On Board Report of YK08-E04 · This project was held by R/V and the manned-submersibleYokosuka...

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On Board Report of YK08-E04

March 18 – March 31, 2008

(Shimizu – Yokohama)

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Preface

This project was held by R/V Yokosuka and the manned-submersible

Shinkai 6500 operated by the Japan Agency for Marine-Earth Science and

Technology (JAMSTEC). The support vessel Yokosuka embarked on March 18,

2008 from the Shimizu port and disembarked on March 31, at the Honmoku pier

in the Yokohama port. This is the preliminary report of the cruise based on on-

board observations and studies.

1. Background and purpose of project

This project aims to verify the geologic structures and tectonics of the

Nankai Accretionary Prism from new viewpoints and scopes. The general idea of

the development of the modern (or young) accretionary prisms has been

suggested through studies of drilled cores and seismic profiles in particular from

that in Barbados and the Nankai trough. However seismic profiles can identify

only large scale geological variation in mostly 2D and drilled cores micro or

small-scale variation along the depth. It is of prime importance to study the

outcrop scale (meso scale) structures and to map their distribution in order to

obtain 3D picture and to understand tectonic development in detail. The outcrop

observation under the sea is only possible using submersible.

On land, geological survey favors along rivers where continuous

exposures are expected. Similarly, under the sea, canyons developed dissecting

an accretionary prism provide the best outcrops. However only few submersible

studies along the canyons have ever been done by two of our team members;

Kawamura et al. (2000; JAMSTEC Deep-Sea Research; Kawamura et al. GSAB

Accepted) to the Tenryu Canyon, and Anma et al. (2002; JAMSTEC Deep-Sea

Research) to the Shionomisaki Canyon, both dissected the Nankai Accretionary

Prism.

During the previous cruises along the Tenryu Canyon (YK05-08 and

YK06-02), we discovered phyllite-like rocks (Pleistocene) and over-consolidated

rocks (age is not determined) from the dive sites of 6K#892 and 6K#893 in the

Tenryu Canyon, respectively. The analysis of illite crystallinity of the phyllite-like

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rocks from 6K#892 indicates that they experienced anomalous high temperature

conditions (~230°C) and vitrinite reflectance of the over-consolidated rocks from

6K#893 shows that the rocks underwent temperature around 90°C. These

temperature conditions are extremely high compared to the surrounding rocks,

indicating either high heat flow along faults or rapid exhumation (or high erosion

rate) of deeply buried sediments.

Thus, during the present YK08-E04 cruise, our primary target was to

recover such low-grade metamorphic rock samples again from those sites to

further study exhumation history of those rocks. We also performed geological

survey cautiously along the Tenryu Canyon: we focused on the directions of

outcrop scale geologic structures and fault displacements to analyze the tectonic

and mechanical history of accretionary prism in relation to collision/ subduction

of the Paleo-Zenisu Rigde and to understand how any extensional surface

collapse was involved during the ridge subduction.

Fig. 1.1 Location of the survey area (Kawamura et al., GSAB).

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Fig. 1.2 Dive sites in the Tenryu Canyon

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2. Participants

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Shipboard Scientific Partypost e-mail

section TEL

FAX

Reseacher

Reseach Group 1

Assistant Professer

Graduate School of Life

Associate Professor

Grad. Sch.of Life Enviro

Associate Professor

Graduate School of Life

ASSISTANT PROFESS

DEPT OF GEOSCIENC

Research Associate

University of Texas

Associate Professor

Dept. of Civil and Earth

Visiting Researcher

Ph.D Student

Doctoral Program in Ear

Student (Master)

Master Program in Geos

Student

Doctor program in Earth

Student

Grad. Sch.of Life Enviro

Ph.D Student

Dept. of Civil and Earth

Undergraduate Student

Agrobioresource science

Research associate

Marine Science Dept.

KYOTO UNIVERSITY

Keisuke Yamada

University of Tsukuba

Satomi Minamizawa

Nippon Marine Enterprises,Ltd.

Tetsu Shimizu


Ayumu Miyakawa

Toshimitsu Suzuki



Satoru Muraoka

Universitiy of Tsukuba

Hiroshi Ikeda

Fukada Geological Institute

Yoko Michiguchi

Yasuhiro Yamada

KYOTO UNIVERSITY

UNIVERSITY OF THE PACIFIC

Nicholas W. Heyman

Institute for Geophysics

Teruyuki Maruoka


KURTIS C. BURMEISTER

Akira Nakamura


Fukada Geological Institute

Ryo Anma


name

affiliation

address

Kiichiro Kawamura

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Group photo (29th March, in front of SHINKAI6500)

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3. Instrument

3.1 Research Vessel “Yokosuka” (adopted from YK03-03cruise report)

R/V Yokosuka is designed to serve as the support vessel for Shinkai 6500 and

has silent engine, an advanced acoustic navigation systems and an underwater

telephone for its state-of-the-art operations. It is also equipped with various kinds

of underway- geophysical equipment, i.e., Multi Narrow Beam Echo Sounder

(Sea Beam 2112.04, SeaBeam Instruments, Inc.), gravity meter (Type S-63,

LaCoste & Romberg Gravity Meters Inc.), ship-borne three-components

magnetometer (Type.SFG-1212, Tierra Tecnica Inc.), and proton magnetometer

(Type.STC10, Kawasaki Geological Engineering Co.,Ltd.). The wet-lab is

equipped with a fumigation chamber, “Milli-Q” water purifier, -80 deep freezer,

incubator, and rock saw. In addition, YOKOSUKA has on-board video editing

capability for DVCAM, S-VHS, VHS, system.

Research Vessel “Yokosuka” The principal specifications

Length: 105.22 m

Breadth: 16.0 m

Height: 7.3 m

Draft : 4.5 m

Gross tonnage : 4439 t

Cruising speed : about 16 kts

Cruising range : about 9000 mile

Accomodation: 15 reserchers’ beds

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3.2 SEA BEAM 2112 -Outline of system – (adoptedfromYK03-03 cruise report)

Bathymetric data were collected by the SEA BEAM 2112 (Sea Beam

Instruments). The SEA BEAM 2112 is a multibeam survey system that

generates data for and produces wide-swath contour maps and side scan

images. It transmits a sonar signal from projectors mounted along the keel of the

ship. The sonar signal travels through the sea water to the seafloor and is

reflected off the bottom. Hydrophones mounted across the bottom of the ship

receive the reflected sonar signals. The system electronics process the signals,

and based on the travel time of the received signals as well as signal intensity,

calculate the bottom depth and other characteristics such as S/N ratio for echoes

received across the swath. Positioning of depths on the seafloor is based on

GPS and ship motion input. The data is logged to the hard disk for post

processing which allows for additional analysis. Plotters and side scan graphic

recorder are also included with system for data recording and display. The

hardware system consists of two main subsystems, transmitter and receiver

respectively. The basic 12 kHz projector array is a 14-foot long linear array

positioned fore and aft along the ship's keel. It forms a downward projected

acoustic beam whose maximum response is in a plane perpendicular to its axis.

The beam angle is narrow, 2 in the fore/aft direction. The receiver array detects

and processes the returning echoes through stabilized multiple narrow

athwartship beams in a fan shape. The hydrophone array has a flat shape in the

case of R/V "KAIREI", although the standard SEA BEAM 2000 series system

has a V-shaped arrayThe system synthesizes 2_2 degrees narrow beams at the

interval of 1 degree, and the swath width varies from 120 degrees at depths from

1500 m to 4500 m, 100 from 4500 m to 8500 m and deeper than 8500 m. The

transmit interval of the sonar signal ping interval increases with water depth, for

example about 20 sec. at 6500 m. So, the horizontal resolution of the bathymetry

data depends on the depth and ship's speed. The accuracy of the depth

measurement is reported at 0.5% of the depth. The software which controls the

system is called the Sea View. It employs the Lynx Operating System. Indy Work

Stations (SGI) are used for operation. The obtained raw data includes data

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records of each ping (bathymetry, side scan image, position), nautical

information and correction parameters such as water velocity structure. Post

processing consists of editing data (deletion of bad data, correction of position

etc.), making grid data files and various maps. Software used is Sea View and

GMT Ver.3.0 (Wessel and Smith, 1995).

Sub bottom profilerSub bottom profiles were obtained by using the SEA BEAM 2112.004

Subbottom Profile Subsystem, which is an additional option to the SEA BEAM

2112 Multibeam Bathymetry System. The capability of the system ranges from

50 m to 11,000 m. Depth penetration varies with bottom composition and may be

as much as 75 m. The system uses an array of 60 TR-109 projectors, operating

at 4kHz to form a vertical beam of 45 degrees athwartship and 5 degrees fore/aft.

The system startup, parameter setting, and real-time control is performed by

Indy Work Station (SGI). The data is displayed on a terminal and EPC recorder,

and stored on hard disk and a data logger.

3.3 Submersible “Shinkai 6500”

Shinkai 6500 is a manned submersible with dive capability of the world

deepest 6,500 meters. Two pilot and one scientist stay in a pressure hull 2

meters in diameter which has three viewing windows. It is equipped with two

manipulators, pan-tilt-zoom color video camera, a fixed-view color video camera,

a 35 mm still camera, two retractable sample baskets, CTD sensors, Gamma ray

spectrometer, CTFM sonar, and a video-image transmission system which

enable us to watch full-color seafloor images every 8 seconds onboard the

mother vessel Yokosuka. Recent innovation of the Shinkai hardware, which

includes two 7-freedom manipulators (Schilling Co., USA) and two retractable

baskets, made this submersible even powerful as a tool for deployment of

various instruments. The total allowable weight for an observer is less than

150kg (in the air) including collected materials. The underwater speed of the

submersible is 0-2.5kts and the speed can be controlled continuously. The top

speed of 2.5kts is just for emergency situations. There are two ways to find the

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position of SHINKAI6500; Long Base Line system (LBL) and Super Short Base

Line system (SSBL). The LBL system needs 3 bottom-mounted transponders to

be deployed in the survey area. The SHINKAI6500 locates her position by

herself and the mother ship determines the position and her position based on

the position of transponders. The LBL system has the advantages of given very

accurate position and the submersible can measure her own position in real time.

