Submarine Volcanism OverviewTeamPublicationsLatest NewsTechnologies What processes form and modify volcanoes in the sea?Volcanic eruptions and flank collapses are significant geologic hazards. While volcanic events and deposits in the ocean are largely concealed from view and more difficult to sample than volcanoes on land, submarine volcanoes are an integral part of the way the Earth works and may cause destructive tsunami.The roles of mid-ocean ridges in plate tectonics and hydrothermal circulation are concepts that were only discovered in the last half century. We are now learning how often the ridges erupt, how big those eruptions are and how explosive they might be, and how much they contribute to global gas and mineral cycles. The Alarcon Rise and recent eruptions at Axial Seamount have been of particular focus.The seamounts offshore of California, such as Davidson Seamount within the Monterey Bay National Marine Sanctuary, were slowly built over abandoned mid-ocean spreading ridges. They now offer rocky habitat for dense populations of deep-sea corals and sponges, high above the muddy abyssal plain. Near-ridge seamounts are chains of seamounts that formed off-axis of spreading ridges. They are influenced by ridge processes but have large calderas so might be capable of especially violent behavior.Hot spot mantle plumes have built many of the thousands of seamounts and islands in the ocean, which are important for species biodiversity, fisheries and other human uses. They can also produce destructive eruptions and landslides.Why are we studying submarine volcanoes?Our goal is to better understand volcanic processes in the deep sea environment and gain insight into potentially destructive eruptions on land or in shallow water. We are studying:Styles of volcanic eruptions at varying depths and lava compositionsFrequency and volume of mid-ocean ridge eruptionsExplosive volcanism in the deep seaSubmarine landslides and the structure of the flanks of volcanoesEvolution of hydrothermal systemsPlio-Pleistocene paleoclimatic history recorded in drowned coral reefsOrigin and evolution of oceanic volcanoesBiogeography of ocean islands and submarine volcanoesHow do we study submarine volcanoes?Most mid-ocean ridges and seamounts lie far below sunlit and SCUBA-accessible depths. At MBARI, our group uses remotely operated vehicles (ROVs) for sampling and video observations and autonomous underwater vehicles (AUVs) to map the seafloor at resolutions of 1 m or better.Please note that our AUV mapping data is being archived in the public domain at the Marine Geoscience Data System (MGDS). Our rock samples are archived at the American Museum of Natural History in New York City and at the Smithsonian’s American Museum of Natural History in Washington, DC. Mid-Ocean ridges Volcanism at mid-ocean ridgesThe great majority of the Earth’s volcanism occurs at spreading centers, most of which are under the ocean, forming the mid-ocean ridge system where new ocean crust is being created. The Earth’s tectonic plates are slowly moving apart, and magma rises up to fill the gap, adding to the deep crust as sheeted dikes and sometimes flowing onto the seafloor as volcanic eruptions. The shallow magma provides a heat source that causes intense circulation of water within the shallow oceanic crust and the venting of the heated, mineral-laden water at the seafloor. These hot springs and spectacular hydrothermal vents transport heat and chemicals into the ocean and provide substrate for chemosynthetic biological communities.The Gorda, Juan de Fuca and Endeavour Ridges have slow (~25 mm/yr) to moderate spreading rates, and are located off Oregon and Washington states and British Columbia. The Alarcon Rise in the Gulf of California and Northern East Pacific Rise have moderate to fast spreading rates. Segments of the Southern East Pacific Rise have super-fast spreading rates (>140 mm/yr), the fastest of which are southwest of Easter Island in the South Pacific.A major focus of our work has been at Axial Seamount, which is a hot spot interacting with the Juan de Fuca Ridge and where eruptions occurred in 1998, 2011 and 2015. We have mapped with our AUV at high resolution the summit caldera, upper flanks, and a large portion of the south rift zone, and extensively sampled with the ROVs lavas and sediments to obtain a record of the eruptive and explosive history of the volcano. Our papers on Axial Seamount are profiled in this Mid-ocean ridge section’s Volcanic Processes, Magmatic Processes, and Explosive Eruptions pages. Our research expeditions are profiled in our cruise logs.Note that off-axis, near-ridge seamounts are discussed in the Seamounts section of this websiteMid-ocean ridge magmatic processesThe axial graben of the Endeavour Segment of the Juan de Fuca Ridge is heavily faulted due to a period of low magmatic activity while the sea floor continued to spread. Summit Seamount, mapped by the MBARI Mapping AUV (see map below), erupted just prior to the formation of the modern axial valley and remnant blocks are strewn across the entire width of the axial valley from its dissection by extensional faults. Age dating of sediments on the seamount gives a minimum age for the seamount, and therefore for the beginning of the most recent tectonic phase of Endeavour’s cyclic geologic history.Summit Seamount on the Endeavour Segment was diced by faults as the ridge spread.The ridge segment is currently in a hydrothermal phase while magmatic activity is beginning to increase. The faults farther south on the ridge provide pathways for hydrothermal fluids that vent as black smokers and