MIS32-P01

Room:Convention Hall

Time:May 24 18:15-19:30

Quaternary radiolarians biostratigraphy in the Alaska margin (IODP Exp.341 Site U1417)
MATSUZAKI, Kenji M.1∗ ; ASAHI, Hirofumi2 ; FUKUMURA, Akemi3 ; KONNO, Susumu4 ; SUTO, Itsuki5
1

Geological Survey of Japan, AIST, 2 Korea Polar Research Institute, 3 Hokkaido University Graduate School of Science, 4 Kyushu
University Graduate School of Science, 5 Nagoya University Graduate School of Environmental Studies

The Gulf of Alaska is marked by the St. Elias orogen largely influenced by the ice-sheet expansion over the past 10 Myr. In thiscontext, the Integrated Ocean Drilling Program (IODP) Expedition 341 drilled several sites in southern Gulf of Alaska in orderto determine the linkage between the tectonic uplift, erosion by ice sheet and climate changes since Miocene. Concerning the
paleontological aspect of the collected cores, siliceous microfossils were not abundant. Cores collected from Site U1417 present
the highest abundance in siliceous microfossils. Indeed, in Site U1417, siliceous microfossils present moderate abundance forthe upper 200 meters CCSF-B, which correspond to the Pleistocene. This interval is composed of dark gray mud with several
interbeds of diatomaceous oozes. For deeper intervals, siliceous microfossils abundances were low, with numerous barren intervals.
Therefore, in this study, samples from the upper 200 m CCSF-B of Site U1417 were analyzed in order to establish the depth-age
model based on shipboard diatom/radiolarian biostratigraphy and paleomagnetic polarity stratigraphy for enables further paleoceanographic studies. Indeed, several radiolarian datum events such as the last occurrences (LOs) of Stylatractus universus ,Lychnocanoma sakaii and Amphimelissa setosa appear to be important for chronostratigraphic use. Particularly, temporal distribution of Amphimelissa setosa is highly interesting because the LO records at the MIS 4/ 5 boundary (77 ka) in the North Pacific,
while this species is still extant in the Arctic Ocean, Norwegian Sea, or in the Labrador Sea. In this study, we could establish
the LOs of Sphaeropyle robusta (1,500 ka, 161.9 m CCSFB at the median depth), Eucyrtidium matuyamaii (1,250 ka, 143.3 m),
Stylatractus universus (450 ka, 74.9 m), Axoprunum acquilonium (350 ka, 61.5 m) and Amphimelissa setosa (77 ka, 25.0 m),
and acme of Lychnocanoma sakaii (61 ka, 18.81 m). On the other hand, the FO of Amphimelissa setosa could be established forthe first time in the northeastern Pacific between the LO of Eucyrtidium matuyamaii and the base of Jaramillo magnetic normal
polarity epoch (1,072 ka).

Keywords: Quaternary, Radiolarians, Biostratigraphy

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MIS32-P02

Room:Convention Hall

Time:May 24 18:15-19:30

Last glacial to deglacial biotic changes on the Great Barrier Reef from offshore boreholes
HUMBLET, Marc1∗ ; WEBSTER, Jody M.2 ; BRAGA, Juan carlos3 ; IRYU, Yasufumi4 ; POTTS, Don C.5 ;YOKOYAMA, Yusuke6 ; ESAT, Tezer M.7 ; FALLON, Stewart8 ; THOMPSON, William G.9 ;THOMAS, Alexander L.10
1

Dep. of Earth and Planetary Sc., Nagoya Univ., 2 Geocoastal Research Group, Univ. of Sydney, 3 Dep. de Estrat. y Paleont.,
Univ. de Granada, 4 Inst. of Geol. and Paleont., Tohoku Univ., 5 Dep. of Ecol. & Evol. Bio., Univ. of California, 6 AORI, Univ.
of Tokyo, 7 ANSTO, Inst. for Env. Res., Australia, 8 Res. Sch. of Earth Sc., Austral. Nation. Univ., 9 Lamont-Doherty Earth
Observatory, USA, 10 School of GeoSciences, Univ. of Edinburgh