The disadvantage of the LBL system is the additional time it takes to deploy and

recover the transponders. Normally, LBL system covers the area within a circle

whose radius is similar to the depth. The SSBL system does not require any

transponder but the accuracy is inferior to the LBL system, and only the mother

vessel can locate the position of SHINKAI6500. In this case, SHINKAI6500 must

be notified of her position by the mother vessel. However, coverage range is

similar to that in LBL system.

3.4 Zodiac

1244

4. Ship log

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Date Time Description Remarks

18Mar08 14:00 Scietists embark on YOKOSUKA

15:00 Leave the Shimizu port Head for Tenryu Canyon survey area

16:00-16:30 Lecture about onboard life

18:00-19:00 Scientific meeting

21:00 Arrived at Tenryu Canyon survey area

19Mar08 5:48 Released XBT 12:00(GMT+9h)

6:21-7:07 MBES mapping survey 34-22.3N, 137-21.9E

7:57-7:59 Lowered transducer & send test command Overcast

8:20 Suspended SHINKAI 6500 submergence due to rough sea ENE-7(Near gale)

8:20 Left resarch area for suruga wan Head for suruga wan Sea very rough

10:09 changed distination to Mikawa wan Head for mikawa wan

14:45 Arrive at Mikawa wan

14:00-16:00 Scientific seminar

20Mar08 09:00-10:00 Brieing 12:00(GMT+9h)

10:30-11:30 Ship tour 1 34-44.5N, 137-08.8E

13:00-15:00 Ship tour 2 Rain

18:00-19:10 Scientific seminar NNW-5(Fresh breeze)

Sea slight

21Mar08 9:21 Com'ced proceeding toresarch area Head for Tenryu Canyon survey area 12:00(GMT+9h)

14:00 Arrived at reseach area 34-18.7N, 137-10.8E

14:06 Released XBT 33-52.2041N, 137-27.2952E Fine but cloudy

15:16-15:48 Carried out MBES mapping survey EW-6(Strong breeze)

18:00 Com'ced "heave to" Sea moderate

18:30-19:10 Scientific seminar

22Mar08 6:00 Finished "heave to" & com'ced proceding to dive point SHINKAI 6500 Dive#1055 (Nankai trough) 12:00(GMT+9h)

6:30 Arrived at dive point (Kiichiro Kawamura) 33-50.9N, 137-33.6E

11:54 Launched SHINKAI 6500 Fine but cloudy

13:13 Landed on the sea bottom (D=2200m) 33-50.9262N, 137-33.5632E NNE-2(Light breeze)

16:20 Took off from sea bottom (D=2141m) 33-50.8286N, 137-33.0688E Sea calm (Rippled)

17:08 SHINKAI 6500 refloated

17:37 Recovered SHINKAI 6500

20:00 Com'ced "heave to"

23Mar08 6:30 Arrived at dive site SHINKAI 6500 Dive#1056 (Nankai trough) 12:00(GMT+9h)

06:37-07:23 Carried out MBES mapping survey (Nicholes W. Hayman) 33-42.4N, 137-31.5E

9:54 Launched SHINKAI 6500 Fine but cloudy

11:20 Landed on the sea bottom (D=2907m) 33-42.3743N, 137-31.4357E South-2(Light breeze)

16:10 Took off from sea bottom (D=2482m) 33-41.4628N, 137-31.4422E Sea smooth



18:41-19:19 Carried out MBES mapping survey


24Mar08 5:30 Arrived at dive point 12:00(GMT+9h)

11:00 Suspended SHINKAI 6500 submergence due to rough sea 33-43.3N, 137-28.9E

18:00-19:00 Scientific meeting Fine but cloudy

WSW-6(Strong breeze)

Sea rough

Date Time Description Remarks

25Mar08 5:55 Arrived at ocean bottom thermometer point SHINKAI 6500 Dive#1057 (Nankai trough) 12:00(GMT+9h)

5:55 Lowered transducer (Kurtis C. Burmeister) 33-50.8N, 137-32.9E

6:00 Send release command Fine but cloudy

6:47 Recovered ocean bottom thermometer NNE-4(Moderate breeze)

9:22 Launched SHINKAI 6500 Sea slight

11:03 Landed on the sea bottom (D=2247m) 33-42.2712N, 137-29.3212E

16:08 Took off from sea bottom (D=2084m) 33-42.5534N, 137-29.4688E




26Mar08 7:00 Arrived at dive point SHINKAI 6500 Dive#1058 (Nankai trough) 12:00(GMT+9h)

9:52 Launched SHINKAI 6500 (Ryo Anma) 33-38.1N, 137-28.2E

11:29 Landed on the sea bottom (D=3159m) 33-38.0930N, 137-28.1677E Cloudy

13:03 Took off from sea bottom (D=3063m) 33-38.1039N, 137-29.9879E NW-4(Moderate breeze)

14:16 SHINKAI 6500 refloated Sea slight


18:00 Com'ced proceeding to dive point


27Mar08 5:45 Com'ced proceeding to dive point SHINKAI 6500 Dive#1059 (Nankai trough) 12:00(GMT+9h)

6:30 Arrived at dive point (Yasuhiro Yamada) 33-42.4N, 137-30.5E

10:12 Launched SHINKAI 6500 33-42.5193N, 137-30.5055E Fine but cloudy

11:35 Landed on the sea bottom (D=2880m) 33-43.0863N, 137-30.1787E NW-4(Moderate breeze)

16:04 Took off from sea bottom (D=2715m) Sea slight




28Mar08 6:30 Arrived at dive point 12:00(GMT+9h)

10:30 Suspended SHINKAI 6500 submergence due to rough sea 33-52.5N, 137-31.5E

11:06-13:00 Carried out MBES mapping survey Fine but cloudy

18:00-19:00 Scientific meeting NW-7(Near gale)

Sea rough

29Mar08 4:10 Com'ced shifting to dive point 12:00(GMT+9h)

6:45 Arrived at dive point 33-38.0N, 137-22.0E

10:45 Suspended SHINKAI 6500 submergence due to rough sea Fine but cloudy

11:00 Com'ced proceeding to research area C (NANKAI Trough) NW-7(Near gale)

15:00 Arrived at research area C Sea very rough18:00-19:00 Scientific meeting

18:30 Com'ced shifting to dive point

30Mar08 6:30 Arrived at dive point SHINKAI 6500 Dive#1060 (Nankai trough) 12:00(GMT+9h)

9:53 Launched SHINKAI 6500 (Teruyuki Maruoka) 33-53.8N, 137-34.5E

11:09 Landed on the sea bottom (D=2105m) 33-53.7846N, 137-34.5515E Rain

16:18 Took off from sea bottom (D=1576m) 33-53.3287N, 137-35.3389E NNW-2(Light breeze)

16:55 SHINKAI 6500 refloated Sea smooth


18:48-20:00 Carried out sub bottom profiler


20:00 Com'ced proceeding to Honmoku

31Mar08 11:45 Arrived at Honmoku

13:00 Scientists disembark from YOKOSUKA

YK08-E04 Shipboard Log & Ship Track 1/2 Position/Weather/Wind/Sea condition (Noon)

YK08-E04 Shipboard Log & Ship Track 2/2 Position/Weather/Wind/Sea condition (Noon)

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5. Weather and Kuroshio Current in this cruise

Weather maps are from Japan Meteorologica Agency, and Kuroshio Current

information is from Japan Coast Guard.

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6. Results

6.1 XBT data

XBT was performed to measure sea water temperature at 34°22.3’N, 137°21.9’E

on 5:48, 19th March, and at 33°52.2041’N, 137°27.2952’E on 14:06, 21st March.

These data were used for collection of SeaBeam data.

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6.2 SeaBeam, Side Scan and subbottom profiler data

All area (SeaBeam)

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Site B-3 (SeaBeam)

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Site B-3 (Side Scan)

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Site B-4 (SeaBeam)

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Site B-4 (Side Scan), Ship track from west to east.

Site B-4 (Side Scan), Ship track from north to south.

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Site B-6 (SeaBeam)

Site B-6 (Side Scan)

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Site B-7

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Subbottom Profiler

North of Site B-7

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6.3 CTD data

We obtained following CTD data using a CTD sensor (SBE19) attached

SHINKAI 6500.

1) ctdo####.txt: data which are collected 1 sec. Interval.

2) Ctdo####.asc: data conducted by Pressure bin procedure.

Pressure bin procedure: data extracted by each 1 kg/cm2.

In this cruise, we used ctdo####.asc data that records temperature and

chlorinity (as proxy of salinity) from take-off time until float time to sea surface.

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7. Dive summaries

Dive #1055 Report

Kiichiro Kawamura (Fukada Geological Institute)

Date: March 22, 2008

Site Name: Tenryu Canyon (B-6 area)

Landing: 33-50.9240N,137-33.5667E, 13:13, 2200 m

Leaving: 33-50.8364N,137-33.0701E, 16:20, 2141 m

Observer: Kiichiro Kawamura (Fukada Geological Institute)

Pilot: Ohno.; Co-Pilot: Ueki,

Objectives:

The objectives of this dive were to clarify the geology and geologic structures

around the Tokai Thrust site, where was dived by 6K#892. In the dive 6K#892,

we collected a low-grade metamorphic rock, which indicated maximum

experienced temperature of 230°C. The porosity was ~20%. That rock may be

transported from deeper part of the prism along the Tokai Thrust. Furthermore,

the radiolarian age of this rock was younger than 0.42 Ma. If so, this rock was

buried, transported and uplifted rapidly from the depositional area. I need much

more rock samples for checking the age, experienced temperature, and physical

properties again.

