Day 8 — Axial Volcano, Western part of the Caldera
August 23, 2009
Latitude 45 degrees 58.06 minutes N
Longitude 130 degrees 1.01 minutes W
The dive today traversed older lava flows on the western side of the caldera floor and up the caldera wall to the southwest flank. We collected 31 rocks from flows we have identified from the AUV map which have not been sampled yet by us or by any of our research colleagues. We also groundtruthed the AUV map in the sense that we could see the structures on the seafloor that appear as different textures on the one-meter resolution AUV map, so we can predict what the seafloor might look like where we haven't yet done an ROV dive.
On the caldera floor, we went through a very complicated area of pillow mounds, lava lakes, and jumbled sheet flows. It was not always clear at the contacts which flow was overlying which. Our assessment of the amount of sediment cover and biological recruitment is not calibrated enough on such varied, older terrain to be unequivocal. It will require results of the lava chemistry analyses to sort out the relationships between these flows. We collected several samples in the caldera wall of massive lava flows that built the edifice and pre-date the formation of the caldera. Up on the caldera rim, we sampled clastic units and nearby lava flows. Since the vibracore hasn't been successful in recovering this sandy sediment, we had to be creative to get enough material to analyze. In a fine-grained volcanic clay unit, we push-cored horizontally into the wall. Below that, a thick, black, glassy unit was so coarse-grained that we used a push-core as a scoop and deposited the sample in the biobox. This sample contained an amazing collection of large limu o Pele flakes, complexly folded tissue-thin limu, and Pele's hairs up to three centimeters long. These are products of lava bubbles being blown and collapsing in mildly explosive eruptions.
Once we have all the older-younger flow relationships worked out, we can determine changes through time of the volcano's chemistry. The amount of time over which those changes occurred will be determined using sophisticated age-dating techniques. How lavas change through time has been a goal of work on mid-ocean spreading ridges for a long time, and with high-resolution maps, precise sampling, and thorough analysis of lava chemistry, it may finally be possible.
The R/V Atlantis and manned submersible Alvin are still working in the area, so for safety reasons we had to stay two kilometers away and modify our dive plan. Once again, we watched as they recovered the Alvin aboard the stern of the vessel. I've been down twice in the sub, and it is fun to see it from this perspective and to reminisce.
Small flow channel, which overtopped its levee on either side.
Volcaniclastic (broken volcanic rock) unit at the top of the caldera wall with black sandy units above and a finer tan muddy unit below. It consists of ejecta from the recent, vigorous eruptions at Axial, during or since the caldera collapsed.
Crab feast: spider crabs gather to devour a jelly that sank to the sea floor.
A deep-sea octopus, Graneledone, crawls across a lava pillow. (Red dots are lasers set 29 cm apart for sizing objects in the image.)
Well, when we started this cruise over a week ago, it seemed like deja vu from three years ago - it seemed as if the almighty gods of the sea were not in particular favour of our mission. But as the first days went by, I recognized, it’s not us they are concerned with, but rather the meteorologists and their attempts to forecast the weather - how dare they! And as the gods of the sea interfered with the meteorologists, the mostly unpleasant forecasts didn't materialize. At least not for the predicted time and space. So, the cruise went on, the pile of collected samples on board grew piece-by-piece, we went sight-seeing around hydrothermal vents and their wild-looking inhabitants, we visited “ancient pillar cities” (I was almost convinced we had discovered the ancient drowned city of Atlantis), our remote controlled vehicle “Doc Ricketts” made friends with rays and octopuses, we stopped by a jellyfish sushi party hosted by a few spider crabs, in other words: everything seemed to follow its normal path - a few drawbacks, a few surprises – nothing entirely out of range. Until a few days ago when a UFO was claimed to be spotted…
An omen, as it turned out. The next day, we had visitors nearby, simply appearing out of nowhere (the R/V Atlantis). Maybe another omen, maybe the last warning by the gods of the sea. Foolish as most of us were, we gave that incident little attention only. A mistake we would have to pay for…
It became clear today, the almighty gods of the sea had turned against us. We were unable to proceed today on our mission as planned out, and seemingly powerless against the will of the gods, we gave in, adjusting our plans…
The R/V Western Flyer is a small water-plane area twin hull (SWATH) oceanographic research vessel measuring 35.6 meters long and 16.2 meters wide. It was designed and constructed for MBARI to serve as the support vessel for ROV operations. Her missions include the Monterey Bay as well as extended cruises to Hawaii, Gulf of California and the Pacific Northwest.