have built large sulfide chimneys for which the ridge segment is most well known. Escanaba Trough is a 130 km long basin in the southern part of the Gorda Ridge, bounded in the south by the Mendocino Fracture Zone. The rift-valley floor is filled with thick sequences of sediments derived from the continent, fallout from the great floods that carved the Columbia Gorge in the Pleistocene. Lava has intruded as sills into the sediments, uplifting broad hills. Some assimilation of the sediment into the intruded lava has changed its chemical composition. This contamination offers insight into the extent to which processes that occur as lava ascends through the crust, as opposed to original mantle source heterogeneity, influence normal mid-ocean ridge basalt composition.Our research on magmatic processes at mid-ocean ridgesLe Saout, M., Clague, D. A., & Paduan, J. B. (2022). Faulting and magmatic accretion across the overlapping spreading center between Vance Segment and Axial south rift, Juan de Fuca Ridge. Geochemistry, Geophysics, Geosystems, 23, e2021GC010082. doi: 10.1029/2021GC010082.Portner, R., Dreyer, B.M., Clague, D.A., Daczko, N., & Castillo, P.R. (2022). Oceanic zircon records extreme fractional crystallization of MORB to rhyolite on the Alarcon Rise Mid-Ocean Ridge, Journal of Petrology, 63, 1-25. doi: 10.1093/petrology/egac040LeSaout, M., Clague, D.A. & Paduan, J.B. (2019). Evolution of fine-scale segmentation at Intermediate-spreading rate ridges, Geochemistry, Geophysics, Geosystems, doi: 10.1029/2019GC008218.Clague, D.A., Caress, D.W., Dreyer, B.M., Lundsten, L., Paduan, J.B., Portner, R.A., Spelz-Madero, R., Bowles, J.A., Castillo, P.R., Guardado-France, R., Le Saout, M., Martin, J.F., Santa Rosa-del Rio, M.A., & Zierenberg, R.A. (2018). Geology of the Alarcon Rise, Southern Gulf of California. Geochemistry, Geophysics, Geosystems. doi: 10.1002/2017GC007348.Jones, M.R., Soule, S.A., Gonnermann, H.M., Le Roux, V., & Clague, D.A. (2018). Magma ascent and lava flow emplacement rates during the 2011 Axial Seamount eruption based on CO2 degassing. Earth and Planetary Science Letters, 494, 32-41. doi: 10.1016/j.epsl.2018.04.044.Chadwick, W. W., Paduan, J. B., Clague, D. A., Dreyer, B. M., Merle, S. G., Bobbitt, A. M., … Nooner, S. L. (2016). Voluminous eruption from a zoned magma body after an increase in supply rate at Axial Seamount. Geophysical Research Letters. doi: 10.1002/2016GL071327.Gill, J. P. Michael, J. Woodcock, B. Dreyer, F. Ramos, D. Clague, J. Kela, S. Scott, K. Konrad, and D. Stakes (2016) Spatial and Temporal Scale of Mantle Enrichment at the Endeavour Segment, Juan de Fuca Ridge. J. Petrol. 1-33. doi: 10.1093/petrology/egw024.Gao, R., J.C. Lassiter, J.D. Barnes, D.A. Clague, W.A. Bohrson (2016) Geochemical investigation of Gabbroic Xenoliths from Hualalai Volcano: Implications for lower oceanic crust accretion and Hualalai Volcano magma storage system. Earth and Plan. Sci. Lett. 442:162-172. doi: 10.1016/j.epsl.2016.02.043.Clague, D.A., B.M. Dreyer, J.B. Paduan, J.F. Martin, D.W. Caress, J.B. Gill, D.S. Kelley, H. Thomas, R.A. Portner, J.R. Delaney, T.P. Guilderson, M.L. McGann (2014) Eruptive and tectonic history of the Endeavour segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages. Geochem., Geophys., Geosyst., 15(8): 3364-3391. doi: 10.1002/2014GC005415.Dreyer, B.M, D.A. Clague, J.B. Gill (2013) Petrological variability of recent magmatism at Axial Seamount summit, Juan de Fuca Ridge. Geochem., Geophys., Geosyst., 14(10): 4306-4333. doi: 10.1002/ggge.20239.Davis, A. S., D. A. Clague, B. L. Cousens, R. Keaten, J. B. Paduan (2008) Geochemistry of basalt from the North Gorda segment of the Gorda Ridge: Evolution toward ultraslow spreading ridge lavas due to decreasing magma supply, Geochemistry Geophysics Geosystems, 9, Q04004, doi: 10.1029/2007GC001775.Mid-ocean ridge volcanic processesA small portion of the Axial 2011 flow is depicted in this map of the difference between before and after bathymetry from MBARI’s Mapping AUV. Eruptive fissures are visible at right, flow channels in the middle, and inflated flow margins at left and lower middle. Color ramp (blue to orange) is 0 to 15 m flow thickness, vertical precision is 0.2 m, horizontal resolution is 1 m, and the area shown is about 2×3 km. Map © MBARI 2012MBARI mapped the 2011 eruption at Axial Volcano with our AUV. Subtracting bathymetry of the summit of Axial mapped between 2006 to 2009 from the 2011 bathymetry revealed the extent, volume, fissures and channel systems of the flow at high resolution. Surprises included how most of the fissures had been pre-existing, and were reused (even widened and deepened) and fed lava into pre-existing channels.A mechanism for how lava is injected at mid-ocean ridges was proposed from evaluation of the seismic and bathymetric data from the 1998 eruption at Axial Volcano. Lava propagated for many kilometers along the rift before extruding at the sea floor.Our research on volcanic processes at mid-ocean ridgesPortner, R.A., Dreyer, B.M., and Clague, D.A., 2020, Mid-ocean-ridge rhyolite (MORR) eruptions on the East Pacific Rise lack the fizz to pop: Geology, v. 49, p. XXX–XXX, https://doi.org/10.1130/G47820.1Le Saout, M., Bohnenstiehl, D.R., Paduan, J.B., & Clague, D.A. (2020) Quantification of eruption dynamics on the north rift at Axial Seamount, Juan de Fuca Ridge. Geochemistry, Geophysics, Geosystems, 21, e2020GC009136. doi: https://doi.org/10.1029/2020GC009136.Maschmeyer, C.H., White, S.M., Dreyer, B.M., & Clague, D.A. (2019) High-Silica Lava Morphology at Ocean Spreading Ridges: Machine-Learning Seafloor Classification at