Kasuga-2 Vent
Latitude: 21.61οN Longitude: 143.64166οE Depth: 297 m bsl
Alternative names: Minami Kasuga, Daini Kasuga, Dai-ni Kasuga (InterRidge Vents Database Ver. 3.3)
Vent Sites: Barnacle Boulders, Crab Slope, Cracked Vent, Flat Bottom, Hairy Mat, Hairy Rock, Mat Ridge, Pinnacle, SW Eels, Whale Rock, Yellow Overlord (InterRidge Vents Database Ver. 3.3)
Kasuga-2 seamount is a heavily eroded caldera (Resing et al., 2009), located in the rear arc of Northern Seamount Province (Bloomer et al., 1989). Based on the freshness of lavas recovered from the volcano and active hydrothermal activity, Fryer et al., (1990) confirm that this volcano is active. Resing et al., (2009) identified two separate hydrothermal sources with distinct chemical signatures. The hydrothermal fluids are enriched in Mg2+, SO42- and depleted in Ca2+ relative to ambient seawater and those values are unusual compared to the fluids from other hydrothermal systems. Some bacteria, eukaryotes including worms, flatfish and even vertebrate shark make their habitat around Kasuga-2 seamount.
Table 1: Operations history for Kasuga 2 vent
| Ship/ Platform | Operation | Year | Dive Number | References |
| TN-153 R/V T. G. Thompson | EM 300 multibeam; CTD tow-yo | 2003 February – March | Not found | Submarine Ring of Fire 2003 |
| TN-167 R/V T. G. Thompson | CTD tow-yo; ROPOS | 2004 March- April | R794 | Submarine Ring of Fire 2004 |
| Shinkai 2000 | Not found | 1997 November | 990 | JAMSTEC E-library of Deep-sea Images (JEDI) (note: Search “Kasuga 2”) |
Table 2: Vent activity and host rocks
| Activity and host rocks | References | |
| Activity | Activity detected in 1987 and also in 2003 |
Fryer., 1990 Embley et al., 2004 Baker et al., 2008 |
| Host Rocks |
Calc-alkaline (medium-high K-basalts and absarokites) and subordinate andesites and dacites Basalt and Andesite |
Stern et al., 1993 Fryer et al., 1997 |
Table 3: Vent fluid characteristics
| Vent Fluids | References | ||
| Temperature (οC) | 39
High Temperature |
McMurtry et al., 1993 Resing et al., 2009 | |
| pH at 27οC | 5.2 | McMurtry et al., 1993 | |
| Composition | Enriched in Mg2+, SO42- and dissolved Si and depleted in Ca2+, Cl– and rich in CO2 relative to ambient seawater.
Degasses H2S |
McMurtry et al., 1993
|
|
| Plume depth (m) | Shallow (355 m – 390 m) | Deep (550 m – 650 m) | Resing et al., 2009 |
| ΔpH | 0.813 | 0.313 | Resing et al., 2009 |
| Particulate Fe (nmol/kg) | 24 | 263 | Resing et al., 2009 |
| TDMn (nM) | 58 | 26 | Resing et al., 2009 |
| TDFe (nM) | 180 | 810 | Resing et al., 2009 |
| Δ3He (fM) | 15.5 | 3.8 | Resing et al., 2009 |
| ΔCO2 (mM) | 265 | 24 | Resing et al., 2009 |
| CH4 (nM) | 94 | 22 | Resing et al., 2009 |
* ΔpH, ΔCO2 – Measured relative to the regional background; Δ3He – Measured above the background.