Dive Summary:

The SHINKAI was landed on a flat floor of the Tenryu Canyon. Then, I measured

heat flow by the SAHF for 20 minutes. In this measurement, I collected core

sample (C-1) and sterilized core sample (S-1). After the measurement, I went

south to find the fault related rocks from the place where 6K892R-002 was

collected. Then I found large outcrop like a small hill on the floor of the Tenryu

Canyon. I collected rock samples (R-1, R-2 and R-3) from there. Then, I moved

to a small hill at west side of the canyon. I collected rock samples (R-4) on foot of

the hill, then I found tube worms on the middle slope of the hill. The root of the

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tube worms was in a gap of a mudstone. After the sampling, I went west along

the contour line. The strata are

Keywords:

Tokai Thrust, Tube worm, Heat flow,

Payloads:

Push cores x2

Sterilized cores x2

Sample Box x2

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Location of Events:

Time Position Depth Event

13:13: 968.5, 411.3, 33 50.9240N, 137 33.5667E, Landing Point D=2200m

13:27: 968.4, 411.2, 33-50.9239N, 137 33.5666E, Sampling core (green, C-1) D=2200m

13:45: 968.4, 411.2, 33 50.9239N, 137 33.5666E, Sampling sterile core (green, S-1) Measure

SAHF D=2200m

14:12: 883.9, 438.6, 33 50.8782N, 137 33.5844E, Sampling 5 Rocks (R-1) D=2201m

14:24: 892.6, 445.3, 33 50.8829N, 137 33.5887E, Sampling 2 Rocks (R-2) D=2200m

14:41: 889.2, 455.9, 33 50.8811N, 137 33.5956E, Sampling some Rocks (R-3) D=2199m

15:28: 851.9, -96.7, 33 50.8609N, 137 33.2373E, Sampling 3 Rocks (R-4) D=2147m

15:48: 869.3, -96.7, 33 50.8703N, 137 33.2373E, Sampling 2 Tube Worm (B-1) D=2141m

15:53: 869.3, -96.7, 33 50.8703N, 137 33.2373E, Sampling sterile core (blue, S-2) & core

(blue, C-2) D=2140m

15:59: 855.2, -134.0, 33 50.8627N, 137 33.2131E, Finding Tube Worm D=2124m

16:20: 806.6, -354.6, 33 50.8364N, 137 33.0701E, Left Bottom D=2141m

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Dive track

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Dive log

Sample description

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R-1-1: Cemented fine sandstone with laminated fine sandstone

R-1-2: Cemented fine sandstone with mudstone. Cross lamina are seen in the

sandstone, and slicken lines are seen on the mudstone surface.

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R-1-3: Fine sandstone with white veins (probably calcite)

R-1-4: Cemented fine sandstone with mudstone. Burrows are visible in the

sandstone.

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R-1-5: Mudstone with fine sandstone with white veins. Many burrows (~3 mm in

diameter) are visible in the mudstone.

R-2-1: Laminated fine sandstone having white veins with mudstone.

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R-2-2: Laminated fine sandstone with white veins. Many black fibers are

concentrated at two horizons in the sandstone.

R-3-1: Mudstone with fine sandstone. May elongated burrows are visible in the

mudstone. Many black fibers are concentrated at two horizons in the sandstone.

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R-3-2: Cemented fine sandstone with cemented mudstone. Burrows, flame

structures and convoluted lamina are visible in the sandstone.

R-3-3: Cemented laminated fine sandstone with white veins. Two burrows filled

with medium sandstone are visible in the sandstone.

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R-3-4: Fine sandstone with sheared mudstone.

R-3-5: Mudstone with mottled fine sandstone. Elongated burrows are visible in

the mudstone.

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R-4-1: Massive siltstone with one black band of a few mm thick.

R-4-2: Massive siltstone with several black burrows.

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R-4-3: Massive siltstone. Sharp boundary as a fault is visible

C-1

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C-2

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S-1, S-2

B-1

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Dive Report of Shinkai 6500 #1056

Nicholas W. Hayman

(UTIG)


Site Name: Area B-4A of Tenryu Canyon, area down-plunge (west) of Yukie

Ridge in footwall of Tokai thrust

On-bottom: 11:21, 33°42.3744’N, 137°31.4358’W, 2907 mbss

Off-bottom: 16:11, 33°41.4628’N, 137°31.4422’W, 2482 mbss

Observer: HAYMAN, Nicholas W.

Pilot: Sakurai, Toshiaki Co-pilot: Chida,

Objectives:

Dive #1056 followed a roughly north-to-south heading along and up the

eastern face of Tenryu Canyon, south of the Tokai thrust and down-plunge (to

the west) of Yukie Ridge. The area was the site of a previous dive, #885 during

YK05-08, where diver-scientist Kiichiro Kawamura observed a broad syncline in

turbiditic strata. Such folding may be related to both the general accretionary

prism evolution, and also the effects of a subducted seamount to the northeast.

Samples from the sedimentary section in this area could also provide thermal

and time-of-deposition constraints on the broader footwall of the Tokai thrust.

Dive Summary:

Dive #1056 confirmed and extended the structural observations of

YK05-08 Dive # 885 (Figure 1, 2: map and cross-section). The dive track

crossed the syncline in turbiditic sediments, and also crossed a local anticline

(Figure 3; dive images). Minor reverse faults were directly observed in the latter

part of the dive (see highlight video at exactly 14:55), and a change in bedding

orientation in the vicinity of these thrusts could indicate a more prominent thrust

or reverse fault in the area. Some high-angle faults were observed, though these

were relatively minor (little displacement). Most of the high-angle faults were

associated “chaotic” units that could be debris flows or “broken formation” within

the section. However, these debris-flow type units could be an effect of the

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outcrop wherein modern debris flows obscure bedrock structures of a non-debris

flow origin (see highlight video starting at 13:58). The stratigraphic section

appeared to transition from a more muddy section to a more sandy section

throughout the dive. The muddy section had prominent, steeply-dipping joints in

a variety of orientations. For more than half of the transect the section was

dominated by rhythmically bedded turbidites with ~20 cm thick sandy layers and

~5-10 cm thick muddy layers. The last hour of the dive crossed vertical cliffs of

perfectly exposed, structurally intact turbidites.

Eight very large samples were collected from eight different sites

(Figure 4; sample photographs). The samples comprise the more muddy

sections because sandy layers tended to disaggregate with sampling. Some

important sedimentary structures include: (1) convoluted bedding in mudstones,

(2) bedding and way-up indicators in sand layers, (3) soft-sediment shear

structures defined by tuffaceous materials, and (4) small-scale normal faults that

developed after lithification of a sand layer, but while the overlying mud was still

partially unconsolidated.

Analysis of the dive videos and estimates of strike and dip from still

images further shows that bedding in the region dips both northwesterly and

southeasterly (Figure 5; stereoplot). Most dips are moderate, but locally bedding

has been tilted to near vertical orientations. The hinges of the folds defined by

these bedding orientations (clearly exposed in at least one place) trend north-

northeast, at a high angle to the interregional east-westerly trend of the Tokai

and frontal thrusts, and related folds.

Tables

Samples and data log (lat, lon in decimal degrees):

11:24 2907 137.5239299 33.70614918 heat flow using SAHF

11:26 2907 137.5238229 33.70605875 Sterilized mud sample: red, 6K#1056

SC1

42

12:23 2832 137.5239299 33.70180858 rock sampling 6K #1056 R1: No1

1sample:

partially consolidated mudstone with

convoluted bedding, silt lenses, hematitic

(?) lenses

12:55 2795 137.524679 33.70153729 rock sampling 6K #1056 R2: No5 some

samples morinaga (basket sampling):

sandy layer with tuffaceous component

exhibiting evidence of soft-sediment

shear; unconformably overlain by tan

mudstone.

13:29 2786 137.524786 33.70090429 rock sampling 6K #1056 R3:No 2 two

samples, No3 two samples, A one

sample (No2, 3: morinaga): sand layer

cut by (post-consolidation) normal faults

(domino-style), overlain by syn-fault

muds (partially consolidated)

14:14 2803 137.5230739 33.69792013 rock sampling 6K #1056 R4:No4 one

sample, A one sample: sandy layers

above mudstone – sandy layers exhibit

forest and wavy bedding and locally

crossbedding

14:43 2822 137.5209338 33.69692541 rock sampling 6K #1056 R5:No6 two

samples: thin sand layers between

thicker mud layers, all partially

consolidated; graded bedding

15:02 2816 137.5211478 33.69647327 rock sampling 6K #1056 R6: B four

samples: thin sand layers between

thicker mud layers, all partially

consolidated; graded bedding

15:39 2635 137.5223249 33.69231353 rock sampling 6K #1056 R7: No7 one

sample: partially consolidated mudstone

43

with hematitic lenses, cut by fractures (at

a high angle to bedding)

16:09 2482 137.5236089 33.6915901 rock sampling 6K #1056 R8: morinaga

one sample: partially consolidate

mudstone

44

45

Figures

Figure 1. Dive map of #1056, with trace of dive #885 included. Symbols include

bedding (strike and dip), joints (staples), high-angle faults (barbs), reverse faults

(teeth), and debris flow (pattern). Strike and dip are only estimated from dive

46

images (uncertainty is approximately +/- 10 degrees for dip, and +/-20 degrees

for strike).

Figure 2. Depth-profile at longitude 137.523°. The cross-section plane is not

precisely parallel to the dive track, and thus positions of strike-and-dip symbols

(tiks) are estimated. The inset is based on the K.Kawamura’s sketch for Dive

#885. Vertical exaggeration is minimized. Dashed line is not a marker bed, but is

simply to display the overall structure. Note that many strikes are out of the plane,

and the trend of many of the folds are north-northeast, also out of the cross-

section plane.

47

Figure 3. Dive photos of outcrops. (a) south-dipping strata in an outcrop of a

mud-rich unit. (b) joints in a mud-rich lithology, (c) anticline in mud-rich lithology,

(d) rhythmically bedded turbidite section.

48

Figure 4. Photos of rock samples: (a) Sample R1, with convoluted bedding in a

partially consolidated mudstone, (b) Sample R2 with shears (soft-sediment)

tuffaceous component in sandy layer, overlain by tan mudstone, (c) Sample R3

with normal faults cutting consolidated sands, overlain by “syn-faulting” muds,

(d) Other piece of sample R3 with bedded mudstone, (e) Sample R4 with sandy

layer above mudstone, (f) Sample R7, mudstone.

