Latitude: 19.542οN Longitude: 146.648οE Depth: 3144 m bsl
Conical Seamount is a smooth sided, nearly circular forearc serpentine mud volcano with a slightly flattened summit region (Fryer, 1996) that is located adjacent to a large forearc graben (Fryer et al., 1990; Fryer, 1992; Newsom, 1992). Conical Seamount is considered active because of the discovery of recent mud extrusions and the venting of fluids with deep slab origins [Fryer and Mottl, 1992]. The fluids are actively flowing through carbonate and silicate chimneys and have elevated pH, high alkalinity and enrichments in CH4, SiO2, SO42-, and H2S. Methane and sulfate in the fluids are probably generated during serpentinization reactions between peridotite and slab derived fluids (Fryer, 1990). Some bacterial mats, small limpets and gastropods are associated with these vents.
Table 1: Operations history for Conical vent
| Ship/ Platform | Operation | Year | Dive Number | References |
| KR06-15 Kaiko | Not found | 2006 November | 0369 | JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Conical”)KR06-15 cruise report |
| Not found | SeaMARK II bathymetry data | Not found | Not found | Fryer et al., 1996; Fryer et al., 1992 |
| Not found | Seasat A Satellite Scatterometer (SASS) data | Not found | Not found | Fryer et al., 1996; Fryer et al., 1992 |
| TN-154 Thompson/ ROV Jason-2 | Not found | 2003 April | J2-032 | Woods Hole Oceanographic Institution: ROV JASON/MEDEA: Operations Summary (note: click “Files- operations summary”) |
| YK03-07 Yokosuka/ Shinkai 6500 | Not found | 2003 September | 785 | YK03-07 cruise report |
Table 2: Vent activity and host rocks
| Activity and Host Rocks | References | |
| Activity | Active mud volcanism | Fryer and Mottl., 1992; Fryer., 1990; IODP-MCME 366 Proposal; Savov et al., 2005 |
| Host Rocks | Serpentinized harzburgite and dunite | Fryer et al., 1990; Savov et al., 2005 |
Table 3: Vent fluid characteristics
| Bottom seawater | Vent Fluids | References | |
| Distance from the trench (km) | 90 | IODP-MCME 366 Proposal | |
| Temperature (οC) | 13.5 οC (hole 780D); 1.5οC | Fryer et al., 1990(c); Mottl et al., 2003 | |
| pH | 7.72 | 9.28 | Fryer et al., 1990 |
| >9.2, 12.5 | Hulme et al., 2010, Fryer et al., 1990 b | ||
| Composition | Indicate deep seated serpentinization sources, enriched in CH4, SiO2, SO42-, H2S | Fryer et al., 1990 | |
| Alkalinity (meq/kg) | 2.3 | High, 41 | Fryer et al., 1990 |
| Clorinity (mmol/kg) | 542 | 260 | IODP-MCME 366 Proposal |
| CH4 (mmol/kg) | 4×10-7 | 2±1 | Mottl et al., 2003 |
| Mn (μmol/kg) | 0 | <0.01 | IODP-MCME 366 Proposal |
| Fe (μmol/kg) | 0 | 2 | IODP-MCME 366 Proposal |
| Sulfate (mmol/kg) | 28 | 46 | IODP-MCME 366 Proposal |
| Mg (mmol/kg) | 0.009 | Fryer et al., 1990 b | |
| Ca (mmol/kg) | 0.6 | Fryer et al., 1990 b | |
| Na (mmol/kg) | 466 | 390 | IODP-MCME 366 Proposal |
| K (mmol/kg) | 10.1 | 15 | IODP-MCME 366 Proposal |
| Li (μmol/kg) | 26 | 1.6 | IODP-MCME 366 Proposal |
| Rb (μmol/kg) | 1.37 | 7.8 | IODP-MCME 366 Proposal |
| Sr (μmol/kg) | 90 | 20 | IODP-MCME 366 Proposal |
| Ba (μmol/kg) | 0.14 | 0.1 | IODP-MCME 366 Proposal |
| B (μmol/kg) | 410 | 3900 | IODP-MCME 366 Proposal |
| Si (μmol/kg) | 190 | 60 | IODP-MCME 366 Proposal |
* IODP-MCME 366- International Ocean Discovery Program-Mariana Convergent Margin Expedition 366.
Table 4: Vent Biology
| General name | Phylum | Class/Order | Family | Genus/Species | References |
| Bacterial mats | Bacteria | Fryer et al., 1990 | |||
| Fish | Chordata | Anguilliformes | JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Conical seamount”) | ||
| Gastropods | Mollusca | Fryer et al., 1990 | |||
| Sea anemone | Cnidaria | Actiniaria | Boloceroididae | JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Conical seamount”) | |
| Sea cucumbers | Echinoderms | Holothuroidea | Pelagothuriidae | Enypniastes eximia | JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Conical seamount”) |
| Shrimp | Arthropoda | Decapoda | JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Conical seamount”) | ||
| Small Limpets | Mollusca | Fryer et al., 1990 | |||
| Sponge | Porifera | JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Conical seamount”) |
Images:
- J-EDI JAMSTEC E-library of Deep-sea Images http://www.godac.jamstec.go.jp/jedi/public/Sec101.jsf note: search “Conical”.
Video Links: None known
References:
- Fryer, P., Saboda, K. L., Johnson, L. B., Mackay, M. E., Moore, G. F., Sto¡ers, P., 1990. Conical Seamount: SeaMARK II, Alvin submersible, and seismic reflection studies. Proc. ODP Init. Rep. 125, 69-80.
- Fryer, P., Mottl, M. J., 1992. Lithology, mineralogy, and origin of serpentine muds recovered from Conical and Torishima forearc seamounts: results of Leg 125 drilling, Proc. ODP Sci. Results 125, 343-362.
- Fryer, P, 1996. Evolution of the Mariana convergent plate margin system. Reviews of Geophysics 31 (1), 89-125.
- Mottl, M. J., Komor, S. C., Fryer, P., Moyer, C. L., 2003. Deep-slab fluids fuel extremophilic Archaea on a Mariana forearc serpentinite mud volcano: Ocean Drilling Program Leg 195. Geochemistry, Geophysics, Geosystems 4 (11) 9009, doi: 10.1029/2003GC000588.
- Savov, I. P., Ryan, J. G., D’Antonio, M., Kelley, K., Mattie, P., 2005. Geochemistry of serpentinized peridotites from the Mariana Forearc Conical Seamount, ODP Leg 125: Implications for the elemental recycling at subduction zones. Geochem.Geophys. Geosyst., 6, Q04J15, doi: 10.1029/2004GC000777.
Website References:
- J-EDI JAMSTEC (Japan Agency for Marine Earth Science and Technology) E-library of Deep-sea Images: http://www.godac.jamstec.go.jp/jedi/public/Sec101.jsf (accessed 11/24/2015)
- Woods Hole Oceanographic Institution: ROV JASON/MEDEA: Operations Summary http://www.whoi.edu/main/jason/operations-summary (accessed 11/24/2015)
Cruise Reports:
- IODP Mariana Convergent Margin Expedition 366, unpublished IODP proposal http://iodp.tamu.edu/scienceops/precruise/mariana/505-Full5.pdf (accessed 01/19/2016)
- Kairei cruise report KR06-15 http://www.godac.jamstec.go.jp/catalog/data/doc_catalog/media/KR06-15_leg1-2_all.pdf (accessed 01/19/2016)
- Yokosuka cruise report YK03-07 http://www.godac.jamstec.go.jp/catalog/data/doc_catalog/media/YK03-07_all.pdf (accessed 01/19/2016)