view is limited and we may be within a collapse. We are on lobate lava with large wavelength. I have a feeling that the sediment cover is less than it was before but need a bigger surface to confirm that. Still travelling on lobate lava with small collapses about a meter or more. There are clear signs of geothermal alteration in some of the rocks. Here are more collapses: not very deep and not very regular. There is a big collapse coming up: really big one. This is a deep one - this is by far the deepest one I have seen so far. This is deep. This has to be tectonic. This tens of meters deep. It is in lobate lava.

1056: This was deep tectonic fissure. I did not get a good feel for the width but it was probably on the scale of 10: 20 m. We are in lobate lava.

1057: Out of the window it is lobate lava. This seems to be much less sediment covered than when we started - much, much less sediment covered. And you can see much more of the glassy surfaces but there is still sediment in the groves of the folds (or inter-lobes. We are in a sheet flow now or crumbled sheet. Collecting sample number 5.

1058: And I can see small geothermal alterations. Settling down on a crumbled sheet with occasional geothermal alteration. I can see no simmering. This is folded sheet flow.

1105: we are sitting on the bottom at sample location 5. Trying to get a sample from the folded curtain (sheets) which will be number 6.

1110: Clearly a contact between folded sheets and lobate lava and now we are in folded sheets, very nice folds. The scale of the folding is from meters and down to centimeters. Beautiful parallel flow structures apparently flowing away from me (ie to the right). A contact again from tightly folded sheet to lobate. A fairly sharp transition you would hardly call it a contact.

1112: Over folded sheets very, very tightly folded which grade into broken up sheets. Sheet flow, folded and partly broken up.

1113: Tightly folded sheet flow and very little broken up. There are collapses. I now have a small collapse only about 2-3 meters but it is getting bigger than I thought in the beginning - irregular collapses ?? Here are some collapses. I can not get a good feeling for orientations but feeling is that they have a direction in the direction we are driving.

1114: Still tightly folded sheets. The sediment cover is thinner than it was (in the beginning). The flow has collapses in it but not very deep and definitely collapses. Very nicely folded sheet flow.

1115: Just coming up to the way point. Here is a lot of biological something and there is a deep collapse here. Just passed over a deep collapse. There is more biology and may be geothermal. No I see no simmering and no definite dead geothermal staining. There is definitely biology. Matt has seen simmering water.

1116 - Simmering water. We are on way point two. Still on way point two taking a temperature measurement. Reading 4.35 Centigrade in a small crack. Looking for suitable bio sample.

1129 - Just changed the tapes. Collected sample no 7.

1130: Just leaving way point 2. As soon as we left we went from folded sheet to more regular lobate lava. Still much less sediment than we had at the beginning of the dive. On the way to way point 3 an we are in pillow lavas now - definitely pillows. Seems to be sloping down to my right. Fairly regular pillows with lots of pillow buds in between: the large pillows up to 3 m in diameter. Now in a mixture of lobates and pillows.

1133 - Travelling over pillows. Look quite glassy. Now in very nice folded sheets: it is all finely folded. And the flow direction is away from me. Now we go from the folded sheets in to lobate lava with occasional pillow.

1136: We are seeing sort of geothermally altered rubble sort of light brownish rubble sitting on the flow. Clearly sitting on top (rather than being part of). Changing into sheet flow features. Sediment cover seems to be quite thick now. Clear contact between sheet flow and broken up sheets. There seems to be less sediment again. Broken up sheet flow with collapses. Coming to a sizable collapse. Sheet flows in the walls and broken sheet flow at the bottom.

1138: Contact between broken up sheet flow and lobate lava. Seem to be travelling along an irregular contact. Does not look like the contact between two lavas only two different morphologies: they definitely grade into one another. I have lobate below be and the broken sheets to my right.

1140: In transit from wp 2 to 3. Gone into broken sheets and into folded sheets, mainly. There are occasional lobes. A fairly deep collapse coming up: might actually be a lava channel but broken sheet at bottom indicate collapses. Sediment cover on flat surfaces over 50%. A pillow lava coming with over 50% sediment cover. Pillow was only one pillow so flow is lobate. It is lobate lava with buds.