49

Figure 5. Stereoplot of poles to bedding estimated from dive video. Great circles

are interpreted strikes and dips of the limbs of major folds, qualitatively

consistent with the poles-to-planes. Despite uncertainty of up to +/- 10 degrees

for dips, and +/- 20 degrees for strikes, there is clearly a north-northeast trend to

the regional fold structure.

Tables (continued from earlier)

Structural measurements:

12:17 2837 137.5239299 33.70180858 bedding 45 35S

12:18 2837 137.524037 33.70171815 joints 80 80SE

12:30 bedding 70 60N

12:39 2796 137.5246255 33.70162772 bedding 30 30NW

12:58 2793 137.524786 33.70162772 bedding 90 40N

13:08 2785 137.524572 33.70099472 joints 83 90

13:11 bedding on north limb 40 45NW

13:11 bedding on south limb 0 20W

13:14 2785 137.524786 33.70090429 bedding on north limb 100 90

13:29 2786 137.524786 33.70090429 bedding on south limb 0 0

50

13:31 bedding on north limb 25 45W

13:31 joints 25 80E

13:36 planar feature 159 70W

13:59 2809 fault? 46 90

13:59 joints or bedding north of

fault

46 80S

14:06 2804 137.5232879 33.69810099 bedding 42 30N

14:14 2803 137.5230739 33.69792013 bedding 50 30N

14:34 joints 107 90

14:34 bedding 54 45NW

14:51 bedding 160 45NE


14:55 reverse fault 134 10W

14:55 bedding 134 60NE




15:32 fault 80 60S

15:45 2615 137.5228599 33.69258482 bedding 80 30S

13:49 joints 160 85W

15:53 2542 137.5229669 33.69177096 bedding 80 30S


15:53 bedding 39 25W

General observations:

12:17 2837 137.5239299 33.70180858 outcrop of damaged, but bedded unit -

bedding is apparent on the east side of

the outcrop

12:30 gently folded strata in moderately

damaged outcrop, overall dipping to the

north.

51

12:39 2796 137.5246255 33.70162772 well-bedded turbidites, no clear

deformation

12:58 2793 137.524786 33.70162772 approximately a strike-parallel view of

dipping turbidites

13:08 2785 137.524572 33.70099472 well-defined joints in muddy section of

turbidites

13:11 Joints are ~axial planar to an anticline

(broad)

13:14 2785 137.524786 33.70090429 samples from the core of the anticline

where bedding is much tighter

13:36 Prominent planar feature, unclear of its

nature - possible fault?

13:59 2809 debris flow feature to the right of a sharp

planar feature (fault?); to the left of the

fault(?) is ~80S dipping joints or

bedding?

14:06 2804 137.5232879 33.69810099 well-defined bedding of dipping turbidites

14:14 2803 137.5230739 33.69792013 well-defined bedding of turbidites

14:15 debris flow cuts bedding of well-bedded

turbidites

14:17 2790 137.5232879 33.6978297 Mud ridges

14:34 prominent joints at a high angle to

bedding

14:34 dip of muddy layers in turbidite well-

exposed

14:35 2823 137.5210408 33.69683498 well-defined bedding of moderately

dipping turbidutes, internal sedimentary

structure of sandy layers is visible

14:51 well-bedded turbidites, change in

bedding orientation!

14:54 another change in bedding orientation in

turbidites

52

14:55 split-second view of a minor reverse fault

(high angle) in dipping turbiditic strata

change in bedding orientation around

reverse fault; beds are ~20 cm thick

15:06 downward, oblique view to dipping strata

15:08 approximately strike-parallel view of

dipping strata

15:32 approximately strike-parallel view of

dipping strata

probable high-angle fault, unclear of

throw (reverse?)

15:45 2615 137.5228599 33.69258482 thinner beds to turbiditic strata, shallower

dip

15:48 2576 137.5230739 33.69231353 the strata here are perfectly exposed, a

little thinner (<20 cm) and contain

prominent ash layers and other features;

excellent section to study for stratigraphy

15:50 debris flow at base of cliff

15:53 2542 137.5229669 33.69177096 bedding maintains orientation

15:56 2521 137.5233949 33.69140924 possibly small scale faults cut ash layer,

but impossible to measure orientations

etc..

more closely spaced bedding planes,

more muddy

bedding planes change orientation

slightly

16:00 2486 137.5236089 33.69122838 ascending to top of cliff, continuous

exposure of thick (20 cm) sand layers

and thinner (<10 cm) mud layers.

53

Dive #1057 Report

Kurtis C. Burmeister (University of the Pacific)


Site Name: West side of Tenryu Canyon (B-6 area)

Landing: 33.70452145N, 42.27128714E, 11:03, 2247m

Leaving: 33.70922376N, 42.55342576E, 16:09, 2087m

Observer: Kurtis C. Burmeister (University of the Pacific)

Pilot: Sasaki, Yashitaka; Co-Pilot: Komuku, Tetsuya

Objectives:

The objectives of dive #1057 included: (1) a cross-strike transect of bedrock

exposures along the western wall of the Tenryu Canyon to describe structural

fabrics in the hanging wall and footwall of the Tokai thrust fault (accomplished);

(2) collection of additional high-temperature samples form the hanging wall of

the Tokai thrust fault (not accomplished); (3) collection of living tube worm and

Calyptogena specimens for geochemical analyses (accomplished); and (4)

collection of sterile and push core samples of ocean bottom sediments for

geochemical and microbiological analyses (accomplished).

The geology of site B-6 was also the focus of dives #892 (YK05-08, by

Kiichiro Kawamura) and #1055 (YK08-E04, by Kiichiro Kawamura). Dive #892

collected samples of rocks that had been heated to low-grade metamorphic

conditions (maximum of 230°C) and had a porosity of approximately 20%.

Kawamura suggests that these temperature and porosity data indicate the rocks

may have been exhumed along the Tokai Thrust from lower levels within the

accretionary prism. Age analysis of the same rock samples using radiolarian

fossils may suggest a age of less than 0.42 Ma, which suggests these rocks

were accreted, buried, and exhumed relatively rapidly. Dive #1055 yielded

additional rock samples from the east and west walls of Tenryu Canyon that

have yet to be analyzed.

54

Dive Summary:

The SHINKAI landed at the foot of a hill (the bathymetric high in the northwest

corner of the Dive Log and Geologic maps), in a small embayment along the

western wall of Tenryu Canyon. Upon landing, heat flow measurements were

collected using the SHAF instrument for approximately 20 minutes. Push and

sterile core samples were not collected at this time in the hopes of encountering

chemosynthetic bio-communities at a later point along the transect. The

SHINKAI proceeded north, slowly ascending the south-facing slope of the

adjacent hill. Please note that the times included in parentheses below

correspond with Camera 2 frames in the dive summary video, Dive#1057.mov.

Outcrops along the transect generally expose thin (less than 5cm) to

moderately (10 to 20cm) bedded sequences of muddy and sandy(?) layers.

However, bedding thickens locally to as much as 30 to 40cm. Mudstone layers

form relatively resistant ridges, while sandier layers commonly weather easily to

form depressions (Kawamura, pers com, 2008). Weathered mudstone

exposures range from red-brown to light green-gray. The intensity of the

reddish-brown color of weathered outcrops appeared to increase with

deformation along the transect. Fresh exposures are commonly light blue-gray.

Strata along the transect

generally strike approximately north-

northeast to south-southwest, and have

moderate dips (see stereonet to right).

Bedding attitudes were estimated from

outcrops using time and orientation

information recorded by Camera 2.

First, the orientation of the field of view

captured by Camera 2 was determined

by comparing the yaw of Camera 2

(clockwise or counterclockwise) to the

true heading as defined by the long

axis of the Shinkai 6500. The strike and

dip of strata was then estimated from

the oriented field of view captured by Camera 2. Finally, a stereonet sketch of

55

the bedding attitude was compared with the field of view in Camera 2 to verify

the estimation. While this method likely is sufficient for estimates of strike with an

accuracy of ± 15°, dip estimates are considerably more difficult. The variable

pitch of Camera 2 distorts the true dip, creating an apparent dip effect that likely

makes estimates with an accuracy of greater than ± 20° impossible.

Strata between 2260 and 2200m are cut by at least three sets of widely

spaced (> 1m) joints that strike roughly northeast, northwest, and east

(12:07:05). Most of the joints observed in this portion of the transect appear to

cut strata normal to bedding, but there are some instances where joints appear

to cut oblique bedding at dips of roughly 60°. Several abrupt changes in bedding

attitude occur near 2200m, which may represent evidence of faulting (12:57:10)

and folding (12:58:05). In addition to the collection of rock sample 1R1

(13:02:20), possible “black seams” and tubeworms were observed in this interval

(13:08:35). The amount of jointing and fracturing begins to increase at ~2177m

(13:24:00) and becomes pervasive in an interval of “broken formation” at

~2174m (13:28:30) where samples 2R2 and 3R3 were collected. At ~2130,

strata are no longer pervasively deformed, but appear to be cut by at least one

fault (14:34:07) and are possibly involved in a fold (14:36:03).

Despite a thin drape of mud covering exposures along the ridge above

the break in slope at roughly 2120m, there were sufficient outcrops to

characterize a sequence of moderately fractured mudstones (e.g., 14:42:28,

15:13:57, 15:14:19). Samples 4R4, 6R5, 7R6, SC1RED, SC1GREEN,

PC1BLUE, and PC2GREEN were collected from this region. Locally, strata

exposed along this gentle slope may include intervals of broken formation (e.g.,

15:16:21 to 15:17:21) and are cut by small, low-angle faults (e.g., 15:19:29). This

portion of the transect also resolved what appears to be an overturned, east

dipping thrust duplex structure (15:21:48 to 15:22:43; please see attached

preliminary sketch).

Keywords:

Tokai thrust fault, folds, “broken formation”, low-angle faults, tube worm, Heat

flow

56

Payloads:

Push cores x2

Sterilized cores x2

Rock samples x6

Location of Events:

Time

(JST)

Dep (m) X Y LAT (d.d) LON (d.d) Description

11:03 2247 500 -590 33.70452145 137.4886867 Landed, mud floor, bottom current: cm/sec to

degrees, visibility: 8m, water temperature: 1.8

degree C.