Alarcon Rise. Geosciences 2019, 9, 245; doi: 10.3390/geosciences9060245Clague D.A., Paduan, J.B., Caress, D.W., Chadwick Jr, W.W., Le Saout, M., Dreyer, B.M., Portner, R.A. (2017). High-resolution AUV mapping and targeted ROV observations of three historical lava flows at Axial Seamount, Oceanography, 30(4), 82-99, doi: 10.5670/oceanog.2017.426.Chadwick, W. W., Jr, J. B. Paduan, D. A. Clague, B. M. Dreyer, S. G. Merle, A. M. Bobbitt, D. W. Caress, B. T. Philip, D. S. Kelley, and S. L. Nooner (2016), Voluminous eruption from a zoned magma body after an increase in supply rate at Axial Seamount, Geophys. Res.Lett., 43, 12,063–12,070, doi: 10.1002/2016GL071327Clague, D.A., B.M. Dreyer, J.B. Paduan, J.F. Martin, W.W. Chadwick, D.W. Caress, R.A. Portner, T.P. Guilderson, M.L. McGann, H. Thomas, D.A. Butterfield, R.W. Embley (2013) Geologic history of the summit of axial seamount, Juan de Fuca Ridge. Geochem., Geophys., Geosyst., 14(10): 4403-4443. doi: 10.1002/ggge.20240Chadwick, W.W., D.A. Clague, R.W. Embley, M.R. Perfit, D.A. Butterfield, D.W. Caress, J.B. Paduan, J.F. Martin, P. Sasnett, S.G. Merle, A.M. Bobbitt (2013) The 1998 eruption of Axial Seamount: New insights on submarine lava flow emplacement from high-resolution mapping. Geochem., Geophys., Geosyst., 14(10): 3939-3968. doi: 10.1002/ggge.20202Yeo, I.A., D.A. Clague, J.F. Martin, J.B. Paduan, D.W. Caress (2013) Pre-eruptive flow focussing in dikes feeding historical pillow ridges on the Juan de Fuca and Gorda Ridges. Geochem. Geophys. Geosyst., 14(9): 3586-3599. doi: 10.1002/ggge.20210Caress, D.W., D.A. Clague, J.B. Paduan, J.F. Martin, B.M. Dreyer, W.W. Chadwick Jr, A. Denny, D.S. Kelley (2012) Repeat bathymetric surveys at 1-metre resolution of lava flows erupted at Axial Seamount in April 2011. Nature Geoscience, 5(7): 483-488. doi: 10.1038/NGEO1496Rubin, K.H., S.A. Soule, W.W. Chadwick Jr., D.J. Fornari, D.A. Clague, R.W. Embley, E.T. Baker, M.R. Perfit, D.W. Caress, and R.P. Dziak (2012) Volcanic eruptions in the deep sea. Oceanography 25(1): 142–157, doi:10.5670/oceanog.2012.12. [Article]Schiffman, P., Zierenberg, R., Chadwick, W.W., Clague, D.A., Lowenstern, J. (2010) Contamination of basaltic lava by seawater: Evidence found in a lava pillar from Axial Seamount, Juan de Fuca Ridge. Geochem., Geophys., Geosyst., 11(4): Q04004, doi:10.1029/2009GC003009.Clague, D.A., Paduan, J.B. (2009) Submarine basaltic volcanism, In: Submarine Volcanism and Mineralization: Modern through Ancient, B. Cousens and S.J. Piercey (eds.), Geological Association of Canada, Short Course 39-30 May 2008, Quebec City, Canada, p. 41-60.Mid-ocean ridge explosive eruptionsThe volcanic eruptions at mid-ocean ridges have been thought only to be quietly effusive, but because we find glassy fragments of lava bubbles (limu o Pele) at mid-ocean ridges, there must be gas-rich mildly explosive eruptions at mid-ocean ridges as well. We have now found these particles at many locations and depths along the earth’s mid-ocean ridge system, so mildly explosive eruptions must be quite common.Benthic foraminifera with agglutinated limu o Pele (foram ~2mm across) Image © MBARI 2003The particles are especially abundant where the lava erupted as jumbled sheet flows, so their formation is related to the rise and release of bubbles of magmatic gas that also drive the lava’s fast eruption rate. The particles take many forms, from curved plates of limu o Pele, to stretched rods and intricately folded and tack-welded thin sheets and hairs. They can be distributed quite a distance from the rocks extruded during the same eruptions, meaning that they must have been entrained in heated megaplumes that lifted the particles high into the water column.Benthic foraminifera often glue particles to their tests, perhaps for protection from predators. These particles may be sponge spicules, sand grains, or other detritus, depending on the materials available and the “specialty” of the foram. In sediment cores from the Gorda Ridge, we found forams that “specialized” in volcanic glass grains and others that “specialized” in limu o Pele. They effectively concentrated the glass samples for us!Our research on explosive eruptions at mid-ocean ridgesPortner, R.A., B.M. Dreyer, & D.A. Clague (2021) Mid-ocean-ridge rhyolite (MORR) eruptions on the East Pacific Rise lack the fizz to pop. Geology, 49 (4), 377-381. 10.1130/G47820.1Portner, R.A., D.A. Clague, C. Helo, B.M. Dreyer, J.B. Paduan (2015) Contrasting styles of deep-marine pyroclastic eruptions revealed from Axial Seamount push core records. Earth Planet. Sci. Lett., 423: 219-231. doi: 10.1016/j.epsl.2015.03.043.Helo, C., D.A. Clague, D.B. Dingwell, and J. Stix (2013). High and highly variable cooling rates during pyroclastic eruptions on Axial Seamount, Juan de Fuca Ridge. Journal of Volcanology and Geothermal Research, 253: 54-64. doi: 10.1016/j.jvolgeores.2012.12.004.Helo, C., Longpre, M.-A., Shimizu, N., Clague, D.A., Stix, J. (2011) Explosive eruptions at mid-ocean ridges driven by CO2-rich magmas, Nature Geoscience, doi:10.1038/NGEO1104. [Supplementary information]D.A. Clague, J.B. Paduan, A.S. Davis (2009) Widespread strombolian eruptions of mid-ocean ridge basalt, Journal of Volcanology and Geophysical Research, 180: 171-188, doi: 10.1016/j.jvolgeores.2008.08.007D.A. Clague, A.S. Davis, J. E. Dixon (2003) Submarine strombolian eruptions on the Gorda mid-ocean ridge, In: Explosive Subaqueous Volcanism, J.D.L. White, J.L. Smellie, and D.A. Clague (eds), Geophysical Monograph 140, American Geophysical Union, 111-128. doi: 10.1029/140GM07A.S. Davis, D.A. Clague (2003) Got glass? Glass from sediment and foraminifera tests contribute clues to volcanic history, Geology, 31(2): 103-106. 