Alvin Dive 4608
Port Observer: John Sinton
3 April, 2010
Dive 4608- Port Observer Transcript
Time
1444
1447
Depth
1457
1706
Hdg
1697
1459
1503
1701
359
1506
1698
358
1507
1702
352
1513
1515
1518
1704
1702
1700
304
319
1523
1683
319
1528
1674
1531
1678
005
1535
1676
357
1536
1673
358
1541
1659
1544
1667
353
1549
1675
353
1551
1554
1557
1674
1674
1674
100 m off bottom
Btm 13 m below us; lobate lava flowing left to right. Small
pockets of sediment and light dusting on surface.
Sample #1; slabby piece of lobate crust, striated on upper
surface. Looks pretty young
Moving off; some sediment on it; definite flow direction
from west. Transitional from lobate to pillows
Elongate pillows; slightly flat, some are collapsed, flowing
from west. Less lobate than landing site. No buds
Coming over drop off maybe 6-7 meters, possibly
constructional flow front.
Settling down to sample, lower lying, similar looking lobate
and similar sediment cover. Probably also from west.
Sample #2 of lower lying, slightly bulbous pillow lava.
Flow from west as we go upslope.
Going upslope, lava from west; dusted with sediment and
small pockets down between pillow lobes. Some collapsed
flow tops. Slightly flattened. Lava lobes up to ~1 meter
across.
Similar looking lavas, elongate pillows, slightly flattened,
no buds but lots of striations. Some sediment pockets,
dusting of sediment on tops.
Lava rise structure of similar lava and sediment coverage;
swinging around to go more northerly
Lava getting more flattened. Lobate lavas. Few shrimp.
Similar sediment cover. Smooth lava
Lava getting broad – lobate lava with flat tops which can
extend for 2-3 m; much higher aspect ratio. Locally more
bulbous lava on top of lobate
More bulbous pillows as slope steepens a bit. Pillows < 1 m
across, mostly; slightly elongate and slightly flattened.
Similar sediment cover.
Just crossing first big scarp, dropping down; bottom out of
sight > 12 m.
Bottom back in sight. After scarp there is a deep cleft, then
it steps back up again. Flattish lavas with similar sediment
cover – some small pockets with dusting on top.
Slope of coffee bean inflation feature (tumulus?), mostly
lobate near base but it then steepens and sheet lavas begins
to appear.
Settling to sample sheet lava
Sample #3; sheet lava on coffee bean.
Rising up slope of bean; surface all sheet lava here. Getting
Alvin Dive 4608
Port Observer: John Sinton
Time
Depth
Hdg
1600
1662
012
1601
1663
1603
1672
010
1611
1672
010
1612
1667
345
1617
1688
1619
1692
1607
1609
1622
1626
1629
1689
1630
1689
1633
1685
087
1635
1687
150
1639
1645
1688
1687
118
3 April, 2010
more jumbled upslope
Deep cleft in top of tumulus. Can see columnar lava down
below but surface is sheet lava.
~5 m above bottom; bottom of cleft has jumbled sheet lava
in it.
Zone of collapsed lobate lava with bathtub rings, lava pillars
~3 m high.
Sample #4 from lava lake area; sample of lobate lava from
around lava pillars. This lava pretty young? Mostly lobate
with lots of collapses.
Spectacular lava pillars, mostly1-3 m high. Some dusting of
sediment but might be younger. Complex of pillars and
collapses.
Past collapse zone back into lobate lavas with dusting of
sediment and some very small pockets of sediment. This
gives way to some somewhat more bulbous pillows.
Coming over downward step into inner graben. At least 4 m
step. Scarp in total almost 20 m down to north.
Settling down to sample. Lobate lavas with lots of collapse
and some bathtub rings. White spots look like shell
fragments.
Settling down; lots of shell fragments on lobate lavas; also
some sheet lava here.
Sample #5. Might be sheet lava; starting to move off.
Seeing lots of shell fragments and some single shelled
gastropods (?) like limpets. Dusting of sediment only.
Moving toward wp 4. mostly jumbled sheet lava with
dusting of sediment. Some cracks oriented ~090
Some lava pillars but mostly jumbled sheet lava. No longer
seeing shell fragments. Dusting of sediment without much
in the way of pockets.
Came through sheets and lobate, now coming onto pillow
lavas possible flowing from north.
Base of scarp in pillow lavas from north. Pillows fairly
broad, >1 m across; fairly heavily dusted with sediment,
probably older than sheets and lobates in axis. Pillows
locally quite bulbous and broad.
Looking for place to sample in broken up pillow mound.
Looks kinda old in terms of sediment dusting; some small
sediment pockets.
Sample #6. Pillow lava on north side of graben.
Back into lobate lava, locally collapsed. Less sediment.
Some more shell fragments. Possible flowing from east;
lots of collapse. Definitely younger than pillows just
sampled.
Alvin Dive 4608
Port Observer: John Sinton
Time
1648
Depth
1684
Hdg
117
1653
1678
076
1655
1670
046
1658
1671
088
1700
1671
079
1703
1669
097
1706
1669
1711
1669
088
1719
1722
1673
1725
1729
1667
1675
021
073
1737
1741
1744
1678
1671
150
195
1754
1674
1757
1663
050
1801
1814
1653
1655
127
1820
1826
1655
3 April, 2010
Sheets and lobates that give way to bulbous pillows. There
is a fault here and pillows are broken. Looks like pillows
overlie sheets but some dusting of sediment on pillows also.
