BCG09-01

Japan Geoscience Union Meeting 2016

Nano-sized biogenic iron oxides produced by neutrophilic Fe-oxidizing bacteria and its
implications for biogeochemical cycling*Shingo Kato1
1.Japan Agency for Marine-Earth Science and Technology
Neutrophilic microaerophilic Fe-oxidizing bacteria (NMFeOB) are thought to play a significant rolein global biogeochemical cycling of Fe and associated elements. They are commonly found at redox
boundaries in both of freshwater and marine iron-rich environments, and produce extracellular ironbiominerals that interact with various elements. However, ecophysiology of NMFeOB is still poorly
understood due to the difficulty of cultivation. Recently, Ferriphaselus amnicola strain OYT1 andFerriphaselus sp. strain R-1, which produce a unique twisted-ribbon-like extracellular ironbiomineral structure called a stalk, have been reported (Krepski et al., 2012; Kato et al., 2014).
The present study demonstrates the strains OYT1 and R-1 also produce extracellular nano-sizedbiogenic iron oxides (nanoBIOS), which are morphologically distinct from stalks. Energy dispersive
X-ray spectroscopy indicates that the nanoBIOS contain P, as well as the stalks. Given the chemical
and morphological characteristics, nanoBIOS may contribute to P, Fe and other metal transport in
the environment as a vector. Furthermore, the first genome sequencing of stalk-forming NMFeOB was
performed in the present study. Comparative genomics propose potential genes involved in theformation of stalks and nanoBIOS, which are similar to genes involved in extracellularpolysaccharide production, and potential genes in iron oxidation, which have been previously
suggested as key iron oxidation genes in other NMFeOB. These genes can be used as marker genes for
detection of NMFeOB producing iron biominerals. Overall, the detailed microscopy and first genomic
analysis of the freshwater stalk-forming NMFeOB provide novel insight into the ecophysiology andbiomineralization of enigmatic NMFeOB.
Keywords: Fe-oxidizing bacteria, Nano-sized iron oxides, Biogeochemical cycling©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-01 -BCG09-02

Japan Geoscience Union Meeting 2016

Cyanobacterial extracellular polymeric substances (EPS) control stromatolite andthrombolite formations*Fumito Shiraishi1, Yuhsaku HANZAWA1, Tomoyo Okumura2, Akihiro Kano3
1.Hiroshima University, 2.JAMSTEC, 3.Kyushu University
Stromatolite and thrombolite are the major components of microbialite. Stromatolite is abundant in
Meso- to Neoproteozoic successions, while it declined in the early Paleozoic and thrombolite became
dominant alternatively. The cause of this transition was previously considered to be due to thebioturbation of evolved metazoans, but recently most of thrombolites are considered to be theprimary structure. Therefore, the reconsideration is necessary for the cause of microbialitetransition in the early Paleozoic. However, stromatolite and thrombolite are rare in the modern
environments, and moreover, there had been no report for the site where they both are formed
together. Nonetheless, such example has been found recently from the tufa site in Okayama
Prefecture. The present study therefore examined this site for revealing the factors controlling
microbialite fabrics.
Water chemistry at the depositional sites of stromatolite and thrombolite are similar, andmicroelectrode measurement revealed that they both are mainly formed by photosynthesis-induced CaCO
3

precipitation. Confocal laser scanning microscopy observation and DNA analysis indicated thatcyanobacteria colonizing the stromatolite are mostly Phormidium sp., and their extracellularpolymeric substances possess acidic group to provide mineral nucleation sites, and resulted in thestromatolite formation. On the other hand, cyanobacteria colonizing the thrombolite are mostly

Leptolyngbya sp., and their extracellular polymeric substances does not possess acidic group to beunsuitable for the mineral nucleation sites, and resulted in the thrombolite formation. These
results indicate that chemical characteristics of extracellular polymeric substances are crucial
for the formation of microbialite fabrics.
By simply applying the results above, we can hypothesize that the evolution of cyanobacteria
lacking acidic extracellular polymeric substances caused the microbialite transition in the early
Paleozoic. Nonetheless, further investigation is necessary for validating this hypothesis.

©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-02 -BCG09-03

Japan Geoscience Union Meeting 2016

Lysine polymerization on amorphous silica: A thermodynamic evaluation*Nishii Akari1, Norio Kitadai1, Hitomi Tokimori, Ken Kurokawa1
1.Tokyo Institute of Technology
When, where and how did life on the Earth originate? To resolve that fundamental question, one mustfirst ascertain the reactivity of biomolecules, and the response of reactivity to changing
environmental conditions such as pH, temperature, dissolved composition, and mineral surfaces.
Amino acids are building blocks of proteins, which are fundamental to life. Therefore, thepolymerization behavior of amino acids has been a topic of many experimental and theoretical works(Shock, 1992).
This study focuses on thermodynamic effects of minerals on amino acid polymerization. To date,widely various oxide minerals and clays has been examined for their roles in this reaction (Cleaves
et al., 2012). Results have demonstrated their positive influences with regard to reaction rate,
peptide length, and the amounts of polymers synthesized. However, reported experiments have mostly
emphasized catalytic properties of minerals. Consequently, in most cases, experiments have been
terminated before polymerization reaches its steady state. It remains unclear whether minerals
promote polymerization in thermodynamics as well as kinetics.
To examine the thermodynamic effects, we have evaluated adsorption behaviors of amino acids andpeptides on minerals by using extended triple layer model (ETLM; Sverjensky and Fukushi, 2006).
Obtained adsorption parameters are used, by combining thermodynamic parameters for amino acids andpeptides in aqueous solution, to predict amino acid/peptide equilibria on mineral surfaces. In thispresentation, we will present our findings for a lysine/amorphous silica system.
Keywords: Adsorption, Lysine, Silica©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-03 -BCG09-04

