Feb. 15, 1999
Transcript of Bill Ryan (Starboard Observer)
[This is based on real-time audio recordings of port hole observations
and subsequent modifications that have been richly-supplemented
by a review of all of the videotape and the navigated track]
Transcript begins:
09:35 2638 270 Landed on the bottom on a smooth sheet flow.
The terrain around is heavily sedimented. Age 2.5 of Ken
Macdonald. The sub dorps over a west-facing cliff onto a terrace
containing a few large bulbous pillow lavas. All the interstitial
spaces between the pillows are filled with and are interconnected
by sediment.
09:37 2646 264 We begin to get underway towards Way Point 2 and
soon cross a surface of large tabular slabs broken from a very
smooth (sheet) flow. Some slabs are titled and jut up from the
surface having been ripped up and carried along in the flow.
09:38 2647 265 This is indeed a very smooth sheet flow whose surface
ta\exture is obscured to a significant degree by the thick and
pervasice sediment cover.
09:39 2647 265 The surface has been smoothered by the sediment
since it was broken up into slabs. Looks like a sidewalk pavement
under and inch or two of fresh snow. No bare slabs or loose talus
is visible right now.
09:40 2646 268 Arriving at Rock Sample Station # 1. Tabular
slabs seen from the starboard viewport, pillows from port viewport.
Sample taken from a pillow bud. The scene transitions into lobates
along vwith fewer and fewer pillows, all the morphology of the
same age and probably bthe same flow unit.
09:44 2646 247 Underway and crossing heavily-sedimented pillows
and lobate flows (Age 2.5). Then rising in water to get
a transponder fix. Pillows seen below in the SIT camera.
09:46 2646 256 Up in water at an altitude of 14 meters. Bottom
temporarily out of sight. A good cfix is obtained for our starting
point.
09:47 2646 261 SIT camera showing heavily sedimented pilllow lavas
on broad pillow mounds.
09:49 2655 295 Over a west-facing escarpment cut into the pillow
lavas
09:50 2653 265 Ribbed and striated pillows cut by a narrow fissure
and then becoming mixed with smooth lobate flows.
09:51 2665 266 Over another west-facing cliff onto more pillows
and lobates.
09:52 2649 264 Over this cliff onto angular talus ramping up against
its base.
09:53 2656 266 Can't see bottom except via the SIT camera. Powering
down.
09:55 2681 261 Bottom coming into view as a mixture ofpillow lava
and elongated pillows.
09:56 2682 263 Over another west-facing scarp about 5-7 m high,
talus at its base consisting of angular blocks and truncated and
broken round pillow heads and trunks.
09:57 2681 265 Up and over a small ~5-meter high east-facing cliff
onto a terrain of elongated pillow lavas. Less sediment than before.
Age 2.0. Elogated pillows have a l:d ration of 4 to 6.
and appear to flow northward.
09:58 2677 265 Dominately pillows with minor lobate flows. Two
small fault-generated steps down to the west in succession.
09:59 2678 266 Crossing a narrow (1-m wide) fissure cutting through
pillows at the base of the second step down.
10:00 2689 263 A thin (0.5-m wide) fissure cutting the pillows.
More lobates now and fewer pillows.
10:01 2690 266 Passing onto smooth lobates cracked open on their
top surface to expose white \hydrothemal staining on the broken
facets. The roof rock of these lobates is thick (estimated 15
cm). Populated by anenomes Age 2.0.
10:02 2690 265 These lobates appear to have less sediment cover
than the pillows just passed. Age <2.0. Some folded
and wrinkled sheet flow among the lobates. Crossing a small west-facing
cliff.
10:03 2691 290 Stopping for Rock Sample # 2 from the rim
of a 1-m wide fissure striking parallel to the roughly N-S valley
trend. Very little sediment in this fissure. The talus present
is extremely fresh. While sampling I can observe bedded lavas
of 20cm to 2 m thickness in the wall of this fissure. They appear
to be truncated lobates and pillows.
10:16 2690 017 Finishing the sampling, turning CCW over sedimented
lobate flows.
10:18 2689 266 Crossing these lobate flow occasionally interspersed
with bulbous pillows\; some of the pillow heads have open skylights.
10:19 2690 263 More lobates and then signs of talus. We are approching
a wall. Then ascending this wall only to drop over a deep 2m wide
fissure cut into the lobates and revealing bedded lavas in its
wall.
10:20 2687 265 Another thin fissure and more talus, leading onto
a 20-meter high, steep, east-facing escarpment bounding the west
edge of the central valley floor.
10:21 2686 266 Talus contains many tabular slabs thought to be
fragments of lobate roof rock as well as blocky pieces and round
trunks of pillows display radial fractures. Talus is very fresh
without any traces of sediment.
