The MBARI mapping autonomous underwater vehicle (AUV) D. Allan B. has collected high-resolution data mapping Axial Volcano’s caldera, flanks, and south rift zone, and several other sites along the Juan de Fuca mid-ocean spreading ridge, where eruptions have occurred in the past 30 years (which are called here “historic flows”). These new maps are at a resolution that allows mapping of individual sulfide chimneys, lava pillars, channels in sheet flows, eruptive fissures and faults, and flow margins. During this expedition, MBARI will return to these sites with the remotely operated vehicle (ROV) Doc Ricketts to collect video observations and samples. Cruise objectives for both legs of the expedition are to use push cores and vibracores to collect the pyroclastic (volcanic ash and glass particles) sediment sequences on the caldera rim of Axial Seamount, image the caldera wall at Axial with ROV video, collect more samples of the Axial 2011 lava flows and other flows discerned on our high-resolution AUV maps using the ROV and a wax-tipped corer, and collect samples and sediment cores for radiocarbon dating at other sites along the Juan de Fuca Ridge. These data will be combined to evaluate timing of eruptions and changes in lava geochemistry and eruption style as a function of spatial location and age.
Specific targets for Leg 2 will be at the summit of Axial Seamount, pillow ridges emplaced on Axial’s south rift during the 2011 eruption, and some cones on Axial’s north and south rift made of lavas containing high concentrations of magnesium (more primitive melts that erupted at higher temperature than most lava found at Axial or elsewhere along the Juan de Fuca Ridge).
Targets for Leg 3 will be on the summit of Axial Seamount, andesite (more evolved melts than usually found at Axial or along the Juan de Fuca Ridge) cones near Axial’s north rift, historic flows on the CoAxial segment of the Juan de Fuca Ridge that erupted in 1993 and between 1982 and 1991, and a large perched lava pond on Axial’s south rift. Read more.
Leg 3, Day 10: Expedition summary
September 1, 2013
Dramatic sunset with albatross. Read more...
Leg 3, Day 9: Heading for port
August 31, 2013
A yellow crinoid (Family Crinoidea) is perched on the peak of a jumbled sheet flow block with its arms outstretched to trap food particles. This type of crinoid can swim by gracefully paddling its feathery arms and uses shorter appendages to grip the substrate. Read more...
Leg 3, Day 8: Lava pond
August 30, 2013
This crab (Macroregonia) calls the jumbled sheet flow home. Read more...
Leg 3, Day 7: Axial Volcano summit caldera
August 29, 2013
Pillow lava erupted in 2011 (at right in the central and top monitors) over-riding a 1998 jumbled sheet flow (left), from the perspective of an observer looking over the shoulder of the scientist at the main camera controls in the ROV control room on the ship. Read more...
Leg 3, Day 6: Great success with new corer
August 28, 2013
A beautiful lava arch formed by molten lava under the cooling crust of an inflated lobate flow. Read more...
Leg 3, Day 5: Revisiting 1993 lava flows
August 27, 2013
We returned to the CoAxial segment today to tie up some loose ends left from five ROV dives we did in 2005, 2009, and 2011, and an AUV mapping survey completed in 2009. Read more...
Leg 3, Day 4: Searching for rare lavas
August 26, 2013
One of the main objectives of our dive today was to see if we could locate these andesitic lavas, to document how they erupted, and to determine how they might be related to the normal mid-ocean ridge basalts that comprise Axial and the surrounding seafloor. Read more...
Leg 3, Day 3: Lava flow layers tell a story
August 25, 2013
Lava flows from hundreds of separate eruptions are exposed in cross-section in this wall, which resembles an enormous layered cake. The size and shape of each exposed lava flow (each layer) testify to the characteristics of the eruption that formed that flow. Read more...
Leg 3, Day 2: Determining the nature of volcanic eruption
August 24, 2013
Our focus today was to find out if, in fact, the cone we selected consisted of pyroclastic rocks and therefore likely erupted explosively. Read more...
Leg 3, Day 1: Transit to Axial Volcano
August 23, 2013
We began our transit this morning at 7 a.m. and are a little less than halfway to our destination. Read more...
Leg 2, Day 11: A petrologist at sea
August 20, 2013
Brian Dreyer shares a typical day at sea. Read more...
Leg 2, Day 10: Leg two wrap-up
August 19, 2013
It has been an eventful cruise that began with a two-day transit from Eureka, California to Axial Seamount, and is just wrapping up with a 29-hour transit from Axial Seamount to Newport. Read more...
Leg 2, Day 9: Designing a new corer
August 18, 2013
As we explained in a recent log, the sediment at Axial is particularly difficult to sample because of its unusual texture. Dave Clague asked me to join this cruise so that I could observe his coring method and possibly come up with a better solution. Read more...
Leg 2, Day 8: Exploring the 2011 lava flow
August 17, 2013
After two full days cruising along the lava flow that was probably erupted in 2011 along the South Rift Zone of Axial Volcano, we are back to Axial Volcano’s summit, chasing lava flows that definitely came from the 2011 eruption. Read more...
Leg 2, Day 7: Axial Volcano's South Rift Zone
August 16, 2013
A Benthoctopus has ventured onto the otherwise rather barren 2011 flow. Read more...
Leg 2, Day 6: An endless array of volcanic formations
August 15, 2013
Today we were the first humans to see the youngest lavas on the Axial Volcano South Rift Zone, which were recently erupted. Read more...
Leg 2, Day 5: Collecting core samples
August 14, 2013
We did two short dives today in order to view two different sections of the caldera wall for Tom Kwasnitschka's photogrammetry, and to core more of the thick clastic deposits on the caldera rim–for which we continue to tune our coring method. Read more...
Leg 2, Day 4: Making the most of bad weather
August 13, 2013
A low-pressure system moved in last night and it has been raining and blowing more than 25 knots all day. The motion of the ocean has the ship moving about more than it has since we left Eureka, but everyone seems to have their sea legs and, as usual on this remarkably stable ship, my coffee cup stays where I put it. Read more...
Leg 2, Day 3: Exploring a caldera
August 12, 2013
Today was our first day at Axial Seamount. The remotely operated vehicle (ROV) went into the water on time and we arrived on the bottom at 0730. We are investigating the northeastern wall of the caldera. The walls are full of information about the old days of Axial Seamount. Read more...
Leg 2, Day 2: Halfway to Axial seamount
August 11, 2013
We have quickly developed a little community. We do everything together. There are only 11 scientists, and we must all work together to make the cruise successful. Read more...
Leg 2, Day 1: Transit day one
August 10, 2013
First things first, as on every one of our cruises, the science party had a safety briefing and the ship's crew carried out a series of safety drills. Read more...