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Large serpentinite mud volcanoes form on the overriding plate of the Mariana subduction zone. Fluids from the descending plate hydrate (serpentinize) the forearc mantle and enable serpentinite muds to rise along faults to the seafloor. The seamounts are direct windows into subduction processes at depths far too deep to be accessed by any known technology. Fluid compositions vary with distance from the trench, signaling changes in chemical reactions as temperature and pressure increase. The parageneses of rocks in the mudflows permits us to constrain the physical conditions of the decollement region. If eruptive episodes are related to seismicity, seafloor observatories at these seamounts hold the potential to capture a subduction event and trace the effects of eruption on the biological communities that the slab fluids support, such as extremophile Archaea. The microorganisms that inhabit this high-pH, extreme environment support their growth by utilizing chemical constituents present in the slab fluids. Some researchers now contend that the serpentinization process itself may hold the key to the origin of life on Earth.
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Download Supplemental Material as a PDF. Includes Supplemental Figure 1 (reproduced below), Supplemental Videos 1-3 (individual videos files also included below), and Supplemental References
Supplemental Figure 1. 3D anaglyph image of Celestial Seamount (image provided by N.C. Becker, created using the technique given in Becker 2005). To view this image in 3D, the reader must wear red/blue 3D glasses (red over the left eye).
Supplemental Video 1. This video shows relocated earthquakes (Engdahl et al. 1998) from 1964 to 2002 plotted only to 50 km depth (colors of dots indicate depths) for the entire Mariana region. The size of the dots gives an indication of the relative magnitude of the events. Notice especially the cluster of events beginning in December 1989 between 14°N and 16°N near Blue Moon Seamount. Download video file (MOV)
Supplemental Video 2. Cross section of the Mariana forearc on one degree either side of a transect through Blue Moon Seamount orthogonal to the curve of the trench showing relocated earthquakes (Engdahl et al. 1998) from 1964 to 2002. Events are plotted only to 50 km depth. The size of the dots gives an indication of the relative magnitude of the events. Notice especially the cluster of events beginning in December 1989 and the fact that there is some relationship between deep earthquakes followed by much shallower ones under the seamounts. The position of Blue Moon Seamount is depicted by the green triangle on the right and Peacock Seamount by the green triangle on the left. Download video file (MOV)
Supplemental Video 3. Cross section of the Mariana forearc on one degree either side of a transect through Quaker Seamount orthogonal to the curve of the trench showing relocated earthquakes (Engdahl et al. 1998) from 1964 to 2002. Events are plotted only to 50 km depth. The size of the dots gives an indication of the relative magnitude of the events. Notice that events frequently appear in vertical groupings and most frequently in the area beneath the seamount. Download video file (MOV)