Facies and stratigraphy of the Middle Caradoc mixed siliciclastic-carbonate sediments in eastern Baltoscandia

The middle Caradoc sedimentary facies, transitions and dynamics, in souther, Estonia and the Gotland area in the Keila, Oandu, and Rakvere stages are described. Grain size analysis of the noncarbonate component demonstrates differences between the major confacies belts. A new name, the Variku Formation, is proposed for a rock unit of intercalating quartzose siltstones, claystones, and marls in southern Estonia, and the late Keila to Rakvere age of this unit is suggested by ostracode data. The change of the deposition type in the Caradoc Baltic Basin lasted for a considerable time and can be characterized by a sequence of successive climatic, isotopic, and eustatic events and change in sedimentary material input. Complex reasons related to the continental drift and continental glaciation are proposed for the Caradoc turnover.