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Use of immobile trace elements for the correlation of Telychian bentonites on Saaremaa Island, Estonia, and mapping of volcanic ash clouds

2008; Estonian Academy Publishers; Volume: 57; Issue: 1 Linguagem: Inglês

10.3176/earth.2008.1.04

1736-7913

T Kallaste, E Kiipli, Tarmo Kiipli, K Orlova,

Geological Formations and Processes Exploration

Thirty suspected altered volcanic ash (bentonite) samples from the Nässumaa-825 and Orissaare-859 sections were analysed by the X-ray fluorescence method.Twenty of these samples revealed chemical signs of pure volcanogenic material, one was of mixed terrigenous-volcanogenic origin, and nine were classified as terrigenous claystones.Twenty of the bentonites were correlated, with variable confidence, with bentonites from earlier studied sections; one sample represents a formerly unknown eruption.New and earlier published bentonite correlations were used for tracing the diachronous nature of the Rumba-Velise formations boundary and for composing new isopach schemes of six Telychian bentonites.