Japan Geoscience Union Meeting 2016

A role of ferruginous ocean in photochemical synthesis of organic compounds*Waka Kawade1, Yuichiro Ueno1, Norio Kitadai2, Yayoi Hongo2
1.Department of Earth and Planetary Sciences, Tokyo Institute of Technology , 2.ELSI
Photochemistry is important for the origin of life and the early earth’s environment. Previous
photochemical experiments suggest that the reaction initiated by UV in CO-rich atmosphere canproduce simple organic compounds mainly formaldehyde and methanol (Bar-Nun and Chang, 1983). The
amount and speciation of organic molecules are known to depend on the redox state of theatmosphere. The reducing ocean containing ferrous iron may also control the redox state of theocean-atmosphere system, though the role of ferruginous ocean for abiotic UV synthesis is poorly
understood. We have conducted photochemical experiments simulating the reducing atmosphere andFe(II)-bearing ocean. The results of our experiment suggest that formate, acetate, propionate, andnormal alkanes are synthesized under CO-atmosphere. When irradiating UV under the presence ofFe(II)-bearing water, the production rate of formate is about three times faster than the simple
CO-H2O system without ferrous iron. Furthermore, formate is formed even when the gas phase is pure
CO2 when liquid-phase contains Fe(II). These results suggest that the production rate andspeciation of organic matter depends on the availability of H2O as well as total redox state of thewhole atmosphere and ocean system. Based on the results, we have modeled the reaction pathway andestimate the flux of each organic compounds supplied to early ocean.
Keywords: origin of life

©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-04 -BCG09-05

Japan Geoscience Union Meeting 2016

Selenium and cesium adsorption onto biogenic iron oxyhydroxides:Comparison with inorganic
iron oxyhydroxides*Sakiko Kikuchi1, Teruhiko Kashiwabara1, Yoshio Takahashi2
1.Japan Agency for Marine-Earth Science and Technology, 2.Department of Earth and Planetary
Science, Graduate School of Science, The University of Tokyo
Iron(Fe) oxyhydroxides are considered to be important sorbents of trace elements in surface
environment. This widely view mainly extends from many laboratory studies using inorganic Fe
oxyhydroxides. However, most of the natural Fe oxyhydroxides are referred to as biogenic Fe
oxyhydroxides(BIOS) which are complex mixtures with various organic matters. The presence oforganic matters in BIOS can cause unique adsorption behaviors of trace elements for BIOS, but they
have not been characterized well. This study aims to reveal adsorption characteristics of traceelements onto BIOS.
Biogenic Fe oxyhydroxides were collected from Sambe hot-spring in Shimane prefecture. The samples
consist of very fine particles of two-line ferrihydrite, coexisting with biogenic organic matters
including stalks, extracellular polysaccharides, and bacterial cells. We have conducted adsorption
experiments of selenium(Se) and cesium(Cs) on BIOS and synthesized ferrihydrite in a batch system.
Our experiments revealed significant differences in Se and Cs adsorption between BIOS and inorganic
Fe oxyhydroxides in a wide range of pH, even though they have similar Fe mineralogy. In the case of
positively-charged Cs, BIOS showed larger adsorption than inorganic Fe oxyhydroxides. In contrast,
negatively-charged Se showed smaller adsorption on BIOS compared with that on inorganic Fe
oxyhydroxides. Especially, the decrease of Se adsorption on BIOS compared to inorganic Fe
oxyhydroxides was more significant in Se(VI) than in Se(IV), corresponding to their formation ofdifferent surface complexes. We consider that the unique adsorption behaviors of Cs and Se on BIOS
and their difference with inorganic Fe oxyhydroxides can be explained by the electrostatic effectcaused by the coexisting biogenic organic matters in BIOS.
Keywords: iron oxyhydroxides, bacteria, adsorption behavior©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-05 -BCG09-06

Japan Geoscience Union Meeting 2016

Limiting factor for weathered granitic rocks to be ion adsorption ore*Yoshio Takahashi1, Tasuku Honda1
1.Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo
Main rock of ion adsorption type deposit which is important as rare earth element (REE) resource isweathered granite, from which we can extract REE readily using aqueous solution such as ammonium
chloride or ammonium sulfate solution, because REE can be extracted from weathered granite by ion
exchange reaction. Previous studies of the ion adsorption type REE deposit has been carried out
mainly using weathered granite found in the Southeast Asia, but there are few studies on theweathered granite present in Japan in terms of the REE deposit. In addition, there are no studies
which clarify the relationship between REE chemical state and extraction properties in theweathered granite at molecular level. Therefore, the aim of this study is (i) to clarify the
relationship between the extraction characteristic of REE in the weathered granite and its chemical
state at the molecular level using XAFS method and molecular orbital calculation and (ii) to study
the dependence of extraction rate of REE on the degree of weathering of the granitic rocks. In thisstudy, we analyzed granite or weathered granite samples collected in Hiroshima, Shimane, andTottori in Japan, Sri-Lanka, and Myanmar. The collection of the samples from various sites arestrongly needed to cover granitic rocks having various degrees of weathering. Initially, themineral and major element compositions were examined by XRD and X-ray fluorescence (XRF) analyses.
After the analysis, local chemical state of Y, one of REE, was determined using bulk XAFS andμ-XRF-XAFS method at SPring-8 and KEK-PF, scanning electron microscopy (SEM), and molecular orbital
calculation. As a result, it was suggested that REE in the samples with high CIA can be readily
extracted and the REE chemical state suggested by Y K-edge EXAFS is outer-sphere complex adsorbed
weakly in the weathered granite. The μ-XRF-XAFS and SEM analyses showed that REE was mainly
adsorbed on phyllosilicates such as halloysite and weathered biotite. On the other hand, theextraction ratio of REE in the samples with low CIA are low and its REE chemical state is
inner-sphere complex, or REE incorporated possibly into primary minerals or phosphate. The ratio ofouter-sphere complex among total REE determined by the fitting of EXAFS spectra in k space ispositively correlated with that of REE extraction ratio. In addition, weathered granite with higher
REE extraction ratio exhibits larger negative Ce anomaly, suggesting that REE with negative anomaly
in aqueous phase was adsorbed to the granitic rocks, which finally induces the correlation between
the degree of negative Ce anomaly and REE extraction ratio. Thus, it is suggested that the degreeof negative Ce anomaly is one of the characteristics of ion adsorption type REE deposit. However,strongly weathered granite samples with CIA values higher than 85 do not show high REE extraction
ratio. Mineralogy of the samples is dominated by kaolinite and gibbsite, which suggests that thefraction of REE adsorbed on clay minerals is minimal for the strongly weathered granites comparedwith intermediately weathered granitic rocks with CIA value around 70. Thus, we can conclude thatmedium weathering characterized by the presence of vermiculate/smectite with CIA value around 70 is
an important limiting factor to establish the sample as an REE ion adsorption ore.

