Expedition goal: Leg 5 of this expedition returns to the mouth of the Gulf of California, to study the seafloor-spreading ridges of the Alarcón Rise and Pescadero Basin and volcanic seamounts nearby. Researchers will map, explore, and sample lavas, sediments, and hydrothermal deposits and vent fluids. Their objective is to understand the tectonic and volcanic processes of the ridges and the transition from spreading ridge to bounding transform faults.

During the 2012 GOC expedition, researchers used the AUV to map the axis of the Alarcón Rise from the Pescadero to Tamayo transform faults at each end, and the ROV to explore and sample features identified in the maps. They discovered two active hydrothermal vent fields, enormous and relatively recent lava flows, abundant faulting, and an unusual, rugged volcanic dome. This dome is made of rhyolite, which is a lava type that had not been found on the seafloor previously but is common in volcanoes on land, particularly explosive arc volcanoes. Why it has formed on a spreading ridge where basalts are usually erupted, and whether similar eruptions might pose hazards by being so close to populated coastline, are among the questions the researchers will address during this dive series.

(left) Tectonic map of the Gulf of California showing the locations of Alarcón Rise, Pescadero Basin, and La Paz, Mexico. The northwestward movement of the Pacific Plate, on which the Baja Peninsula rides, relative to the North American Plate is responsible for the spreading of the East Pacific Rise mid-ocean ridge system, the Alarcón Rise, and the smaller spreading centers up in the gulf, and also for the strike-slip motion in the transform faults between spreading centers and eventually of the San Andreas Fault, which begins at the NW end of the gulf.
(right) Hydrothermal chimney in the Ja Sít vent field discovered on the Alarcón Rise in 2012. This image mosaic from ROV Doc Ricketts video shows the upper half of a 13-meter tall black smoker, and the colorful community of chemosynthetic bacteria, tube worms, crabs and fish supported by the >300º C, mineral-rich vent fluids.

ROV dives are planned on the rhyolite dome and other sites along the Alarcón Rise, at a nearby volcanic seamount with a large caldera, and in the Pescadero Basin to the east of La Paz, which formed by seafloor spreading but has never been explored. Lavas and hydrothermal fluids will be sampled for chemical analysis and sediments will be cored to analyze the deposits and to date the underlying flows.

This work will enable the researchers to learn how big the eruptions are and how often they occur, and to make a geologic map of the ridge, like is done routinely on land. These investigations will contribute to our general understanding of the mid-ocean spreading system in the Earth’s crust, and are especially important here because this area, close to shore yet not easily accessible and hidden in the deep sea, is geologically very active.

About this expedition:

Eve Lundsten and Charlie Paull

A team of 11 from MBARI will be participating in an international research expedition on the Korean Polar Research Institute (KOPRI) icebreaker Araon from August 21 to September 17, 2022.  MBARI will be providing state-of-the-art autonomous underwater vehicles (AUVs) and a remotely operated vehicle (ROV) to study the seafloor under the Canadian Beaufort Sea along the southern edge of the Arctic Ocean. On this expedition we will investigate the effects of thawing submarine permafrost in this remote area of the Arctic Ocean.

 

Korea icebreaker Araon

Permafrost is ground that remains frozen throughout the year. Global warming has focused considerable attention on the decomposition of permafrost on land and its impact on shaping the landscape. In contrast, almost nothing is known about the decomposition of relict permafrost under the sea. The Arctic Ocean is rimmed by vast shallow areas, such as the continental shelf in the Beaufort Sea. During periods of low sea level associated with glaciation, these shallow areas have been periodically exposed to the frigid air temperatures suitable for permafrost formation. Because of the lack of moisture in the Arctic, this area was not blanketed in glaciers and therefore experienced mean annual air temperatures that were often -15°C (5° F) or colder. These cold air temperatures caused the development of thick permafrost. In contrast, when sea level rises during interglacial periods, as happened about 12,000 years ago, the permafrost is flooded by the relatively warm seawater. Because the permafrost here was so thick and the diffusion of heat was so slow, ancient Pleistocene permafrost bodies that are still 100’s of meters thick remain beneath the continental shelf of the Beaufort Sea, even after 12,000 years.