11:10 2247 490 -580 33.70443102 137.4887937 SAHF measurement

11:35 2247 490 -580 manipulator error, SAHF drop

13:07 2200 760 -630 33.70687261 137.4882587 Rock sampling; No. 1 R1 (some)

13:10 2201 760 -630 33.70687261 137.4882587 tube worm

13:14 2202 760 -640 33.70687261 137.4881517 Rocks sampling ; No.1 R1 (some)

13:35 2174 830 -640 33.70750561 137.4881517 Rocks sampling ; No.2 R2 (some)

13:54 2143 950 -570 33.70859076 137.4889007 Rocks sampling; No. 3 R3 (some)

15:09 2101 1140 -550 33.71030891 137.4891147 Rock sampling No4:R4 (some)

15:22 2095 1120 -410 33.71012805 137.4906128 coca cola can

15:33 2095 1070 -430 33.70967591 137.4903988 Rock sampling No6:R5:3 samples

15:47 2096 1030 -400 33.70931419 137.4907198 Sterilized mud sampling, SC1:red, SC2:green,

shell fragments?

15:52 2096 1030 -400 33.70931419 137.4907198 Push coring sampling, PC1:blue, PC2:green, shell

fragments floor

16:02 2089 1010 -360 33.70913333 137.4911478 Rock sampling No7:R6:several samples

16:09 2087 1020 -360 33.70922376 137.4911478 Return to surface

57

Dive log

58

59

Geologic map

60

61

Rock Samples

R-1-1: Thinly laminated, gray

mudstone & siltstone

R-1-2: Gray bioturbated mudstone

R-2-1: Gray, thinly laminated

mudstone with local bioturbation.

Surfaces of sample are covered with

slip lineations.

62

R-2-2: Gray mudstone

R-2-3: Gray mudstone. Surfaces of

sample are covered with slip

lineations.

R-2-4: Gray, bioturbated mudstone.


slip lineations.

63



slip lineations.



slip lineations.

R-3-1: Gray, finely laminated

mudstone with local bioturbation

64

R-3-2: Gray, bioturbated siltstone

R-3-3: Gray siltstone

R-3-4: Gray, bioturbated (dark gray

burrow in-fills?) mudstone. The

surfaces of this sample are covered

with slip lineations.

65




66




67




68




69

Push Core Samples

C1

C2

Sterile Core Samples

Red sterile core

70

Sterile core samples

Biological Sample

B1

B2

Future studies

The structural data and the geologic map from dive #1057, including strike and

dip estimates of bedding and joint surfaces and fault interpretations will be

71

reevaluated. These data will then be combined with structural data collected

using similar methods from the records of dives #892 and #1055 to create a

comprehensive geologic map and cross sectional interpretation of the bedrock

geology of the B-6 site. These data may be used in combination with similar

results from other sites along Tenryu Canyon to support further research on the

evolution of regional structural fabrics (e.g., evolution of northeast-trending fold

axes, surface expression of the Tokai thrust fault, and the effects of seamount

subduction).

72

Dive 6K#1058 report

by Ryo Anma (University of Tsukuba)


Site Name: Tenryu Submarine Canyon (B-3 site)

Landing point: 33: 38.1015 N, 137: 28.1787 E Depth: 3,159 m

Left bottom: 33: 38.1054 N, 137: 27.9903 E Depth: 3,063 m

Observer: Ryo Anma (University of Tsukuba)

Pilot: Keita Matsumoto (JAMSTEC)

Co-pilot: Kazuhiro Chiba (JAMSTEC)

Objectives:

Primary objective of the dive 6K#1058 is to observe internal structures of a NE-

SW trending ridge developed in the western Tenryu canyon (B-3), that is

hypothesized to be a continuation of the Yukie ridge. The B-3 ridge is

asymmetrical about the NE-SW axis with steeper slope in south, and seems to

be the youngest structure next to surface sliding judging from crosscutting

relationship of the surface topography. As reported from the Yukie ridge, we

expect distribution of strike-slip faults and chemosynthetic biocommunities in the

southward slope of the B-3 ridge. We plan to collect rock, sediment and

biological samples systematically across the B-3 for various laboratory studies

(density, porosity, AMS, strength and dating for rocks, stable isotopic studies for

sediment and biological samples, etc.).

Dive Summary:

The dive 6K#1058 found an outcrop of siltstone at the landing point at 11:39

(3,159 m bsl) located in mid axis of an E-ward trending gully. The siltstone has

nearly horizontal bedding plane (dipping 10 to 20 degree to the northeast). A

rock sample (6K#1058 R-1) was collected from this outcrop. The SHINKAI 6500

then set the course to 290° from the landing point toward the peak of the B-3

ridge. Bedrock exposure was good along the track, although thin layer of mud

covered outcrops. Vertical cliffs and fractures trending NNE were developed in

subhorizontal sediments. Sandstones with breccias and lenses of siltstones

73

have rugged appearance in the cliffs. Vertical fractures with fresh rupture surface

were preserved on dip slopes. They have strike slip + minor extension

component and strike N30W & N15E. 6K#1058 R-2 sample is a loose block of

siltstone large enough for laboratory testing. A core sample and a sterile sample

of sandy surface deposits were obtained in a small (50 m x 50 m) depression

surrounded by bedrock outcrops. Due to heavy weather condition at the surface

water, the SHINKAI left bottom at 13:02, just after correcting 6K#1058 R-3

sample at the base of a vertical cliff. Rock samples collected from 3 localities

were moderately consolidated siltstones and fine-grained sandstones.

Keywords:

Strike-slip ridge, deformation, chemosynthesic biocommunity

Payloads:

Push cores x 2

Sterile mud sampler x 3

Sample Box x 2

Location of Events:


11:29 33° 38.1015’N 137° 28.1787’E 3159 m Landing

11:39 33° 38.1015’N 137° 28.1787’E 3159 m Sample #R-1

12:26 33° 38.1155’N 137° 28.0364’E 3105 m Sample #R-2

12:42 33° 38.1007’N 137° 28.0084’E 3094 m Core #C-1 (Push core)

Mud #SC-1 (Sterile sampler)

12:57 33° 38.1011’N 137° 27.9817’E 3087 m Sample #R-3

13:03 33° 38.1054’N 137° 27.9903’E 3063 m Left Bottom

74

75

Video Digests:

11:26 Outcrop of siltstone at the landing point. The bedding plane dips ~15

degree to ENE. 6K#1058 R-1 was sampled. Joint sets are developed in two

directions (N10W 70W & N55E 90). Sea anemone on the outcrop (11:38).

11:39 Stratified outcrop nearby the R-1 outcrop (dip ~10 degree to NNE).

11:45 Stratified outcrop (dip ~10 degree to NE and ~15 degree to NNE).

Joint (N45E 90).

11:46 Outcrop with vertical fractures (N56W70W & N35E70E, N35E80W).

11:46 White layer (cover?)

11:47 Rugged outcrop above the white layer (deformed?). Foliation developed in

N60W20S. Joint sets (N80W90 & N30W60W).

Bedding plane: N45W 15E, Joint: N30E90.

11:49 Dip slope: N60W 10N (= bedding plane).

11:50 Dip slope: N30W 30E (= bedding plane).

11:50 Sea cucumber.

11:52 Deep sea cod.

11:53 Outcrop with fallen-off surface. Dip slope: N75E 20N (= bedding plane).

Joint: N40W 90.

76

11:54 Sea cucumber. Gutter (010) on slope (EW 10N).

11:58 Cliff (cliff surface: N30E 70E). Alternation of sandstone and mudstone

(bedding plane: N20E 10E).

12:02 Gully (025) and exposure of white layer with rugged appearance (N80W

20N).

12:04 Alternation of mud and sand (bedding plane: N70W 10N).

12:06 Dip slope: N80E 15N (= bedding plane).

12:16 Extension (strike-slip?) faults on surface (N45W 90).

12:16 Cliff (015). Upper bedding plane: N45W 20N. Lower bedding plane (dip

slope): NS 20E.

12:23 Cliff (surface: N20E 80E). Bedding plane dips slightly to W.

12:24 Faults on surface (N15E90)? Dip slope: N70W 20N.

12:24 Ripple.

12:25 Loose stone (6K#1058 R-2).

12:29 Faults on surface: N50W 90. Dip slope: dips slightly to N (= bedding plane

of white layer).

12:31 Fault (N30W 90) on surface of sub-horizontal (dip slightly to N) dip slope

covered by debris. Gully (072).

12:39 Muddy bottom. Sterile mud sampler (red), push core (green).

12:44 Outcrop of breccias with rugged appearance underlain by siltstone.

Bedding plane: N70E 15N. Joint: N20E 90, N70W 90.

12:45 Faults on surface (N30W 90 & N15E 90 (minor component)).

12:46 Outcrop with rugged appearance (breccias with lenses). Bedding plane:

N30E 15E.

12:50 Siltstone block.

12:53 Debris.

12:56 Rocky debris (6K#1058 R-3)

12:59 Vertical cliff (20 m high; N40E-80E). Outcrop of sandstone with siltstone

lenses (?)(N20W 20E) overlain by bedded siltstone (EW 15N ~ horizontal).

Joint: N20W 80W.

13:01 Top of the cliff. Dip slope: N45E 15E (= bedding plane).

13:02 Left bottom

77

Description of samples:

R-1: Brownish (oxidized part) siltstone ~ fine-grained sandstone. The specimen

exhibits irregular laminae. Moderately consolidated. R-1: 21 x 11 x 5 cm.

R-2: A large block of loose stone dropped from nearby outcrop. Moderately to

firmly consolidated gray siltstone with loose sand cover on surfaces.

Broken into four pieces in the sample basket. R-2-1: 31 x 28 x 10 cm, R-

2-2: 19 x 10 x 3 cm, R-2-3: 10 x 8 x 5 cm, R-2-4: 9 x 6 x 4 cm. Fine planar

78

laminae were observed.

