R/V KAIREI Cruise Report KR13-14 R/V KAIREI + ROV KAIKO7000II Deep Sea Research Structure and dynamics of subduction channels in intraoceanic subduction zones (Ohmachi Seamount, Izu-Bonin arc) August 30, 2013 – September 12, 2013 Yokosuka – Naha Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
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R/V KAIREI Cruise Report KR13-14 · PDF fileR/V KAIREI Cruise Report . KR13-14 . ... Steward SEIJI HONDA . ... Scientist YUKA NISHIKAWA National Taiwan University
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R/V KAIREI Cruise Report
KR13-14
R/V KAIREI + ROV KAIKO7000II Deep Sea Research Structure and dynamics of subduction channels in intraoceanic
subduction zones (Ohmachi Seamount, Izu-Bonin arc)
August 30, 2013 – September 12, 2013 Yokosuka – Naha
Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
Contents 1. Cruise Information 2. Backgrounds and objectives
3. Operation and preliminary results 3.1 Side scan sonar imaging 3.2 Dive report (7K#609 and7K #610) 3.3 Dredge 3.4 MBES
4. Summary 5. Acknowledgements 6. Notice on using
1. Cruise information
(1) Name of vessel & Cruise ID R/V KAIREI KR13-14
(2) Title of the cruise 2013 Deep Sea Research: R/V KAIREI / KAIKO 7000II:
Ohmachi Seamount, Izu-Ogasawara (Bonin) arc.
(3) Proposal number and scientific title S13-36 Structure and dynamics of subduction channels in intraoceanic arcs.
(4) Period of the cruise From August 30 to September 12, 2013
(5) Port calls Departure: Yokosuka (August 30, 2013)
Arrival: Naha (September 12, 2013)
(6) Research area Ohmachi Seamount (1000 - 4000 m bsl)
28º30.0’ – 29º30.0’N, 140°20.0’E - 141°00.0’E
(7) Researchers [R/V KAIREI Crew]
Captain YOSHIYUKI NAKAMURA Chief Officer HIROYUKI KATO 2nd Officer TOSHIYO OHARA 3rd Officer SATORU YOSHIDA Chief Engineer KIYONORI KAJINISHI 1st Engineer KENZO KATO Jr. 1st Engineer KOJI FUNAE 2nd Engineer RYOZO MIKAMI 3rd Engineer NAOOMI UEMURA Chief Electronics Operator HIROYASU SAITAKE 2nd Electronics Operator YOSHIKAZU KURAMOTO 3rd Electronics Operator TAKAYUKI MABARA Boat Swain YASUYOSHI KYUKI Able Seaman SHUICHI YAMAMOTO Able Seaman HATSUO ODA Able Seaman YUKITO ISHII Able Seaman SAIKAN HIRAI Sailor SHUN MIURA
09:00 Departure from Sumitomo Heavy Indus., Yokosuka. 10:00-10:40 Lecture for shipboard life and safety. 10:45-11:05 KAIKO briefing. 11:08-11:15 Scientists’ meeting.
31-Aug-13 15:00 Arrived at the research area. 8/31 12:00 (UTC+9h) 29-58.7N,140-42.2E fine but cloudy WSW-3 (gentle breeze) 2 (sea smooth) 2 (Low swell long) Visibly: 8'
15:20 Released XBT. 16:14 Deployed transponder B. 16:36 Deployed transponder A. 16:58 Deployed transponder C. 17:48-18:55 LBL transponder calibration.
09:50 KAIKO started SSS survey. 14:00 KAIKO finished SSS survey. 15:55 KAIKO came up to the surface. 18:30-18:50 Scientists’ meeting. 18:46- Began MBES survey.
04:46-04:56 Dive point MBES survey. 08:49 Launching KAIKO (KAIKO#609Dive). 11:10 KAIKO landing (3,372m). 14:37 KAIKO left the bottom (3,345m). 16:46 KAIKO came up to the surface. 19:17- Began MBES survey. 20:00-20:10 Scientists’ meeting.
08:39 Launching KAIKO (KAIKO#610Dive). 11:05 KAIKO landing (3,361m). 14:04 KAIKO left the bottom (3,335m). 16:11 KAIKO came up to the surface. 18:45- Began MBES survey.
08:00-08:42 Recovered transponder B. 08:54-10:43 Recovered transponder A. 10:52-11:28 Recovered transponder C. 12:47-20:34 MBES survey. Transit to off Chichi jima island for rigging.
3.4 MBES During the intervals of dives and dredges at night, bathymetry around the Ohmachi Seamount
were mapped by KAIREI SeaBeam. The blank areas which had not yet been mapped in the survey
area were almost fully filled with the acquired depth data. Together with the previous data,
bathymetric features on and around the seamount were imaged enough for topographic analyses and
for designing future surveys.
4. Summary Results of this cruise is briefly summarized as:
(1) KAIKO 7000II vehicle successfully revisited to the same outcrop as 6K#609 Loc. 4 (the
locality of an amphibolitized eclogite collected in 2001), whose location was aimed greatly
relying on the side-scan sonar images newly acquired by the KAIKO launcher with LBL
ecolocation. Two markers were left on the outcrop for future exploration.
(2) Detailed observation and sampling concluded that this outcrop probably consists wholly of
serpentinite. Two float stones of amphibolite collected from the outcrop surface close to a
ridge crest suggested that the amphibolite exposure lies a little more upslope, where our
exploration did not reached.
(3) Repetitive dredges around 6K#609 Loc. 4 collected 44 new amphibolite samples of varying
lithotypes as well as numerous antigorite schists. The largest block weighted ~9 kg
voluminous enough both for various kinds of laboratory analysis. Precise positioning of the
transponder attached to the main wire greatly helps to infer distribution of amphibolite
bodies by lithotypes.
(4) Detailed bathymetric map without blanks was completed on and around the Ohmachi
Seamount.
5. Acknowledgements
The scientific team thanks captain and crew of the R/V KAIREI, the KAIKO operation team, JAMSTEC Navigation Group, and scientific supports by Nippon Marine Enterprise Ltd. and Marine Works Japan Ltd. This study is supported by JSPS KAKENHI Grant no. 22540464.
6. Notice on using this cruise report This cruise report is a preliminary documentation as of the end of the cruise. It may not
be corrected even if changes on content (i.e. taxonomic classifications) are found after
publication. It may also be changed without notice. Data on the cruise report may be raw
or not processed. Please ask the Chief Scientist for the latest information before using.