
Yuji SanoKōchi University · Center for Advanced Marine Core Research
Yuji Sano
PhD
Director and Professor of CMCR, Kochi University.
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518
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Introduction
Yuji Sano currently works at the Center for Advanced Marie Core Research , Kochi University. Yuji does research in Volcanology, Geochemistry and Petrology. Their current project is 'Shallow marine hydrothermal system.'
Publications
Publications (518)
Ulleungdo, a volcanic island located in the back-arc basin (East Sea/Sea of Japan) of the Japanese arc, is one of the Cenozoic intraplate volcanoes in Northeast (NE) Asia. Due to the distinctive geotectonic properties of transitioning from a past back-arc environment to a current intraplate tectonic setting, the elucidation of the magma origin of t...
Phosphorus and molybdenum play important roles in the formation of microbial cell structures and specific enzymes crucial for metabolic processes. Nevertheless, questions remain about the preservation of these elements within ancient microfossils. Here, we present shape-accurate ion images capturing phosphorus and molybdenum on Palaeoproterozoic fi...
Numerous geothermal systems are hosted by extensional rifts that transect the Himalayas and Lhasa block in the Himalayan–Tibetan orogen. However, the relationships between hydrogeological processes and geothermal fluid circulation in different tectonic units remain unclear. Here, we report an integrated dataset of chemical and isotopic compositions...
Volatiles such as helium and carbon dioxide provide insights into geological processes spanning from the Earth’s deep interior to its surface. Integration with geophysical data providing enhanced vertical resolution with a wider horizontal range better elucidates the mantle dynamics and its interactions with the crust. Here we present geochemistry...
Secondary microbial methane could provide a valuable energy source if it were better understood. Although coal seam is an ideal environment for investigating secondary microbial methane, there are few studies to trace the secondary microbial methane of high-rank coals. Here, we collected co-produced water samples from coalbeds in the Qinshui Basin...
A notable decrease of groundwater Na/K ratios was observed several months before the 2018 Hokkaido Eastern Iburi earthquake (M6.7) at a site approximately 20 km west of the earthquake’s epicenter. To investigate the cause of the decreased Na/K ratios, we analyzed groundwater samples (commercially bottled drinking water) to assess the contribution o...
CO2 released from subduction zones plays a vital role in the tectonic carbon cycle. However, the contribution of submarine backarc components to carbon emissions remains poorly understood compared to subaerial arc volcanos. This study utilized a combination of geochemical and hydrodynamic approaches to investigate the sources and flux of dissolved...
The active Himalayan-Tibetan orogen, where India underthrusts into Asia, is an important geological source of carbon dioxide (CO2) emission into Earth’s atmosphere. However, the extent to which Indian underthrusting could stimulate the mobilization of deeply-sourced carbon and its subsequent emission remains unknown. Here, we use a combination of f...
New standard zircons applicable to in situ analysis of Hf/W ratio by Nanoscale secondary ion mass spectrometer (NanoSIMS) were prepared and applied to Hf-W dating of a differentiated meteorite classified as mesosiderite. The standard zircons were synthesized by high-pressure experiment from starting materials which were mixture of hafnium oxide, tu...
Plate tectonics plays an essential role in the redistribution of life-essential volatile elements between Earth's interior and surface, whereby our planet has been well tuned to maintain enduring habitability over much of its history. Here we present an overview of deep carbon recycling in the regime of modern plate tectonics, with a special focus...
The Karakoram fault (KKF) is an important strike‐slip boundary for accommodating deformation following the India‐Asia collision. However, whether the deformation is confined to the crust or whether it extends into the mantle remains highly debated. Here, we show that the KKF is overwhelmingly dominated by crustal degassing related to a ⁴He‐ and CO2...
Wakamiko Caldera is an isolated basin located in the northern part of Kagoshima Bay. The underwater caldera is known for the active fumaroles that continuously discharge volcanic substances into the overlying water. Due to the limited exchange of waters in the caldera with the surrounding area, the water column gets stagnant and stratified from spr...
