A method for determining the ages of shoshonitic volcanics erupted within the last 5000 years is presented and assessed. This method is based on 226Ra/230Th radioactive disequilibrium and on a leaching procedure and γ-counting of volcanics containing Th-enriched, Rainitial-depleted mineral phases detected by microprobe analyses. K is used as a Ra-stable chemical analogue. The data are plotted on (226Ra/228Ra)− K(228Ra) Osmond-type diagrams in order to evaluate the 226Raradiogenic230Th activity ratio of the Th-enriched, Rainitial-depleted phases. Four samples of volcanics from Vulcano Island (southern Italy) gave ages consistent with historical reports andK/Ar chronology.
Voltaggio, M., Branca, M., Tuccimei, P., Tecce, F. (1995). Leaching procedure in dating young potassic volcanic rocks by 226Ra/230Th method. EARTH AND PLANETARY SCIENCE LETTERS, 136, 123-132.
Leaching procedure in dating young potassic volcanic rocks by 226Ra/230Th method
TUCCIMEI, Paola;
1995-01-01
Abstract
A method for determining the ages of shoshonitic volcanics erupted within the last 5000 years is presented and assessed. This method is based on 226Ra/230Th radioactive disequilibrium and on a leaching procedure and γ-counting of volcanics containing Th-enriched, Rainitial-depleted mineral phases detected by microprobe analyses. K is used as a Ra-stable chemical analogue. The data are plotted on (226Ra/228Ra)− K(228Ra) Osmond-type diagrams in order to evaluate the 226Raradiogenic230Th activity ratio of the Th-enriched, Rainitial-depleted phases. Four samples of volcanics from Vulcano Island (southern Italy) gave ages consistent with historical reports andK/Ar chronology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