R-3: Moderately consolidated siltstone to very fine-grained sandstone. Fine

planar laminae were observed. R-3-1: 20 x 17 x 9 cm, R-3-2: 12 x 8 x 6

cm.

C-1: Push core (green); 11.5 cm long column of sandy deposits. See Chapter 11:

Geochemistry

79

SC-1: Sterile mud sampler (red); 50 ml sandy mud sample. See Chapter 6:

Microbiology

Future studies

Rock samples will be used for laboratory studies at U. Tsukuba, including thin

section observation and AMS measurement for fabric analysis aiming to

understand rock deformation history. Radiolarian fossils will be separated from

siltstones to determine depositional age. The sterile mud sample will be used for

extracting DNA by Prof. Nakamura, U. Tsukuba. The push core sample will be

processed by Prof. Maruoka for stable isotope analyses.

80

Dive #1059 Report

Yasuhiro Yamada (Kyoto University)


Site Name: Possible strike-slip fault in Tenryu Canyon (B-6 area)

Landing: 33° 42.5193N, 137° 30.5055E, 11:35, 2880 m

Leaving: 33° 43.0863N, 137° 30.1787E, 16:04, 2715 m

Observer: Yasuhiro Yamada (Kyoto University)

Pilot: Ohno, Y.; Co-Pilot: Saito, F.

Objectives:

The objectives of this dive were to clarify the structural and topographical

features related to a possible strike-slip fault exposed in Tenryu Submarine

Canyon. We collected rock samples for age dating and laboratory analyses

(structural analysis of micro deformation features, physical properties, etc.), as

well as samples of soft mud for biological and geochemical analyses. We also

measured heat flow data with SAHF. This is the 5th in a series of 6 dives (#1055

to #1060) carried out during YK08-E04.

Dive Summary:

Dive 1059 trace map and dive log are shown in Figs. 1059-1 and 2. This

dive was on the western slope of the Tenryu Canyon area where the current

direction of the Canyon shows a sharp bend. Since this bend is located at a

distinct lineation shown in the local topography, we interpret that this bend may

be produced by an unknown strike-slip fault. This ‘fault’ produces a gully flowing

easterly to the Tenryu Canyon and a small hill divided by the gully. Our traverse

started from south of the gully and proceeded northward to cross the gully at the

middle of the dive, then climbing up the small hill.

Rock exposures are mostly continuous, except for the bottom of the gully

where soft mud is deposited on the flat floor of 30-40 m width. Both sides of the

gully consisted of series of cliffs, total height of which were about 60 m (south)

and 20 m (north). Several slope failures (failed sediments) and faults/fracture

81

systems were observed on the east-facing slope at the south of the gully. We

also observed a few minor topographic lows in N20W direction at the eastern

slope of the small hill, north of the gully.

We collected rock samples at five sites, push core samples at two sites

and sterile samples at three sites. We also measured heat flow with SAHF tool

at the bottom of the gully.

Keywords:

Strike-slip fault, gully, fracture, slope failure

Payloads:

SAHF x1

Sterile core sampler x3

Push cores x2

Sample Box x2

Location of Events:


11:3533° 42.5193N 137° 30.5055E 2880m Landing

12:14 33° 42.5240N 137° 30.4917E 2854m Sample some Rocks (#R-1)

12:33 33° 42.5743N 137° 30.4535E 2851m Sample sterile core #1 (red)

13:10 33° 42.7130N 137° 30.4561E 2794m Sample some Rocks (#R-2)

13:58 33° 42.8046N 137° 30.2611E 2840m Sample push core #1 (blue)

14:22 33° 42.8046N 137° 30.2611E 2840m Sample sterile core #2

(green)

14:26 33° 42.8046N 137° 30.2611E 2840m Measurement SAHF

14:41 33° 42.8147N 137° 30.2943E 2824m Sample 1 Rock (#R-3)

15:17 33° 42.9391N 137° 30.2831E 2798m Sample 2 Rocks (#R-4)

15:47 33° 43.0863N 137° 30.1787E 2717m Sample push core #2 (green)

Sample sterile core #3 (blue),

Sample 1 Rock (#R-5)

16:04 33° 43.0863N 137° 30.1787E 2715m Left Bottom

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Description of Samples

R-1-1: Mudstone (hard) including biogenic pipes (f: 5mm) with surface

slickenside

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R-2-1: Mudstone (hard) massive including brown fragments (2-3mm) with

surface slickenside

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R-3-1: Mudstone (hard) with sandy lamina (mm) including biogenic pipes (f:

5mm) with surface slickenside

R-4-1: fine Sandstone, massive, including black fragments (mm)

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R-4-2: granule Conglomerates of round sandstone and shale with matrix of fine-

medium sandstone

R-5-1: Mudstone (hard) with brown lamina (mm) including biogenic pipes (f:

5mm) with surface slickenside

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Dive 6K#1060 report

By Teruyuki Maruoka (University of Tsukuba)


Site Name: Tenryu Submarine Canyon (B-7 site)

Landing point: 33: 53.7846 N, 137: 34.5515 E Depth: 2,105 m

Left bottom: 33: 53.3287 N, 137: 35.3389 E Depth: 1,576 m

Observer: Teruyuki Maruoka (University of Tsukuba)

Pilot: Yositaka Sasaki (JAMSTEC)

Co-pilot: Yousuke Chida (JAMSTEC)

Objectives:

Primary objectives of the dive 6K#1060 are to clarify the geologic structures

above the thrusts at the Tenryu Canyon and to compare them with the geologic

structures around the Tokai and Yukie Thrust. We plan to collect rock, sediment

and biological samples systematically across the B-7 for various laboratory

studies (density, porosity, AMS, strength and dating for rocks, stable isotopic

studies for sediment and biological samples, etc.).

Dive Summary:

We landed on a flat floor of the Tenryu Canyon. There, we measured heat flow

by the SAHF for 20 minutes. During the measurement, we collected a sterilized

core sample (SC-1). After the SAHF measurement, we went southeast and

climbed up a hill. We found several small-scale (10m-height) cliffs on a gentle

slope. At each cliff, we collected a few rocks. On the gentle slope, we also

collected one more sterilized core sample. Step outcrops start from 1800m-

depth and continue to 1600m-depth. We collected rocks from the outcrops. At

the site where we collected rock samples R#6, we also collected some animals,

such as starfish and crinoids. At the flat place on the top of the hill, we collected

a sterilized core and a push core.

Keywords: heat flow, biological food web, microbiology

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Payloads:

Push cores x 2

Sterile mud sampler x 4

Sample Box x 2

Location of Events:


11:09 33° 53.7846’N 137° 34.5515’E 2,105 m Landing

11:37 33° 53.7846’N 137° 34.5516’E 2105 m SAHF-measurement

Sampling Mud #SC-1

(Sterilized core sampler)

12:38 33° 53.5440’N 137° 34.7898’E 2009 m Sampling Rock #R-1

Sampling Rock #R-2


13:44 33° 53.4867’N 137° 34.9213’E 1915 m Sampling Mud #SC-2





Sampling Animals #B-6

16:13 33° 53.3287’N 137° 35.3390’E 1577 m Sampling Mud #SC-3


Sampling Mud #C-1

(Push core sampler)

16:18 33° 53.3287’N 137° 35.3389’E 1576 m Left Bottom

Dive log

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Video Digests:

11:07 Landing point

11:13 SAHF measurement

11:17 Sampling a sterilized core (SC-1)

12:30 Outcrop

12:36 Sampling rocks R#1

13:42 Sampling a sterilized core (SC-2) at a shallow hole (maybe nest of

some animals)

13:48 Small outcrop

14:22 Found a rope

14:25 Outcrop (long-lasting steps)


14:41 Found a reel

14:45 Step outcrop


Sampling starfish

15:35 Many starfishes on the floor

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16:18 Left the bottom

Description of samples:

R-1: Siltstone with a black band of 1 cm thick. Broken into two pieces in the

basket.

R-1-1: 24kg (39x30x16 cm); R-2: 0.7 kg (12x9x7 cm)

R-2-1: Moderately consolidated sandstone, 0.5 kg (12x9x5 cm). Burrows were

observed.

R-2-2 Moderately consolidated sandstone, 0.8 kg (16x8x8 cm)

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R-3-1: Sandstone, 0.7 kg (13x9x6 cm) R-3-2: Sandstone, 0.6 kg (13x8x5

cm)

R-4-1: Sandstone, 3.9 kg (25x12x12 cm)


cm)

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cm)

C-1: Push core; 12 cm long column of sandy deposits. See Chapter 5:

Geochemistry

B-2: Crinoids B-6: Starfish

Future studies

Sterile mud sample will be used for extracting DNA by Dr. Nakamura, U. Tsukuba.

Push core sample will be observed by X-ray tomography by Dr. Maruoka.

Biological samples will be used for isotope analysis by Dr. Maruoka.

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8. Heat flow measurement instrument and Long-termtemperature recorder system

8.1 SAHFStand-Alone Heat Flow meter (SAHF) (Adopted and modified from YK03-03

Onboard Report by Hideki Hamamoto, Satoko Asai (ERI, Univ. Tokyo))

Stand-Alone Heat Flow meter (SAHF) is designed to measure heat flow using

manned submersible and ROV. A SAHF consists of an electric circuit and battery

installed in a pressure tight case and five thermistors situated along a probe at 11

cm intervals. The following is description of SAHF.

Description

(Short-term temperature monitoring type)

SAHF S-6

Material Alloy of titanium

Weight 3.1 kg in air

1.5 kg in seawater

Length of pressure case 525 mm

Diameter of pressure case 58 mm

Length of probe 600 mm

Diameter of probe 13 mm

Number of thermistors 5

Intervals of thermistors 110 mm

Accuracy 0.01 °C

Resolution 0.001 °C

Interface RS232C

(9600BAUD, 8 BIT, Non-Parity, 2 STOP BIT)

Small temperature meter

(Nichiyu Giken Kogyo Co., Ltd.)