10:22 2686 266 Climbing this talus ramp with some signs of low
remperature hydrothermal biology. Up three small scarps easch
separated from the next by very narrow benches. Massive flows
and thin bedded lavas observed in the direct bedrock outcrop in
the wall. Climbing up its steep face for an altutude of 11 meters.
10:23 2679 265 Reaching lobate flows at the top rim. Age 2.0.
Then over a thin spur and down 5 meters to another bench. This
latter bench is cut by N-S thin fissures running through lobates
of Age 2.5.
10:24 2668 264 Descending a narrow ramp of talus.
10:25 2671 265 Very smooth and heaviliy sediments lavas whose
surface texture is hidden by the sediment cover. Some lobate flows
have shattered but as yet uncollapsed roofs.
10:26 2676 257 Some minor collapse pits in these lobates and shattered
roof rock. Age 2.5.
10:27 2673 258 Lobates, small collapses and pillars. Massive rock
with columnalr jointing in the wall of a track-normal fissure.
10:28 2671 259 Collapsed lobate lavas with a heavy coating of
brown to orange hydrothermal sediment among old and extinct chimneys
and degraded edifices. Some chimneys have half a dozen separate
spires. Umber color to the sediment. Lava surfaces no longer visible.
We are down in a lartge collapse depression. Bottom looks lumpy.
Age 2.5 and locally 3.0 in the areas of thick sediment
of hydrothermal origin.
10:30 2667 256 All the volcanic relief is presumambly buried under
the thick blanket of hthe ydrothermal sedimentary materials and
precipitates.
10:31 2666 257 Extinct sulfide mounds, and an enormous sulfide
chimney.
10:32 2667 261 Tabular and smooth lavas cut by a narrow but deep
fissure.
10:33 2663 260 Heaviliy sedimented smooth sheet flows and very
smooth lobate flows beneath the significant sediment cover.
1034 2662 259 Talus leading to a 12 m high wall directly in front
of and fracing us.Talus is sloping away to the starboard side.
Loose tabular fragment of presummable lobate roof-rock.
10:35 2659 260 Climbing the wall. Cross a narrow N-S fissure and
back onto smooth flows cut by more fissures.
10:36 2650 261 More talus and shattered rock, broken pillow heads
and trunks and thin tabular slabs. Up a big wall in front of us
revealing in its face not only massive and bedded pillow lavas,
but truncated thin sheet flows, and lense-scaped lobated flows
all truncated and exposed by faulting. The lobates are commonly
empty.
10:37 2647 258 Reach top of this wall, populated by lobates. The
altimeter in the stern of Alvin registers 14 meters. Lobates are
smooth and heaviliy sedimented. Age 3.0. Cross small fissure
1 m wide.
10:38 2634 260 Another valley-parallel and 2-m wide fissure cutting
the lobate surface. Talus on its floor. Thin layers of bedded
sheet flow exposed in the fissure wall. Lobates are the stratigraphically
highest rock on the wall. Another fissure and then over a cliff.
10:39 2632 260 SIT camera shows talus at the base of a giant collapse
depression, eight meters below us. The floor of this depression
is populated with tall and perfectly vertical pillars standing
among lumpy sulfide mounds. Large extinct sulfide chimneys.
10:41 2640 260 Passingby a 9-m tall and dead chimney on the floor
of this collapse depression. The lobate flows around it are very
heavily sedimented.
10:42 2640 250 Crossing a 1-m wide fissure on floor of this deepression.
Sediment cover is impressively continuous and thick. Age 3.0.
Stepping over a west-facing escarpment dropping down 8 m onto
faulted pillow lavas with large (>1m) diameter bulobous heads
and heaviliy sedimented.
10:44 2647 260 Pillow terrain on floor of the giant depression,
densely fractured. Wall directly in front of us whose presence
is manifested by a ramp of angular and blocky talus with hydrothermal
staining on broken facets. Talus here is extremely fresh, no sediment
dusting at all.
10:45 2647 259 Preparing to motor up the east-favcing wall. As
we do so, massive rock faces come into view as the bedrock outcrop
appears interbedded with thiner (20-40 cm thick) strata that look
like truncated pillows and lobates. Reaching the top of a 15-meter
ascent, we find the rim to be heavily sedimented lobates of Age
3.0.
10:46 2629 260 Cross a N-S running fissure in a generally flat
terrain of lobate flows, with huge pockets of sediment between
the individul lobate tongues.
10:47 2629 261 The smooth flat and practically featureless terrain
is cut by thin (< 0.5 m wide) fissures running though an almost
100% sediment cover. The occasional rock exposure is lobate flow
and very sparce pillows.
