scholarly journals Chemical and lithium isotope characteristics of murakamiite and Li–rich pectolite from Iwagi Islet, Southwest Japan

2021 ◽  
Vol 116 (1) ◽  
pp. 9-25
Author(s):  
Teruyoshi IMAOKA ◽  
Jun–Ichi KIMURA ◽  
Qing CHANG ◽  
Tsuyoshi ISHIKAWA ◽  
Mariko NAGASHIMA ◽  
...  
Keyword(s):  
Lithium Isotope ◽  
Southwest Japan

Characterization of groundwater based on δ2H, δ18O and Cl− concentration beneath the Osaka Plain, Southwest Japan

2019 ◽  
Vol 53 (4) ◽  
pp. 235-247
Author(s):  
Tsuyoshi Shintani ◽  
Harue Masuda ◽  
Kaori Okazaki ◽  
Emilie Even ◽  
Masahiko Ono ◽  
...  
Keyword(s):  
Southwest Japan

LITHIUM ISOTOPE VARIATIONS IN THE PALABORA CARBONATITE COMPLEX: A TALE OF TWO HUMITES

2020 ◽  
Author(s):  
Qian Yuan ◽  
◽  
Richard L. Hervig ◽  
Ziliang Jin ◽  
Maitrayee Bose
Keyword(s):  
Lithium Isotope ◽  
Carbonatite Complex

Oxygen, Hydrogen, Boron and Lithium Isotope Data of a Natural Spring Water with an Extreme Composition: A Fluid from the Dehydrating Slab?

2017 ◽  
Vol 23 (5-6) ◽  
pp. 299-313 ◽  
Author(s):  
Tiziano Boschetti ◽  
Lorenzo Toscani ◽  
Paola Iacumin ◽  
Enricomaria Selmo
Keyword(s):  
Spring Water ◽  
Lithium Isotope ◽  
Isotope Data ◽  
Natural Spring Water ◽  
Natural Spring

scholarly journals Driving stress and seismotectonic implications of the 2013 Mw5.8 Awaji Island earthquake, southwestern Japan, based on earthquake focal mechanisms before and after the mainshock

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Kazutoshi Imanishi ◽  
Makiko Ohtani ◽  
Takahiko Uchide
Keyword(s):  
Stress Field ◽  
Stress Tensor ◽  
Nankai Trough ◽  
Source Region ◽  
Local Scale ◽  
Southwest Japan ◽  
Stress Tensor Inversion ◽  
Earthquake Fault ◽  
Reverse Faulting ◽  
Before And After

Abstract A driving stress of the Mw5.8 reverse-faulting Awaji Island earthquake (2013), southwest Japan, was investigated using focal mechanism solutions of earthquakes before and after the mainshock. The seismic records from regional high-sensitivity seismic stations were used. Further, the stress tensor inversion method was applied to infer the stress fields in the source region. The results of the stress tensor inversion and the slip tendency analysis revealed that the stress field within the source region deviates from the surrounding area, in which the stress field locally contains a reverse-faulting component with ENE–WSW compression. This local fluctuation in the stress field is key to producing reverse-faulting earthquakes. The existing knowledge on regional-scale stress (tens to hundreds of km) cannot predict the occurrence of the Awaji Island earthquake, emphasizing the importance of estimating local-scale (< tens of km) stress information. It is possible that the local-scale stress heterogeneity has been formed by local tectonic movement, i.e., the formation of flexures in combination with recurring deep aseismic slips. The coseismic Coulomb stress change, induced by the disastrous 1995 Mw6.9 Kobe earthquake, increased along the fault plane of the Awaji Island earthquake; however, the postseismic stress change was negative. We concluded that the gradual stress build-up, due to the interseismic plate locking along the Nankai trough, overcame the postseismic stress reduction in a few years, pushing the Awaji Island earthquake fault over its failure threshold in 2013. The observation that the earthquake occurred in response to the interseismic plate locking has an important implication in terms of seismotectonics in southwest Japan, facilitating further research on the causal relationship between the inland earthquake activity and the Nankai trough earthquake. Furthermore, this study highlighted that the dataset before the mainshock may not have sufficient information to reflect the stress field in the source region due to the lack of earthquakes in that region. This is because the earthquake fault is generally locked prior to the mainshock. Further research is needed for estimating the stress field in the vicinity of an earthquake fault via seismicity before the mainshock alone.

scholarly journals Ore Genesis of the Takatori Tungsten–Quartz Vein Deposit, Japan: Chemical and Isotopic Evidence

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 765
Author(s):  
Yuichi Morishita ◽  
Yoshiro Nishio
Keyword(s):  
Oxygen Isotope ◽  
Early Stage ◽  
Isotope Ratios ◽  
Equilibrium Temperature ◽  
Granitic Rocks ◽  
Granitic Magma ◽  
Lithium Isotope ◽  
Vein Deposit ◽  
Pressure Independent ◽  
Isotope Equilibrium

The Takatori hypothermal tin–tungsten vein deposit is composed of wolframite-bearing quartz veins with minor cassiterite, chalcopyrite, pyrite, and lithium-bearing muscovite and sericite. Several wolframite rims show replacement textures, which are assumed to form by iron replacement with manganese postdating the wolframite precipitation. Lithium isotope ratios (δ7Li) of Li-bearing muscovite from the Takatori veins range from −3.1‰ to −2.1‰, and such Li-bearing muscovites are proven to occur at the early stage of mineralization. Fine-grained sericite with lower Li content shows relatively higher δ7Li values, and might have precipitated after the main ore forming event. The maximum oxygen isotope equilibrium temperature of quartz–muscovite pairs is 460 °C, and it is inferred that the fluids might be in equilibrium with ilmenite series granitic rocks. Oxygen isotope ratios (δ18O) of the Takatori ore-forming fluid range from +10‰ to +8‰. The δ18O values of the fluid decreased with decreasing temperature probably because the fluid was mixed with surrounding pore water and meteoric water. The formation pressure for the Takatori deposit is calculated to be 160 MPa on the basis of the difference between the pressure-independent oxygen isotope equilibrium temperature and pressure-dependent homogenization fluid inclusions temperature. The ore-formation depth is calculated to be around 6 km. These lines of evidence suggest that a granitic magma beneath the deposit played a crucial role in the Takatori deposit formation.

scholarly journals Downstream and seasonal changes of lithium isotope ratios in the Ganges‐Brahmaputra river system

2017 ◽  
Vol 18 (8) ◽  
pp. 3003-3015 ◽  
Author(s):  
Takuya Manaka ◽  
Daisuke Araoka ◽  
Toshihiro Yoshimura ◽  
H. M. Zakir Hossain ◽  
Yoshiro Nishio ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
River System ◽  
Isotope Ratios ◽  
Lithium Isotope ◽  
Brahmaputra River ◽  
The Ganges
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