Bulletin of the Geological Society of Finland (Dec 1971)

Syndepositional deformation in the Kurkiselkä esker, Kiiminki, Finland

  • R. Aario

DOI
https://doi.org/10.17741/bgsf/43.2.003
Journal volume & issue
Vol. 43, no. 2
pp. 163 – 172

Abstract

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Syndepositional and metadepositional deformation structures from an esker section in Kiiminki, Finland, are described and discussed. The small folds are suggested to be a response of cohesive, hydroplastic material to the drag of turbulent flow, and the accompanying differential pressure conditions. The data indicate a rippling mechanism. The small folds have a transition into more complicated structures derived mainly from syndepositional or metadepositional horizontal movements, apparently in part gravity-induced, which operated contemporaneously with the rippling mechanism. The syndepositional deformation structures of the category described are rather common in the Oulu vicinity, probably due to the widespread occurrence of water-laid deposits composed of fine sand, a grain size that favours this kind of deformation. They can readily be confused with deformation structures of other origin, which exist in juxtaposition within the same area.