Zircon grains preserve records of crystallization, growth, and/or deformation that can be envisaged from their internal structures and through the U–Pb isotope analysis. Electron backscatter diffraction (EBSD) is a non-destructive method for visualizing undeformed domains to differentiate them from those that are plastically deformed. In this study...
Carbon dioxide (CO2) is one of the main components of greenhouse gases, and there is a great concern about emissions mainly from human activities. However, long term CO2 emissions during the Earth’s history are largely related to natural emissions by geological factors. Natural CO2 emissions are mainly at highly permeable passages below the surface...
The helium isotope ratio (³He/⁴He), concentration ratio of neon-20 to helium-4 (²⁰Ne/⁴He), argon (Ar), krypton (Kr), and xenon (Xe) concentrations were measured in the porewater of surface sediments of several submarine mud volcanoes. From the ³He/⁴He values (0.18–0.93RA), the estimated He origin is almost 90% crustal He, with little contribution f...
Degassing of deeply-derived fluids (e.g., He and CO2) prevails along seismically active faults in continental collision settings such as the Tibetan Plateau, where potential insights into seismogenesis through tectonic degassing remain less understood. Here, we present a quantitative geochemical study on hydrothermal gases from a Y-shaped active fa...
Relative nitrogen abundance normalized by carbonaceous chondrites in the bulk silicate Earth appears to be depleted compared to other volatile elements. Especially, nitrogen behavior in the deep part of the Earth such as the lower mantle is not clearly understood. Here, we experimentally investigated the temperature dependence of nitrogen solubilit...
Hot thermal fluids flow through the Earth's crust and carry valuable information about the deep subsurface. The monitoring of natural tracers transported in geothermal fluids, such as gases or ions, are relevant to better understand the geological processes in the Earth's subsurface and their relation to deep fluid dynamics. Recently developed tech...
Northwest Africa (NWA) 2977 is a lunar basaltic meteorite that was found in 2005 and has been classified as an olivine cumulate gabbro. This meteorite contains a shock melt vein (SMV) induced by an intense shock event. We report herein on an in-situ analysis of phosphates in the host gabbro and the shock vein for the U–Pb dating of NWA 2977 using a...
Plain Language Summary
Basaltic rocks occur on numerous planetary bodies, including Mars, the Moon, and the asteroid Vesta. Shock metamorphic features in meteorites from such bodies are the ancient imprints of past impact events. We can extract information about the bombardment histories experienced by such bodies if we have an accurate method to l...
Stratovolcanoes form conical mountains by ejecta and lava, while caldera volcanoes have depressions caused by post caldera collapse. Few studies have investigated relationships between this morphology difference and discharged fluid geochemistry. Here we present helium isotope ratios of geothermal fluids and groundwater inside and outside the calde...
Basaltic rocks occur widely on the terrestrial planets and differentiated asteroids, including the asteroid 4 Vesta. We conducted a shock recovery experiment with decaying compressive pulses on a terrestrial basalt at Chiba Institute of Technology, Japan. The sample recorded a range of pressures, and shock physics modeling was conducted to add a pr...
Stable carbon isotope records in metasedimentary rocks showed that life has existed in the early Archean. Therefore, it may become next subjects of interest what kind of ecosystem existed and whether life existed prior to Archean. However, they are still ambiguous because little information other than isotope records is available from the early Arc...
The evolutionary history of early prokaryotes is recorded in Paleoproterozoic sedimentary rocks. The ca. 1.88 Ga Gunflint Formation is considered key to constrain the course of Paleoproterozoic microbial evolution. However, whether the multicellularity of prokaryote and eukaryote was already present by the Gunflint age remains uncertain. Here, we r...
The origin of major volatiles nitrogen, carbon, hydrogen, and sulfur in planets is critical for understanding planetary accretion, differentiation, and habitability. However, the detailed process for the origin of Earth’s major volatiles remains unresolved. Nitrogen shows large isotopic fractionations among geochemical and cosmochemical reservoirs,...
In the exploration of the origin and evolution of early life on Earth, age determinations of fossil occurrences are of critical importance. Purported microbial fossils preserved in chert and jasper are commonly assigned indirect dates due to a lack of suitable minerals for geochronology in the fossil-bearing horizons. Such indirect dating methods c...
