Urashima Vent



Latitude: 12.917οN               Longitude: 143.650οE          Depth: 2922 mbsl

Urashima site is located north of Pika site in the southern Mariana arc/trough region. In 2010 several gray smokers venting hydrothermal fluids (280°C) were observed (Nakamura et al. 2013). The site includes black dead chimneys, red-brown shimmering chimneys, and areas of yellow microbial mat exposed to low-temperature hydrothermal fluids (Toki et al., 2015).  In addition to microbial mats there are anemones, crabs and shrimp were also found in the area (YK10-10 cruise report).

Table 1: Operations history for Urashima vent 

Ship/ Platform Operation Year Dive Number References
RR1413 R/V Roger Revelle/ Jason XBT, CTD

EM122 multibeam logging

2014 J2-797, J2-801 Submarine Ring of Fire 2014-Ironman
YK10-10 Yokosuka/ Shinkai 6500 Not found 2010 August 1214- 1219 YK10-10 cruise report
YK10-11 Yokosuka/ Shinkai 6500 Not found 2010 September 1220, 1227, 1228

YK10-11 cruise report

Beauliue et al., 2011

Table 2: Vent activity and host rocks 

Activity and host rocks References
Vent Activity Active Submarine Ring of Fire 2014-Ironman
Host Rocks Not found

Table 3: Vent fluid characteristics 

Vent Fluids References
Temperature (°C) 321, 280 to 70 YK10-10 cruise report
pH 2.85 Toki et al., 2015
Composition Active gray smoker, and clear fluid chimneys with iron mat including one big ~10m YK10-10 cruise report
CO2 (mM) 23.2 Toki et al., 2015
Mn (mM) 2.22 Toki et al., 2015
Fe (mM) 6.37 Toki et al., 2015
(3He/4He) 8.09 Toki et al., 2015
CH4 (mM) 0.0108 Toki et al., 2015
Cl- (mM) 623 Mino et al., 2013
Na (mM) 456 Mino et al., 2013
K (mM) 37 Mino et al., 2013
Ca (mM) 31 Mino et al., 2013
NH4+ (μM) <100 Mino et al., 2013
SO42- (mM) -4.11 Mino et al., 2013
H2S (mM) 2.4 Mino et al., 2013
Alkalinity (meq/kg) -1.42 Nakamura et al., 2013
Table 4: Vent biology
General name Phylum References
Bacterial iron mats YK10-10 cruise report
Anemone Arthropoda YK10-10 cruise report
Crabs Arthropoda YK10-10 cruise report
Shrimp Arthropoda YK10-10 cruise report


  • Sulfide chimneys coated with iron-based microbial mat at the Urashima vent site (note: search “sulfide chimneys”).

Video Links:


  1. Mino, S., Makita, H., Toki, T., Miyazaki, J., Kato, S., Watanabe, H., … & Sawabe, T. (2013). Biogeography of Persephonella in deep-sea hydrothermal vents of the Western Pacific.
  2. Nakamura, K., Toki, T., Mochizuki, N., Asada, M., Ishibashi, J. I., Nogi, Y., … & Okino, K. (2013). Discovery of a new hydrothermal vent based on an underwater, high-resolution geophysical survey. Deep Sea Research Part I: Oceanographic Research Papers, 74, 1-10.
  3. Toki, T., Ishibashi, J., Noguchi, T., Tawata, M., Tsunogai, U., Yamanaka, T., and Nakamura, K., 2015, Chemical and Isotopic Compositions of Hydrothermal Fluids at Snail, Archaean, Pika, and Urashima Sites in the Southern Mariana Trough. In: Ishibashi, J., Okino, K., Sunamura, M. (Eds.), Subseafloor Biosphere Linked to Hydrothermal Systems: TAIGA Concept. Springer Japan, 587-602.

Website References:

  1. Submarine Ring of Fire 2014  (accessed 11/26/2015)

Cruise Reports:

  1. Submarine Ring of Fire 2014-Ironman cruise report (2/26/2017)
  2. Yokosuka Cruise Report YK10-10 (accessed 11/26/2015)
  3. Yokosuka Cruise Report YK10-11  (accessed 11/26/2015)