Monterey Bay Aquarium Research Institute

Hawaii Cruise
March 13, 2001 to June 2, 2001
Monterey to Hawaii and back
Logbook

May 14, 2001: Leg 4; Day 6


A beehive of geological sediment and gravel samples from our most recent dives. Photo by Ed Seidel.

Dave Clague writes: We started later than usual today following the marathon day and night yesterday. The ROV hit the water at 8:45 am and then had a slow descent as the engineering department made adjustments to the level-wind on the drum that handles the tether for the ROV. The dive was located on a series of submarine vents starting at about 2050 meters depth. The cones are related to the rejuvenated stage Koloa Volcanics on the south flank of Kauai, and are located close to the site of the dive on May 10.

The main objectives of the dive were to sample glassy basalt for volatile analyses and to observe the eruptive deposits on the cones to understand more about submarine eruptions. The first cone was an immediate surprise in that its surface was almost entirely covered by agglutinated spatter instead of the expected pillow basalt and hyaloclastite. The next two cones consisted almost entirely of hyaloclastite, some containing dense basalt clasts, and some spatter. We finally found pillow lava on a ridge at the base of the fourth cone we observed. However, the main cone appears to be of hyaloclastite yet again, although we only saw the base of the cone before ending the dive.

In processing the rock samples in the lab this evening we found that one sample has a breadcrust texture and another appears to be a volcanic bomb. We are finding that submarine eruptive products are more similar to those of subaerial eruptions than is generally believed and that spatter, previously undescribed from the submarine environment, may be a common submarine eruptive product. We collected yet another new sea star (nine-legged), a large sponge and a blue-purple sea cucumber. The cucumber was quite a troublesome critter, floating from the biology box and having to be recaptured. We have enough video of this particlar sea cucumber and his capture (twice) to make a short comedic movie! Tomorrow we will return to a flat-topped cone in the channel between Oahu and Kauai, where we attempted to dive on our first day but were stymied by strong winds and currents and high seas.



Equipment setup for Kelsey's conductivity measurements.

Ship's crew finish their work just before this morning's launch.

An unidentified species of sea star collected today at 1950 meters.

A peaceful moment on the bow with the sun setting over Niihau (from the ship's rolling perspective!).

Gold coral and basket star.

Mound of what appears to be spatter from a volcanic eruption. The molten rock splatted into the mound, then began to remobilize and form drips before it completely chilled.

Dave and Jennifer pack up rock samples that are dried and ready to be sealed in shipping containers.

This purple sea-cucumber was initially captured when this photo was taken, but later when we stopped to collect another sample, it flew out of the bio-box

This sample has some pieces of spatter on its surface. The textures just to the left of the sample's center are striated and folded, unlike the rest of the rock's surface.

An unidentified sponge (I originally thought it might be a bryozoan, but after looking at a sample under the scope saw that it was indeed a sponge) collected 2072 meters.

Cathy, Jackie and Brian work the rock sample processing assembly line.

 

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