Estimation of sulfur, fluorine, chlorine and bromine fluxes at Mid Ocean Ridges using a new experimental crushing and extraction method

Sulphur geodynamic cycle

“…They easily adhere to the inner surface of a vacuum crushing vessel. We have developed a gas-extraction method, ‘Frozen Crushing Method’, by which sulphur gases are fixed immediately in semi-frozen alkaline solution during mechanical fracturing of glass 7 . The abundance of helium and 3 He/ 4 He ratios were measured using a noble gas mass spectrometer (VG5400; Waters Corp.) at the Atmosphere and Ocean Research Institute (AORI).…”

“…Blank contributions of sulphur and helium were considerably smaller than the actual amounts in samples. Experimental details are presented in an earlier report 7 . Sulphate ion in the alkaline solution was converted into BaSO 4 precipitations by adding BaCl 2 solution and δ 34 S values obtained with an elemental analyzer (vario PYRO cube; Elementar Analysensysteme, GmbH) coupled to an isotope-ratio mass spectrometer (Delta XP; Thermo Fisher Scientific Inc.) via an interface (ConFlo IV; Thermo Fisher Scientific Inc.) at the University of Ottawa.…”

“…Mantle carbon flux of 2 × 10 12 mol/y was derived from the MOR 3 He flux and CO 2 / 3 He ratio in MOR basalt glass 6 . However, except for a very rough estimate 7 , no report in the literature has described an estimation of mantle sulphur flux at MOR as calibrated against the mantle 3 He flux because no S/ 3 He ratios in MOR basalt glasses have yet been reported.…”

Groundwater oxygen isotope anomaly before the M6.6 Tottori earthquake in Southwest Japan

“…In order to combine two individual observations: δ 18 O anomaly of groundwater and helium isotopic change in hot springs in region close to the epicenter of the 2016 Tottori earthquake, we have conducted a preliminary experiment where rock was crushed in frozen water 29 (see Method). There is no reference that showing oxygen and helium isotope anomalies at the same time related to a single seismic activity.…”

“…Water was frozen by cooling the ball mill into liquid nitrogen and head space gases were evacuated. Then, the ball mill was shaken 500 times and helium in rock was extracted by mechanical fracturing 29 . At first gas extracted by the crushing was introduced into vacuum purification line and helium abundance and isotopic composition were measured by a noble gas mass spectrometer after separation 26 .…”