IODP Expedition 325 drilled 34 boreholes into submerged reef structures along the shelf edge of the Great Barrier Reef (GBR).
The boreholes were drilled between 42 and 167 mbsl at 17 sites along four transects at three geographic locations (Hydrographers
Passage, Noggin Pass, and Ribbon Reef). The last glacial to deglacial reef sequence (˜8 ka to ˜27 ka) varies in thickness from˜5.5 m to ˜34 m and consists primarily of coralgal boundstone with various proportions of microbialite. We use a detailed
chronostratigraphic scheme based on numerous C14 and U-Th ages to discuss the evolution of the coralgal communities since
the last glaciation. Exp. 325 cores show that different phases of sea level change promoted different shallow reef-building coral
species at the study sites. The onset of the deglacial (16-19 ka) is characterized by a peak abundance of Seriatopora and Tubipora
whereas the following rapid sea level rise (<16 ka) is marked by the dominance of massive Isopora and Acropora with mediumto robust-size branches. The shift in composition of coral communities around 16 ka coincides with the flooding of a pre-LGM
MIS2 reef terrace, an event which had a major influence on reef growth and reef composition. We discuss the impact of thisevent on coralgal communities in the GBR and its significance for Quaternary reef evolution in general.
Keywords: IODP Expedition 325, Great Barrier Reef, Coralgal assemblages, Sea level changes, Glacial, Deglacial

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MIS32-P03

Room:Convention Hall

Time:May 24 18:15-19:30

Geochemical variation of Izu rear-arc volcanic rocks at drill Site U1437: Preliminary
results from IODP Expedition 350
SATO, Tomoki1∗ ; TAMURA, Yoshihiko1 ; MIYAZAKI, Takashi1 ; GILL, James B.2 ; HAMELIN, Cedric3 ;SENDA, Ryoko1 ; VAGLAROV, Bogdan S.1 ; HARAGUCHI, Satoru1 ; CHANG, Qing1 ; KIMURA, Jun-ichi1 ;IODP EXPEDITION 350, Scientists4
1
3

Japan Agency for Marine-Earth Science and Technology, 2 Earth and Planetary Sciences, University of California, Santa Cruz,
Centre for Geobiology, University of Bergen, 4 International Ocean Discovery Program