©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-06 -BCG09-07

Japan Geoscience Union Meeting 2016

Adsorption behavior of organoarsenic compounds in soils– Influence of organic matters –*Masato Tanaka1, Yoshio Takahashi11.Graduate School of Science, The University of Tokyo
Anthropogenic originated organoarsenic compounds such as diphenylarsinic acid (DPAA) are a waterpollution source as well as naturally occurring inorganic ones. For example, DPAA polluted well
water caused serious health problems in Kamisu, Japan. However, their adsorption behavior in soils
is still well unknown. In general, the adsorption property of chemical compounds influences its
migration process in natural environments such as soil-water system. In soils, organic matters(OMs) affect adsorption behavior of trace metals on minerals. Thus, it is important to understandthe adsorption mechanism of the arsenic compounds with taking account of influence of OMs topredict future fate of them in environment. In this study, we conducted adsorption experiments forseveral soils which have different contents of Fe/Al-(oxyhydr)oxides and OMs, and adsorption
amounts and structures were analyzed by ICP-MS and As K-edge XAFS measurements. The same
experiments and analysis were conducted with OM extracted soils to understand the influence of OMs.
The As K-edge EXAFS spectra for arsenic compounds adsorbed on soil samples were well fitted withcorresponding EXAFS spectra As adsorbed on Fe- and Al-(oxyhydr)oxides. The fact indicates thatthese arsenic compounds adsorbed on these minerals mainly. The adsorption ratios for Fe- andAl-(oxyhydr)oxides were estimated by the fitting, and the deviation of the ratio from the Fe/Al
content was larger with increasing the OM content in soils. In addition, in most cases, theadsorption amounts of arsenic compounds increased by removing OMs. Thus, it is considered that theOMs prevent arsenic compounds from being adsorbed on minerals by covering their surface. However,even though OMs were removed from soils, the adsorption ratios were still not always reflected
Fe/Al content ratio by removing OMs depending on the arsenic compounds. This fact indicates thatthe affinity of arsenic compounds for Fe/Al-(oxyhydr)oxides is different.
Keywords: organoarsenic compound, adsorption, soil, XAFS

©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-07 -BCG09-08

Japan Geoscience Union Meeting 2016

Change processes of microfabrics in the Nankai Trough muddy sediments from several
centimeters through several hundreds meters in burial depths*Mebae Kuranaga2, Kiichiro Kawamura1
1.Yamaguchi University/JAMSTEC, 2.Yamaguchi University
Microfabrics in deep-sea sediments prior to incorporation in an accretionary prism give us
important visual information for deformation fabric analyses. Analyses of primary sedimentaryfabrics and compaction processes of deep-sea sediments are a key to understanding formation
processes of the decollement zone. This paper discusses the microfabric development processes of
unconsolidated hemipelagic sediments and mass transport deposits (MTDs) during early diagenesis
from deposition, burial compaction-cementation, and deformation by means of microfabrics
observations and physical/mechanical property measurements using drilling core samples andsubmersible samples as follows.
1) The submersible samples were collected from the landward trench slope in the Nankai Trough usinga MBARI-type corer. The water depths were from 2500 to 3000 m. The sediment cores of 3K#1345C-1,-2, -3, -4 and 3K#1346 C-1 were mostly 20 cm in length. We measured physical and mechanicalproperties in the core sediments.
2) The drilling core samples were collected in the Nankai Trough using a Hydroric piston corer. The
water depths were from about 3000 m. The sediment cores of C0018A were 314.5 m in length. C0018A is
divided into Unit IA is composed Hemipelagic mud layer that is frequently volcanic ash layer issandwiched between and six MTD layer volcanic ash layer is caught. Unit IB is composed of a sandy
turbidite layers. In addition, it deals only Unit IA in this announcement. Mechanical properties in
the core sediments were used on board data.
The main objective of this paper is to understand the microfabrics changing processes in the
Hemipelagic sediments from several centimeters to several hundreds meters in depth during long-term
burial compaction. The burial compaction processes have been mainly studied using consolidation
tests in laboratories for a short-term, although, sediments are consolidated gradually during
geologic time as an age effect. Microfabrics changing processes by age effects are not wellunderstood. Hemipelagic sediments are the best examples for long-term compaction study, because
they have mostly constant sedimentation rates through geologic time and homogeneous structures andcomponents.
The samples for microfabrics observation were treated by freeze-drying and embedding methods inorder to avoid volume shrinkages by air-drying. The microfabrics in the Hemipelagic sediments and
MTDs are mainly constituted of clay aggregations (ped) and clay linkages (connector) as shown inbelow.
1) In the Hemipelagic mud layers, the microfabrics are characterized by a horizontal preferredorientation of clay flakes in Face-to-Face contact.
2) In the MTD layers, most of the clay flakes constitute in regular/irregular aggregations. The
regular aggregations range from 1 to 5 µm and irregular aggregations are larger than 20 µm in
diameter.
Keywords: Microfabric, Nankai trough, Mass transport deposits©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-08 -BCG09-09