10.1130/0091-7613(2003)031<0103:GGGFSA>2.0.CO;2Mid-ocean ridge hydrothermal systemsWhite microbial mat supported by warm fluids coats a cavity in still-cooling lava from the 2011 eruption at Axial Seamount.Hydrothermal vents were first discovered at the Galapagos spreading center in 1977, and high-temperature black smokers were first discovered at 21oN along the East Pacific Rise in 1979. Since then, hydrothermal vents have been found at many points along the Earth’s mid-ocean spreading ridges. They are important for many reasons, including global fluxes of elements, deposits of economically-valuable minerals, and diverse assemblages of previously unknown animals and bacteria that are supported by the chemically-rich waters emanating from the vents The fluids are derived from seawater that circulates through the brittle upper ocean crust. When the fluids become heated by the magma chamber at the mid-ocean ridge they become buoyant and vent at the sea floor much like geysers do on land. While circulating, the fluids react with the surrounding rocks and pick up metals and volatiles. When the hot water contacts cold seawater, minerals precipitate to build chimneys. Dissolved elements are transported in a buoyant plume that rises above the vent site and may take years to dissipate.Our research on hydrothermal systems at mid-ocean ridgesWheat, C.G., Zierenberg, R.A., Paduan, J.B., Caress, D.W., Clague, D.A., & Chadwick Jr, W.W. (2020) Changing brine inputs into hydrothermal fluids: Southern Cleft Segment, Juan de Fuca Ridge. Geochemistry, Geophysics, Geosystems, 21, e2020GC009360. doi: 10.1029/2020GC009360Clague, D. A., Martin, J. F., Paduan, J. B., Butterfield, D. A., Jamieson, J. W., Le Saout, M., et al. (2020) Hydrothermal chimney distribution on the Endeavour Segment, Juan de Fuca Ridge. Geochemistry, Geophysics, Geosystems, 21, e2020GC008917. doi: 10.1029/2020GC008917.Paduan, J.B., Zierenberg, R.A., Clague, D.A., Spelz, R.M., Caress, D.W., Troni, G., Thomas, H., Glessner, J., Lilley, M.D., Lorenson, T., Lupton, J., Neumann, F., Santa Rosa del-Rio, M., & Wheat., C.G. (2018) Discovery of hydrothermal vent fields on Alarcón Rise and in Southern Pescadero Basin, Gulf of California, Geochemistry, Geophysics, Geosystems, 19(12), 4788-4819. doi: 10.1029/2018GC007771.Goffredi S.K., S. Johnson, V. Tunnicliffe, D. Caress, D. Clague, E. Escobar, L. Lundsten, J.B. Paduan, G. Rouse, D.L. Salcedo, L.A. Soto, R. Spelz-Madero, R. Zierenberg, & R. Vrijenhoek (2017) Hydrothermal vent fields discovered in the southern Gulf of California clarify role of habitat in augmenting regional diversity. Proc. R. Soc. B 284: 20170817. doi: 10.1098/rspb.2017.0817.Jamieson, J.W., D.A. Clague, & M.D. Hannington (2014) Hydrothermal sulfide accumulation along the Endeavour Segment, Juan de Fuca Ridge. Earth and Planetary Science Letters, 395: 136-148. doi: 10.1016/j.epsl.2014.03.035Jamieson, J.W., M.D. Hannington, D.A. Clague, D.S. Kelley, J.R. Delaney, J.F. Holden, M.K. Tivey, L.E. Kimpe (2013) Sulfide geochronology along the Endeavour Segment of the Juan de Fuca Ridge. Geochem., Geophys., Geosyst., 14(7): 2084–2099. doi: 10.1002/ggge.20133.Kelley, D.S., S.M. Carbotte, D.W. Caress, D.A. Clague, J.R. Delaney, J.B. Gill, H. Hadaway, J.F. Holden, E.E.E. Hooft, J.P. Kellogg, M.D. Lilley, M. Stoermer, D. Toomey, R. Weekly, and W.S.D. Wilcock (2012) Endeavour Segment of the Juan de Fuca Ridge: One of the most remarkable places on Earth. Oceanography 25(1):44–61, doi: 10.5670/oceanog.2012.03.Hein, J.R., D.A. Clague, R.A. Koski, R.W. Embley, R.E. Dunham (2008) Metalliferous sediment and a silca-hematite deposit within the Blanco Fracture Zone, Northeast Pacific, Marine Georesources and Geotechnology, 26:317–339. doi: 10.1016/j.oregeorev.2016.09.010Von Damm, K. L., C. M. Parker, M. D. Lilley, D. A. Clague, R. A. Zierenberg, E. J. Olson, and J. S. McClain (2006), Chemistry of vent fluids and its implications for subsurface conditions at Sea Cliff hydrothermal field, Gorda Ridge, Geochem. Geophys. Geosyst., 7, Q05005, doi: 10.1029/2005GC001034.Von Damm, K.L., C.M. Parker, R.A. Zierenberg, M.D. Lilley, E.J. Olson, D.A. Clague and J.S. McClain (2005) The Escanaba Trough, Gorda Ridge hydrothermal system: Temporal stability and subseafloor complexity, Geochimica et Cosmochimica Acta, 69:21, 4971-4984. doi: 10.1016/j.gca.2005.04.018Clague, D.A., R. Zierenberg, A. Davis, S. Goffredi, J. McClain, N. Maher, E. Olsen, V. Orphan, S. Ross, K. Von Damm, (2001). MBARI’s 2000 expedition to the Gorda Ridge. RIDGE Events, 11, 5–12. PDFBack arc spreading ridgesBehind the trench and volcanic arc of a subduction zone, the lithosphere may stretch and extend and volcanic spreading centers may develop. Such a back arc setting is found in the Lau Basin, behind the Tonga Trench in the South Pacific. West Mata is one of two volcanoes in the Lau Basin that were explored and sampled with the ROV Jason2 and mapped with the MBARI Mapping AUV in May 2009. It lies to the NE of the zone of back arc spreading, between it and the well-established volcanic arc, and may be where a new volcanic arc is beginning to form. Active eruptions were occurring near the summit of the volcano. Lavas with the unusual, ultramafic chemistry of boninite were collected. Explosive bursts were observed close up, which was rather exciting, and the formation of vesicular lava fragments and of pillow lavas cascading from the vent were also recorded with the ROV. Seamounts Intraplate seamounts researchIntraplate seamount volcanism is of different typesMany chains