The Izu-Bonin-Mariana (IBM) arc is a good place to understand oceanic arc evolution. Crustal composition of the Izu segmentof the arc differs beneath the arc-front and rear-arc (e.g. in terms of K, LREEs) (e.g. Hochstaedter et al., 2001; Ishizuka et al.,
2003; Tamura et al., 2007). However, the magmatic history of the Izu rear-arc has not been well studied because Oligocene
and Eocene Izu rear-arc lavas and volcaniclastics produced before the opening of the Shikoku basin have not been recoveredby dredging or ROV sampling. Site U1437, drilled during IODP Expedition 350, is the first drill site in the Izu rear-arc andaimed to recover a record of volcanism in the rear arc from the present day to the Paleogene. This study will present preliminary
major element (measured by X-ray fluorescence, XRF), trace element (measured by XRF and inductively coupled plasmamass spectrometry, ICP-MS) and isotope ratios such as Sr, Nd, Pb and Hf (measured by ICP-MS and thermal ionization mass
spectrometry, TIMS) to examine the geochemical signature of the recovered material and whether it can be related to the present
day rear-arc or arc-front.
Site U1437 is located in a basin between the Manji and Enpo rear-arc seamount chains, about 90 km west of Myojinsho
volcano on the Izu arc-front. Drilling reached 1806.5 meters below seafloor (mbsf), and the recovered rocks were divided into
seven lithostratigraphic units and one igneous unit (a rhyolite intrusion). Lithostratigraphic Units I to V (0-9 Ma) dominantly
consist of tuffaceous mud/mudstone. Below 1320 mbsf, Units VI and VII (older than 9 Ma) are composed chiefly of volcaniclastic
layers, including coarser (>2 cm) volcanic clasts that are possibly derived from more proximal sources (Tamura et al., 2015).
Initially we have analyzed the major and trace element compositions of the volcanic clasts from Units VI and VII. Those showa wide range of compositions, from basalt to rhyolite, but are mainly intermediate (average SiO2 = 54.1 wt%). The K2 O contentsof the basalt to andesite clasts within the volcaniclastics are <0.9 wt%, with the exception of one clast, and their Zr/Y are <3.2
(average = 2.4), with the exception of two clasts. These characteristics are within the range of both the present day Izu arc-front
and rear-arc. The present rear-arc type lavas are strongly enriched in LREEs, whereas the arc-front type are depleted. However,the chondrite normalized REE patterns of the clasts are flat (La/Yb ∼ 1.0) or show slight depletions in LREEs relative to HREEs,
so it is not clear if these proximal clasts are similar to the current arc-front or rear-arc. The deepest clasts that have been analyzed(from 1797.26 and 1798.57 mbsf) are basaltic andesites and have relatively high Zr/Y (3.5 and 4.1, respectively), similar to thepresent day rear-arc. However, their K2 O contents (0.89 and 0.35 wt%, respectively) and flat REE patterns are not.
The wide range of clast compositions make it difficult to distinguish whether the clasts from the deeper part of Site U1437 arederived from the present day Izu arc-front or rear-arc and whether or not this geochemical distinction existed when this material
was erupted on the basis of major and trace elements alone. Analyses from additional samples and the isotope compositions of
the clasts may be more diagnostic.

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MIS32-P04

Room:Convention Hall

Time:May 24 18:15-19:30

High temperature metamorphism recorded on chromitite samples in drilling cores fromocean floor
ABE, Natsue1∗ ; HARIGANE, Yumiko2
1

R&D Ocean Drilling Science, JAMSTEC, 2 Institute of Geology and Geoinformation, AIST

Metag-gabbro and some serpentinites are not only extremely altered, but also metamorphosed at high temperature up to midamphibolite facies. Chromian spinel included in those samples, which is normally well preserved under the condition of ocean
floor metamorphism, also metamorphosed into chrome-bearing magnetite and/or magnetite. The crystal orientation varies insidea grain with chemical modification of the metamorphism. We discuss the possibility of such high temperature metamorphism inthe deep oceanic plate.
Keywords: chromitite, IODP Exp. 345, high temperature metamorphism, Moho transition zone, oceanic crust, ODP Leg 209

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MIS32-P05

Room:Convention Hall

Time:May 24 18:15-19:30

Mud logging in hard rock drilling
SUGIHARA, Takamitsu1∗ ; MOE KYAW, Thu2 ; AOIKE, Kan1
1

CDEX/JAMSTEC, 2 ODS/JAMSTEC

Mud logging in a riser drilling operation has been powerful tool in the scientific drilling. Since fast and safe drilling areminimum requirements in the deep drilling operation, it is generally difficult that continuous coring is carried out to obtaingeological sample (rocks and fluid). Therefore, cuttings survey and mud gas monitoring in mud logging are essentially importantin the riser drilling for scientific research. Some hard rock drilling operations by using the Chikyu have been planned (e.g.,IBM, MoHole). Since continuous coring in the hard rock drilling is technically more difficult as compared with the drillingfor sedimentary rocks and slow rate of penetration results in consuming much of operation time, the cuttings survey is a uniqueapproach for lithological characterization in the hard rock drilling. In addition, fluid sampling from hard rock core is also difficult,even if core sample is obtained. Thus, the mud logging is especially important for the hard rock drilling, not only minimizing
operation time but also maximizing scientific result. In this presentation, we will introduce current technology of advanced mud
logging and discuss on potential of the mud logging for the hard rock drilling.
Keywords: Mud logging, Deep drilling, Hard rock drilling, Riser drilling, Mud gas monitoring, Cuttings

