A5009924676- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Groundwater and Isotope Geochemistry
- Geological and Geochemical Analysis
- Hydrocarbon exploration and reservoir analysis
- Isotope Analysis in Ecology
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Radioactive element chemistry and processing
- earthquake and tectonic studies
- Geological and Geophysical Studies
- Geochemistry and Elemental Analysis
- Chemical Synthesis and Characterization
- Marine Biology and Ecology Research
- Marine Bivalve and Aquaculture Studies
- CO2 Sequestration and Geologic Interactions
- Microbial Community Ecology and Physiology
- Atmospheric and Environmental Gas Dynamics
- Karst Systems and Hydrogeology
- Groundwater flow and contamination studies
- Diabetes, Cardiovascular Risks, and Lipoproteins
- Peroxisome Proliferator-Activated Receptors
- Mine drainage and remediation techniques
- Geological formations and processes
- Clay minerals and soil interactions
Okayama University
2010-2023
Hokkaido University
1982-2022
Graduate School USA
2017
Okayama University of Science
2013
Kyushu University
1994-2012
Tokyo University of Science
2008-2010
Japan Agency for Marine-Earth Science and Technology
2006
Kanazawa University
1996
The University of Tokyo
1996
Fermi National Accelerator Laboratory
1989
Research Article| February 01, 1997 Acidic and sulfate-rich hydrothermal fluids from the Manus back-arc basin, Papua New Guinea Toshitaka Gamo; Gamo 1Ocean Institute, University of Tokyo, Nakano, Tokyo 164, Japan Search for other works by this author on: GSW Google Scholar Shipboard Scientific Party ManusFlux Cruise; Cruise Kei Okamura; Okamura Jean-Luc Charlou; Charlou 2IFREMER/Centre de Brest, B.P. 70, 29280 Plouzane Cedex, France Tetsuro Urabe; Urabe 3Geological Survey Japan, Tsukuba,...
Phase-separation and -segregation (boiling/distillation of subseafloor hydrothermal fluids) represent the primary mechanisms causing intra-field variations in vent fluid compositions. To determine whether this geochemical process affects formation microbial communities, we examined communities at three different sites located within a few tens meters one another. In addition to chimney structures, colonization devices capturing entrained by fluids were studied, using culture-dependent...
Increasing levels of CO2 in the atmosphere are expected to cause climatic change with negative effects on earth's ecosystems and human society. Consequently, a variety disposal options discussed, including injection into deep ocean. Because dissolution seawater will decrease ambient pH considerably, consequences for deep-water have been predicted. Hence, associated natural reservoirs sea, dynamics gaseous, liquid, solid such environments, great interest science We report here biogeochemical...
Geochemical characteristics of hydrothermal fluids in the Iheya North field, mid-Okinawa Trough, was investigated. Twelve-years observation reveals temporal variation vent fluid chemistry potentially controlled by temporally varying pattern phase-separation and -segregation, while constant Element/Cl ratios among periods chimneys indicate stable chemical composition source prior to undergoing phase-separation. The high K contents estimated are typical arc-backarc systems due reaction with...
Abstract The Yonaguni Knoll IV hydrothermal vent field (24°51′N, 122°42′E) is located at water depths of 1370–1385 m near the western edge southern Okinawa Trough. During YK03–05 and YK04–05 expeditions using submersible Shinkai 6500 , both precipitates (sulfide/sulfate/carbonate) high temperature fluids (Tmax = 328°C) presently venting from chimney‐mound structures were extensively sampled. collected had a wide range chemistry (Cl concentration 376–635 mmol kg −1 ), which considered as...
Thriving chemosynthetic communities were located for the first time in Indian Ocean between 2420 and 2450 m, on a volcanic knoll at eastern crest of an axial valley, approximately 22 km north Rodriguez Triple Junction. The distributed 40m by 80m field around knoll. At least seven active vent sites, including black smoker complexes that emitting superheated water 360°C, observed field. faunal composition hydrothermal had links to both Pacific Atlantic assemblages. This discovery supports...
In the Mariana forearc, horst and graben structures are well developed in outer forearc basement, which is composed of both island arc oceanic crust-mantle rocks. A zone dome-shaped diapiric seamounts, mainly serpentinized peridotites, formed on basement regions. Serpentine minerals peridotites from seamounts mostly chrysotile and/or lizardite. Antigorite, however, rarely found recovered Conical, Big Blue, Celestial, South Chamorro Seamounts. Antigorite-bearing always contain secondary...
The Sr isotopic behavior in hydrothermally altered rocks of a complete section through the Wadi Fizh oceanic crust Oman ophiolite was investigated order to evaluate seawater‐rock interaction crust. On basis rock‐types, secondary mineral assemblage, alteration temperature, average 87 Sr/ 86 hydrothermal fluids, and degree alteration, is divided into following 5 sequences: (1) mainly basalts clay minerals, low 0.70634, 78% alteration; (2) chlorite, minerals calcite, fairly 0.70584, 76% (3)...
We have measured chemical compositions (CO2, CH4, N2, O2, H2S, H2, He, Ne and Ar), isotopic of light elements (δ13C, δ15N δD) rare gases (He, Ne, Ar, Kr, Xe) in seven gaseous four fluid samples collected Icelandic geothermal areas. Major constituents the gas are CO2, H2 H2S. Isotopic Compositions Kr Xe indistinguishable from those atmosphere within experimental accuracy this study. There slightly lower 40Ar/ 36Ar ratios than air for with extremely high 3He/4He ratios. No positive evidence...
Sulfur isotope fractionation factors between sulfate and sulfide at 600 to 1, 000°C were experimentally determined by decomposing anhydrous Na2SO3 in melts of NaCl LiCl-KCl mixture (6 : 4 molar ratio). exchange equilibrium was attained formed decomposition sodium sulfite within 120 minutes 600°C the melt 30 810°C melt. The observed (α) obey relationship experimental temperature range: 1000 lnαsulfate-sulfide = 7.4 × 106/T2 − 0.19. In alkali chloride melts, would exist as HS-, S2-, NaHS NaS-,...
Hokusetsu Region in Osaka, Japan. The As contamination was investigated through the geochemical mapping and analysis of river waters bed sediments over an area 440 km2. Sulfur from sulfides rocks dissolved sulfates water were compared via isotopic to assess their origin subsequently released As. fate (transport, binding on settling particles) evaluated total fractions trace metals Fe, Mn Al waters. showed that exceeded maximum limit concentration 10 ppb several places. highest levels (waters...
The TAG hydrothermal mound on the Mid‐Atlantic Ridge (26°08′N, 44°50′W) was revisited in August 1994 with submersible Shinkai 6500 order to characterize time‐series fluid chemistry prior ODP drilling. Fluid samples were taken from both black smokers and white smokers. Si, pH, alkalinity, H 2 S, major cations (Na + , K Ca 2+ Mg ), anions (Cl − SO 4 2− minor elements (Li, Sr, B, Fe, Mn, Cu, Zn, Br) as well Sr isotope ratios measured. We report first Br/Cl for fluids, showing no fractionation...