ALVIN Dive #4597
Dive Transcript
Deborah Eason
Pilot: Dave Walter
Divers: Karl Gronvold (P) / Deborah Eason (S)
Time
15:31
Depth
2776 m
Heading
196.5
15:37
2781
15.7
15:44
2804
15.7
15:48
2804
330.0
15:58
2804
318.9
16:01
2804
318.8
16:03
2803
250.6
16:05
16:17
2802
2779
251.3
264.4
16:20
16:21
2779
2778
287.5
314.9
16:24
2778
8.8
16:28
2773
334.5
16:32
2773
341.5
Comment
Landing position. First visual of the seafloor. We’re
on a slope, all pillows with small amount of sediment.
Proceed to WP1.
Driving above bottom so not much in visual.
WP1: lobate/sheet flows with fairly significant
sediment cover. Large pockets of thick sediment, with
moderate-to-heavy dusting over rounded surfaces.
Heavily sedimented.
Try sampling chunks of lobate flows, but difficult with
all the sediment. Crumbled with the hand, so Dave
tries the scoop, but it kicks up a cloud of sediment…
After first attempt, can’t see to sample. We give up
and move on to another location.
Sample 1: small chunk of lobate flow at WP1. Basket
loc: 3a.
Proceed to WP2.
Quickly transition into pillows as we climb to higher
elevation approaching WP2. Lighter sediment here,
but still a moderate dusting on lobes. Large pillow
lobes up to ~1 m across.
Pillows are smaller here.
Sample 2: long pillow toe from WP2. Basket loc: 2b.
Proceed to WP3.
Progress into smaller pillows as we approach WP3 (~
2ft in diameter or less). Elongate pillows on the
slopes.
We’ve crossed the saddle between these two mounds;
looks very similar to WP2.
More sediment here. Crossing the boundary between
the mound with WP2 and the one to the E with WP3.
Approaching WP3, pillows get slightly bigger again,
more continuous, more elongate; transitioning into
lobate morphology. Fewer little buds. Harder to
sample. Looks a lot like WP2, with some slightly
more lobate flows. No distinguishable difference in
sediment cover.
16:44
2763
55.8
16:50
2763
19.3
16:56
2763
351.2
16:59
17:01
2762
2762
38.9
(all over)
17:14
2788
82.6
17:16
2789
99.9
17:21
2789
100.8
17:26
2784
100.0
17:29
2781
100.1
17:31
2780
113.2
17:56
2754
56.3
17:58
2753
69.1
18:01
2753
75.0
18:03
2750
78.7
18:07
2749
123.3
18:08
2749
79.0
First sample attempt at this site, breaks off entire lobe
that’s far too big to carry with us. Mess with it for a
while and then abort.
Second sample attempt results in small chunk, drops.
Third time’s a charm.
Sample 3: pillow chunk from along slope, ~3m from
WP3. Lose some of surface during sampling (rind
crumbles off), but it appears we still have some glassy
rind remaining. Basket loc: 2a.
Proceed to WP4.
Confusion... terrain is not matching Dave’s underlay
map.
Underlay map does not match our map. Map for dive
4595 is loaded.
Wrong underlay loaded in the NAV screen. We’re
able to correct it once we realize what’s wrong. We
stop momentarily while Dave loads the correct map
into the NAV screen.
Underway again with correct underlay map loaded.
Just crossed the saddle between WP3 and 4. Seem to
have slightly more sediment cover here. Could be a
contact, but the distinction is fairly week.
As we move into steeper slopes, there continues to be
thicker sediment cover despite change in topology.
Get the feeling that there was, indeed, a contact
between WP3 and 4.
Fairly certain now that there is a contact between the
hill with WP3 and the one to the E (with WP4). The
hill NW of WP4 (that we pass en route) clearly has a
thicker sediment layer than the “beans” to the west.
Sample en route to WP4. Sample 4: elongate pillow
toe/tube from S slope of hill. Basket loc: 3b.
Proceed towards WP5. Driving up into saddle,
flattens out quite a bit.
Crossed saddle; slope switches to starboard side.
Pillows change to more ornamented pillows, now
flowing down from the S. Abundant pillow buds,
perhaps lighter sediment cover.
The pillows on this new slope look glassier than the
other previous mounds.
Sample 5: glassy-looking pillow from N slope of hill
to our S. Pillows coming down from the S. Appears
to be glassier than Sample 4. Basket loc: 1a.
Continue towards WP5.
