Monterey Bay Aquarium Research Institute

 


Seafloor lava flows
Day 11: Cruise finale
August 6, 2011

Location: Transit to Newport
Latitude: 44° 37.48' N
Longitude: 124° W

More details about the science operations of this leg of the expedition:

Other work at Axial, and a primary objective of the cruise before we started, was also partly achieved. We have tried twice before to sample a roughly 1-2 meter thick section of volcaniclastic sediments on the rims of the volcano. Each time we have come away with less than 25 centimeters and usually less than 15 centimeters of the glass sand sediment. This time, we used some new meter- long push cores to be able to see what was happening inside the core barrel and recovered cores as long as 66 centimeters from several locations around the caldera. These sediments record a time series of the activity at Axial over long expanses of time—perhaps 20 thousand or more years. We now have samples of much more of that record. Other short push cores were collected to allow us to date a few more flows on the caldera floor and to help us build a timeframe for previous eruptions.

We completed a lot of work on the Endeavour Ridge, including three new AUV surveys that extend our coverage of high-resolution bathymetry to the north along the ridge and fill in more of the flanks near the central portion of the ridge. Three dives collected many new lava samples, especially from the flanks of the ridge, new sulfide deposits were discovered and sampled, and push cores should provide minimum ages for about 40 lava flows.

At the CoAxial site of the 1993 eruption, we accomplished more than half what was originally planned and added many more lava samples for chemistry and push cores for age dates. We learned that the western half of the neovolcanic zone here consists of quite old flows covered by thick sediment. We have yet to run into any hydrothermal deposits here and cannot see any in our AUV maps, despite there having been two eruptions in the last few decades of the previous century.

At the North Cleft site of the 1986 eruption, we ran two ROV dives (Leg 1 of the expedition) to better define the age relations of the sheet flows in the southern half of our survey. A planned AUV survey to expand our mapping coverage here was sacrificed so we could add the surveys of the new lava flow at Axial Seamount.

The single dive at Vance Seamounts, while shortened by ROV electrical problems, was still long enough to show that the few samples collected here previously were representative of the clastic section and are much finer grained than at Axial Seamount. We also learned that lava flows on top of the clastic section occur there, as well as at Axial.

While we did not dive on the south rift of Axial Seamount this trip, the AUV was deployed there to map an amazing drained lava pond that is up to 80 meters deep. This map will be combined with results from several dives done there a few years ago to complete the story of how this pond formed.

Several additional AUV surveys are planned for the transit home from the northeast Pacific. These will map a site in the northern Escanaba Trough where a large eruption occurred several hundreds to perhaps a thousand years ago that intruded magma into the thick sediments that fill the Escanaba Trough. These intrusions uplifted the sediment and are the site of numerous hydrothermal vent deposits. We hope to be able to map the lava flow in detail and determine its source vent, and to map the distribution of the hydrothermal deposits on the uplifted sediment hills.

All this will take some time to work up once we return to our offices and lab, but the excitement of discovery is just beginning, as each new analysis will show us another piece of the geological puzzles we seek to understand.

—David Clague

Back to Day 11 log


Leg 2
 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 the ROV'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.


 Crew

R/V Western Flyer

George Gunther
Master


 

Lance Wardle
Chief Engineer


 

Andrew McKee
First Mate


 

Paul Tucker
First Engineer


 

Olin Jordan
Oiler


 

Vincent Nunes
Bosun


 

Dan Chamberlain
Electronics Officer


 

Patrick Mitts
Steward


 

ROV Doc Ricketts

Knute Brekke
Chief ROV Pilot


 

Mark Talkovic
Senior ROV Pilot


 

Randy Prickett
Senior ROV Pilot


 

Bryan Schaefer
ROV Pilot/Technician


 

Eric Martin
ROV Pilot/Technician


 

 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, processing the high-resolution MBARI Mapping AUV data and interpreting the maps using ROV observations and samples from our research sites. On this cruise, she will 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. 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.

Linda Kuhnz
Senior Research Technician
MBARI

Linda specializes in the ecology of small animals that live in marine sediments (macrofauna), and larger invertebrates and fishes that live on the seafloor or just above it (megafauna). She conducts habitat characterization studies in benthic (seafloor) ecosystems using underwater video and by collecting deep-sea animals. She hopes to find some new and interesting animals in the unique habitats we are visiting on this cruise.