This investigation presents methane, noble gas isotopes, CTD, and stable isotopic data for water samples collected in Niskin bottles at Tatar Strait during the spring seasons of 2015 and 2019 onboard the Russian R/V Akademik M.A. Lavrentyev. The results are compared to previous research carried out in 1999 in a nearby portion of the Strait and demo...
Zircon, a common accessory mineral in igneous and metamorphic rocks, highly resistant to alteration, preserves records of its magmatic crystallization or growth and recrystallization during metamorphic events. Backscattered electron (BSE) and cathodoluminescence (CL) imaging are generally adopted to detect pristine domains in zircons that are used...
The observed large variation in the abundance of deuterium (D) in the interstellar medium suggests that a significant fraction of D may be depleted into polycyclic aromatic hydrocarbons (PAHs). Signatures of the deuteration of PAHs are expected to appear most clearly through the C–D stretching modes at 4.4–4.7 μ m, whose strengths in emission spect...
This study presents an almost entirely unpublished dataset of 121 samples of groundwater analyzed for helium concentration and its isotopic ratio (3He/4He) in two adjacent watersheds of the St. Lawrence Lowlands, in a region with intensive agricultural activities in the southern Québec Province, Eastern Canada. Most of the samples were collected in...
Plain Language Summary
Helium (including ³He and ⁴He isotopes) is an element mainly outgassing from Earth's interior to the atmosphere. The fluxes and isotopic compositions of helium are critical parameters for monitoring the hazardous volcanic eruptions and earthquakes, estimating the fluxes of other volatile species (e.g., CO2 and N2) from the so...
Shock metamorphism of minerals in meteorites provides insights into the ancient Solar System. Calcite is an abundant aqueous alteration mineral in carbonaceous chondrites. Return samples from the asteroids Ryugu and Bennu are expected to contain calcite‐group minerals. Although shock metamorphism in silicates has been well studied, such data for aq...
Shock metamorphism of minerals in meteorites provides insights into the ancient Solar System. Calcite is an abundant aqueous alteration mineral in carbonaceous chondrites. Return samples from the asteroids Ryugu and Bennu are expected to contain calcite-group minerals. Although shock metamorphism in silicates has been well studied, such data for aq...
The observed large variation in the abundance of deuterium (D) in the interstellar medium (ISM) suggests that a significant fraction of D may be depleted into polycyclic aromatic hydrocarbons (PAHs). Signatures of deuteration of PAHs are expected to appear most clearly through C-D stretching modes at 4.4--4.7 micron, whose strengths in emission spe...
We have developed a method to analyze all rare earth elements in silicate glasses and zircon minerals using a high lateral resolution secondary ion mass spectrometer (NanoSIMS). A 2nA O⁻ primary beam was used to sputter a 7–8-μm diameter crater on the sample surface, and secondary positive ions were extracted for mass analysis using an accelerating...
Hydrothermal activity and seismicity are abundant along the Yushu-Ganzi-Xianshuihe fault system (YGXFS) in the eastern Tibetan Plateau. However, the processes and factors that control hydrothermal fluid circulation at a regional scale remain less constrained, and the relationship between geothermal anomaly and seismic activity is poorly known. In t...
The fine-scale concentration of platinum in a hydrogenetic ferromanganese crust (Takuyo-Daigo Seamount 2987 m water depth) was determined using secondary ion mass spectrometry (SIMS). The crust was analyzed chronologically, and the spatial resolution of the SIMS depth profiling was 0.013 μm, corresponding to 5 years of the crust growth. SIMS depth...
Northwest Africa (NWA) 7203 is a quenched angrite, showing mineralogical features typically not present in other quenched angrites. NWA 7203 exhibits textures whose grain size varies from fine grains (<10 μm) to coarse grains (~3 mm), while other quenched angrites show only single-sized textures. Fine-grained and coarse-grained lithologies have nea...
The sudden eruption of submerged calderas can potentially pose imminent danger to nearby communities. Hence, it is crucial to closely monitor the changes in volatile effluents in these environments. Unlike subaerial volcanoes, underwater volcanic activity is difficult to observe. Wakamiko, a submerged caldera in southern Japan shares a magma source...
