A rapid procedure for Io (Th230) dating of sediments with accumulation rates in the range of several cm/1000 years is described. Studying of large sample populations with very small Io-excess activity is possible as the counting time (around 1500 min/sample) are 2 to 5 times shorter than with the standard Io-excess method. Improved sensitivity of the Io-excess measurement is achieved by:1) extraction ( ~90 %) of the authigenic Io-excess with EDTA, with minor leaching ( ~30 %) of the allogenic Th232 and Io-supported,2) processing samples as large as 10 g or more.The procedure was applied to sediments from the Caribbean (V 12-122) and from the Ionian Sea (M22_48 and M17_17). In the case of the standard core V 12-122 our results are in good agreement with previous time-consuming Io determinations. The resulting average accumulation rates of 2.0 ± 0.3 cm/1000 years for the Ionian Sea cores are close to the average derived from magnetic reversal studies of a nearby core.

Supplement to: Mangini, Augusto; Dominik, Janusz (1978): Th230-excess EDTA extraction: A modification of the ionium method for high accumulation rate determinations. Meteor Forschungsergebnisse, Deutsche Forschungsgemeinschaft, Reihe C Geologie und Geophysik, Gebrüder Bornträger, Berlin, Stuttgart, C29, 6-13