ROV Doc Ricketts
ROV Doc Ricketts is MBARI's next generation ROV. The system breaks new ground in providing an integrated unmanned submersible research platform, with many powerful features providing efficient, reliable and precise sampling and data collection in a wide range of missions.
R/V Zephyr is the primary support vessel for MBARI's autonomous underwater vehicle (AUV) program. This 26-meter vessel is also used to maintain environmental moorings, collect time-series data along the California Current, and support scuba divers as they study near-shore habitats.
AUV D. Allan B.
The MBARI Mapping AUV is a torpedo-shaped vehicle equipped with four mapping sonars that operate simultaneously during a mission. The multibeam sonar produces high-resolution bathymetry (analogous to topography on land), the sidescan sonars produce imagery based on the intensity of the sound energy's reflections, and the subbottom profiler penetrates sediments on the seafloor, allowing the detection of layers within the sediments, faults, and depth to the basement rock.
A push-core looks like a clear plastic tube with a rubber handle on one end. Just as its name implies, the push core is pushed down into loose sediment using ROV Tiburon's manipulator arm. As the sediment fills up the core, water exits out the top through one-way valves. When the core is pulled up again, these valves close, which (most of the time) keeps the sediment from sliding out of the core tube. When we bring these cores back to the surface, we typically look for living animals and organic material in the sediments.
Niskin bottles are used to collect water samples as well as the tiny bacteria and plankton in that volume. The caps at both ends are open until the bottles are tripped, when the caps snap closed.
The box fits in a partition in the sample drawer. It is shown open, with an animal being placed into it by the ROV's manipulator. When the lid is closed, the box will hold water to protect the animals inside.
This device is used to collect volcanic glass fragments from the surface of a flow. It is made of about 450kg of lead and steel and is launched over the stern of the ship on a wire. Fragments of rock that break off of the lava flow on impact are trapped in wax-tipped cones mounted around the crusher. The wax is melted in the lab to liberate the rock particles for analysis.
Sample drawer with partitions
The benthic toolsled is attached to the bottom of the ROV for our geology dives. Its components are the manipulator arm and the sample drawer. The sample drawer is shown open on deck, full of rocks. Normally it is closed when the vehicle is operating and is opened only when a sample needs to be stowed. Partitions in the drawer help us keep the rocks in order. The rocks often look alike, but the conditions and chemistries of the eruptions are different so it is important that we know where each came from.
Glass suction sampler
This equipment is used to vacuum glass particles and larval animals from cracks and crevices. The carousel of small plastic jars fitted with wire mesh will be mounted in the benthic toolsled. The hose will be held by the ROV's manipulator and a suction will be drawn by the pump.
Canvas bags on a T-handle for collecting gravel or other materials that fall out of a push-core.
Held by the ROV's manipulator, the wire on the right is placed into the fluid emitted from a hydrothermal vent to record the temperature.
Vibracoring is a common technique used to obtain samples from water-saturated sediment. These corers work by attaching a motor that induces high frequency vibrations in the core liner that in turn liquefies the sediment directly around the core cutter, enabling it to pass through the sediment with little resistance.
Senior Scientist, MBARI
Dave's research interests are nearly all related to the formation and degradation of oceanic volcanoes, particularly Hawaiian volcanoes, mid-ocean ridges, and isolated seamounts. Topics of interest include: compositions of mantle sources for basaltic magmas and conditions of melting; volatile and rare-gas components in basaltic magmas and their degassing history; chronostratigraphic studies of eruption sequence and evolution of lava chemistry during volcano growth; subsidence of ocean volcanoes and its related crustal flexure, plate deformation, and magmatic activity; geologic setting of hydrothermal activity; origin of isolated seamounts; and monitoring of magmatic, tectonic, and hydrothermal activity at submarine and subaerial volcanoes.