We report here hourly variations of Mg/Ca, Sr/Ca, and Ba/Ca ratios in a Mediterranean mussel shell (Mytilus galloprovincialis) collected at the Otsuchi bay, on the Pacific coast of northeastern Japan. This bivalve was living in the intertidal zone, where such organisms are known to form a daily or bidaily growth line comprised of abundant organic m...
Mantle degassing transect across different tectonic units within a plate convergent setting has been well documented for oceanic convergent margins by systematic changes in geochemistry (e.g., ³He/⁴He, δ¹³C, and CO2/³He) of hydrothermal gases. However, little is known about spatial variations in volatile geochemistry across a continental convergent...
A large number of gases are releasing from the medium-high temperature geothermal fields distributed along the large-scale strike-slip fault zones in the southeastern margin of the Tibetan Plateau. In this study, 11 hot spring water and the associated bubbling gas samples were collected along the Xianshuihe-Anninghe fault zones (XSH-ANHFZ) and anal...
Extensional rift systems provide important pathways for the release of large amounts of deeply-sourced CO2 into the atmosphere. Continental rifting zones (e.g., East African rift) are thus invoked to be important for understanding the links between CO2 outgassing and global climate change associated with continental breakup. However, deeply-sourced...
The episodic growth of high-elevation orogenic plateaux is controlled by a series of geodynamic processes. However, determining the underlying mechanisms that drive plateau growth dynamics over geological history and constraining the depths at which growth originates, remains challenging. Here we present He-CO2-N2 systematics of hydrothermal fluids...
Earth’s surface environment underwent the first major step-change in atmospheric oxygen levels during the Paleoproterozoic Great Oxidation and Lomagundi–Jatuli events. A decrease in atmospheric oxygen levels after the Lomagundi–Jatuli Event has previously been suggested, but details of the environmental transitions at 2.0–1.8 Ga are still debated....
Multi-channel seismic reflection and sub-bottom profiling data reveal landward-dipping normal faults as potential conduits for mantle-derived fluids in the coseismic slip area of the 2011 Tohoku earthquake (Mw9.0). Normal faults below the helium isotope anomaly sites appear to develop through the forearc crust (i.e., the seafloor sedimentary sectio...
Detailed age information of the Pingtan-Dongshan Metamorphic Belt in the coastal Cathaysia Block is important in understanding geodynamics of the Late Mesozoic South China continental margin. Geochronological determinations on monazite and zircon inclusions and zircon separates from five mica schists and two granites intruding schists are used to c...
We report here hourly variations of Mg/Ca, Sr/Ca and Ba/Ca ratios in a Mediterranean mussel shell ( Mytilus galloprovincialis ) collected at the Otsuchi bay, on the Pacific coast of northeastern Japan. This bivalve was living in the intertidal zone, where such organisms are known to form a daily or bidaily growth line comprised of abundant organic...
Plate bending-related normal faults (i.e. bend-faults) develop at the outer trench-slope of the oceanic plate incoming into the subduction zone. Numerous geophysical studies and numerical simulations suggest that bend-faults play a key role by providing pathways for seawater to flow into the oceanic crust and the upper mantle, thereby promoting hyd...
Understanding origin and circulation regime of geothermal fluid in geothermal system is essential to achieve sustainable utilization of geothermal energy. Gas samples were collected from fumaroles and hot springs in three geothermal areas (Wayang Windu, Patuha, Tampomas, and Tangkuban Perahu) around the Bandung Basin, west Java, Indonesia. Their bu...
Carbon capture and storage (CCS) is considered a key technology for reducing CO2 emissions into the atmosphere. Nonetheless, there are concerns that if injected CO2 migrates in the crust, it may trigger slip of pre-existing faults. In order to test if this is the case, covariations of carbon, hydrogen, and oxygen isotopes of groundwater measured fr...
Abstract Six wells were continuously monitored in Hokkaido, northern Japan, to relate groundwater level changes to regional seismic activity. Groundwater level changes following the 2018 Hokkaido Eastern Iburi earthquake were detected in three of the six wells, even though they are located hundreds of kilometers from the epicenter. The groundwater...