Trace elements in Upper Devonian rocks of the Andoma Hill zone of fold-and-fault dislocations (southeastern Onega region) as indicators of source areas

Resumo

The paper reports the results of lithogeochemical studies of the Upper Devonian rocks from the Andoma Hill zone of fold-and-fault dislocations (SE Onega region). The rocks are characterized by the negative Eu anomaly (from 0.4 to 0.65) that maks them different from modern sediments of the White Sea. The latter can be regarded as the average composition of mainly Archean (Karelian–Kola) part of the Baltic Shield. In terms of the contents of some trace elements, they also differ from the Vendian rocks of the Zimnii Bereg area. Since the considered rocks are geochemically similar to the Svecofennian metamorphic rocks and Paleoproterozoic granite rapakivi, they could be formed by the erosion of these complexes. The clastic material was transported via a channel confined to the Baltic Shield and Russian Platform junction known as the Polkanov geoflexure.