TY - JOUR
T1 - ESR dating of marine barite in chimneys deposited from hydrothermal vents
AU - Okumura, Tasuku
AU - Toyoda, Shin
AU - Sato, Fumihiro
AU - Uchida, Ai
AU - Ishibashi, Jun Ichiro
AU - Nakai, Shun'Ichi
N1 - Funding Information:
This work has been supported by a Grant-in-Aid for Scientific Research on Innovative Areas ‘‘TAIGA’’ of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan and by the Inter-University Program for the Common Use of the Japan Atomic Energy Research Institute (JAERI) Facilities, Japan.
PY - 2010/1/1
Y1 - 2010/1/1
N2 - Electron Spin Resonance (ESR) dating of marine barite in chimneys deposited from hydrothermal vents was attempted to determine the time since hydrothermal activity occurred. In this study, we used Barite (BaSO4) precipitated in icroenvironments in the chimneys deposited from the hydrothermal vents at the Archaean site in South Mariana spreading centre (12°56.4'N, 143°37.9'E) and at Hakurei site in the Izena caldron (27°15'N, 127°04'E) for ESR measurements. ESR spectrum of marine barite is characterized by an electron-type centre with g values of 2.0034, 2.0022 and 1.9995 attributed to SO3-. The signal intensity increased with gamma ray dose. The dose rates of hydrothermal chimneys from the Archaean site and from the Hakurei site were calculated using a model that assumed a grain size and that incorporation of radionuclides after 226Ra in U series into the chimney, and assuming the efficiency of the defect formation by alpha particles to be the same as that for OSL. The ESR ages were estimated to be 470 years old for barite from the Archaean site and 5670 years old for one from the Hakurei site, although there is a considerable difference between the present ESR ages and the 210Pb/226Ra disequilibrium ages previously reported.
AB - Electron Spin Resonance (ESR) dating of marine barite in chimneys deposited from hydrothermal vents was attempted to determine the time since hydrothermal activity occurred. In this study, we used Barite (BaSO4) precipitated in icroenvironments in the chimneys deposited from the hydrothermal vents at the Archaean site in South Mariana spreading centre (12°56.4'N, 143°37.9'E) and at Hakurei site in the Izena caldron (27°15'N, 127°04'E) for ESR measurements. ESR spectrum of marine barite is characterized by an electron-type centre with g values of 2.0034, 2.0022 and 1.9995 attributed to SO3-. The signal intensity increased with gamma ray dose. The dose rates of hydrothermal chimneys from the Archaean site and from the Hakurei site were calculated using a model that assumed a grain size and that incorporation of radionuclides after 226Ra in U series into the chimney, and assuming the efficiency of the defect formation by alpha particles to be the same as that for OSL. The ESR ages were estimated to be 470 years old for barite from the Archaean site and 5670 years old for one from the Hakurei site, although there is a considerable difference between the present ESR ages and the 210Pb/226Ra disequilibrium ages previously reported.
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U2 - 10.2478/v10003-010-0019-z
DO - 10.2478/v10003-010-0019-z
M3 - Article
AN - SCOPUS:78651064859
SN - 1733-8387
VL - 37
SP - 57
EP - 61
JO - Geochronometria
JF - Geochronometria
IS - 1
ER -