of seamounts (submerged mountains) are of hot spot or subduction arc origin. However, some intraplate seamounts have different origins. Near-ridge seamounts erupted near the axes of mid-ocean ridges onto recently derived oceanic crust. In the north-east Pacific, these include the Vance and President Jackson seamounts near the Juan de Fuca and Gorda Ridges, respectively, and the Taney Seamounts off San Francisco, which are no longer associated with an active spreading center (map, 50 kb). Some isolated seamounts and other linear seamount chains have erupted onto much older oceanic crust, and their formation is enigmatic: they do not appear to have erupted as hot spot volcanoes or near-ridge seamounts, and they are not associated with subduction processes. Examples of these include Davidson, Pioneer, and Guide seamounts (map, 118 kb) near the California coast, and the Line Islands chain in the middle of the Pacific Ocean. Note that our work at Axial Seamount is covered in the Mid-ocean Ridge section.Near-ridge seamountsSeamounts erupted near mid-ocean ridgesThere are many linear chains of seamounts that originate near mid-ocean ridges and are somehow due to excess magmatic activity that erupts intermittently but profusely over extended periods at that same point of the ridge. They are especially common near fast spreading ridge segments, and seem to be preferentially located near bends or offsets in the ridge crest. The chains are often asymmetric, with many more seamounts located on one side of a ridge than on the other. The cones are often flat-topped with pronounced calderas.Perspective view of the Vance Seamounts, showing nested flat-topped calderas. Vertical exaggeration is 2x. Image © MBARI 1999A new family, genus, and species of enteropneust worm from the President Jackson Seamounts is reported on the eclectic topics page. Go to the MBARI mapping program for more maps and information about these seamounts.Our research on near-ridge seamountsCoumans, J.P., J. Stix, D.A. Clague, W.G. Minarik (2015) The magmatic architecture of Taney Seamount-A, NE Pacific Ocean. Journal of Petrology, 56(6): 1037-1067. doi: 10.1093/petrology/egv027.Portner, R.A., D.A. Clague, J.B. Paduan (2014) Caldera formation and varied eruption styles on North Pacific seamounts: the clastic lithofacies record. Bull. Volcanol. 76:845. doi: 10.1007/s00445-014-0845-3.Davis, A.S. and D.A. Clague (2000) President Jackson Seamounts, northern Gorda Ridge: tectonomagmatic relationship between on- and off-axis volcanism, Journal of Geophysical Research, 105(B12): 27,939-27,956. doi: 10.1029/2000JB900291Clague, D.A., J.R. Reynolds, and A.S. Davis (2000) Near-ridge seamount chains in the northeastern Pacific Ocean, Journal of Geophysical Research, 105(B7): 16,541-16,561. doi: 10.1029/2000JB900082Continental margin seamountsSeamounts along California’s continental marginDiverse invertebrate community on Davidson Seamount Image © MBARI 2000Davidson Seamount is one of several seamounts along the California continental margin. It is located about 120 km southwest of Monterey, CA, and rises to within 1300 m of the sea surface. It is oriented northeast-southwest and is a complex series of cones on parallel ridges without a summit caldera, not a typical conical shape. Lavas are basaltic, and range from tholeiite to trachyte. Hyaloclastite deposits indicate that mildly explosive eruptions occurred. Spotlight on Davidson SeamountOther California continental margin seamounts are similar to Davidson in shape, lithologies, and range of ages. They are different from typical ocean-island volcanoes or near-ridge seamounts: they do not line up with each other and are not progressively older like a hot spot chain; they erupted onto much older crust, meaning that they were not associated with mid-ocean ridges. They instead are thought to have erupted along existing zones of weakness because of melting in response to strain on the tectonic plate.A study of deep sea coral distributions at Davidson Seamount is reported on the eclectic topics page. More information about Davidson Seamount is under the MBARI mapping program. This seamount is proposed to become a national marine sanctuary.Xenolith translates to “foreign rock”; it is a clast of another composition entrained in the erupted lavas and can offer clues to the magmatic processes in the volcano. Xenoliths are also discussed in Hot spot: Magmatic processes.Our research on other topics at seamountsHill, T.M., M. LaVigne, H.J. Spero, T. Guilderson, B. Gaylord, and D. Clague (2012). Variations in seawater Sr/Ca recorded in deep-sea bamboo corals. Paleoceanography, 27(3), PA3202. doi: 10.1029/2011PA002260.Lundsten, L., S.B. Johnson, G.M. Cailliet, A.P. DeVogelaere, D.A. Clague (2012) Morphological, molecular, and in situ behavioral observations of the rare deep-sea anglerfish Chaunacops coloratus (Garman, 1899), order Lophiiformes, in the eastern North Pacific, Deep Sea Research I, 68, 46–53, doi:10.1016/j.dsr.2012.05.012Pauly, B.D., P. Schiffman, R.A. Zierenberg, D.A. Clague (2011) Environmental and chemical controls on palagonitization, Geochem. Geophys. Geosyst., 12, Q12017, doi:10.1029/2011GC003639.Pauly, B.D., P. Schiffman, R.A. Zierenberg, D.A. Clague (2011) Environmental and chemical controls on palagonitization, Geochem. Geophys. Geosyst., 12, Q12017, doi:10.1029/2011GC003639.Clague, G.E., W.J. Jones, J.B. Paduan, D.A. Clague, R.C. Vrijenhoek (2012) Phylogeography of Acesta clams from submarine seamounts and escarpments along the western margin of North America. Marine Ecology, 33, 75-87, doi:10.1111/j.1439-0485.2011.00458.x.Hill, T. M., H. J. Spero, T. Guilderson, M. LaVigne, D. Clague, S. Macalello, and