10:48 2629 257 Pass what looks like an Alvin drop weight dusted
with sediment lying on lobate flows and elongated pillows. All
depressions between the pillows are filled and linked together.
Age 3.0.
10:50 2629 242 Arrive at Way Point 2 and begin turn CCW to Way
Point 3. Very smooth lobate flows transitioning to sheet flows
whose surface texture can not be recognized because of the thick
sediment cover.
10:52 2629 182 Still turning to come steady on a SE track and
moving slowly over smooth low-relief lobates and sheets with small
collapse features such as skylights.
10:55 2629 113 Turn completed and now dropping off a 14-meter
high east (valley) facing cliff. SIT camera shows angular talus
at the base of the cliff spilling onto a fissured pillow lava
terrain.
10:57 2647 112 When arriving on the floor beyond the base of the
cliff, the fissured pillows have now transitioned into fissured
lobate flows and they make a smooth and nearly flat substrate.
The sediment cover here is less than at the top of the cliff just
descended. Age 2.5.
10:58 2643 122 Beginning to hunt for Rock Sample 3. Finding
a suitable sample becomes difficult and time consuming.
11:09 2642 328 Turning slowly CW to a fissure in the lobate to
find a way to pry off the surficial flow. Lobates transition to
folded sheet flows and back to lobates.
11:14 2642 277 Sample taken.
11:17 2643 186 Turning back towards Way Point 3 and underway.
11:18 2641 111 Crossing a N-S oriented fissure cutting though
these lobate flows.
11:19 2640 110 Traversing another fissure. Some lobate surfaces
display small collapse features with 1-m wide skylights through
the roof rock which reveal them to be >1 m thick and now mostly
empty conduits.
11:20 2640 112 Another narrow (0.5 m wide) valley-parallel fissure.
and over an east-facing cliff. SIT camera slows talus at the base
of a 10-meter high vertical face. Talus is angular blocks and
tabular slabs.
11:21 2651 111 Bottom comes into sight through the porthole. Heavily
sedimented and thinly-fissured lobates with small collapse pits
and fractured and sagging roof rock.
11:22 2654 108 A narrow ~N-S fissure followed soon by a second
fissure, both oriented in the same direction.
11:23 2656 114 Very smmoth lava surface that is probably sheet
flow.
11:24 2659 114 Passing over and thne motoring down a 5-m high
east-facing cliff oriented parallel to the trend of the valley
(graben). Rubble at its base.
11:25 2664 114 Settling down on shattered lobates with small (<2m
dia) roof collapses and cut by narrow (0.5 m wide) fissures. Talus
has poured into this fissure from the cliff just passed.
11:26 2661 113 Floor below us is now mostly lobates as we njow
fly over and motor down another 8-m high east-facing cliff to
arrive in a narrow N-S depression.
11:27 2675 112 Its floor of broken but very smooth sheet flow
is densely fissured. Truncated thin sheet flows are exposed in
the vertical face of the fissure walls. More than 6 thin fissures
are crossed in rapid succession ,all cut deeply into these flat
sheet flows.
11:28 2676 113 Reach a talus ramp at the bounding west-facing
and 6-meter high wall of the narrow N-S depression. The talus
is mostly thin tabular material, presumably shed from outcropping
sheet flows in the escarpment that now looms dead ahead of the
sub. The talus is quite fresh with only a thin but uniform dusting
of sediment.
11:29 2677 113 More talus now containing some pillow fragments
displaying the typical radial fracture patterns on the cut faces.
11:30 275 113 Arriving at the west-facing wall. Sulfide chimneys
populate the talus ramp at its base. Start to climb the cliff.
End of video Tape 1.
11:31 2668 112 Over this rampart and down onto the floor of the
axial depression. Lots of talus now heavily coated with brown
to ocher-colored hydrothermal sediment.
11:32 2676 115 Extensive sulfide mounds, all extinct, some broken
and degraded. Shattered ores are yellow-stained. Cross a thin
fissure near the base of an east-facing valley-floor bounding
wall. Talus is found in a fissure, presumably shed from wall since
it contains broken pillow fragments.
11:33 2573 114 Crossing the contact from the base of talus ramp
onto the external terrain of large bulbous pillows and elongated
pillows. This is the youngest lava (non-taus) terrain we have
seen. Age 1.5.
11:34 2681 114 Pillows everywhere. Some are superficially cracked
and reveal yellow hydrothermal staining on the crack walls. Minor
sediment betweem the pillows.
11:35 2680 111 Slowing to search for a location to sample these
pillows.
11:36 2679 109 Stop in a patch of elongated pillows with buds.