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MIS32-P06

Room:Convention Hall

Time:May 24 18:15-19:30

Distribution of physical properties and pore pressure of sediments off Costa Rica: IODP
Expedition 344
SAIKI, Ayakia1∗ ; HASHIMO, Yoshitaka1
1

Kochi University

Evolution of physical properties in subduction zone is a key to understand lithification processes, location of decollement,
and stress distribution. In this study, we examined the physical properties of sediments using on-board data and laboratory
experimental data on sediments obtained off Costa Rica margin to understand the distribution of acoustic properties.
Target sites are in the Integrate Ocean Drilling Program (IODP) Expedition 344 off Costa Rica, including reference sites(U1381 and U1414), frontal prism site (U1412), mid-slope site (U1380) and upper-slope site (U1413). In this study 4 samples
from reference sites are from Unit I in shallower Unit. Only one sample in U1381 is located in Unit II below the Unit I. Anothersamples is from UnitII.
Laboratory experiments for velocity and porosity measurements were conducted with variation of effective pressure.
In U1381, porosity, P-wave velocity, and S-wave velocity were represented about 50-72%, 1.4-1.7m/s and 0.75-0.85 m/s,
respectively, during the experiments. From the value, Vp/Vs, bulk modulus and shear modulus were calculated to be 1.85-2.02,
1.8-2.6GPa and 0.8-1.0GPa, respectively. A sample in U1381 was from Unit II, which has relatively low bulk density, indicates
80-66% of porosity, 1.5-1.6 m/s of Vp, 0.85-0.9 m/s of Vs, were obtained, and 1.74-1.78 of Vp/Vs, 1.7-2.0GPa of bulk modulus,
and 1.0-1.1GPa of shear modulus correspond to obtained Vp and Vs.
In Unit 1414, similarly described above, porosity, P-wave velocity, and S-wave velocity ranges, 55-73%, 1.5-1.7km/s, and0.85-0.95 km/s, respectively. Vp/Vs, bulk modulus and shear modulus were computed to be 1.85-2.02, 1.8-2.6GPa and 0.81.0GPa, respectively.
Finally, Unit 1412, porosity, P-wave velocity, and S-wave velocity covers, 73-76%, 1.51 -1.56km/s, and 0.75-0.77 km/s,
respectively. Vp/Vs, bulk modulus and shear modulus were obtained as 2.0, 0.91-0.95GPa, and 2.4-2.7GPa, respectively.
Vp-porosity relationships from on-board data and from laboratory experiments are comparable nicely and also represents agood agreement with global empirical model, although Site U1381 Unit II has relatively high velocity. This comparable trend in
Vp-porosity relationship suggests that the physical properties of sediments except for U1381 Unit II can be similar.
In Vs-porosity relationship, Vs increases with depth increment in each site although the difference in porosity is very small
around 0.7 in the obtained state. The sample from U1412 has relatively high both in Vp and Vs even the sample depth is shallow
around 14 mbsf.
In terms of bulk and shear moduli, samples from reference sites represent a constant bulk modulus with wider variation ofshear modulus. U1381 Unit II shows relativly low bulk modulus in middle value in the variation of shear modulus due to low
bulk density and relatively high Vs. A sample from U1412 shows relatively high bulk modulus and low shear modulus.
For sediments in Unit I of reference sites, the trend of constant bulk modulus with variation in shear modulus is similar to thatreported from off Osa Peninsula, Costa Rica (ODP Leg 170) (Gettemy and Tobin, 2003). It might be a common evolution inreference site with depth. The samples from U1412 is located at frontal prism even in shallow portion. The sediments should be
affected by shear deformation, which may make Vp and Vs increased. Therefore, the bulk modulus is relatively high among thesamples. The sample in U1381 Unit II has low bulk modulus due to higher porosity in deeper portion. The higher porosity is
kept by skeletons of nanofossils which act as a cement in the sediment. The change in physical properties from Unit I to Unit II islarge at the boundary. The effect of the change in physical properties on fluid pressure at the unit boundary should be examinedin the near feature.