N. Jang (2011), Temperature and vital effect controls on bamboo coral (Isididae) isotope geochemistry: A test of the “lines method”, Geochem. Geophys. Geosyst., 12, Q04008, doi:10.1029/2010GC003443.Staudigel, H., Clague, D.A. (2010) The geological history of deep-sea volcanoes: biosphere, hydrosphere, and lithosphere interactions. Oceanography 23(1): 58–71. doi:10.5670/oceanog.2010.62Lundsten, L., McClain, C.R., Barry, J.P., Cailliet, G.M., Clague, D.A., DeVogelaere, A.P. (2009) Ichthyofauna on Three Seamounts off Southern and Central California, USA. Marine Ecology Progress Series 389:223-232. doi: 10.3354/meps08181Lundsten, L., J.P. Barry, G.M. Cailliet, D.A. Clague, A.P. DeVogelaere, J.B. Geller (2009) Benthic invertebrate communities on three seamounts off southern and central California, USA, Marine Ecology Progress Series, 374: 23-32. doi: 10.3354/meps07745Paduan, J.B., D.A. Clague, A.S. Davis (2007) Erratic continental rocks on volcanic seamounts off the US west coast, Marine Geology, 246: 1-8, doi:10.1016/j.margeo.2007.07.007Holland, N.D., D.A. Clague, D. P. Gordon, A. Gebruk, D.L. Pawson, M. Vecchione (2005) ‘Lophenteropneust’ hypothesis refuted by collection and photos of new deep-sea hemichordates, Nature, 434, 374-376. doi: 10.1038/nature03382DeVogelaere, A.P., E.J. Burton, T. Trejo, C.E. King, D.A. Clague, M.N. Tamburri, G.M. Cailliet, R.E. Kochevar, W.J. Douros (2005) Deep-sea corals and resource protection at the Davidson Seamount, California, U.S.A., in: A. Freiwald and J.M. Roberts (eds), Cold-water Corals and Ecosystems, Springer-Verlag, Berlin, Heidelberg, 1189-1198. doi: 10.1007/3-540-27673-4_61Linear seamount chains in the Central Pacific. Map © MBARI 2004, after Davis et al, 2002Non-hot-spot linear chainsSome linear chains do not fit the standard modelsSome linear chains of submarine volcanoes, such as the Line Islands in the Central Pacific, are not associated with a hot spot or mid-ocean ridge, and do not become progressively older with distance. Our research on non-hot-spot linear chainsA.S. Davis, L.B. Gray, D.A. Clague, and J.R. Hein (2002) The Line Islands revisited: New 40Ar/39Ar geochronologic evidence for episodes of volcanism due to lithospheric extension, Geochemistry, Geophysics, Geosystems, 3(3), doi:10.1029/2001GC000190.Eclectic seamounts topicsOur discoveries at seamounts are quite diverseEnteropneust worm off Hawaii. The dome-shaped proboscis and lobed collar are about 2cm in length. Image © MBARI 2001Our expeditions to the sea floor result in biological as well as geological observations and collections. A sea star has been named after our very own Dave Clague. An enteropneust worm found at the President Jackson Seamounts is of a new family, genus, and species, and we have observed others like it at Rodriguez Seamount and off Hawaii. New fish and sponge species have also been discovered. In another study, deep sea coral distributions on Davidson Seamount were examined with video and GIS, and the isotopes in their skeletons were used to study past climate change.On all our dives to seamounts, we have found that erratic rocks are surprisingly abundant and can be from the continent and even from other seamounts. The erratics were probably transported by biological means, rather than icebergs or turbidity flows.Our research on other topics at seamountsWalz, K.R., D.A. Clague, J.P. Barry, and R.C. Vrijenhoek (2014) First records and range extensions for two Acesta clam species (Bivalvia: Limidae) in the Gulf of California, Mexico. Marine Biodiversity Records, 7: 6 pp. doi: 10.1017/S1755267214000165.Hill, T.M., M. LaVigne, H.J. Spero, T. Guilderson, B. Gaylord, and D. Clague (2012). Variations in seawater Sr/Ca recorded in deep-sea bamboo corals. Paleoceanography, 27(3), PA3202. doi: 10.1029/2011PA002260.Lundsten, L., S.B. Johnson, G.M. Cailliet, A.P. DeVogelaere, D.A. Clague (2012) Morphological, molecular, and in situ behavioral observations of the rare deep-sea anglerfish Chaunacops coloratus (Garman, 1899), order Lophiiformes, in the eastern North Pacific, Deep Sea Research I, 68, 46–53, doi:10.1016/j.dsr.2012.05.012Pauly, B.D., P. Schiffman, R.A. Zierenberg, D.A. Clague (2011) Environmental and chemical controls on palagonitization, Geochem. Geophys. Geosyst., 12, Q12017, doi:10.1029/2011GC003639.Clague, G.E., W.J. Jones, J.B. Paduan, D.A. Clague, R.C. Vrijenhoek (2012) Phylogeography of Acesta clams from submarine seamounts and escarpments along the western margin of North America. Marine Ecology, 33, 75-87, doi:10.1111/j.1439-0485.2011.00458.x.Hill, T. M., H. J. Spero, T. Guilderson, M. LaVigne, D. Clague, S. Macalello, and N. Jang (2011), Temperature and vital effect controls on bamboo coral (Isididae) isotope geochemistry: A test of the “lines method”, Geochem. Geophys. Geosyst., 12, Q04008, doi:10.1029/2010GC003443.Staudigel, H., Clague, D.A. (2010) The geological history of deep-sea volcanoes: biosphere, hydrosphere, and lithosphere interactions. Oceanography 23(1): 58–71. doi:10.5670/oceanog.2010.62Lundsten, L., McClain, C.R., Barry, J.P., Cailliet, G.M., Clague, D.A., DeVogelaere, A.P. (2009) Ichthyofauna on Three Seamounts off Southern and Central California, USA. Marine Ecology Progress Series 389:223-232. doi: 10.3354/meps08181Lundsten, L., J.P. Barry, G.M. Cailliet, D.A. Clague, A.P. DeVogelaere, J.B. Geller (2009) Benthic invertebrate communities on three seamounts off southern and central California, USA, Marine Ecology Progress Series, 374: 23-32. doi: 10.3354/meps07745Paduan, J.B., D.A. Clague, A.S. Davis (2007) Erratic continental