Syndepositional deformation in the Kurkiselkä esker, Kiiminki, Finland

• Main Author: R. Aario
• Format: Article
• Language: English
• Published: Geological Society of Finland 1971-12-01
• Series: Bulletin of the Geological Society of Finland
• Online Access: http://www.geologinenseura.fi/bulletin/Volume43/sgs_bt_043_2_pages_163_172.pdf

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.