Keywords: Drilling, IODP, Costa Rica, Expedition 344, Physical properties

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MIS32-P07

Room:Convention Hall

Time:May 24 18:15-19:30

Structures characterizing the megasplay fault across shallow slope sediments of the Nankai
accretionary prismOOHASHI, Kiyokazu1∗ ; OLIVIER, Fabbri2 ; YAMAGUCHI, Asuka3
1

Graduate School of Science and Engineering, Yamaguchi University, 2 University of Franche-Comte, Besancon, France, 3 Atomosphereand Ocean Research Institute, The University of Tokyo
LWD measurements at Hole C0022A and coring at Hole C0022B during IODP Expedition 338 confirm the early suggestion
from seismic reflection imaging that a branch of the mega-splay fault crosses shallow slope sediments and may thus get close
to the sea bottom. At C0022A, the evidence include (1) the presence of moderately to steeply dipping fractures between 86.6
and 105.5 mbsf and (2) the presence of a low-resistivity zone at the same interval, with a particularly low resistivity interval
at 100-101 mbsf. At C0022B, the evidence include (1) three age reversals recognized between 76.48 and 84.48 mbsf, between
132.38 and 142.70 mbsf, and between 142.70 and 148.46 mbsf, (2) a bedding disturbed interval from 73.49 to 143.82 mbsf,(3) poor core recovery in the interval of 94.5-99.5 mbsf, suggesting highly fractured or disturbed material, and (4) the presenceof three intervals of clay characterized by a composite planar fabric (338-C0022B-10T-5, 49-51 cm, 10T-CC, 19-20 cm, and
11H-1, 18-19 cm). By comparison with the nearby 3D seismic reflection image, the C0022A low-resistivity image at 100-101
mbsf could correspond to the megasplay fault core zone where displacement is supposed to be the largest. The sudden drop incore recovery at this interval indicates that coring at Site C0022 likely missed the megasplay fault core zone. Conversely, coring
likely sampled secondary fault zones characterizing the damage zone of the megasplay fault branch at Site C0022. Post-cruise
investigations aim at examining all structures and microstructures associated with this supposed damage zone.
Based on CT scan images, seven intervals were selected from Core 10T (three from section 5, one from core catcher) and fromCore 11T (three intervals). For each interval, a slab was cut, dried, epoxied and polished before being analysed by XRF scannerfor compositional mapping. Polished thin sections were made from the most deformed-looking parts of the slabs.
XRF scanning analysis brings two main results: At least three gently dipping planar surfaces outlined by iron sulphide (mostlikely pyrite) cross the cores. It is not clear whether these surfaces are faults or not but, in one case (11T-1, 72-83 cm), thesurface separates clays with different Ca contents, suggesting some offset. The presence of iron sulphide along the surfaces may
be related to fluid flow having allowed recrystallization of this mineral species. Shipboard observation revealed three intervals
characterized by weakly marked planar fabrics. Two of these intervals (338-C0022B-10T-5, 49-51 cm and 11H-1, 18-19 cm) arecharacterized by a depletion in Ca and Sr and an enrichment in K with respect to the surrounding sediments.
Lastly, preliminary optical microscope observation indicates that some incipient non-coaxial shear deformation (asymmetricalsand lenses and composite planar fabric) affected the intervals with planar fabrics. Put together, these results indicate that deformation so far recognized in C0022B cores is weak to moderate. This is not an unexpected result given (1) the young age of thesediments and (2) the fact that samples likely come from the damage zone a few meters and not from the core zone.
[Acknowledgements]
We thank the crew of D/V Chikyu and all drilling personnel who contributed to the overall success of Expedition 338. We also
thank Kyuichi Kanagawa, Takehiro Hirose and Kentaro Hatakeda for constructive discussions and technical help. This researchused samples and data provided by the Integrated Ocean Drilling Program (IODP). Funding for this post- expedition research
was provided by CDEX, JAMSTEC.