Much less sediment here on these axial floor pillows than anythingwe
have seen before. A constructional terrain with very little tectonic
disruption. Rock Sample 4.
11:41 2676 113 Underway across this constructional pillow lava
substrate.
11:42 2676 116 No interstitial sediment in pockets between the
pillow heads and tubes. Pillows are ribbed and striated. Surface
texture clearly visible with only a thin dusting of sediment.
11:43 2676 116 Briefly stop to look closely at these pillow-skin
textures and then back underway across the pillows at a slow speed.
Cross a large (2-m wide) fissure cutting N-S through the pillow
lava mound.
11:44 2676 116 Large (>1m dia) pillow heads not strongly tectonized
by valley-parallel-cutting fissures. Some fissures display small
(1-m amplitude) throws.
11:45 2675 115 Pillows become elongated and appear to have flowed
down a slight incline to the east. Good pictures of the elongated
fabrics on the SIT camera. Age 1.5.
11:46 2679 116 Pillows end in lobates that are slighltly more
heavily sedimented (Age 2.5). Sulfide stain is observed
on this sediment. Many small fissures cutting through the lobates.
Looked like the pillow mound just cross has buried some of these
fissures and thus represents a distinctly younger stage in the
evolutrion of the valley (graben).
11:48 2678 115 Smooth lobate flows extending eastward to be onlapped
by a talus ramp coming from the east-bounding wall. Anemomes,
fish and crabs of a presumed low temperature hydrothermal diffuse
vent nearby. Talus is angular, blocky and rather fresh-looking.
11:49 2679 115 Starting to climb this poorly-sorted talus incline.
11:50 2670 116 Motoring up the 16 meter high wall abovev the talus
ramp and observing bedded lavas both thin and massive (with columnar-like
jointing) in the bedrock exposures. Lobate flows cap the rim of
this escarpment. Hydrothermal staining on some facets exposed
on the wall. A small valley-parallel fissure cuts the lobates
a meter or so in (eastward) from the valley rim. We then discover
that this rim is a down-dropped sliver and that behind it this
fissure opens upwards to be the continuation of the wall. Some
talus shed from the higher wall has scattering into this fissure
(an opening of the cliff-face by a valley-parallel joint).
11:52 2663 116 More bedrock comes into view in the wall. Again
its is both horizontal and somewhat rythmically bedded spaced
by massive layers several meters thick with clean flat partings.
Layered pillow truncations in the outcrop.
11:53 2665 117 Approaching now the real top of this west-facing
wall
11:54 2662 151 Lobates occur again right at the rim. Altimeter
displays 19 meters down to the inner valley floor as the sub crests
the rim. We stop at the top for Rock Sample 5 in these
bedded lobates which pass transitionally into folded sheet flows.
11:55 2662 150 Maneuving to pluck off a digit from the lobates.
11:56 2661 158 Sample taken. These flows are rather heavily dusted
with sediment Age 2.5.
11:58 2647 158 Underway crossing this terrain of lobate flows
and subsequently rising up a precipituous 14-meter high west-facing
cliff that makes the highest rampart of the inner valley wall.
11:59 2649 119 Heavily sedimented (age 2.5) lobates at
the top with some scattered pillow lavas.
12:00 2648 117 Pillows becoming more abundant, heavily sedimented,
pockets between adjacent pillows are fully interconnected.
12:01 2646 117 Cross a fissure perpendicular to the sub's track
(~N-S). Now there are vast pockets of sediment between the lava
bedforms.
12:02 2647 117 Becoming more and more pillowed at the expense
of the lobate flows.
12:03 2649 119 Another N-S fissure cutting through a predominately
pillow lava terrain. Bottom drops away into an 8-meter deep N-S
trough (tiny graben) bounded by steep scarps. Large fragments
of pillow lava (heads and trunks) scatter its floor along with
more tabular talus. Talus of all sizes from baseball to basket
ball to garbage can. The wall ahead as it is climbed reveals bedded
outcrop and is capped by heavily sedimented pillow lavas. None
are observed as flowing down the scarp.
12:04 2643 117 At top the pillows are mostly elongated into tubes
with a 4:1 to 6:1 aspect ratio (l:d) oriented to the east.
12:05 2643 119 Cross ~N-S ridges and troughs that look like small
horsts and grabens each with 2-4 m of relief and a few meters
across the tops and bottoms. This faulting cuts and offsets (vertically)
the elongated pillows and tubes. The terrain appears to have received
a little more sediment. Some lobates encountered have small skylight
windows and cracked roof rook. Looking in these portals shows
the lobate flow to be <1 m deep and mostly void. Last fault
encountered is an 8-meter step up onto what I presume to be the
high rim of the east wall of the valley.