Table 4: Vent Biology
| General name | Phylum | Species | References |
| Chemosynthetic bacteria | Bacteria | Submarine Ring of Fire, 2006 | |
| Tube worms | Annelida | Submarine Ring of Fire 2004 | |
| Nematode worms | Nematoda | Submarine Ring of Fire 2006 | |
| Small flatfish | Chordata | Symphurus thermophilus | Submarine Ring of Fire 2006
Tunniclife et al., 2010 |
| Vertebrate- Shark | Chordata | Submarine Ring of Fire | |
| Bythogreid crab | Arthropoda | InterRidge Vents Database | |
| Barnacle | Arthropoda | InterRidge Vents Database | |
| Tonguefish | Chordata | InterRidge Vents Database |
Images:
- J-EDI JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Kasuga 2”)
- Scientists were surprised by a rare sighting of a shark at the Kasuga-2 hydrothermal system.
- A close-up of the tubeworm (Lamelli brachia) found at Kasuga-2
Video Links:
- J-EDI JAMSTEC E-library of Deep-sea Images (JEDI) (note: search “Kasuga 2”)
References:
- Baker, E. T., Embley, R. W., Walker, S. L., Resing, J. A., Lupton, J. E., Nakamura, K., de Ronde, C. E. J., Massoth, G. J., 2008. Hydrothermal activity and volcano distribution along the Mariana arc: Journal of Geophysical Research 113 (B8), 1-16.
- Bloomer, S. H., Stern, R. J., Fisk, E., Geschwind, C. H., 1989. Shoshonitic Volcanism in the Northern Mariana Arc. 1. Mineralogic and Major and Trace Element Characteristics. Journal of Geophysical Research 94 (B4), 4469-4496.
- Embley, R. W., Baker, E. T., Chadwick, W. W. JR., Lupton, J. E., Resing, J. A., Massoth, G. J., Nakamura, K., 2004. Explorations of Mariana Arc. Eos 85 (4), 37-44.
- Fryer, P., 1990. Recent Marine Geological Research in the Mariana and Izu-Bonin Island Arcs. Pacific Science 44 (2), 95-114.
- Fryer, P., Gill, J. B., Jackson, M. C., 1997. Volcanologic and tectonic evolution of the Kasuga seamounts. Journal of Volcanology and Geothermal Research 79, 277–311.
- McMurtry, G. M., Sedwick, P. N., Fryer, P., VonderHaar, D. L., Yeh, H. W., 1993. Unusual geochemistry of hydrothermal vents on submarine arc volcanoes Kasuga Seamounts, Northern Mariana Arc. Earth and Planetary Science Letters 114, 517-528.
- Resing, J. A., Baker, E. T., Lupton, J. E., Walker, S. L., Butterfield, D. A., Massoth, G. J., Nakamura, K., 2009. Chemistry of hydrothermal plumes above submarine volcanoes of the Mariana Arc. Geochemistry, Geophysics, Geosystems 10 (2), 1-23.
- Stern, R. J., Jackson, M. C., Fryer, P., Ito, E., 1993. O, Sr, Nd and Pb isotopic composition of the Kasuga Cross-Chain in the Mariana Arc: A new perspective on the K-h relationship. Earth and Planetary Science Letters 119, 459-475.
Website References:
- International cooperation in ridge-crest studies: InterRidge Vents Database Version 3; http://www.interridge.org/irvents/content/kasuga-2-seamount (accessed 11.19.2015)
- J-EDI JAMSTEC E-library of Deep-sea Images http://www.godac.jamstec.go.jp/jedi/public/Sec102.jsf (accessed 12/02/2015)
- Submarine Ring of Fire 2004 http://oceanexplorer.noaa.gov/explorations/04fire/logs/april15/april15.html (accessed 12/02/2015)
- Submarine Ring of Fire 2006 http://oceanexplorer.noaa.gov/explorations/06fire/background/biology/biology.html (accessed 11.19.2015)
Cruise Reports:
- Submarine Ring of Fire 2003 http://oceanexplorer.noaa.gov/explorations/03fire/logs/summary/marianas_cruisereport.pdf (accessed 11.19.2015)
- Submarine Ring of Fire 2004 http://oceanexplorer.noaa.gov/explorations/04fire/logs/summary/media/marianas2004cruisereport.pdf (accessed 11.19.2015)