Model NWT-DN

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No. 162

Material Alloy of titanium

Length 212 mm

Diameter 41 mm

Number of thermistor 1

Accuracy 0.05 °C

Resolution 0.001°C

Weight 0.64 kg in air

0.40 kg in seawater

Weight (with table) 8.5 kg in air

4.5 kg in seawater

Fig. 8.1 Schematic illustrate of SAHF system

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8.1.1 Method of heat flow measurement

While descending, transit and ascending, SAHF is located on a special fixing

bracket prepared by Shinkai-6500 operational team. After landing on the target

seafloor, SAHF probe is set using the manipulator to penetrate into sediment

vertically and then, left to measure temperature gradient. Ordinary short-term

temperature monitoring system need at least 15 minutes (preferably 20 minutes)

for measurement.

Fig. 8.2 Load of SAHF system

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Fig. 8.3 Measurement in 6K#1055

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8.1.2 Preliminary results of temperature gradient

measurement by SAHF

Fig. 8.4 Temperature data and thermal gradient of 6K#1055 at site B-6.


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Fig. 8.8 Temperature data and thermal gradient of 6K#1060 at

site B-7.

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8.2 Long-term temperature recorder system

We recovered long-term temperature recorder system on 25 March 2008 just

before 6K#1057. It was set in 33°51.1363’N and 137°33.1165’E on 16 January

2006 during R/V Kaiyo cruise KY07-01. The water depth was 2214 m. We started the operation at ~5:50 a.m. First, we confirmed the water depth of the

recorder using a transducer on board. It was mostly 2214 m. Second, we sent a

recover command at 6:00 a.m., then the recorder system took off safely from the

seabed. Finally, the recorder system floated on sea surface at ~6:35 a.m. The

average ascending speed was ~70 m/s.

Recovered recorder.

Specification of the temperature recorder system by Dr. Yamano (Earthquake

Research Institute, University of Tokyo).

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9. Uniaxial compression strength of the rock samples

Uniaxial compression strength of the rock samples were tested by needle

penetration test machine SH-01 of Maruto Co. Ltd., which is measured the

needle penetration pressure and the needle penetration length. As the needle

penetrates into the hard rock samples, the penetration pressure needs much

more. The penetration length and the pressure depend on the rock hardness.

Such the rock hardness is converted into the uniaxial compression strength as

below calculations.

y = 0.978 x + 2.621

y = logarithm of uniaxial compression strength (kN/m2)

x = logarithm of (penetration pressure (N) / penetration length (mm))

Fig. 9.1 Needle penetrometer

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Fig. 9.2 Conversion diagram

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9.1 Results

Fig. 9.3 Measurement results

Table 9.1 Measurement results Dive# Sample# Rock type Direction Needle penetration length (mm) Penetration pressure (N) Penetration gradient (N/mm) >log (N/mm) > > Uniaxial compressive strength (MPa)

#1055 R-1-1 Sandstone 2.00 100.00 50.00 1.70 4.28 19168.70 19.17

#1055 R-1-1 Sandstone 2.00 100.00 50.00 1.70 4.28 19168.70 19.17

#1055 R-2-1 Sandstone 2.00 100.00 50.00 1.70 4.28 19168.70 19.17

#1055 R-3 Sandstone 2.00 100.00 50.00 1.70 4.28 19168.70 19.17

#1055 R-4 Siltstone 10.00 25.00 2.50 0.40 3.01 1023.73 1.02

#1056 R-1 Siltstone Perpendicular to bed 10.00 30.00 3.00 0.48 3.09 1223.56 1.22


#1056 R-3-1 Siltstone Perpendicular to bed 10.00 68.33 6.83 0.83 3.44 2736.97 2.74

#1056 R-4-1 Laminated v.f.s Perpendicular to bed 10.00 23.33 2.33 0.37 2.98 956.93 0.96

#1056 R-5-2 Siltstone Perpendicular to bed 9.54 0.98 3.58 3791.98 3.79

#1056 R-6-2 Siltstone Perpendicular to bed 10.04 1.00 3.60 3986.30 3.99

#1056 R-7 Fine sandstone Perpendicular to bed 10.00 68.33 6.83 0.83 3.44 2736.97 2.74






#1057 R-5-1 Siltstone Perpendicular to bed 10.00 0.00 0.00





#1058 R-2-1 Siltstone Parallel to bed 10.00 41.67 4.17 0.62 3.23 1687.15 1.69


#1058 R-3-1 Siltstone Parallel to bed 10.00 30.00 3.00 0.48 3.09 1223.56 1.22

#1058 R-1-1 Mudstone Perpendicular to bed 6.17 100.00 16.22 1.21 3.80 6372.81 6.37

#1058 R-2-1 Mudstone Perpendicular to bed 10.00 88.33 8.83 0.95 3.55 3518.11 3.52

#1058 R-3-1 Mudstone or laminated mudstone Parallel to bed 3.88 100.00 25.77 1.41 4.00 10025.88 10.03

#1058 R-4-1 Sandstone ? 10.00 20.75 2.08 0.32 2.93 853.19 0.85

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10. Geochemistry Teruyuki Maruoka (University of Tsukuba)

10.1 Isotope study of organic matter from

chemosynthetic-based organisms

The chemically reduced molecules, such as methane and hydrogen

sulfide from cold-seepages are oxidized above the sediment and mixed with the

components in the sea water. Their oxidized products, i.e., bicarbonate and

sulfate, are abundant in the sea; therefore, it is difficult to estimate isotopic

composition of CH4 and H2S from those of their oxidized products near the cold

seepages. We must collect CH4 and H2S before their oxidation.

When we analyze the isotopic composition of an element, we must

concentrate the element using a proper method. For H2S dissolved in water, we

can concentrate the elements from a large quantity of the water using chemical

treatments (conversion to ZnS by addition of Zn-acetate solution and then

conversion to Ag2S by addition of AgNO3 solution). However, this is not a proper

way for the study at the places where we cannot approach easily. The bottom of

the deep sea is one of the examples of such places. Also, we never obtain the

water existing at the past time. Therefore, continuous measurements are

required, if the fluid flows discontinuously. This is also not a proper way for the

research at the deep see. To overcome the difficulties for the studies at the deep

sea, we may use organism as a time-recorder for isotopic composition.

Some elements, such as carbon, nitrogen, and sulfur, are concentrated

in the organic matter of organism. The organisms at cold-seepages incorporate

H2S and CH4 below the sediment surface and before oxidation. Therefore, we

can use organic matter of organism at cold seepages to know isotopic

compositions of hydrogen sulfide (δ34S) and methane (δ13C) in the fluid emitted from cold seepages. Although isotopic fractionation occurs during assimilation of

organic matter (See 5.4), the isotopic difference of the fluids of cold seepages

from the seawater are much larger than the isotopic fractionation during

assimilation.

In addition, the hard tissues, such as shell, bone, and nail, preserve the

isotopic composition of the time when these elements are incorporated.

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Therefore, using the hard tissues as a time-recorder, we may obtain the isotopic

composition of CH4 and H2S at the past time.

At the dive 6K#1055, two tube worms were collected at cold-seepages

and a push-core sample (6K#1055 C-1) was also collected near them (See the

photos below). The core sample was cut into several pieces every 1 or 2 cm. We

kept the tube worms and core pieces into the refrigerator at -40ºC during this

cruise and will keep them in the refrigerator until analysis. After drying these

specimens in a vacuum chamber at University of Tsukuba, we will analyze

isotopic composition of carbon, nitrogen and sulfur of each part of tube worms

and organic matter from the core. Especially, tubes of the tube worms have

stripes. We will determine isotope composition for each stripe, if possible. Using

these data, we can discuss whether tube stripes can be used for the

time-recorder of the fluid flux or not. We cannot obtain information about

elements except for carbon, sulfur and nitrogen only from organic matter. We will

use the core sample for the studies of other elements (See 5.3).

10.2 X-ray tomography of a push-core sample

An 11.5-cm-core sample without perturbation was obtained at the dive

6K#1058 (see the photo below). Generally, we cut a core sample into several

pieces, but we kept the core samples for analysis with X-ray tomography, which

we can observe the 3D-distribution of density without destruction. Based on the

observation from the surface, we could find black grains. Using X-ray

tomography, we will observe the 3D-structue of such grains in the core and we

may observe a density profile that we cannot recognize with our naked eyes.

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10.3 Fe isotope analysis for the blood in tube worms

Calyptogena and tube worm have hemoglobin in their blood that

contains Fe2+ in their structure. We will analyze Fe isotope ratio to examine how

much percentage of Fe2+ is supplied by the Fe3+-reducing bacteria. The

Fe3+-reduing bacteria may live in the sediments related to cold seepage, where

sulfate-reducing bacteria exist. Both Fe3+-reducing bacteria and sulfate-reducing

bacteria can live only in anaerobic environment. Using isotope ratio of iron, we

can separate bacteria-produced Fe2+ from Fe2+ of other origins. Two tube worms

were collected at the dive 6K#1055. We will obtain isotopic composition of Fe in

blood of the tube worms. A core sample was also obtained near the site

sampling the tube worms. We can compare the isotopic composition between

iron from tube worm and from sediment. We can use isotope ratio obtained form

the sediment as a reference value for the non-bacterial Fe2+.

10.4 Isotopic fractionation during assimilation of

organic matter at the deep-see environment

Isotopic fractionation during assimilation of organic matter occurs in the

environment where the photosynthesis controls the food-chain. For example,

δ15N values increase by ∼3 ‰, when increasing trophic level by one. This rule can be applied to the photosynthesis-basic food-chain for freshwater and marine

environment. However, we do not know whether the same rule can be applied to

the deep-see environment, where the organic matter available for organisms is

restricted. Although the chemical reactions related to organic matter assimilation

generally prefer heavier isotopes (13C and 15N) than lighter isotopes (12C and

Black grain

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14N), the reaction may use all isotopes without preference at the environment

where organic matter available for organism is restricted.

At the dive 6K#1060, animals that incorporate organic matter at the

bottom of deep sea were collected and core samples were also obtained near

the animals. We will analyze isotopic ratios of the animal and the organic matter

obtained from the core samples to obtain the isotopic fractionation during

organic matter assimilation at the deep see environment.