Japan Geoscience Union Meeting 2016

Chemical forms of arsenic in marine sediments and dissolution mechanisms into porewater ofKumano Basin, Nankai TroughHaruka Yoshinishi1, Shigeshi Fuchida2, *Harue Masuda1, Emilie EVEN1
1.Graduate School of science,Osaka City University, 2.Center for Global Environmental
Research,National Institute for Environmental Studies
The purpose of this study is to clarify the accumulation process of arsenic and the behavior during
an early stage of diagenesis in modern marine sediments.
The cored sediments and porewaters at Sites C0002 and C0022, Nankai Trough. At the Site C0002(0-1050mbsf), sediments at <800mbsf was composed of forearc basin sedimentary rock (terrestrial
sediment) and the lower part was of accretionary prism.
In the Site C0002, total arsenic concentrations of sediments increased at 0-330mbsf with depth.
The highest concentration was recorded at 330mbf (13ppm). Then, the concentration decreased, andbecame constant about 5ppm below 500mbsf. Total arsenic concentration was higher in forearc basin
sedimentary rocks than the underlying accretionary prism sediments. It suggest that the primaryarsenic was mostly derived from subareal region via detrital fragments.
The result of BCR sequential extraction analysis showed that about 40% of As in the sediment was
fixed in insoluble phases, i.e., structure of sulfide and/or silicate minerals. Arsenic in
insoluble phase was >80% in the sediment at 1000mbsf, implying that the arsenic was fixed inauthigenic pyrite in the deep part of the sediment column.
The ratio of dissolved arsenic arsenic (porewater) to Total arsenic of the sediment was especiallyhigh at those depth. Thus, the arsenic dissolution was promoted at those depth. Similar highdissolved arsenic ratio was shown at 100-200mbsf, Site C0022, suggesting the same mechanisms torelease arsenic in the sediment at these depth.
Speciation of arsenic-being phases in the adsorbed fractions onto sediment particles were analyzed
by HPLC and analyzed by ICP-MS/MS. Arsenate, arsenite, MAA, and AsB were only detected from thesediments at C0002, C0022. Total concentration of these arsenic compounds was 60% of total arsenicof the sediment, and most of them were arsenate and arsenite. It indicate that over half of totalarsenic in the sediment was adsorbed as inorganic arsenic onto the mineral surface. The
concentration of arsenite increased below 100mbsf, suggesting that the arsenate was reduced below
this depth. The MAA was not large compared to the total arsenic, however, it is important toevaluate the contribution of microbiological activity to the arsenic cycle in the marine sediments.
As mentioned above, arsenic fixed in the sediments releases into the porewater at 100-200mbsf.
Decomposition of organic matters are extensive in 0-150mbsf evidenced by increasing concentrationof NH4+ of porewater and Br- (accumulate in red algae). Thus, MAA would be a product ofdecomposition of organic arsenic compounds, such as arsenosugar contained in algae.
Below 200mbsf, increasing pH controlled arsenic dissolution. The average of pH was 7.79 in
0-200mbsf, then graduate increased below this depth. It’s peak was about 7.98 at 400mbsf. Surface
potential of iron oxyhydroxides/oxides changes at pH=7.9. Negatively changed arsenic (mainly
arsenate) was intensely released into the solution at pH>7.9. Observation of this study showed thatthe small change of pH considerably controls the dissolved arsenic in porewater.
This study demonstrates the importance of input of subareal detrital materials for the arsenic
cycle in the crust through hydrosphere and microbiological activity to change the arsenic phases in
the marine sediments at the very early stage of diagenesis.

©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-09 -BCG09-09

Japan Geoscience Union Meeting 2016

Keywords: arsenic, IODP, porewater©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-09 -BCG09-10

Japan Geoscience Union Meeting 2016

Selenite sorption on magneaium oxide under the highly alkaline conditions*Shun Miyasita1, Kesuke Fukushi2, Shoji Morodome3
1.Division of Environmental Science and Engineering, Graduate School of Natural Science andTechnology, Kanazawa University, 2.Institute of Nature and Environmetal Technology, Kanazawa
University, 3.Kunimine Industries co., LTD.
Selenium occurs widely throughout nature. It is one of essential the elements for human, but itshows toxicity at degree to double of the necessary quantity. Selenium is environmental standard
designation item.
After earthquake disaster, the contribution of the nuclear power generation in the electricity
source of supply in Japan decrease, while that the thermal power generation increases. In
coal-fired station, the selenium concentrations more than industry waste water regulation (100ppb)
in the drainage has been reported to occur in a desulfurization processes of the gases which is
generated during burnt coral (Central Research Institute of Electric Power Industry, 2005). The
solutions used in the desulfurization processes is kept alkaline in order to facilitate thedissolution gases.
Selenium mainly exists as selenite(HxSeO42-x, Se(Ⅵ)) or selenite(HySeO32-y, Se(Ⅳ)) in solution. Mostof selenium exists as selenite in waste water in desulfurization process (Central ResearchInstitute of Electric Power Industry, 2005). A general selenite removal method in the solution
includes the adsorption on iron oxide. However, adsorption significantly decrease under the alkali
condition because the surface charge of iron oxide become to minus at alkaline conditions (Fukushi,
2008). Therefore, the effective removal of selenite under the alkali condition is expected.
The anions of which oxygens coordinate to the center atom are called oxyanions. There are manyoxyanions which cause the water pollutions, e.g., arsenite and bronate. It is reported thatmagnesium oxide (MgO) has ability for the removals of aresnite and bronate (Liu et al., 2011;
Fuente and Eugenio, 2006). It can be expected that MgO has ability for removal for selenite insolution. MgO is metastable phase under the Earth surface environmental, and it transforms tobrucite (Mg(OH)2) in solution with time (Yabe et al., 2011). Liu et al., (2011) studied the removalof arsenite from solution by MgO with high sace area. They suggested that the tranformation insolution is related to the uptake of arsenite, i.e., the sorption mechanism of aresenite on MgO
under the high arsenite concentration condition is formation of an “arsenite-Mg compound” following
transformation to Mg(OH)2. Their study was conducted under the very high sorbate concentration(>1ppm) condition. There were no arguments about the mechanisms under the low concentration
condition with sub-ppm order. The water pollution related to selenium mainly becomes problem withlow concentration around the waste water satandards (100ppm order). It is thought that
understanding the sorption behavior in the low concentration condition is necessary. I conductedbacth sorption experiments of selenite by MgO and magnesium hydroxide which is stable phase in thisstudy to examine the selenite uptake behavior and mechanism on MgO.
Keywords: Selenite, Magnesium Oxide, Metastable Phase, Magnesium Hydroxide, Alkaline Conditions©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-10 -BCG09-11