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MIS32-P08

Room:Convention Hall

Time:May 24 18:15-19:30

Distribution and evolution of organic matters in deep seafloor sediments collected during
IODP Exp.338 and 348
FUCHIDA, Shigeshi1∗ ; MASUDA, Harue1 ; OKAZAKI, Kaori1 ; KUROKAWA, Syoki2
1

Department of Geoscience, Osaka City University, 2 Japan Petroleum Exploration Co., Ltd. (JAPEX)

Seafloor sediments are important as a significant reservoir of organic matter, especially organic carbon and nitrogen. Sedimentary organic matters are mainly supplied through a photosynthetic process of phytoplankton biomass and other metabolismsof zooplankton and maturated during diagenesis (Lee et al ., 1988). Proteins, peptides, and amino acid monomers are the main
components and account for 30 ‒ 40% of the total nitrogen and 10 ‒ 15% of the total organic carbon content of seafloor
sediments (Burdige and Martens, 1988). Some studies revealed the distribution and concentration of organic matters includinghydrolyzable amino acids in shallow seafloor area (e.g., Cowie and Hedges, 1992; Kawahata and Ishizuka, 1993). The recent
Integrated Ocean Drilling Program (IODP) Nankai Trough Seismogenic Zone Experiment (NanTro SEIZE) Expedition 338 and
348 at Site C0002 drilled and cored successfully up to 3059 mbsf. In this study, concentrations of hydrolyzable amino acids andmaturation stage of organic matters in the sediments collected during the expeditions were determined in order to evaluate the
distribution and evolution of sedimentary organic matters during diagenesis in deep seafloor.
Sediment core samples collected at Site C0002 (202.1 ‒ 2216.9 mbsf), C0021 (3.7 ‒ 186.4 mbsf), and C0022 (1.2 ‒ 411.4
mbsf) were dried and powdered manually with an agate mortar on shore. The type and maturity of sedimentary organic matterswere determined using Rock ‒ Eval pyrolysis method at Japan Petroleum Exploration CO., LTD.
A part of the sediments were hydrolyzed to extract the amino acids from the hydrolyzable peptides and proteins. 1.0 g of thedried sediment was reacted with 6 N HCl at 110 ℃ for 22 h. The amount of total hydrolyzable amino acids (THAA) in the treatedsample solutions were measured by high performance liquid chromatograph using postcolumn ortho-phthalaldehyde derivation.
The concentrations of THAA in the core collected at Site C0002 vary between 819.9 ‒ 177.1 nmol/g, and Gly was the mostabundant amino acid followed by Asp, Ser, Ala, Val, and Phe. At Site C0021 and C0022, the concentrations of THAA were4679.2 and 6729.7 nmol/g at surface, respectively, and decreased drastically with depth. The THAA carbons account for <1%of total organic carbon and nitrogen, indicating that most of the biogenic organic matters would be changed into kerogens.
The amounts of hydrocarbons generated through thermal cracking of non-volatile sedimentary organic matter (S2 ) were 1.2 ‒0.15 mg/g. The low S2 values and TOC (1.2 ‒ 0.3 %) indicate that most of kerogen in the cores is categorized as type III. The
temperatures at which the maximum release of hydrocarbons from thermal cracking of kerogen occurs during pyrolysis (Tmax )were 379 ‒ 416 ℃ at the shallow area (1.2 ‒ 91.7 mbsf), increased gradually with depth, and reached to 439 ℃ at 2216.9 mbsf.
Rock ‒ Eval data indicate that the maturation of kerogens could be progressed with depth in seafloor sediment.
Keywords: Rock Eval, Kerogen, Amino Acids