10.5 Isotopic composition of carbon and oxygen in

calcite in calcite veins

We will determine isotopic composition of carbon and oxygen in calcite

in calcite-veins in some rocks obtained during this cruise.

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11. Microbiology

Akira Nakamura (Univ. of Tsukuba)

11.1 Objectives

1) Isolation of L-glucose-utilizing microorganisms

Most of all the living organisms can use D-glucose as energy and

carbon sources, which is produced by plants, algae and photo-synthetic

microorganisms through photosynthesis. On the other hand, there are no

reports on microorganisms utilizing L-glucose, the stereoisomer of D-glucose.

L-glucose is classified as one of “rare sugars”, carbohydrates that do not exist or

scarcely exist in nature.

Very recently, we have succeeded in isolation of L-glucose-utilizing

bacteria from surface soils and sediments of ponds near University of Tsukuba.

In this cruise we aimed the isolation of L-glucose-utilizing microorganisms from

marine sediments.

2) Isolation of nitrogen-fixing microorganisms

Nitrogen is one of the most important atoms for living organisms,

because it consists of proteins, nucleic acids and other important smaller

compounds in the cells. In the deep sea, as NH4+ and NO3

- ions are scarce in

the seawater and organic nitrogen is also limited, it seems likely that some

microorganisms can utilize dissolved N2 gas in the seawater through nitrogen

fixing activity. As the DO meter on “Shinkai 6500” indicates that oxygen is

present in the deep sea at about half the amount of the sea-surface, enough

amount of dissolved N2 gas seems to be present in the deep seawater.

However, there seems no reports on the isolation of microorganisms with

nitrogen-fixing activity from the deep sea-muds. With the mud samples

obtained through this cruise, we will try to isolate nitrogen-fixing microorganisms.

3) Comparison of microbial communities between mud samples and rock

samples

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The PCR-DGGE method is now commonly used to analyze and

compare microbial communities in environments. To do so, extraction of DNA

from samples was conducted on-board. With the extracted DNA in this cruise,

we will compare microbial communities between mud samples. We also tried

to extract DNA from several mud rocks (rather soft ones) obtained in this cruise.

Analyses with DNA from rock samples may reveal “former” microbial

communities related to the Geologic ages that these rocks were made.

11.2 Methods

1) Sampling of deep sea-muds in sterile condition

We used the “sterile-core sampler” from Dr. C. Kato (JAMSTEC). The

sampler was steriled by autoclaving prior to dive. Mud samples were collected

by manipulators of “Shinkai 6500”. We also collected samples from the

wastewater treatment system of “R/V Yokosuka” for isolation of

L-glucose-utilizing microorganisms.

2) Cultivation of L-glucose-utilizing microorganisms

Samples were plated directly onto a minimal agar medium (10 mM

MgSO4, 10 mM KH2PO4, 10 mM NH4Cl, 10 mM KCl, 2 ml/L trace elements, pH

7.0) containing 0.25% L-glucose, and cultivated at room temperature.

3) Extraction of DNA

Extraction of DNA from the mud samples was conducted by the

Beads-Bead method with a FastDNA Spin for Soil kit (MP Biomedicals, Ohio)

and an FP120 instrument. For extraction of DNA from rock samples, surfaces

of rocks were sterilized with ethanol flame, rocks were cut by sterile spatulas,

and some particles were used for extraction.

11.3 Results


We obtained several hundreds of colonies with different morphology on

the L-glucose minimal plates from samples of the wastewater treatment system

after 3 days of cultivation at room temperature. Some colonies were picked

122

and streaked onto a new plate, and we observed formation of colonies after 2

days of cultivation, indicating that they are actually utilizing L-glucose.

As for 10 mud samples (until 6K#1059 dive), we obtained several

colonies from SC-1 and SC-2 samples of 6K#1055 and SC-1 sample of

6K#1056 after cultivation of 7 days. This suggests that L-glucose-utilizing

microorganisms are also present in the deep-sea environment.

2) Extraction of DNA

From 13 mud samples obtained, we extracted DNA by the Beads-Bead

method. We also extracted DNA from several rock samples (6K#1055 R4,

6K#1056 R6, 6K#1057 R1-1 and R6, 6K#1058 R1, and 6K#1059 R4). These

rocks were easily broken after Beads-Beading, suggesting that DNA was

extracted properly.

11.4 Proposal for Post-Cruise Study


Using enrichment cultivation technique with a medium containing

L-glucose as the sole carbon source, we will try to isolate L-glucose-utilizing

microorganisms from all the samples. After isolation, we will examine how

those microorganisms utilize L-glucose.


We will first examine the contents of NH4+, NO2

- and NO3- ions in the

deep seawater in the samples, and also the contents of organic nitrogen in the

mud samples (by the aids of Dr. T. Maruoka). We will also try to isolate

nitrogen-fixing microorganisms by using enrichment technique with a

nitrogen-free minimal medium.


samples

We will first examine whether DNA was properly extracted from the

mud and rock samples, by PCR-amplification with primer sets for Bacterial and

Archaeal ssu rRNA genes. Then we will conduct the PCR-DGGE analysis to

123

compare microbial communities between mud and rock samples.

12. Post-cruise Study of YK08-E04

Kiichiro Kawamura

Exhumation problem around site B-4.

I will study exhumation problem around site B-4 using Illite crystallinity data

(Nick), vitrinite reflectance data (Nick), radiolarian microfossils (Motoyama-san,

onshore scientist) and physical properties data (Michiguchi-san), and also

studying with Kurt and Muraoka-san.

Ryo Anma

U-Pb and FT age estimation of volcanic zircon from 6K#1056R-2 and detrital

zircon from 6K#1055R-1~R-3.

Teruyuki Maruoka

* ISOTOPE study of organic matter from chemosynthetic-based organisms

* X-RAY TOMOGRAPHY of a push-core sample

* Fe istotope analysis for the blood in tube worms

* Isotopic fractionation during assimilation of organic matter at the deep-sea

environment

Satoru Muraoka

GEOLOGIC MAPPING using video data mainly PRISM TOE (Anma-san’s #1058

and previous dive video) and comparison study between Nankai Prism and Boso

Prism. 本潜航，また過去の潜航での露頭観察から，現世付加体の平面図・断面図

を作成し，地質構造の議論をする．特に，付加体先端である，付加体となって間もな

い地域の地質構造を理解したい．また，付加体であるか，海底地すべりであるか議論

されている房総半島南端に位置する千倉層群の平面図，断面図と比較し，千倉層群

の地質構造についての議論ができることに期待したい．

タイトル『天竜海底谷における現世付加体のプロファイル』

124

本潜航，また過去の潜航での露頭観察から，現世付加体の平面図・断面図を作成し，

地質構造の議論をする．特に，付加体先端である，付加体となって間もない地域の

地質構造を理解したい．また，付加体であるか，海底地すべりであるか議論されてい

る房総半島南端に位置する千倉層群の平面図，断面図と比較し，千倉層群の地質

構造についての議論ができることに期待したい． "Profiles of the pressent accretionary prism in the Tenryu Canyon"

I'll draw plan profile sections and cross profile sections of the present

accretionary prism observed by this dives and the past dives, and then, I'll

discuss about these geological structures. In particularly, I'd like to understand

structures of prism toe, a young accretionary prism, besides, I hope that I

compare these profile sections with the Chikura Group's profile sections.

Yasuhiro Yamada

Structural style around the Tokai Thrust

This is primarily a geologic cross-section based on 4 dives (North to South: Dilek,

YY, Kawamura, Nick) and may be combined with similar studies by

Kawamura-san, Nick and Dilek(?). I am also going to work together with

Miyakawa-kun.

Yoko Michiguchi

Clarification of formation process and mechanism for BLACK LAYERS

–comparing the Nankai Accretionary Prism with prism at southern Boso

Peninsula-

1. Porosity measurement of the rock samples

2. Compare the black layers and deformation structures in the Nankai

Accretionary Prism with those in southern Boso Peninusla.

Hiroshi Ikeda

Macro-scale and Micro-scale TOPOGRAPHIC ANALYSES using dive video data,

bathymetric maps and subbottom profiling images

125

Ayumu Miyakawa

Title: Vp measurement to combine with seismic profile at Tokai Thrust.

Contents:

We will measure the P-wave velocity of the samples and we estimate the

acoustic impedance with the density.

We plan to compare these acoustic impedance and seismic profile data

along the Tenryu Canyon at Tokai Thrust.

Samples:

We already keep some samples from #1056. We also want some sample from

other sites to compare sample data and seismic profile spatially.

We just measure P-wave velocity. These measurements are nondestruction.

We propose that we are going to return samples after the measurement

even if we took too much samples.

Workers plan:

A. Miyakawa, Y.Yamada and T.Tsuji(onshore scientist)

Toshimitsu Suzuki

「泥岩中のcalcite veinにおける硫黄同位体の研究」 (Sulfur isotope composition in calcite vein)

Keisuke Yamada

Title: Screening of the nitrogen fixation microorganisms in the deep-sea

sediment. 深海底で窒素固定を行っている微生物を探す。

Toshimitsu Shimizu

深海底泥におけるＬグルコース資化菌の純粋分離と同定，その代謝機構の解明

Akira Nakamura


Using enrichment cultivation technique with a medium containing

126

L-glucose as the sole carbon source, we will try to isolate L-glucose-utilizing

microorganisms from all the samples. After isolation, we will examine how

those microorganisms utilize L-glucose.


We will first examine the contents of NH4+, NO2- and NO3- ions in the

deep seawater in the samples, and also the contents of organic nitrogen in the

mud samples (by the aids of Dr. T. Maruoka). We will also try to isolate

nitrogen-fixing microorganisms by using enrichment technique with a

nitrogen-free minimal medium.


samples

We will first examine whether DNA was properly extracted from the

mud and rock samples, by PCR-amplification with primer sets for Bacterial and

Archaeal ssu rRNA genes. Then we will conduct the PCR-DGGE analysis to

compare microbial communities between mud and rock samples.

Date post:	03-Sep-2020
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On Board Report of YK08-E04 · This project was held by R/V and the manned-submersibleYokosuka...

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