Japan Geoscience Union Meeting 2016

Predictive model for Pb(II) adsorption on soil minerals (oxides and low crystalline
aluminum silicate) consistent with spectroscopic evidence*Keisuke Fukushi1, Tomoki Ushiyama2
1.Institute of Nature & Environmental Technology, Kanazawa University, 2.Division of Natural
System, Graduate School of Natural Science and Technology, Kanazawa University
Mobility of Pb(II) in surface condition is governed by the adsorption processes on soil mineralssuch as iron oxides and low crystalline aluminum silicates. It has been documented that theadsorption effectiveness and the surface complex structures of Pb(II) sensitively varies with thesolution conditions such as pH, ionic strength, Pb(II) loadings and electrolyte anion types.
Present study aims to construct the quantitative model for Pb(II) on the soil minerals, which canpredict the adsorption effectiveness and surface complex structures under any solution conditions
by means of extended triple layer model (ETLM).
The Pb(II) adsorption data on goethite, ferrihydrite, quartz and low crystalline aluminum silicate(LCAS) were analyzed with ETLM to retrieve the surface complextion reactions and these equilibrium
constants. The adsorption data on goethite, ferrihydrite and quartz come from previous studies.
Those on LCAS were measured in present study under wide range of pH, ionic strength and Pb(II)loadings in NaNO3 and NaCl solutions. All adsorption data can be reasonably regressed by ETLM withthe assumptions of inner-sphere bidentate complexation and inner-sphere monodentate ternarycomplexation with electrolyte anions, which are consistent with the previously reported
spectroscopic evidences. The predictions of surface speciation under wide range of solution
conditions by ETLM revealed that the inner-sphere bidentate complex is predominant species atneutral to high pH conditions. The inner-sphere monodentate ternary complex becomes important at
low pH, high surface Pb(II) coverage and high electrolyte concentrations, of which behavior isconsistent with the spectroscopic evidences.
The comparisons of the obtained adsorption constants on goethite, ferrihydrite and quartz exhibited
good linear relationships between the reciprocals of dielectric constants of solids and adsorption
constants. The linear relationships enable the predictions of the adsorption constants of alloxides based on Born solvation theory. The adsorption constants of LCAS are comparable to those ofgoethite. The comparisons of the adsorption constants of soil minerals suggest that the
ferrihdyrite, goethite and LCAS are three most important sorbents for Pb(II). Ferrihydrite andgoethite are ferric oxides which are unstable in reducing conditions while LCAS is insensitive tothe redox changes. The present study also implies that adsorption of Pb(II) in subsurface soil
conditions may be governed by LCAS.
Keywords: soil minerals, surface coplexation modeling, Pb(II), oxides, low crystalline aluminumsilicate©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-11 -BCG09-P01

Japan Geoscience Union Meeting 2016

Interactions among mineral, water and biomolecule by shock wave: morphological changes ofolivine grains reacted with amino acid solutions by impact process*Yuhei Umeda1, Nao Fukunaga1, Toshimori Sekine1, Takamichi Kobayashi2, Yoshihiro Furukawa3, Takeshi
Kakegawa3
1.Graduate School of Science, Hiroshima University, 2.National Institute for Materials Science,
3.Graduate School of Science, Tohoku University
Early oceans on Earth might have contained a certain amount of biomolecules such as amino acids,
and were subjected to meteorite impacts, especially during the late heavy bombardment. When
hypervelocity meteorites impact to oceans on Earth, some minerals contained in meteorite may reactwith solutes in oceans under high pressure and temperature conditions and subsequent pressure
release processes induced by impact process. We performed shock recovery experiments to simulate
shock reactions of marine meteorite impacts among olivine as meteorite components, water andbiomolecules as oceanic components. Olivine is one of the most typical minerals in ordinarychondrites that represent about 90% of flying meteorites to Earth. In the present study, weinvestigate reactions between olivine and amino acids in water during impact process. We present
the results of changes of olivine grains. We conducted shock recovery experiments by using apropellant gun at National Institute for Materials Science. Shock recovery experiments were
performed that a metal flyer as projectile accelerated by a propellant gun impacted to the metal
sample container after sealed with two screws as targets. Amino acid solutions (130 μl) were set
with olivine powders (200 mg) and air gap in the sample room in sample containers. Impact
velocities measured by using the magnetoflyer method were about 0.9 km/s. Shock pressure wascalculated with the measured impact velocity using the impedance match method. After experiments,
experimental products were collected from holes drilled on the impact surfaces of the recovered
containers. Recovered solid samples were analyzed using X-ray powder diffraction method (XRD),
scanning electron microscopy (SEM), electron probe microanalyser (EPMA), and transmission electron
microscopy (TEM) with energy dispersive X-ray spectrometry (EDX). The analytical results on theshocked sample of water-amino acid-olivine mixtures demonstrated the metallic material, shocked
olivine grain affected by water and carbon rich material like spike as experimental products.
Analytical result of EPMA indicated the metallic material derived from stainless 304 of sample
container, and a detectable decreasing deviation in the atomic ratio of Mg/Si in shocked olivine
relative to that of the starting olivine. The shocked olivine was shown the traces of watermolecule impacting on surface by TEM observation. The results of TEM observation and EDX analysis
indicated the carbon rich material derived from amino acids. The present study suggests thewater-amino acid-olivine system under shock reaction is able to interact with each other.
Especially, organic compounds related to origin of life in early ocean might transform to solidstate by meteorite impacts. Hence, it is necessary to consider the phase change of initialmaterials on pre-biotic experiments simulated natural condition.
Keywords: Meteorite impact, Olivine, Amino acid©2016. Japan Geoscience Union. All Right Reserved.

