The Global Seamount Census

Abstract

aBstr aCt. Seamounts are active or extinct undersea volcanoes with heights exceeding ~ 100 m. They represent a small but significant fraction of the volcanic extrusive budget for oceanic seafloor and their distribution gives information about spatial and temporal variations in intraplate volcanic activity. In addition, they sustain important ecological communities, determine habitats for fish, and act as obstacles to currents, thus enhancing tidal energy dissipation and ocean mixing. Mapping the complete global distribution will help constrain models of seamount formation as well as aid in understanding marine habitats and deep ocean circulation. Two approaches have been used to map the global seamount distribution. Depth soundings from single-and multibeam echosounders can provide the most detailed maps with up to 200-m horizontal resolution. However, soundings from the > 5000 publicly available cruises sample only a small fraction of the ocean floor. Satellite altimetry can detect seamounts taller than ~ 1.5 km, and studies using altimetry have produced seamount catalogues holding almost 13,000 seamounts. Based on the size-frequency relationship for larger seamounts, we predict over 100,000 seamounts > 1 km in height remain uncharted, and speculatively 25 million > 100 m in height. Future altimetry missions could improve on resolution and significantly decrease noise levels, allowing for an even larger number of intermediate (1-1.5-km height) seamounts to be detected.Recent retracking of the radar altimeter waveforms to improve the accuracy of the gravity field has resulted in a twofold increase in resolution. Thus, improved analyses of existing altimetry with better calibration from multibeam bathymetry could also increase census estimates.

Microbiology of Seamounts: Common Patterns Observed in Community Structure

“…There are estimated to be over 100,000 seamounts that reach a kilometer or more above the seafloor (see Wessel et al, 2010 figure 1. cross section of a typical submarine arc volcano with an active hydrothermal system.…”

Seamounts off the West Antarctic margin: A case for non-hotspot driven intraplate volcanism

“…Although only a fraction of them have been mapped by ship-based echo-sounding, satellite altimetry has identified more than 13,000 seamounts taller than 1.5 km and predicts more than 100,000 seamounts higher than 1 km (e.g., Smith and Sandwell, 1997;Wessel et al, 2010). Seamounts are important probes of the composition and dynamics of the oceanic mantle and, if they form parts of hotspot tracks, they can also be important recorders of past plate motions (Hofmann, 2003;Tarduno et al, 2003;Koppers et al, 2012).…”

Future accreted terranes: a compilation of island arcs, oceanic plateaus, submarine ridges, seamounts, and continental fragments

“…In general, seamounts are submarine volcanoes, smaller in areal extent than oceanic plateaus and submarine ridges, with geochemical signatures that suggest different sources for different seamount chains. The number of seamounts > 1.5 km in height currently on the ocean floor is estimated to be more than 13 000 based on satellite altimetry (Wessel et al, 2010), and these numerous features often alter subduction zone by blocking the subducting interface or causing uplift in the accretionary prism . Seamounts can be formed by various processes: they can be the result of upper mantle mini-convection cells under mid-ocean ridges or transforms (Buck and Parmentier, 1986), deep mantle upwellings, short-lived hotspot volcanism, upper asthenospheric upwelling, and lithospheric cracking (Forsyth et al, 2006;Briais et al, 2009;Sandwell and Fialko, 2004).…”