12:06 2643 119 Shattered lobate roof rock, sometimes collapsed
into pits, mostly still intact as roof material but slightly sagged.
Approaching Age 3.0 up here on the rim.
12:07 2640 131 Large collapse pit, >5 meters in diameter. Fallen
roof rock of lobate flows scattered on its floor. The period of
collapse is old bhecause the debris on the floor is heavily sedimented.
12:08 2643 128 Cross sa mall fissure incised into a terrain 90%
covered by sediment. Then another fissure or alternately a mini
horst & graben structure with 3 to 4 meter amplitude of the
fault throws.
12:09 2644 134 Another wide fissure. All the talus in this region
is very fresh-looking with only the slightest sediment dusting.
The fissure is disecting lobate flows.
12:10 2640 133 Very smooth and flat lava terrain whose texture
can not be discriminated due to the thick sediment cover. Cross
over an east-facing scarp 6-m high and down into either a wide
fissure or another mini grabem. The floorof the narrow depression
is scattered with talus that has less sediment cover than the
rim. Cross this talus and then up onto a bench.
12:11 2643 133 A complex terrain of spurs and troughs that might
be faulted crustal slivers or very wide and shallow fissures.
The host terrain is lobate lava. Talus is present only in the
immediate vicinity of the steep scarps.
12:12 2641 148 Shattered lobate flows and some collapse pits,
seen from a high altitude of 8 m as we fly over the up & down
landscape. Slowing to look for a suitable sample site for Rock
Sample 6. Pass onto folded sheets and snuggle up to the rim
of a very wide (>2m) and deep (>8m) fissure with verticle
sides.
12:13 2640 150 With SIT camera we look down on the talus below
us that has fallen into this fissure and from the port hole out
onto the bedded bedrock exposed in its wall. The talus contains
both angular blocks and round fragments of presumed pillow heads
or truncks shed from the wall.
12:17 2645 155 The sample is obtained from the exposure right
at the rim at the far side (east) of the fissure. The more we
look, the more it appears that it might be an exposed lava tube
opening to the west.
12:20 2645 156 Underway and turning CW to the south west to Way
Point 4. Crossing another large fissure or more likely, a collapsed
tube and several other collapse pits in a host of lobate lava.
12:24 2640 237 Over a 6-m drop off and into one of these pits
whose floor is littered with talus.
12:25 2638 238 The terrain outside the depressions becomes predominately
pillow lava, still Age 3.0. Pillows are also in the floor
of the depressions and lobates around the rims.
12:27 2642 235 Another large collapse depression in the lobates
with quite fresh roof-rock and talus on its floor. (The colllapse
seems to have been much more recent than when the lavas erupted).
12:28 2641 237 Without dropping into these depressions, we continue
to the SW and cross shattered lobate lava whose surface texture
is obscured by the thick (1cm) sediment cover. All the subtle
relief is hidden. In the scene 90% of the region is sedimented,
10% is rock exposure.
12:29 2638 237 Cross over a large west-facing escarpment 15-meters
in relief. The SIT camera shows a talus ramp at its base. Altimeter
reaches 19 m as we park at the top with the stern of Alvin hanging
out over the cliff. The rim is lobate flows.
12:32 2655 238 The down-dropped block (in a relative sense) comes
into view and is also lobate lava upon which the fresh (sediment
free) talus is scattered. This is the base of the outer East Wall
of the valley. The lobates are sedimented with an estimated Age
of 2.5. It is clearly a younger terrain than that of the rim
area and theEast wall summit area, but not by much. The lobates
display small skylights that show its roof rock to very very thin
(<5cm).
12:33 2657 237 A collapse pit in the lobates scattered with sediment-free,
shattered and tabular roof-rock and fresh blocky talus.
12:34 2656 236 Bedded lavas are seen in the walls of the depression
that appears to be about 5-m deep. Large pillow heads and trucks
have broken off the walls and are scattered on the floor among
the roof-rock.
12:35 2650 237 Continuing over the uncollapsed lobate terrain
.
12:36 2652 237 Crossing a fissure about 2-m wide and nearly filled
with fresh talus.
12:37 2652 238 Back onto intact and heavily sedimented lobate
flows, then skirting some small collapses occupied the same fresh
talus as before. These collapses or fissures also contain bedrock
outcrop in their walls. Then climbing a small N-S trending and
east-facing fault scarp whose base is lined by talus. Bedrock
outcrop in its wall and sheet flows and lobates on its rim.
12:38 2652 237 More mini horst and graben looking terrain of verticle
but low relief (<4 m) ridges and troughs cut into the predominately
lobated lava terrain.