- BCG09-P01 -BCG09-P02

Japan Geoscience Union Meeting 2016

Experimental study of adsorbed methane in a methane-seep carbonate from the upper Miocene
in Joetsu City, Niigata Prefecture*Yusuke Miyajima1, Akira Ijiri2, Masafumi MURAYAMA3
1.Graduate school of Science, Kyoto University, 2.Kochi Institute for Core Sample Research,
JAMSTEC, 3.Center for Advanced Marine Core Research, Kochi University
Submarine methane seeps where methane-charged fluids seep out of the seafloor have been regarded as
major sources of methane which is a main component of natural gases and a potent greenhouse gas. In
methane seeps, anaerobic oxidation of methane (AOM) by microbial consortia increases alkalinity andinduces methane-derived authigenic carbonate precipitation. Ancient methane seeps can be recognizedfrom low stable carbon isotopic compositions derived from methane and lipid biomarkers of microbes
performing AOM recorded in carbonate rocks hosted in sedimentary strata. They have a greatsignificance as direct evidences of generation, migration, and emission of methane in thegeological past. Methane is generated by microbial or thermal degradation of organic matter inshallow or deep sediment depths, respectively, and the origins of methane can be distinguished byproxies such as carbon isotopic compositions of methane. Identifying the origin of methane inancient seep fluids can provide an insight into origin and pathway of seep fluid, and oil andnatural gas generation in the past, but the way to directly estimate origins of methane in ancient
seeps has not been established yet. Authigenic carbonates are reported to adsorb hydrocarbon gases
in surrounding sediments (Ijiri et al., 2009). If ancient seep carbonates could also adsorb“paleo-methane” dissolved in seep fluids, it may be possible to estimate the origins of methane inancient seeps by analyzing isotopic compositions of the adsorbed methane. This study attempted to
extract adsorbed gas from an ancient seep carbonate and analyze stable carbon isotopic compositions(δ13C values) of methane to estimate its origin. Studied material is a methane-seep carbonate
collected from the upper Miocene Nodani Formation in Joetsu City, Niigata Prefecture, central
Japan. This carbonate mainly consists of dark-grey matrix of micritic aragonite and has abundant
void spaces rimmed with creamy-colored acicular aragonite cements. Both of the micritic part andacicular aragonite have low δ13C values (−42.6 to −15.4‰ vs. PDB), and the former contains lipid
biomarkers of anaerobic methanotrophic archaea, pentamethylicosane and crocetane, showing that the
carbonate was precipitated in a methane seep. Adsorbed methane was liberated by dissolution ofcarbonate powders by adding phosphoric acid, and then introduced into GC-IRMS to analyze
concentration and δ13C values of methane. Methane was successfully extracted from all samples, andthe δ13C values of methane ranged widely from −60.7 to −40.0‰. This suggests that the extracted
methane is composed of a mixture of biogenic and thermogenic methane in various ratios and/or
contains biogenic methane enriched in 13C due to fractionation through AOM. The δ13C values of theextracted methane and those of the carbonate powders from which gases were extracted showed a weak
positive correlation, and void-filling acicular aragonite mostly have lower δ13C values ofextracted methane and carbonate than those of micritic parts. This result implies that the methane
contained in the seep fluid could be trapped in the host carbonate phases during theirprecipitation, and there was some relation between precipitation of each carbonate phase, either insediment or void, and origin and/or flux of methane trapped in it. Because it is also possible thatthe methane was adsorbed after precipitation and during burial of the carbonate, further
investigation of the preservation state of the gases in the seep carbonate is required to elucidate
where and how the methane was trapped within the carbonate.