Julie Martin
Senior Research Technician
MBARI

Julie works with the submarine volcanism group, where she currently produces high resolution maps of the seafloor that are used to identify geologic features along submarine ridges and seamounts. Her research interests also include modeling of volcanic ash from sub-aerial, large-scale explosive eruptions.

Ryan Portner
Postdoctoral Fellow
MBARI

Ryan's work with the submarine volcanism project primarily focuses on the formation and distribution of volcaniclastic deposits on active and extinct seamounts and mid-ocean ridges. By categorizing the diversity in these deposits with respect to volcanic landforms he hopes to better understand the underlying controls on explosive vs. non-explosive deep marine eruptions. His background research on deep-marine gravity flow deposits preserved in sedimentary-volcanic successions exposed on land lends a comparable platform to study similar deposits of the modern oceans.


Brian Dreyer
Institute of Marine Sciences
UC Santa Cruz

Brian is an isotope geologist in the Institute of Marine Sciences at UC Santa Cruz where he studies the recent magmagenesis and petrology of the Juan de Fuca Ridge. His interest in the petrology of mid-ocean ridges began during his postdoctoral fellowship with MBARI's Submarine Volcanism Group; there, he utilized uranium-series disequilibria within individual lavas of Axial Seamount to clarify eruption and petrogenetic timescales. At mid-ocean ridge systems globally, Brian is interested in a) how variability in lava morphology, geochemistry, and petrology reflect deeper mantle-melting and magmatic processes and their complex interplay with tectonism and b) improving the chronological framework of the ridge magmatic plumbing systems. Brian received his B.S. in Geology from Cal State East Bay in 2000 and PhD in Earth and Planetary Science from Washington University in St. Louis in 2007. When not on the Western Flyer this summer, Brian defends the left side of the infield for the Surfing Squirrels, MBARI's coed softball team.

Andrew Burleigh
Oregon State University

Andrew received his bachelors in geology at Oregon State University in 2011 and is currently a graduate student at Oregon State University. His research focuses on the geochemistry of plagioclase ultraphyric basalt from mid ocean ridges to investigate how and why they form. Particularly, he is interested in using major and trace element variations in mineral phases to better understand magma chamber processes that modify melts in residence and transit prior to eruption.

John Jamieson
University of Ottawa

John's research interests focus on sulfide deposits that form on the seafloor as a result of venting of hydrothermal fluids. In particular, he uses radioactive isotopes to determine the ages of sulfide deposits in order to better understand the history of a vent field, as well as the rates at which sulfide accumulates along ocean ridges. John also studies the mineralogy and trace element geochemistry of seafloor sulfides, in order to better understand the tectonic controls on massive sulfide formation. The broad aim of this research is to constrain the impact of hydrothermal activity on the metal and sulfur budgets of the ocean and evaluate the geo-economic viability of seafloor massive sulfides as a source of copper, zinc, gold and silver.

Amy Lange
Oregon State University

Amy received her bachelors in geology from Hanover College in 2008 and is currently a Ph.D. student at Oregon State University. Recently she has been working on the geochemistry of plagioclase ultra-phyric basalts from mid-ocean ridges globally to understand why they erupt and what information they can tell us about crustal magma chamber processes. Her research uses trace element and isotopic microanalyses of mineral phases to unravel the pre-eruptive history of magmas. This is Amy's first cruise and she is excited to actively participate in ocean research!

Sean Scott
New Mexico State University

Sean received his B.S. degree in geology from Central Washington University in 2009 and is currently pursuing his M.S. degree at New Mexico State University. Sean is presently working on uranium series geochemistry of Endeavour basalts to evaluate spreading dynamics and chemical variation through time. Never did he think that he would have the opportunity to go on a research cruise with MBARI to his thesis area, and he is absolutely ecstatic about this trip!

Kevin Werts
University of Florida

Kevin graduated from Texas Tech University with a bachelor's degree in geology. He is currently working towards his M.S. degree with Dr. Michael Perfit at the University of Florida. Kevin's research focuses on the phase chemistry of evolved mid ocean ridge lavas from the Cleft segment of the Juan de Fuca Ridge. He is using phase chemistry to better understand the processes of differentiation that produced such evolved lavas at this mid ocean ridge.