Exploring Guaymas Basin in the Gulf of California
Deep within central Gulf of California, the North Guaymas Basin was previously interpreted to be hydrothermally inactive based on submersible dives in the 1980s. However, surveys conducted at that time showed evidence of past hydrothermal activity, and in 2015 an active black smoker site was discovered in 2015--causing scientists to take a closer look at this unique region. Since that time the Guaymas basin has been extensively studied through scientific drilling and submersible surveys, and this Nautilus expedition will focus on unexplored regions with possible hydrothermal vent and seeps systems. Launching October 20-27, 2017, this expedition marks the first exploration in the Gulf of California for E/V Nautilus and the Corps of Exploration.
Lead Scientist Dr. Adam Soule, Woods Hole Oceanographic Institution and Expedition Leader Dr. Dwight Coleman, Director of the Inner Space Center will be guiding the expedition aboard Nautilus, joined by Lead Scientists Ashore Dr. Jeffrey Karson, Syracuse University and Dr. Pete Girguis, Harvard University. Research partners from Universidad Nacional Autónoma de México, Dr. Elva Escobar Briones and Esmeralda Morales Dominguez, will also be participating in exploration. Research support for this expedition comes from NOAA Office of Ocean Exploration and Research.
Go With the Flow: Investigating Vents and Seeps
The cruise objectives are to characterize the range of hydrothermal vent and seep fluid flow sites within North Guaymas Basin and collect specimens of fluids, rocks, sediment, and biology. Sites to investigate and sample include high temperature hydrothermal vents, warm vents, and cold seeps.
Nautilus has explored several hydrothermal vent systems in the Galapagos Rift Vents off the coast of Ecuador and Endeavour Vent Field near Vancouver Island, Canada. These hydrothermal vents appear along the seafloor where the earth's tectonic plates are spreading apart, and magma is welling up creating new crust. In some places, water is being drawn down below the surface, superheated by the magma (to temperatures over 400°C/750°F), and expelled through hydrothermal vents. These vents deposit dissolved minerals on the seafloor and overtime build up to become large chimneys.
In addition to collecting data about the sediment composition and chemosynthetic communities relying on these extreme ecosystems, hydrothermal activity at Guaymas Basin is being studied as an example of a primary mechanism in Earth’s history that may have induced global climate change, ocean anoxia, and mass extinctions. Additionally, this site along an active spreading center is being examined to determine whether its unique magmatic accretion--the formation of new oceanic crust--is common to similar spreading centers globally, which would change common understanding of accretion at spreading centers.
Expedition Objectives and Dive Targets
This expedition will explore the Northern Guaymas Basin including unique regions of the northernmost end of the East Pacific Rise, a mid-oceanic ridge that is a tectonic plate boundary and active spreading center. Target sites have been identified at a variety of distances from the spreading center axis that display a range of thermal settings from on-axis black smokers, to warm and cold seeps. Recent exploration of this region by deep-towed sidescan sonar surveys, deep-towed camera surveys, and limited AUV (autonomous underwater vehicle) and HOV (human occupied vehicle) dives have helped the Nautilus team identify priority target regions to explore with ROVs Hercules and Argus.
Site 1: Black smoker hydrothermal vents
This active black smoker system was identified in 2015. The site has been photographed, but has never been explored by ROV. This dive will characterize the site and collect specimens of vent fauna, hydrothermal fluids, sediments, and rocks.
Site 2: Ring vent
The N. Guaymas basin experiences unusual magmatic intrusions, when magma cools and solidifies before reaching the surface, releasing carbon and driving hydrothermal circulation. Previously mapped by AUV and visited by HOV Alvin, this site has been noted as the warmest in the Guaymas basin and hosts seep and vent animals, including Riftia tubeworms. This dive will characterize the whole of the 500m wide ring vent structure.
Site 3: El Faro
This site is characterized by a very bright sidescan sonar reflector, which indicates very hard substrate like volcanic formations. Initial surveys with a towed camera found tubeworms, bacterial mats, and carbonates.
Site 4: Gemelos
Two sites host tubeworms and bacterial mats and methane concentrations above background levels. Additional dive time may be devoted to exploration of the nearby active fault.
Exploration Tools
ROVs Hercules & Argus
In-situ mass and laser spectrometers
Isobaric gastight fluid samplers
Push cores
Niskin Bottles
Kongsberg EM-302 Multibeam Echosounder
Gulf of California
Moving closer to shore, Nautilus will begin to explore the Gulf of California (GOC), one of the most notable bodies of water on Earth. Thanks to the nutrient-rich waters that once flowed from the Colorado, the GOC was among the most productive of seas and is diverse in its geography, geology, oceanography, and biology. The GOC is an area of active seafloor spreading directly linked to the San Andreas Fault System.