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MIS32-P09

Room:Convention Hall

Time:May 24 18:15-19:30

Vitrinite reflectance of carbonaceous materials in cuttings retrieved during the IODP Expedition 348
FUKUCHI, Rina1∗ ; YAMAGUCHI, Asuka1 ; YAMAMOTO, Yuzuru2 ; ASHI, Juichiro1
1

Atmosphere and Ocean Research Institute, The University of Tokyo, 2 Japan Agency for Marine-Earth Science and Technology(JAMSTEC)
Integrated Ocean Drilling Program (IODP) Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) Expedition 348
took place from 13 September 2013 to 29 January 2014. During the Exp. 348, cuttings, core samples, mud gas, and logging data
were collected from Holes C0002N and C0002P down to 3058.5 mbsf. Four lithologic units were identified at Site C0002 basedon geological and geochemical characteristics of core and cuttings samples: Unit II (475-512.5 mbsf in Hole C0002M), Unit III(875.5-975.5 mbsf in Hole C0002N), Unit IV (975.5-1665.5 mbsf in Hole C0002N), and Unit V (1665.5-2325.5 mbsf in Hole
C0002N, and 1965.5-3058.5 mbsf in Hole C0002P)(Tobin et al., 2015).
To evaluate whole thermal structure of the Site C0002, we performed vitrinite reflectance analysis for cuttings samples collected every 100 m of Holes C0002N and C0002P. Vitrinite reflectance (Ro ) is an indicator to estimate maximum paleotemperature, which has been widely applied to reveal tectonic evolution of on-land accretionary complex (e.g. Underwood et al., 1992;
Sakaguchi, 1996; Ohomori et al., 1997) and thermal anomalies along fault slip zones reflecting frictional heating due to seismic
slip (e.g. Sakaguchi et al., 2007; Sakaguchi et al., 2011). This is the first study that applied vitrinite analyses systematically tothe entire modern accretionary prisms.
In this presentation, we report preliminary results of vitrinite reflectance analysis. Ro values are 0.15 to 0.20 in Unit III (forearc
basin strata), 0.20 to 0.27 in Unit IV (accretionary prism strata), and 0.20 to 0.45 in Unit V (hemipelagic sediment). In general,
Ro values tend to be gradually and continuously increasing with depth. Estimated paleotemperatures of Unit IV and V are approximately 40 ℃ and 90 ℃, respectively, which are consistent with estimated modern temperatures (Sugihara et al., 2014).
Keywords: vitrinite reflectance, carbonaceous matter, paleotemperature, accretionary prism

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MIS32-P10

Room:Convention Hall

Time:May 24 18:15-19:30

Preliminary results of anelastic strain recovery (ASR) measurements during IODP Expedition 337
LIN, Weiren1∗ ; TANIKAWA, Wataru1 ; YAMAMOTO, Yuhji2 ; MORITA, Sumito3 ; YAMADA, Yasuhiro4 ;INAGAKI, Fumio1
1

Kochi/JAMSTEC, 2 Kochi University, 3 GSJ/AIST, 4 ODS/JAMSTEC

During IODP (Integrated Ocean Drilling Program) Expedition 337 ”Deep Coalbed Biosphere off Shimokita”, a deep riserdrilling borehole was penetrated to 2,466 meters below seafloor (mbsf) by D/V CHIKYU at Site C0020 in off Shimokita, Japan.
To determine three-dimensional stress, we measured anelastic strain recovery of core samples caused by stress release. The
measurements are time sensitive, so were conducted onboard the ship.
We collected seven whole round core samples from a depth range between 1,370 - 2,448 mbsf, and successfully obtained highquality anelastic strain recovery data from six core samples. The successful ASR measurement of the core sample from 2,448
mbsf was the deepest application of ASR in ocean drilling programs. From the strain data, three-dimensional stress orientations
were preliminarily determined. The shallower five core samples’ strain data showed normal faulting stress regimes, whereas
the deepest core sample from 2,448 mbsf reveals a nearly reverse faulting stress regime. In addition, the maximum horizontal
stress orientations of all the six core samples were dominantly in west-east direction, and distributed between west-northwest
and south-southwest.
We gratefully acknowledge the IODP for providing core samples used in this study and the supports of the IODP Expedition
337 scientists, D/V Chikyu drilling crew, and laboratory technicians.