1142: Travelling over lobate lava with a fair amount of pillows in them. Gone from lobate into pillows. Going again from the lobate flow into pillow. We are now in folded sheets. The folded sheets have a fair amount of sediment in them.

1143: Collecting a sample number 8.

1150: Leaving sample collection point and travelling over a pillow field. Fairly large pillows and striated with a lot of buds in between. Here is a crack: this is definitely a tectonic. We are going across a tectonic fault at 1150. The fault is about 2- 3 meters wide and I can see at least ten meters down and the rocks are clearly broken on both sides.

1153: Still traveling across folded sheets: flow direction from my left to my right. Very clean sheet flow covering a large area. We seem to be going up slope and sideways (relative to the lava flow direction). Here we can see the sheet flow turn into lobate flow and now it is lobate.

1154: Clean lobate flow.

1155: Navigational uncertainty.

1158: Travelling over lobate flows: lots of spaghetti bio.

1159: Just crossed a collapse in the lobate flow. Sediment cover over 50% definitely.

1159: Coming up to a collapse - this looks tectonic. There is a deep collapse here the throw is at least 20-30 m.: possibly more. Here is another one: this is a beauty - about 4 meters wide and I can see at least 50 meters down. This is clearly tectonic: no doubt about it. The edges are lobate flow. (This fault had no vertical component purely tensional). Another nice fault. We took a small circle to have a look at the fault.

1202: Octopus.

1204: Moving toward way point 3 over lobate flows. Collapse - a nice big collapse.- probably 20-30 m deep with sheets on the bottom. Coming off the collapse on to a sheet flow and onto another collapse 20-30 m deep. Coming to the other side of the collapse: this was quite a big collapse but I can not get a good feeling for vertical displacement. And yet another big collapse: looks like tens of meters displacement with irregular bottom. Into sheet flows: still with collapse structures and pillars. Some of the pillars are very narrow. We are now in folded sheeted flows with lost of collapse structures. There is a big collapse pit: sort of oval shaped. Folded sheet flows with collapses of all sizes from 1 meter upwards. I see signs of old geothermal alteration. There are patches of brownish staining. More collapses. Thin folded sheets. More collapses. In very collapsible area.

1209: Still travelling in folded sheets and lobes and collapses are still there but less pronounced.

New tape.

1214: Travelling between way points 2 and 3 with 260 m to go. Crossing lobate lava with ver heavy sedimentation almost 100 % sediment cover.

1216: Heavily sediment lobate lava. 145 m to way point 3. Still on lobate lava heavily sedimented: markedly more so than in the collapse area.

1218: Still on a lobate flow.

1219: 50 m from way point 3. Lobate with pillow lava with heavy sediment cover. Mainly lobate with pillows popping out now and then.

1227: At way point 3 and collecting a sample 9.

1231: Have left waypoint 3 for nr 4. We are in heavily sedimented lobate flows.

1234: Heavily sedimented lobate flow. Sediment cover close to 90%. Lobates, lobates. Seeing some pillows with buds. Clearly folded sheet.

1236: Traveling over heavily sedimented lobate flow with occasional folded sheets. Seem to be lava channels in places with folded sheets.

1237: Starting to get sheet flows mixed in with the lobate lava. Now travelling in sheeted rubble. Sediment cover is still very heavy.

1239: Still in sheet flows with patches of lobate lava. The first collapse with a roof partly standing. I did not see the depth of this but it was quite deep. Lava is more sheet like rather than lobate.

1241: We are in lobate flows with patches of broken up sheets. Moving into lobate flows - there are not many sheets at the moment.

1242 - Still travelling in lobate flows with occasional pillows sticking out. There are a lot of buds with the pillows. Now we move from lobate to sheet channel. There is channel of sheet flows not very much broken up. There are collapses now. One about 10-20 m across and 4-5 m deep. Here is another coming up may be the continuation of the other one with sheeted flows in the walls. There is another collapse coming up: not very deep. So we are in sort of lobate and folded sheet terrain now.