The first systematic high-tech mapping along the edge of the continental shelf of the Canadian Beaufort Sea was conducted in 2010. These maps revealed a band of unusually rough seafloor terrain along a 95-kilometer (59-mile) stretch of the shelf, roughly 180 kilometers (110 miles) offshore. This rough topography coincided with what was once the seaward edge of that relict Pleistocene permafrost. Sections of this topography were subsequently remapped multiple times using MBARI AUVs. These repeated surveys show that multiple new sinkholes have formed in this area over just a few years. The volume of the largest new sinkhole, developed in less than 9 years, is equivalent in size to a city block of 6-story apartment buildings. The rate of morphologic change associated with the decomposing relict permafrost seen here is among the most rapid seen anywhere on Earth.

Route that the Araon will take during the 2022 Arctic expedition. MBARI will be participating in the second leg (in red), from Utqiagvik to Nome.

Route that the Araon will take during the 2022 Arctic expedition. MBARI will be participating in the second leg (in red), from Utqiagvik to Nome.

On this upcoming expedition in August 2022, the MBARI science party will be boarding the Araon in Utqiagvik, Alaska (formerly Barrow), along with other researchers from Korea, Canada, and the US. From Utqiagvik, the Araon will transit east passing along the entire north shore of Alaska before entering into the study areas in Canadian waters.

MBARI is contributing to the expedition two AUVs that are designed to map the seafloor. These untethered, free-swimming robots will descend to and independently navigate over the bottom terrain to map the seafloor along pre-programmed routes. The AUVs carry multi-beam mapping sonars that collect data at a resolution that exceeds what can be collected with a ship mounted system. These highly-detailed maps help illuminate the processes that shape the seafloor and, when conducted at repeated intervals, reveal how dynamic areas like these change over time.

MBARI’s MiniROV will be used to explore and sample the freshly altered seafloor. This ROV was designed to be small and robust so that it could be easily shipped to remote ports, providing access to study areas beyond the west coast of North America. The MiniROV utilizes an articulated arm to collect water samples, sediment samples, and animals, while recordings from a high-resolution video camera provide insight about the precise context of their locations.

Pre-cruise preparations

Expeditions like this take years to plan and require an enormous amount of work from numerous people from all of MBARI’s divisions. Engineering efforts, permitting acquisition, funding agreements, and safety training all begin years before we can set foot on the boat. It is only with considerable organization, and a little bit of good luck, that it all comes together to allow us conduct the research of interest to our team.

Physical preparations for this expedition began at MBARI in the fall of 2021 with the building of new ROV control room specifically designed for this expedition. The space was fabricated within a 20-foot shipping container with just enough floor space reserved to house the two mapping AUVs during shipping.

Tests of the new ROV control room were conducted at sea in Monterey Bay through early 2022 to ensure everything worked prior to packing, which commenced in March 2021. Two additional shipping containers were needed to hold the MiniROV, the ROV winch, and other assorted equipment needed for the expedition.

Our three shipping containers had to make an arduous journey from Oakland, California to Korea before heading up to the Arctic. Transpacific shipping delays and backlogs left some of our gear behind­–fortunately, it caught the last possible ship, arriving in Busan, Korea, just in the nick of time. To our knowledge all the MBARI gear is safely stowed onboard the Araon, awaiting our arrival in Utqiagvik.

The two container ships which carried MBARI’s equipment to Korea.
 

Maritime safety training

MBARI staff enjoyed a unique experience completing a required 5-day safety training and survival class that included the basics of fighting fires, CPR, first aid, and at-sea survival. Far outside our normal routines as scientists and engineers, it had us in full fire fighter gear, donning a self-contained breathing apparatus to put out a fire in a confined space, and we had to practice jumping off a mock ship (a high dive) and flipping an overturned life raft. It was a wonderful experience that we hope to never have to use in real life.

Learning how to work as a team to advance on a fire during firefighting training.
Life raft flipping test.

Expedition Logs

Team

Directory

Collaborators

Jong Kuk Hong (Korean Polar Research Institute), Young Keun Jin (Korean Polar Research Institute), Tae Siek Rhee (Korean Polar Research Institute), Scott Dallimore (Geological Survey of Canada). Mathieu Duchesne (Geological Survey of Canada)

Technologies

All Technologies