Monterey Bay Aquarium Research Institute

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

April 6, 2001: Leg 2; Day 6


Kyra Schlining writes: Finally!! We got to see many very, very cool animals today! Stalked sponges & crinoids. All kinds of wonderful gorgonians. I think my favorite was the spiderfish, Bathypterois, which we saw at least three of them.


I also enjoyed this bright red crustacean, Plesiopenaeus, that had large swimming legs and long sergestid-like antennae. Many others too, but you'll have to wait for another time. I hope you enjoy Juli's update. We let her choose the cool rock images for the day.



Bedded layers of volcanic sandstone.

Juli Morgan writes: Once again, we challenged the Hawaiian waters and retreated. We transited southward from the west side of Kohala Volcano overnight, to rendezvous with Loihi Volcano this morning. Strong currents and winds forced us to return to the leeward South Kona coast, site of several poorly understood submarine landslides. Here, we carried out a most interesting dive upon a scarp marking the southern lateral detachment to the Alika debris slide, thought to have occurred about 120,000 years ago. This dive offered the rare opportunity to look inside the broken flank of Mauna Loa, to determine the stratigraphy and structure of the volcano.

Most of the rocks observed along the dive were fractured and broken pillow basalts, apparently deposited on low submarine slopes as the volcano grew; these were often well preserved in cross-section within cliff faces. Occasional ledges of fragmental basalt or breccia were observed, one of which was overlain by a massive, tabular basalt flow. Two distinctive outcrops of sediments were observed: one near the base of the section, composed primarily of basalt glass, and the second at the very top of the traverse, with greater abundance of foraminifera tests and sponge spicules. The predominance of pillow basalts in this section, and relative scarcity of fragmental basalt breccias and sandstones suggests that we were looking into the primary volcanic edifice that existed prior to the collapse of the flank to form the Alika landslide.


Basaltic flow unit on top of breccia.

Jenny Paduan writes: We're rockin' and rollin' toward Loihi Seamount now. The plan tomorrow is to drop some gravity cores at 06:00 and then launch the ROV. So this will be a quick note! Attached is a map of where we've dived so far on this cruise. The map extent is from Oahu to the Big Island. The dive locations have arrows pointing to them and are numbered with the Tiburon dive number (the number of dives the vehicle has made in its lifetime to date). Today's dive was 280. You may notice that the dives aren't all in places we had planned for this leg: some were planned for the next leg, and several were chosen as fallbacks. We have had to get creative because the weather is foiling our attempts to work as we intended on the windward sides of the islands.



Ropey surface on lava flow.

Pillow basalt, including some intact pillows.

Radial fractures in the interior of a lava pillow, which was probably truncated by the landslide.


 

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