Monterey Bay Aquarium Research Institute

Juan de Fuca Ridge Cruise
July 20 - August 1, 2000
Over 650 km (~400 miles) off the Washington-Oregon Coast
Logbook

July 27: Day #8


Foundered edge of a massive sheet flow. This is where we were able to determine the age relationship between two flows.

Log Entry: Today we started our dive where we ended yesterday’s, in order to try and answer some questions about the age relationship between two distinct lava flows that we had come across. Which came first? That was the main question we were attempting to answer. Upon reaching the area, we studied it closely and determined that the pillow flows were from a more recent eruption than the massive unit, which was an enormous "block" up to five meters thick in places. We came across another inactive sulfide vent which was on the massive unit, and took a sample for further analysis. The rest of the dive was spent traversing the transect line away from the axis, and saw some beautiful drain back features as well as more deep fissures in the ocean surface. As we traveled farther and farther from the axis, the terrain became less and less distinct, dominated by flat, sediment covered bottom populated with a few sparse lava pillows. Tonight we will be in transit to Axial seamount, an underwater volcano farther to the north of us. Tonight everyone will get a good night’s sleep, as we will not be doing any wax coring while the boat is underway. At Axial seamount tomorrow, Thomas Chapin and Josh Plant will be deploying their osmoanalyzers and osmosamplers at a few predetermined locations. We will see some more low-temperature vent sites where they will be placing their instruments to sample the water which is coming out of the vents. Please see the "Gear" section of this website in order to learn more about their equipment.


These are hollow drainback features which form when lava recedes after a flow. The pillars are vents where gases were escaping.



A colony of tunicates on a rock. Similar tunicates covered the seafloor for at least five minutes as we flew by

Another beautiful drainback feature.


One of many deep fissures in the seafloor that we passed over during our transect.

We sampled from this extinct sulfide tower during today's dive.

These are the wax cores which Tiburon presses up against rocks. You can see the glass that sticks to the wax.

Robbie Young carefully dissecting hydrothermal vent worms after yesterday’s dive.

Today's Menu

Breakfast:
Chilled fruit
Oatmeal with raisins and brown sugar
Eggs to order
Omelets: Ham, mushroom, bell pepper, cheese ,onion
Hash browns
Creamed beef
Pancakes
Cinnamon crumb muffins

Lunch:
Tossed salad, fruit salad
Tomato bisque
Turkey a la king, Egg noodles
Hot dogs
Baby peas

Dinner:
Salad bar
Tomato bisque
Pork roast
Mashed potatoes and gravy
Turkey a la king, egg noodles
Maple glazed carrots
Banana cream pudding


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