rocks on volcanic seamounts off the US west coast, Marine Geology, 246: 1-8, doi:10.1016/j.margeo.2007.07.007Holland, N.D., D.A. Clague, D. P. Gordon, A. Gebruk, D.L. Pawson, M. Vecchione (2005) ‘Lophenteropneust’ hypothesis refuted by collection and photos of new deep-sea hemichordates, Nature, 434, 374-376. doi: 10.1038/nature03382DeVogelaere, A.P., E.J. Burton, T. Trejo, C.E. King, D.A. Clague, M.N. Tamburri, G.M. Cailliet, R.E. Kochevar, W.J. Douros (2005) Deep-sea corals and resource protection at the Davidson Seamount, California, U.S.A., in: A. Freiwald and J.M. Roberts (eds), Cold-water Corals and Ecosystems, Springer-Verlag, Berlin, Heidelberg, 1189-1198. doi: 10.1007/3-540-27673-4_61 Margin processes Margin processesProcesses of a tectonically-active continental marginThe continental margin of California was a subduction zone until the mid-Cenozoic. The Farallon tectonic plate subducted under the North American plate and was eventually consumed, sedimentary and crustal material was accreted to the continental margin (now exposed in the Patton Escarpment in the California Borderland), and the granite batholiths in the Sierra Nevada range were emplaced.Perspective view from the west of a map of Hydrate Ridge off Oregon, in the accretionary prism of the Cascadia Subduction Zone and where methane hydrates have been found. Image © 2001 MBARIThe tectonics of central California changed with the passage through the area of the triple-junction now off Mendocino; subduction is still occurring off Oregon and Washington. Now our continental margin is being deformed by the generally strike-slip motion of the San Andreas fault, as the Pacific plate moves north-west relative to the North American plate, carrying the sliver of coastal California with it. Adjustments to the motions of the plates have occurred, which in some places generated tensional forces and subsequent volcanic activity (see the continental margin seamounts page), and in other places generated compressional forces, such as are currently uplifting the Santa Cruz mountains.Related to the active tectonics of the area, are the erosion that shapes the Monterey canyon and the seepage of methane and sulfide-rich fluids that influences the biology. Our group has been involved in these studies, despite there not being a volcanic component.Gas hydrates and cold seepsGas hydrate deposit detection and instabilityBacterial mat (orange) fueled by chemical-rich fluids seeping through the walls of Monterey Canyon. Image © MBARI 1997Chemosynthetic biological communities are evidence of the presence of reduced, chemical-rich fluids at the seafloor. When the fluids are generated at ambient temperatures, as opposed to high temperatures such as at hydrothermal vents, they are said to be “cold seeps”. Cold seeps have now been found in diverse locations, such as on canyon walls, on active continental margins, from limestone escarpments, and above hydrocarbon deposits.Acoustic surveys also provide evidence of cold seeps, and of layers of gas hydrates (carbon-dioxide, methane, and other hydrocarbon gases frozen into an icy slush at high pressure and low temperature) within the sedimentary pile. Gas hydrates are large reservoirs of methane, which is a fossil fuel and green-house gas. Methane is also the compound required by methane oxidizing microbes whose by-product feeds the hydrogen-sulfide oxidizing microbial symbionts that feed the cold-seep biota. Instabilities of the gas hydrate reservoirs may be a consequence of slumping and earthquakes on a local scale, and of increasing ocean temperatures on a global scale.Our research on gas hydrates and cold seepsC.K. Paull, B. Schlining, W. Ussler III, J.B. Paduan, D. Caress, and H.G. Greene (2005) Distribution of chemosynthetic biological communities in Monterey Bay, California, Geology 33(2): 85-88. [Abstract] [Article]C.K. Paull, P.G. Brewer, W. Ussler III, E.T. Peltzer, G. Rehder, D. Clague (2003) An experiment demonstrating that marine slumping is a mechanism to transfer methane from seafloor gas-hydrate deposits into the upper ocean and atmosphere, Geo-Marine Letters 22(4): 198-203. [Abstract] [Article]D.A Clague, N. Maher, and C.K. Paull (2001) High-resolution multibeam survey of Hydrate Ridge, offshore Oregon, In: Natural Gas Hydrates: Occurrence, Distribution, and Detection, C.K. Paull and W.P. Dillon (eds), Geophysical Monograph 124, American Geophysical Union, 297-303.Map of the California Borderland, which is a broad area of basins and ranges with some islands off Southern California. Map © MBARI 2006California BorderlandCalifornia borderland geologyThe geologic history of the region offshore of Southern California is poorly understood. Its interpretation is complicated by the fact that it is largely submerged, is heavily sedimented, and many of the rocks from which interpretations have been made were probably erratics transported offshore from continental beaches tangled in kelp holdfasts, in tree roots, or in sea lion stomachs. The Patton Escarpment marks the edge of the continental shelf (where the orange drops off to greens and blues in the map above), and is a relict accretionary wedge from a subduction zone that was active in the Mesozoic into the Cenozoic.Note that our work on the seamounts off of California is on the Seamounts: Continental Margin page, and our work on erratic rocks is on the Seamounts: Eclectic topics page.Our research on California Borderland geologyClague, D., Marsaglia, K.M., Cousens, B.L., Paduan, J.B. (2019) Oligocene and Miocene volcanics in the sedimentary forearc of the Outer California Borderland. Society for Sedimentary