12:39 2648 237 The up & down trip continues as if it is a
series of successive wide fissures each accompanied by modest
vertical displacement, again all incised into and offsetting a
lobated lava surface of Age 2.0.
12:40 2648 239 Over a very large west-facing cliff bounding the
inner rift valley that initially drops 10 meters onto a narrow
bench of the same shattered lobate flows.
12:42 2661 238 Blocky talus on this bench.
12:43 2664 237 Motoring down the cliff that is directly behind
us. Altimeter is 9 m, but as we go over the next step of the cliff,
the bottom falls away by 30 meters down an almost vertical escarpment.
12:44 2684 236 Still motoring down, altitude is 16 m.
12:45 2696 237 Botttom coming into view as we prepare to land
in the inner rift. Pillows and tubes seen in the SIT camera strewn
with blocky talus. Sediment cover much reduced from that existing
on the top of the escatpment.
12:46 2694 238 Rising onto a small mound in the center of the
inner valley floor composed of much younger pillow lavas. Age
1.5.
12:47 2691 300 Turning CW and looking for a place to sample this
pillow terrain. The pillows and minor lobates here are colonoized
by anenomes. Rock Sample 7.
13:01 2692 334 After much struggle, a sample is successfully obtained
and secure in the basket. Back underway to Way Point 4.
13:02 2706 286 Descending off the pillow mound in the center of
the inner valley onto a surface of lobate lavas cut by very deep
fissures and with small collapse pits and dusted with more sediment
that the pillows behind us. Age 2.0.
13:03 2692 260 Lobate lava fairly heaviliy sedimented here in
the "moat" along the base of the west wall of the inner
rift valley.
13:04 2692 242 Lobates flowing westward into this moat and cross-cut
by thin fissures and cracks displaying white and yellow hydrothermal
staining.
13:05 2693 241 The lobate surface here is quite smooth with tongues
clearly elongated and headed westward as the floor deepens in
the direction of travel.
13:06 2694 241 Lobates transitioning into elogated pillows as
the "moat" right at the foot of vthe bounding wall is
approached. Sudden apprearance of talus from the steep eastward-facing
wall straight ahead. The talus is extremely fresh, with no sediment
dusting at all. Hydrothermal staining in local regions of the
talus.
13:07 2698 243 More talus and rocky talus accompanied by chutes
of glassy gravel and sand (presumsably derived from the glassy
rinds of thelavas exposed in the wall ahead). Chutes in the talus
ramp that we are just climbing with concentrations of very black
gravel and sand.
13:08 2694 241 Beginning to motor up this cliff. Above the talus
ramp of 4-meters height is a massive bedrock outcrop on a vertical
face. Reach a narrow bench some 7 m above the foot bof this wall.
The bench is strewn with talus. Now climbing another vertical
face directly above this bench.
13:09 2682 241 Altimeter registers 11 meters as the cliff faces
reeveals masasive outcrop on sheer joint surfaces. No forward
progess.
13:10 2682 276 Altimeter is now 18 meters as we still motor up
this escarpment to another narrow bench cut by a fissure. This
is a sliver of the rock face that has not yet detached along valley-parallel
joint planes. Talus in this fissure has been shed from the 15
meters of cliff face still above us.
13:11 2667 328 Reach the top and arrive on a lobate surface immediately
cut by cliff-face parallel and narrow fisures. (Are these futher
slices of the crust pealing away from the cliff on joint planes?)
The lobate surface immediately out of the inner valley is regionally
flat yet is populated with large local collapse pits and depressions
with 2 to 4 meters of relief from rim to floor. Can see a small
and extinct hydrothermal chimney in the very first pit as I stare
through its skylight opening.
13:12 2668 293 Momentarly stop to look into a collapsed lobate
and see very thinnly layered rock (2-cm bedding thickness) which
looks much more like successive sheet flows that have moved through
a subsurface tube rather than bathtub rings. The lobate rim that
wraps these strata is about 10 cm thick and in cross-sectioon
looks like spary calcite. Its circumference is folded in spots
and not at all circular.
13:13 2669 265 An excellent look into another collapse opening
in the lobate surface.It is littered with former tabular roof
rock that is now extensively shattered and scattered.
13:14 2668 255 Stopped at a pillar to sample the lobate surface
that makes up its top. Rock sample 8.
13:16 2669 260 Back underway over another collapse pit in the
lobate terrain. Relief just 2 to 3 meters maximum.
13:17 2666 225 Another pillar in this depression with "bathtub"
rings surrounded by rubble that looks like extensively shattered
former, and thin roof rock. The scattered rocks in the depressions
have less sediment dusting than the lobate sufaces which hosts
the pits.