©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Keywords: Methane seep, Carbonate, Miocene, Joetsu City, Adsorbed gas©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Hydrothermal experiments between basalt and H2O at 130°C and 230°C*Kyoka Ikeda1, Tomoharu Miyamoto2
1.Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University,
2.Department of Earth and Planetary Sciences, Faculty of Science, Kyushu University
Water-rock interaction occurs during weathering on ground surface, hydrothermal alteration aroundhot spring on continental crust, and reaction in oceanic crust. Many hydrothermal experiments havebeen conducted to examine the rock alteration and/or chemical composition of solution under various
reaction temperature conditions, but most of them were focused on compositional variation afterreactions between seawater and rock samples. In this study, as a primary, pure water was reacted assolvent with basalts samples under 130°C and 230°C conditions to understand the temporal evolutionof composition of the basalts and solution under simple reaction in different temperature
conditions.
In the experiments at 230°C, many kind of elements were dissolved in the solvent from basalts
after reactions. Especially, concentrations of SiO2 and Na2O decreased by their dissolutions, on
the other hand, Fe2O3 and MgO increased by their insolubility, relatively. The run products at 230°
C experiments changed their compositions from starting materials more greatly than those at 130°C.
In such run products, coarse grains(>200µm) were more outstanding at 230°C experiments, on theother hand, fine grains(<200µm) were kept leaving after long-term experiments at 130°C. It issuggested that groundmass as glass components and fine crystals dissolved precedingly at 230°C
during reactions.
Solubility in the solvent showed different temporal variations every element. However, they can beclassified into three major patterns. First, concentration of element increased primary and thendecreased (pattern I). Secondly, concentration increased primary, decreased secondly, and thenincreased again (pattern II). Thirdly, concentrations repeated increasing and then decreasing twice(pattern III). Decreasing of elemental concentrations shows its precipitation by saturation after
dissolution of starting material. Concentration increasing after decreasing suggests that the
precipitated materials dissolved again under unsaturated situation by over precipitation. In theexperiments at 130°C, behavior of Fe, Mg and Al, which are classified into pattern I, suggest
immediate precipitation unless redissolution after reactions. In contrast, behavior of Si, Na, K,
Ca, and Nb, pattern II, suggest that such elements redissolve it easily by the situation of thesolution changing even if they were precipitated by oversaturation. Such elemental behaviors insolution are consistent with temporal variations of compositions of solid materials modified after
basalt samples: increasing Fe and Mg, decreasing SiO2, progressively. On the other hand,experiments at 230°C showed immediate precipitations of Fe, Na, K and Nb (pattern I) andre-precipitations of Si, Mg, Ca, and Al after redissolution(pattern III). It is expected that thedegree of dissolution and variation of elements in the solution depend on temperature. And then,such factors changed basalt compositions variously detailed in different run products, caused bydifference of elemental precipitation or dissolution during reactions.
Keywords: Hydrothermal experiments, Basalt , Alteration©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Lichen-substratum interactions in severe environment polluted by heavy metals*Yuri Sueoka1, Masayuki Sakakibara1, Sakae Sano1, Koichiro Sera2
1.National University Corporation Ehime University, 2.Iwate Medical University
Heavy metal pollution is a worldwide problem. The use of native organisms for assessment andmonitoring of polluted sites is an approach that could contribute to a reduction on costs andsecondary environmental impacts. Because several fruticose lichens occur even in areas highly
polluted by heavy metals, lichens may meet the requirements. Therefore, interactions between
lichens and substrata is an important key to determine the behavior of heavy metals in surface
environment polluted by heavy metals.
Although, no studies have investigated interactions of fruticose lichens and the corresponding
substrata comprehensively from the aspect of biogeochemical behavior of heavy metals. Therefore,
several fruticose lichens, including Stereocaulon exutum and several Cladonia Spp., fromcontaminated abandoned mine sites and the corresponding substrata were investigated (1) todetermine the behavior of heavy metals during the weathering of slag mediated by S. exutum, (2) todetermine the distribution of the heavy metals in the thalli of S. exutum, and (3) to determine thecorrelations between the heavy metal concentrations of lichens and those of the corresponding
substrata.
The slag that is a substratum of S. exutum consists primarily of willemite, fayalite, and/or
magnetite and contains matte drops, which are mainly Cu-metals, -alloys, and -sulfides. The
willemite and matte drops are ultimately converted to Fe-hydroxides during the weathering process.
In addition to abiotic weathering, the heavy metals are dissolved during the biotic weathering bysubstances from the lichen and hyphal penetration. The dissolved heavy metals are absorbed into
the lichen thalli. Absorbed Cu and Zn are distributed within the cells of hyphae, whereas Fe andAs are distributed on the surface of hyphae. Fe-hydroxide-like materials are occur on the surfaceof hyphae (Fig).
Based on previous studies, cations in thalli are distributed into four fractions, e.g. theintercellular and surface, ion exchange site, intercellular, and residual fractions. Although theform of the ions was not identified in this study, the distribution of elements in the hyphal cells
may indicated the possible absorption of ions into the cytoplasm through ion exchange sites fromexternal solutions. For the Fe and As concentrated on the surface of hyphae as Fe-hydroxide-likematerials, this distribution could be explained by elemental precipitation or the formation ofcompounds on the hyphae.
The concentrations of Cu, Zn, As, and Pb of Cladonia Spp. thalli were positively correlated withthose of the corresponding substrata. Distribution maps of the average heavy metal concentrationsof the lichens and the corresponding substrata were made to determine the practical applications of
the lichens as a biomarker. The maps for the distribution of Cu, Zn, and As in the lichens had very
similar distributions to those of the corresponding substrata at the scale of all study sites insouthwest Japan. Therefore, a large-scale analysis of lichens with many samples successfully
detected the distribution of heavy metal pollution of soil.
In conclusion, C.ladonia Spp. lichens can be used in practical applications for biomonitoring andassessment of heavy metal pollution of soil. Because lichen is a pioneer organism in polluted areas
by heavy metals worldwide, the investigation of interactions between lichens and substrata could
contribute to determine the elemental cycle between biosphere and lithosphere during natural
recovery process of polluted areas.

©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Keywords: abandoned mine site, weathering of slag, fruticose lichen, absorption of heavy metals,
biomarker©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Reaction rate of ferric hydroxide formation at pH 2–4
Sagakuni Nagasaki1, *Tadashi Yokoyama1
1.Department of Earth and Space Science, Graduate School of Science, Osaka University
Iron hydroxides widely exist in the Earth’s environment, and their formation processes, adsorption
properties, and transport behavior have been attracting great attention. Dissolved Fe3+ reacts withwater and transforms to ferric hydroxide (Fe(OH)3) as time passes. We focused on the early processof ferric hydroxides formation and evaluated the reaction rate constants and activation energies
under a wide range of solution conditions (pH 2–4, initial Fe concentration 5–300 ppm, temperature
5–55 °C, and dissolved anion species Cl−, NO3−, SO42−). Aqueous solutions containing ferric ions wereprepared by dissolving one of the following FeCl3, Fe(NO3)3·9H2O, and Fe2(SO4)3·nH2O in pure water.
As dissolved ferric ions change to ferric hydroxide, the pH of the solution gradually decreases.
The time variation of pH was monitored under the constant temperature, and the rate constant k wasdetermined by converting the pH change to the change in the concentration of dissolved ferricspecies (assumed to be a 1st order reaction as with Grundl and Delwiche, 1993) using a geochemicalcode PHREEQC (Parkhurst and Appelo, 1999). Comparison of the k values of ferric hydroxide
formation at pH 2–3 under the presence of the different anion species revealed that the k values
for Cl− and NO3− were almost the same and that for SO42− was approximately one half to one fourth ofthe values for Cl− and NO3−. Despite the dependence of the rate constants on the anion species,
activation energies were almost the same between Cl−, NO3−, and SO42− (~120 kJ/mol). In theexperiment using FeCl3 solution, the k value increased as the initial pH increased from 2 to 4. On
the basis of the pH dependence of k at 25 °C, an equation to predict k for various pH was obtained.
Keywords: Ferric hydroxide, Reaction rate