Come up against a fault scarp of faulted pillows. Might be
dikes exposed in wall according to starboard observer.
Chewed up pillow lava; doesn’t’ look too young. Fair
amount of sediment on it.
Heading back toward north side of axis. Broken large
pillows. Chopped up area of broken pillows and talus.
Shattered pillows and lobate. Possibly flowing from east
but hard to tell.
Entering hydrothermal chimney field including some very
active black smoking chimneys.
Sitting in front of smoking chimney; seems to be several
extinct ones around. Not much life, mainly just crabs.
Chimnneys are 4-5 m high.
Measured temperature at 294 deg C. Some dead worm
tubes, probably tevnia ?? mainly skinny tubes about 40-60
cm long in a bundle near base of active chimney.
Still in vent field, several are active some not. Mainly sort
of skinny chimneys. Lava host is broken up pillow lava.
Moving off toward wp 6. Large pillow lavas flowing from
right to leftas we head NE; some hydrothermal sediment
around but as we move away from field, essentially no
sediment.
Crossing series of cracks. Then bottom out of sight.
Bulbous pillows flowing from in front of us. Steep slope of
faulted pillows.
Sample #7 of pillows from north side of axis.
Moving over very faulted up terrain.
Very bulbous pillows, light dusting of sediment but no real
pockets. Flow direction uncertain. A few shell fragmens.
Edge of seamount, saw a black smoker as we came up but
then turned, dropped down and lost it. Then back up
through broken pillows and a faulted face.
Back into hydrothermal field. Some extinct some active.
Not much biology but some worm casts and some crabs.
More vent in front of us. Active chimneys.
Sample #8. Almost unsedimented pillow mound, very light
dusting of mostly brownish sediment. Pillows range from
bulbous to elongate.
Moving east toward wp 8.
Turning north to get back on cracks. Pillow lavas, not much
sediment; dusting of brown sediment. Bulbous pillows.
Might be on south side of highest point of seamount? Flow
Alvin Dive 4608
Port Observer: John Sinton
Time
Depth
1829
1645
1833
1834
1839
1650
062
1844
1848
1647
1671
110
1849
1851
1671
1853
1671
101
1855
1674
103
1857
1675
103
1559
1901
1672
1665
103
1903
1906
3 April, 2010
Hdg
010
1666
1910
1913
1661
106
1917
1673
053
1922
1662
100
direction from north.
Crossed into fissure running east-west; water is very cloudy.
Turning to follow fissure to east.
Chimney field.
Really active black smoker
326 deg C. in vigorously smoking chimney. Trying to
sample it.
Sample #9; hydrothermal stuff flying all over the place.
Zone of collapsed lobate lavas and lava pillars, just outside
hydrothermal zone.
Uncollapsed lobate lavas. Very sparsely sedimented.
Hydrothermal chimneys, most (all?) look to be inactive,
quite brown, lots of brown sediment around. Formed on top
of lobate lavas.
More bulbous pillows. Moving along edge of field above
scarp. Not much sediment
Flat lobate lavas, some sediment in pockets, white sediment
now so maybe somewhat older than the lobate lavas farther
west.
Collapsed lava and maybe some almost sheet like lava.
Also seeing some bathtub rings in the collapses.
Area of collapsed lobates with excellent pillars.
Bit of step up, fault scarp so moved up one level. Lobate
lavas coming into view. Slightly elongate maybe flowing
from north?
Looking to sample; some small pockets of sediment. Flow
direction maybe from northeast?
Sample # 10. Lobate lava with small pockets mostly less
than 20-30 cm across of white sediment. Probably just
above a small step up fault.
Crossing out of lobate lava into some lineated sheet lava,
looks like a small lava channel here. Sheets appear to be on
top of pillows and lobate lava; probably some kind of lava
break out. Overall it is mostly slightly collapsed lobate with
a little bit of sheet lava and some more bulbous pillows.
Small thin pockets of white sediment with thin dusting of
sediment on top.
Pillows with drop off on left. Quite large and bulbous
pillows here. Very smooth; no buds at all.
Might have been set to south side of hill but now moving
back toward it. Seeing some sheet flows; moving right
along contact between sheets and lobate lavas. Some folded
and jumbled sheets on port side. Maybe some lobate on top
of sheet lava.
Getting pushed around by current. Mostly lobate lava, some
Alvin Dive 4608
Port Observer: John Sinton
Time
Depth
1927
1931
1664
1661
1937
1939
1657
1669
1941
1669
1943
3 April, 2010
Hdg
033
023
is collapsed. Some small pockets of sediment accumulating
between lobes.
Sample # 11. piece of lobate lava
Moving across area of lobate lava. Some sediment between
lobes. Approaching a drop off down in front of us. Drops a
few meters
Scarp at least 8-9 meters high.
Settling to sample. Doesn’t look super young. Bit broken
up.
Sample #12 from axial mound. Dusted with sediment. Not
much in the way of sediment pockets. Also not much
fracturing.
Dropping weights. Dive pau.