13:18 2666 211 More views of the talus in these depressions and
clues to how it has been shattered into small fist-sized fragments
and not large tabular slabs.
13:19 2668 213 Down in a collapsed depression with lots of former
roof rock and small pillars.
13:20 2669 211 The shattered rock all around suggests that the
roof had once been extremely fragile (possibly very thin or extensively
fractured before collapse).
13:21 2668 210 Another collapse hole in the lobate surface and
more shattered roof rocks as debris on its floor.
13:22 2669 210 Crossing an extemsive areas of shattered roof rock
among the pillars. Impressed by its small size (more like cobbles
than boulders). Hydrothermal staining on the debris and some hints
of vent fauna (fish and anenomes).
13:23 2668 209 Flying 5 to 6 meters above these shattered lobates
as the port-side observer describes a large pillar with bathtub
rings. Then up on to the non-collapsed lobate lavas that are extensively
cracked but still form a more or less intact surface. The cracks
form polygon shaped patterns simiar in desugn to the plates on
the back of a turtle.
13:24 2667 211 More collapsed regions, more rock scattered on
their floors, and an extinct hydrothermal mound with discolored
sediment around its base (orange, yellow and white). Then back
up onto the lobate surface and down into another pit (all with
the eyeballs as the sub stays high and flies more or less at a
constant depth).
13:25 2667 208 Shattered roof rock as we reach Way Point 4 and
turn CCW to Way Point 5 located to the southeast.
13:26 2668 146 Moving now in rapid succession from one pit to
another with only small regions of intact roof. The relief of
the pits continues to be only a couple of meters. Some of the
pieces of roof rock scattered on the floor are 10 cm in thickness,
others are <5cm. Slab after slab is observed in this quire
wild scene of "destruction".
13:27 2668 147 The scattered roof rock continues across a depression
floor as I look into cavities in its wall. It is as if a large
percentage of this subsurface landscape had been hollow and only
supported by pillars and narrow buttresses with vast amounts of
the locality subsequently collapsed. The young (sediment free)
nature of the debris on the floor in contrast to the sedimented
intact lobate suggests that the devestation took place long after
the initial lava eruption that produced the lobates surface and
its honeycombed interior.
13:28 2669 144 Animals of a nearby hydrothermal low temperature
vent area and sulfide sediment among degraded extinct sulfide
chimneys in one of these collapse depressions. The overlay of
sediment on the collapsed roof rock suggests that the hydrothermal
activity postdates the collapse.
13:29 2666 144 A greater concentration of anenomes, crabs and
suspended mater in the water.
13:30 2666 144 Crossing now a huge (15 meter-deep) collapse depression
as its talus-littered bottom falls away out of sight.
13:31 2673 177 Crabs, polycheat worms, fish, and heavy concentrations
of hydrothermal sediment all around us while we motor down to
the bottom.
13:32 2681 257 Altitude is 11 meters nd we abort the attempt to
drive to the floor of this deep chasm, but instead fly over it.
Its walls lined with talus are almost white from the attached
tiny polycheats. We can see diffuse flow coming out of the rubble.
Crabs everywhere by the hundreds amassing around extinct chimneys
and all across the debris surface.
13:35 2668 152 After a lot of maneuvering high off the bottom
to get to its margin, we see more vent fauna in patchy concentrations.
13:36 2673 154 We realize that we are on an east dipping steep
slope leading to the inner valey floor. The SIT camera shows this
to be scattered talus and rubble. Some patches of folded sheet
flows and more talus as if the flows in the past had poured down
this pre-existing slope.
13:38 2688 145 Still descending this slope across the talus surface
.
13:39 2697 148 Rapidly descending the slope leading into the inner
valley floor and now observing that in places through the talus
there are now elongated pillows that flowed down hill to the east.They
transition with lobates that have long east-directed tongues and
are intact and untectonized. Age 2.0.
13:40 2697 148 Having arrived on the inner valley floor of smooth
lobates with lots of fresh digits we decide to stop to take Rock
sample 9.This fresher-looking smooth lobate flow in the axis
of the graben has an age of 1.5. It takes much maneuvering
and time to find a protrusion to sample with the manipulator arm.
13:43 2694 186 Much turning at a creeping spped over the lobates
and transitional elongated pillows.
13:46 2695 163 Low relief tongues on the lobates as we still hunt
for a sample that can be plucked off the lava surface. Then we
clearly see the fresher lobates that have flowed around older
higher standing pillows which have a distinctly thicker dusting
of sediment caught in their ribs and striations.
13:48 2695 170 Stopped.
