Monterey Bay Aquarium Research Institute
2009 Pacific Northwest Expedition


Leg 4 Logbook - Submarine Volcanism I
Day 6 — Axial Volcano, South Rift 1998 Flow
August 21, 2009

Latitude 45 degrees 52.15 minutes N
Longitude 129 degrees 59.10 minutes W

Our ROV dive today was on the south rift of Axial Seamount. The dive was shortened due to unsettled weather in the morning, but it was productive nonethless. Aided by maps generated from brand-new AUV data, we re-examined several lobes of lava that had been previously mapped by others as part of a widespread lava flow that erupted in 1998. During the dive, we collected in situ samples of these lobes as well as high-definition video of the flow textures and contacts throughout. In the evening, with the ROV back on deck, we deployed a wax-tipped rock crusher overboard to collect glass samples from an additional location on the seafloor.

Previous work by MBARI scientists and collegues have shown that the composition of lavas at Axial Seamount are remarkably homogeneous yet distinct from lavas that occur nearby. Back on shore, we'll analyze these new samples and their geologic relationships to determine if they are from the same lava flow, and if so, whether that flow was indeed erupted in 1998. Young lavas, such as the ones collected on today's dive, commonly have abundant fresh glass at their surface; because this glass is essentially quenched liquid, it preserves composition of the melt. Further analyses will help us determine the composition and origin of the robust magma chamber beneath Axial Seamount.

—Brian Dreyer

Many eruptions, and surges within eruptions, have built the seamount and paved its surface. This influences our estimate of eruption frequencies and volumes at this volcano. We wonder, for example, whether the two flows we see below occurred many years apart, or as part of the same eruption (the "Tuesday-Thursday debate"). If they are composed of lava with similar chemistry and show similar alteration and sediment accumulation, it is likely that they are from the same eruption.

skylight
Skylight in broad lobate lava pillow offers a glimpse of a striated sheet flow beneath.
deeper collapse
Composite skylight. Two superimposed collapse structures suggest the flow inflated to the level of the upper flow surface, drained (flowed elsewhere) to lower the surface of the flow a bit, forming the middle flow surface, then drained a lot more. Unsupported here, the flow surfaces collapsed.
pillows over sheet flow
The always useful contact between lava units: we can say for sure the pillow flow is younger than the lineated sheet flow.
deploying rock crusher
Karen and Kyra on the well deck (stern) of the Western Flyer, preparing to assist with the deployment of the wax-tipped rock crusher.

The rock crusher is lowered on a wire to the seafloor, where it breaks the glassy surface of the lava, some of which sticks to the wax of the nose cones. We'll melt the wax away from the glass chips in a heated pot to recover the sample. Low tech, but it is a useful tool for sampling an area we won't have time to dive on, or on a day when it is too rough for ROV ops. Obviously, this evening it was the former case!

—Jenny Paduan

 


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Leg 4
 Equipment

R/V Western Flyer

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

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.

Push cores

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

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.


Biobox

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.


Rock crusher

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.

Benthic toolsled/
Manipulator arm/
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.

Sediment scoops

Canvas bags on a T-handle for collecting gravel or other materials that fall out of a push-core.


Temperature probe

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.

Vibracores

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.


 Research Team

David Clague
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.

Jenny Paduan
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.

Brian Dreyer
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.

Kyra Schlining
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 Salamy
Software Engineering Technician, MBARI

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.

Christoph Helo
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.

Marilena Calarco
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.

Nicola Wheatley
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.