Raukas, A., Koch, R., Jüriado, K., Järvelill, J.-I.

Anomalous radioactivity level and high concentrations of heavy minerals in Lemme area, South-West Estonia

Abstract

As early as in the 1960s, extensive heavy-mineral concentrations containing zircon, monazite, and xenotime were discovered in the Lemme region of south-western Estonia. These concentrations contribute to the elevated radioactivity levels of the enclosing sediments. The near shore sands of the Litorina Sea contain up to 10-cm-thick interlayers with a heavy mineral content of up to 80%. These anomalous layers were formed during the transgressive phase and result from a complicated cross- and alongshore migration of sedimentary material, derived mainly from local Devonian bedrock. Radioactivity level in the study area is higher relative to the majority of the Devonian plateau. The Lemmeoja buried soil has 13 radiocarbon dates in an area of renewed interest for the investigation of the Baltic Sea history.



Doi 10.5200/baltica.2014.27.19

Keywords Radioactivity, Heavy minerals, Transgressions, Nearshore, Aeolian deposits

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