1245: Over lobate lava with thick, over 80% sediment cover. A sample collection nr 10. Into bin 8. From lobate lava.

1254: Leaving sample locality 10.

1255: Coming towards a big collapse: big and deep with lava pillars: not very big but with bath tube marks. Got both lobate flow and broken rubble at the bottom. Something even deeper coming up now: another collapse. This is quite a big one. This is tens of meters deep and with folded sheet flows on the bottom. The folds sheet at the bottom has not been broken up - it is very intact.

1257: Still traveling over a lobate flow. Not sue about the sediment thickness but think it is still the same 90% when you have a good surface. 80-90%. A big collapse coming up in front of us: this is deep. It has folded sheet flow at the bottom. I can now see geothermal alteration in the cracks just below me. We are at x 2435 y 4095

1259: There is geothermal below.

1307 - Doing sonar test at the bottom.

1317: Just sampled 11 and 12. This is a lava pillar. Sample 11 from the top and sample 12 from the middle of the pillar. (Sample 13 was the bottom of the pillar.)

1323: Moving away from the pillar and over collapse pits in lobate lava: still with thick sediment cover. Here is a deep collapse pit coming up ö quite deep. 20 m probably with pillars.

1326: Lot of collapses and lots of lava pillars.

1327: Over fold sheet flow curtain with clear fold structures in the way the orientated. Big collapse coming up.

1328: Over lobate lava with collapse pits with broken up sheets at the bottom. Just over a big collapse. Just on the edge of a big collapse. Over the bottom of the collapse which has folds on it.

1331 - At way point 4 and collecting sample number 14.

1338: Traveling to way point 5 over folded sheet flow with collapses. Quite sizable collapses here. Can see some geothermal coloring on cracks in the sheet flow. No sign of active geothermal. More collapses now elongated and possibly more like lava channels. Yes, I have a definite feeling we are over lava channels.

1340: Going over sheet flows with very elongated folds - fine scale elongated folds and then flat in between. Small elongated collapses. Collapses parallel to the elongation of the folds.

1341: Folded sheets very pronounced folding regular folding . We travel at an angle to the direction of the folding.

1342: Still on folded sheet: folded on the fine scale few cm and very elongated. There are collapses but not as pronounced as before. Folded sheet flows.

1344: Changed to lobate flows. There are collapses here in the lobate flows. Now it is pure lobate flows with fairly large wavelength.

1346: Still over lobate flow: large wavelength with collapses. Collapses have various diameters from meters to tens of meters. Some are quite deep. Going over a collapse about 20 m deep with pillars

1349: Large wavelength lobate flow. The sediment cover seems to be less (than where it was at maximum). A collapse with a cave extending away from it.

1351: Lobate flow with collapses.

1355: Reached waypoint 5 and settling down on a large wavelength lobate flow and attempting to sample.

1405: Just finished sampling number 15.

1409: Going to head due east from point five. Going over big collapses. Going over a sizable collapse with some pillars in it: very conspicuous pillars. You can see sheets in the collapse walls and the bathtub marks on the pillars.

1411: Continuing over large wavelength lobate flows. Large lobates with fairly heavy sediment cover. Still lobate but collapses have not been seen for a while. Seem to be back into 80% sediment cover. Still travelling over lobate flows. We are now flying higher so visibility is decreasing. Bottom still lobate flows with lot of sediment cover but no collapses here.

1414: Still lobate flow as far as I can see. Depth is increasing but still seems to be lobate flow.

1438: We drove 850 m due east from waypoint 5 and are now settling down on the bottom. Sitting on lobate flow with quit a lot of buds in between them: medium wavelength of the lobes and heavy sediment cover 80% on flat surfaces. All very similar to where we started at waypoint 1. Sample 16.

1506: We continuing due east to do 1000 meters from way point 5 to collect a final sample number 17.

1518: On our way to the surface. Last sample number 17 was collected 1000 m east of way point 5. The locality was again a fairly large wavelength lobate flow with at least 80% sediment on larger surfaces.