13:50 2694 108 Moved again very slowly over to a narrow fissure
and see signs that the lobate lavas had poured into this opening.
13:55 2693 183 Finally sample a bud from the lobate surface.
13:57 2693 184 Underway and turning CCW back to a southeast heading
to Way Poiint 5. Cross a narrow N-S fissure as the lobates transition
back into pillow lavas of a comparable age. The pillows are elongate
as the valley floor slighly deepens eastward from a very low relief
central mound just sampled. .
13:58 2694 153 The lobates and elongated pillows are cut by a
N-S valley-parallel thin fissure. For the most part this is a
tectonically undisrupted terrain.
13:59 2693 151 Lobates become quite smooth with long tongues.
14:00 2692 151 Another narrow but very deep clean fissure as the
lobates transition to folded sheet flow of Age 2.0.
14:01 2690 151 Encountering the west-facing wall of the inner
valley on the valley's east side. It rises in a moderately steep
but not precipitous slope. Talus at the base.
14:03 2686 150 Climbing over pieces of broken pillow lava and
the shattered skin of lobate flows.
14:04 2684 148 Continuing to climb this ramp and across a fissure.
14:05 2681 150 The talus passes upslope into elongated west-directed
pillow lavas and tubes that are split apart with white hydrothermal
staining in the cracks. A valley-parallel fissure cuts these pillows.
The latter have clearly flowed down hill towards the valley floor.
14:06 2680 146 Cross another N-S fissure 2-m wide and very deep.
Bedrock is observed to outcrop on its vertical wall. Can not see
to the bottom of this clean cleft. Then followed by another fissure
of the same valley-parallel tectonic trend.
14:07 2680 150 The sub is now high above the bottom as the east-ascending
ramp is being scaled. Its leads directly on to a near-vertical
cliff.
14:08 2681 148 Cross another deep and wide fissure on the way
vto the cliff and encounter the bedrock outcrop in the shear west-facing
wall. Motor 10 meters up this cliff to its top.
14:09 2670 150 Stop at the rim to sample slabs of sheet flow in
place as the topmost strata. Rock Sample 10.
14:19 2670 347 In basket as the sub gets underway. Cross a fissure
in lobate terrain still of age 2.0. Moving very slowly.
Bedrock outcrop in the wall of this fissure.
14:22 2671 005 As the sub spins CW it crosses slowly over a gaint
valley-parallel fissure. The bottom drops away 15 meters in this
black hole. The walls are vertical as we both peer down with the
aid of the SIT camera to talus in its floor. The walls are masaive
bedrock cleaning cut by a joint surface. As we cross this cleft
and are now heading SE, the east rim is again lobate flows.
14:25 2681 121 Back on course to Way :Point 5 while re-crossing
this same cleft and then on to a lobate surface at the far rim.
The lobates momentarily transition into folded and smooth sheet
flows.
14:26 2670 121 Then back into smooth lobates which once again
are intermixed with sheet flow.
14:27 2669 121 Small open trap doors in the lobates showing them
to be mostly void. The surfaces are cracked and sometimes shattered.
14:28 2669 119 Onto a talus ramp and then quickly climbing the
rest of the east wall. One sees in the outcrop a superb view of
truncated pillows and bedded lavas. The talus here is very fresh
with no sediment dusting.
14:29 2657 122 As we rise 25 meters up this face to its crest
there is much bedrock exposed through patches of the fresh talus.
We encounter a spur that is a thin sliver that has detached everc
so slighly from the east wall along a valley parallel joint plane.
We head up and over this spurs and arrive on a heavily-sedimented
and mixed lobate and sheet lava terrain. Age 2.5.
14:30 2646 118 The SIT camera shows talus 7 meters below us as
we look down into a depression scattered with talus.
14:33 2656 082 The terrain below is now pillow and lobates of
Age 3.0 as we move on eastward away from the belt of talus.
14:34 2656 081 The lobates are cracked and greatly obscured under
a think layer of sediment. We stop to sample from the rim of a
valley-parallel fissure. Rock Sample 11.
14:37 2654 356 As the pilot announces that we are "almost
out of juice" we encounter severely degraded knobs of former
hydrothermal chimnies surrounded by thick hydtrothermal sediments.
Not wanting to sample altered rock, the sub maneuvers away from
tgis area back onto the lobate surface with occasional pillows.
14:40 2655 171 Heading very slowly south we cross pillows and
lobates intermixed with each other and decide to hunt for a digit
on a pillow. This terrain is age 2.5.
14:46 2655 138 Sample is in the basket.
14:48 2655 135 Weights away as we begin our trip back the surface.
Thank you Bob Waters for the hard work in so successfully sampling
these deleciate rocks.