Keywords: Stress, ASR, IODP, Exp 337

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MIS32-P11

Room:Convention Hall

Time:May 24 18:15-19:30

Stress State in the Tip of Ilan Plan and Its Applications for Taiwan Geothermal Plan
WU, Fang-yih1∗ ; YEH, En-chao1 ; KAO, Tsu-en1 ; SHIU, Chi-shun1 ; LIN, Weiren2 ; WANG, Tai-tien3 ;HUNG, Jih-hao4 ; SONG, Sheng-rong5
1

Department of Earth Sciences, National Taiwan Normal University, Taipei, Taiwan, 2 Kochi Institute for Core Sample Research,
Japan Agency for Marine-Earth Science and Technology, 3 Institute of Mineral Resources Engineering, National Taipei Universityof Technology, Taipei, Taiwan, 4 Department of Earth Sciences, National Central University, Jhongli, Taiwan, 5 Department ofGeosciences, National Taiwan University, Taipei, Taiwan
Understanding the relationship between in-situ stress and fluid-conduits is one of the most important keys for developing theenhanced geothermal system. At the same time, understanding this relationship also provide insights into evaluating the welllocations and drilling direction.
The Ilan Plain of northeastern Taiwan is located between the Hsuehshan Range and Backbone Range and is influenced by
the compression of mountain building between the Eurasian and Philippine Sea Plates and the back-arc extension of Okinawa
Trough simultaneously. As a result, the 3D stress field is complicated and the attitude and spatial distribution of fluid conduits
is not clear. To develop the technology of the enhanced geothermal system, this study focused on the evaluation of in-situ stressstate on multiple scales.
Stress inversion of regional focal mechanism suggests that the stress state varies dramatically in the region and it is strike-slip
faulting stress regime with NNE-SSW compression in the tip of Ilan Plain. The paleostress inversion results from the southernfoothills show that the stress pattern of strike-slip faulting and normal faulting regime took place repeatedly and horizontal
minimum stress orientation switched between N-S and W-E orientation. Analysis of anelastic strain recovery experiments on the
retrieved cores of 720-920m indicates that a strike-slip faulting stress regime with NNW compression and NEE tension. Several
hydraulic fracturing tests were conducted in the interval of 750-765m. The shut-in pressure is determined as 13.57MPa andreopening pressure is estimated as 12.66MPa. Diameter Core Deformation Analysis and rock mechanics experiments are also
conducted. Integration of different stress assessments and rock strength data will provide insights to understanding the reasonable
3D in-situ stress in the tip of Ilan plain and further help the development of enhanced geothermal system.

Keywords: in-situ stress, enhanced geothermal system, Taiwan, Ilan Plain, hydraulic fracturing, ASR

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MIS32-P12

Room:Convention Hall

Time:May 24 18:15-19:30

Introduction of a new XRF core scanner and application of marine core science
MURAYAMA, Masafumi1∗ ; MATSUZAKI, Takuya1 ; IRINO, Tomohisa2 ; TADA, Ryuji3
1
3

Center for Advanced Marine Core Research, Kochi University, 2 Faculty of Environmental Earth Science, Hokkaido University,
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo

A new XRF core scanner (ITRAX) by COX was introduced to Center for Advanced Marine Core Research, Kochi University
last year. ITRAX is an automated core scanning instrument that records optical, radiographic and elemental variations in sedimentcores at a high resolution (200 microns) using photography,x-radiography and XRF analysis. Here, we will introduce someexamples of application of marine core analysis.
Keywords: XRF core scanner, ITRAX, marine core science

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