Discovery of the Ordovician Kinnekulle K-bentonite at the Põõsaspea cliff, NW Estonia

Abstract

A previously unknown outcrop of the Kinnekulle K-bentonite (metabentonite) is reported from the Põõsaspea cliff, NW Estonia. The bed has a sharp lower and a gradational upper contact and comprises ca 28 cm of clay overlain by ca 10 cm of hard K-feldspar-rich variety. The latter contains a layer of breccia, which indicates early onset of recrystallization and hardening of volcanic material. The discovery shows that the Põõsaspea cliff section is younger than previously thought and includes rocks of both Haljala and Keila stages.

Keywords

• Kinnekulle K-bentonite
• metabentonite
• Ordovician
• Keila Stage
• Baltoscandia