18:15
2748
81.6
18:22
2707
81.1
18:24
2704
109.6
18:28
2694
110.3
18:35
2683
118.6
18:43
2683
96.0
18:45
2683
102.7
18:55
2677
233.5
18:56
18:56
2677
2677
155.3
232.6
19:00
2673
165.2
19:10
2683
123.0
19:11
2683
139.2
19:18
2678
129.0
19:22
2676
168.6
19:27
2676
116.4
19:31
19:38
2676
2676
94.4
312.8
19:39
2676
313.5
Sediment is definitely lighter here than on mounds to
the W.
Sediment thickness increases briefly again in the
saddle area (WP5) where the topography is flat.
Proceed past WP5. Continue to see very glassy
looking pillows! Continue on towards WP6.
Section of talus heading down slope. Steep here.
Less talus here; still steep. Small, often elongate
pillows running down slope. Looks constructional.
More talus... dominated by small chunks of broken
pillow. Very steep slope.
Continue to see abundant amounts of talus on slope.
Periodically some pillow outcrop visible. Quite steep.
Sample 6: pillow chunk from N slope of pillows,
sampled en route to WP6. Still in glassy pillows.
Consensus is they appear to be slightly lighter in
sediment cover. Basket loc: 6a.
Continuing on towards WP6.
Pillows along these slopes are very glassy with
abundant little pillow buds and other ornamentation.
Surfaces look fresher, younger than WP1-4.
Cut across saddle (WP6 location); We’re flying across
to conserve power (clear that we’re running low at this
point and won’t finish our dive track), so we lose
bottom for a while (until ~19:09).
Past WP6. More sediment again now. (Not as heavy
as WP1; more similar to WP2, 3).
Stop briefly to deal with oxygen meter (low battery
problem? Buzzing for no reason). Stopped until
19:15.
Small area of slightly lighter(?) sediment here.
Pillows are glassy, but not as glassy as the material
between WP5-6. Heading around SW side of
complex. Very steep slopes. Starting to see talus.
Slope nearly covered in talus. Broken pillows. Fairly
continuous until ~19:31. Very steep.
Slope still all talus, but not nearly as steep here.
Back into pillows. Slope looks constructional here.
Sample 7: pillow from S slope of large complex.
Steep slope of pillows/pillow talus. Basket loc: 4a.
Change out video tapes and lose 2nd video feed! Can’t
get a new tape inserted in the port side tape deck.
Taking video with starboard camera view only! (Until
19:47).
19:47
2675
54.9
Proceed towards WP8.
19:49
2678
140.0
19:54
2686
170.4
19:57
2691
153.1
20:01
2692
128.0
20:16
2704
81.9
20:23
2707
103.0
20:26
2706
158.5
Steep slope on port side. Mostly talus (until ~19:57).
Still abundant glass, disintegrated pillows.
Talus somewhat coarser here; still almost no pillows
that are actually in place… just coarse pillow
fragments.
Back into pillow lavas. elongate pillow lobes.
Material still very glassy.
Sheer cliff. Our view has dropped out from under us
(and cut back into the wall a bit). Possible fault? Karl
sees lots of broken pillows in the wall. Dave estimates
the drop is at least 40 m (not sure how much is above
us, but there’s ~40 m below). We lose visual for a
couple of minutes.
Off the steep slopes; back into pillows, still very
glassy, often still elongate (heading downhill). There
is perhaps slightly more sediment here, but likely just
related to the flattening slope.
Sample 8: elongate pillow from near WP8. Abundant
pillow buds here. We are somewhere in the saddle
area. We believe (though the nav on our screen
doesn’t quite agree) that we may have reached the W
wall of the small mound in between the large complex
and Pinguino. Basket loc: 4b.
Proceed towards WP9.
20:35
2724
84.2
20:36
2728
78.4
20:41
2733
2.0
20:42
2733
2.7
Pillows not as glassy here. Small, elongate and very
ornamental, but don’t look as fresh.
Sediment thickness is much heavier here. Large
coalesced pockets, moderate dusting on rounded
surfaces. We think not quite as heavy sediment cover
as WP1, but definitely thicker than at all other
locations. Material is no longer as fresh and glassy
looking.
Sample 9: pillow lava from SE corner of small mound
between large complex and Pinguino. Steep slopes.
Significantly heavier sediment here. Basket loc: 5a.
End of dive. Very low on power – can’t quite reach
the contact between this small mound and Pinguino.
We get permission to drop weights and surface.