Senior Research Technician, MBARI
Jenny works with Dave Clague in the Submarine Volcanism project. On this expedition, Jenny will be in charge of the GIS work, including use of the recently acquired, high-resolution MBARI Mapping AUV data of our dive sites. She will also stand watches in the ROV control room, help with rock and sediment sample workup and curation once the vehicle is on deck, and coordinate these cruise logs for our group's two legs of the expedition. She is now quite solidly a marine geologist, but her degrees are in biochemistry (Smith College) and biological oceanography (Oregon State University). She is thankful for the opportunities that have led her to study volcanoes, and loves being involved with the research and going to sea. She looks forward to discovering more about how the Earth works.
Science Postdoctoral Fellow, MBARI
Brian completed his Ph.D. in igneous geochemistry at Washington University in Saint Louis in 2007 and has since been working in MBARI's Submarine Volcanism Group. Brian applies the principles of isotope geochemistry to young samples of volcanic rocks to gain insight into aspects of magmatism. Much of his postdoctoral work focuses on eruption and petrogenetic timescales of Axial Seamount, the most volcanically active portion of the Juan de Fuca Ridge. His other research interests include geochemistry of the Earth's mantle, magmatic interaction between oceanic spreading centers and hotspots, and exploiting the systematics of rare isotope species to quantify material flux through subduction zones.
Senior Research Technician, MBARI
Kyra has been working in the Video Lab at MBARI for 13 years. She received her BS from the University of Victoria, BC, and her MS from Moss Landing Marine Labs. Kyra's specialty is identifying deep-sea fish and invertebrates and operating MBARI's video and annotation system, VARS. On this expedition she will assist in the identification, collection, and preservation of biological organisms. She is looking forward to some time in the field getting up close and personal with interesting spineless subjects.
Karen worked as a research technician for many years at MBARI before moving into the software engineering department. She was recruited for this cruise due to her knowledge and experience with ocean sediments and marine geology. Karen's duties on the cruise will include control room work and sample handling for the scientists. She is excited to participate on a marine geological research cruise again after working on computers for so many years.
PhD Student, McGill University
Christoph completed his degree in geology at the University of Munich and is a Ph.D. student at McGill University, Montreal since 2006. His research focuses on Axial Volcano, specifically on the processes that lead to the formation of the hyaloclastites, the evolution of the magmatic gasses and potential trigger mechanisms for the explosive eruptions. He has been out on a MBARI cruise before, on the Vance 2006 expedition.
PhD student, La Sapienza University Rome, Italy
Marilena is a marine geologist. Her research focuses on submarine flanks of volcanic islands. She mainly works with seafloor mapping and samples collected around Aeolian and Pantelleria volcanic islands, Tyrrhenian Sea, Italy. Her active research interest is the combination of marine morphologies and volcanological data.
John Skutnik Student, Endicott College
John will be experimenting with newly modified squeeze water samplers at hydrothermal vents on Axial Seamount during this expedition. He will perform various chemical analyses of the samples on two dives. He feels the opportunity to participate in this expedition provides great insight and experience for his future.
Graduate Student, Naval Postgraduate School Lieutenant, Royal Navy
Nicola graduated from University of Plymouth, UKwith a BSc (Hons.) in Ocean Science. Her research topic included determining the turbidity of seawater using an ROV and modulation transfer theory. In 2001, she joined the Royal Navy becoming a Hydrographic, Meteorological and Oceanography Officer in 2004. She has been involved in hydrographic survey operations, meteorological and oceanographic forecasting and more recently instructed tactical oceanography and meteorology. Currently, she is studying for her MS in Physical Oceanography at the Naval Postgraduate School.
Nichelle Baxter University of Florida, Gainesville
Nichelle is a PhD student at the University of Florida. Her research interests are in near-ridge seamounts, such as the Vance and Lamont seamount chains. By studying trace elements and isotopes in lavas from both chains, she hopes to better understand how these seamounts form and what they may illustrate about melting processes in the underlying mantle.