©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Distribution of arsenic and uranium between lake waters and sediments in saline lakes inSouthern Mongolia.
*Eigo Imai1, BAASANSUREN Gankhurel2, SUGARJARGAL Tumur2, Keisuke Fukushi3, Nagayoshi Katsuta4,
Davaadorj DAVAASUREN2, Noriko Hasebe3, Yukiya TANAKA 5, Kenji Kashiwaya3
1.School of Natural System, College of Science and Engineering, Kanazawa University, 2.Departmentof Geography, School of Art & Sciences, The National University of Mongolia, 3.Institute of Natureand Environmental Technology, Kanazawa University, 4.Science Education (Earth Science) Department,
Faculty of Education, Gifu University, 5.Department of Geography, Faculty of Sciences, Kyung Hee
University
The health risks associated with toxic chemicals in saline lake become environmental problems(Barber et al. 2009). In saline lakes, the dissolved matters are enriched in solutions because of
the evaporation of lake water. The enrichments result in the formation of the contaminated lakewater and salts deposits containing high levels of the toxic chemicals (Barber et al. 2009).
The toxic elements distribution between the sediments and lake water are essential for theunderstandings of the enrichment processes and the mobility of toxic species in surrounding
environments. In present study, we investigated the distribution processes of arsenic and uranium
by analyzing the lake waters, suspended matters and sediments in saline lakes (Olgoi Lake, Boon
Tsagaan Lake and Orog Lake) in Southern Mongolia.
Barber, L.M., Peterson, R.K.D., Montagne, C., Inskeep, W.P., Schleier III, J.J. (2009) A dietaryrisk assessment for indigenous consumption of natural salt deposits in the Darhad Valley, northern
Mongolia. Human and Ecological Risk Assessment, 15 (5), pp. 907-922.
Keywords: Saline lakes, mongolia, arsenic, uranium©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

Laminated textures of deposits in Shiohitari hot spring, Kagoshima Prefecture*Chizuru Takashima1, Nami Tsuzuki1
1.Human Life and Environment Course, Faculty of Culture and Education, Saga University
Fe-rich deposits and travertine (carbonate-rich deposits) are precipitated from hot springs
containing amount of minerals. Some of these deposits have laminated textures and origins oflaminated textures are explained by several papers. In terms of Fe-rich deposits, metabolism ofiron-oxidizing bacteria and symbiosis of cyanobacteria and iron-oxidizing bacteria forms laminatedtextures (Takashima et al., 2008; Takashima et al., 2011). On the other hand, lamination of
travertine are contributed by photosynthetic bacteria showing daily cycle (Takashima and Kano,,
2008; Okumura et al., 2013). This study focuses on laminated deposits in Shiohitari hot spring.
Shiohitari hot spring is located at Kirishima city, Kagoshima Prefecture and emit naturally without
artificial effects. This is registered in Kirishima Geopark.
The hot spring deposit occur along10-m-long flow path. The water from the vent first flows about 2
m on a narrow (30 cm) and gentle passage and then widely on a steep slope on the travertine dome.
Below the dome, the water flows into Amafuri River. Unconsolidated Fe-rich deposit is precipitatedat the vent is, and in the lower part, travertine covered by green colored biofilm is. Bothdeposits have laminated texture.
This water is 51.2 degree celsius, neutral pH and microaerobic. The water is rich in Ca2+, Na+ andCl-, and poor in Mg2+ and SO42 -. To the downstream, the water temperature decreases, pH increase,and conversely alkalinity and Ca2+ concentration decrease. This is consisted with travertine
deposition. Because an oxygen isotopic ratio of the water (-6.8 per mill) is similar to that of
surface and shallow groundwater in southern Kyushu area (-7~-6 per mill; Mizota and Kusakabe,1997), the origin of water may be fresh water. A carbon isotopic ratio of the water is -6.8 permill which is similar in that of magmatic gases.
Mineralogy of the Fe-rich deposits in Shiohitari hot spring is ferrihydrite and exhibit micron
order laminations which alternate with a dense part and a not dense part. The dense part iscomposed of dendritic structure ferrihydrite. In addition, meshwork atructure like organic matter
is observed from specimens treated with citric acid. This possibly shows that precipitation of
ferrihydrite is induced by bacterial metabolism.
The travertine in Shiohitari hot spring is mainly composed of aragonite forming dumbbell-shape andspherical crystals. Between crystals, organic matter like EPS is observed. The lamination of thetravertine is likely formed by photosynthetic bacteria same as other travertine.
[References]
Takashima, C. and Kano, A. (2008) Microbial processes forming daily lamination in a stromatolitic
travertine. Sedimentary Geology, 208, 114-119.
Takashima, C., et al (2008) Laminated iron texture by iron-oxidizing bacteria in a calcite
travertine. Geomicrobiology Journal, 25:3 193-202.
Tkashima, C.,et al (2011) Bacterial symbiosis forming laminated iron-rich deposits in
Okuoku-hachikurou hot spring, Akita Prefecture, Japan. Island Arc, 20, 294-304.
Okumura, T., et al(2013) Processes forming daily lamination in a microbe-rich travertine under low
flow condition at the Nagano-yu Hot Spring, Southwestern Japan. Geomicrobiology Journal, 30,
910-927.
Mizota, C. and Kusakabe, M. (1994) Spatial distribution of dD-d18O values of surface and shallow
groundwaters from Japan, south Korea and east Chian. Geochemical Journal, 28, 387-410.

©2016. Japan Geoscience Union. All Right Reserved.

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Japan Geoscience Union Meeting 2016

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