Geology, 110, 22-42. doi: 10.2110/sepmsp.110.04Marsaglia, K.M., A.S. Davis, K. Rimkus, D.A. Clague (2006) Evidence for interaction of a spreading ridge with the outer California borderland, Marine Geology, 229: 259-272. doi: 10.1016/j.margeo.2006.02.006 Hot spot research Diamond Head at sunset. Photo © J.B. Paduan, 2006Life-cycle of Hawaiian hot spot volcanoesThe Hawaiian Islands and Emperor Seamount chain of volcanoes are the product of a mantle hot spot in the middle of the Pacific Plate. The hot spot’s current activity is underneath the southern end of the island of Hawaii and the next volcano in the chain, Lo’ihi Seamount, is forming on the sea floor just to the south of Hawaii and should emerge in another 200,000 years. (See maps of the entire chain.)The volcanoes undergo a progression of eruption styles and chemistries as they age, from pre-shield stage (e.g., Lo’ihi), through the major shield-building stage (e.g., Kilauea), to post-shield (e.g., Haleakala) and rejuvenated stages (such as Diamond Head on Oahu when it erupted). As the enormous mountains build on top of the ocean crust, the crust flexes downward and the islands slowly sink. Coral reefs grow around the islands when sea level changes slowly enough for them to keep up with the sinking of the islands, and the reefs drown or are exposed if sea level rises or drops too quickly. Erosion takes an enormous toll on the islands: giant landslides have occurred off all the islands, and some of the debris has traveled hundreds of kilometers offshore.Once the volcanoes are extinct, the islands continue to erode until they slip below sea level. The Emperor Seamount chain was once over the hot spot and probably looked much like the modern Hawaiian Islands, but the volcanoes have since submerged. The Pacific Plate is carrying the entire chain of islands and seamounts to the northwest as it drifts slowly to the Aleutian Trench and its ultimate subduction. Volcanoes resources MBARI Videos Submarine Volcanism ResourcesNews storiesMBARI news release about eruption dynamics of the 2015 eruption at Axial SeamountMBARI news release about hundreds of chimneys being discovered at Endeavour from our mapping data.MBARI news release about mapping of Loihi SeamountNews stories about our November 2018 return to Pescadero Basin on the R/V FalkorMBARI news release about our expeditionMarine Technology News “SOI mission discovers new hydrothermal vent and species”Motherboard “Scientists discover upside-down lakes and waterfalls at the bottom of the ocean” by Sarah EmersonScience Alert “An incredible new ecosystem has been discovered at the bottom of the ocean” by Michelle StarrMBARI news release about Gulf of California hydrothermal vent organism diversityNature Geoscience article about the February 2017 Submarine Volcanism Chapman ConferenceMBARI news release about Axial 2015 lava flow mappingMBARI news release and YouTube video about our 2015 cruise to Pescadero BasinUCSC Science Notes – story, podcast and video about our project by Tanya LewisMBARI news story about mapping the Axial 2011 eruption with our AUVMBARI news stories about our 2012 GOC expedition:discovering new hydrothermal ventsreturning to the Gulf of Californiapresentations at the 2012 AGU meetingMBARI news story about Dave Clague “Blowing the lid off underwater volcanoes”MBARI news story about Mapping AUV related presentations at the 2011 AGU meetingLau Basin 2009 expedition (blog and Vents Program announcement)Ridge Events newsletter article (starts on page 5) offline November 2021MBARI news story about seamounts off Southern California that once were ancient islands External data sites Marine Geo Science Data System PetDP Team Directory David A. Clague Senior Adjunct/Geologist/ Volcanologist Jennifer B. Paduan Senior Research Specialist Publications All Publications Gao, R., J.C. Lassiter, D.A. Clague, and W.A. Bohrson. 2022. Evolution of Hawaiian volcano magmatic plumbing system and implications for melt/edifice and melt/lithosphere interaction: Constraints from Hualālai xenoliths. Journal of Petrology, 63(9): 1–24. https://doi.org/10.1093/petrology/egac091 Portner, R., B.M. Dreyer, D.A. Clague, N.R. Daczko, and P.R. Castillo. 2022. Oceanic zircon records extreme fractional crystallization of MORB to rhyolite on the Alarcon Rise mid-ocean ridge. Journal of Petrology, 63: 1–25, https://doi.org/10.1093/petrology/egac040 Le Saout, M., D.A. Clague, and J.B. Paduan. 2022. Faulting and magmatic accretion across the overlapping spreading center between Vance Segment and Axial South Rift, Juan de Fuca Ridge. Geochemistry, Geophysics, Geosystems, 23: 1–12. https://doi.org/10.1029/2021GC010082 Murch, A., R.A. Portner, K.H. Rubin, and D.A. Clague. 2022. Deep-subaqueous implosive volcanism at West Mata seamount, Tonga. Earth and Planetary Science Letters, 578: 1–15. https://doi.org/10.1016/j.epsl.2021.117328 Paduan, J., D. Clague, D. Caress, M. Le Saout, and B. Dreyer. 2021. Systematic variations in lava flow morphology along the north and south rift zones of Axial Seamount. AGU Meeting, Fall 2020: 1–20. https://doi.org/10.1002/essoar.10505810.1 Latest News All News News Listening to an underwater eruption News 09.08.20 News Hundreds of hydrothermal chimneys discovered on the seafloor off the Pacific Northwest News 04.28.20 News Mapping the next Hawaiian island News 04.25.19 Technologies All Technologies Vehicle, Autonomous Underwater Vehicle (AUV), Dorado Class Seafloor Mapping AUV Technology Seafloor Mapping AUV The Dorado class autonomous underwater vehicles are optimized for meter-scale seafloor mapping. Data All Data Sorry, no results were found.