The Volkhov–Kunda transition and the base of the Holen Limestone at Kinnekulle, Västergötland, Sweden

Abstract

The transition between the Volkhov and Kunda Baltoscandian stages (Darriwilian, Middle Ordovician) is associated with a notable sea-level fall. This study documents the lithologic and sedimentologic expression of this event in the “orthoceratite limestone” at the Hällekis quarry, Kinnekulle, Sweden. The uppermost Volkhov strata are characterized by abundant limonitic hardgrounds and relatively coarse carbonate textures, including intraclasts and ferruginous coated grains. The top of a conspicuous wacke-packstone interval is identified as the local Volkhov–Kunda and Lanna Limestone–Holen Limestone boundary. The boundary is overlain by marly limestone, in which limonitic hardgrounds become uncommon and a temporary fining of carbonate textures occurs. An overall trend of increasing (mainly skeletal) grain concentration and diversity is seen throughout the studied succession. Based on the collective observations, a sea-level curve for the upper Volkhov and lower Kunda is presented.

Keywords::

• Kinnekulle
• Lanna Limestone
• Holen Limestone
• carbonate sedimentology
• Volkhov
• Kunda

Acknowledgements

This study was funded by the Johan Christian Moberg travel scholarship fund and the Royal Physiographic Society in Lund. Anders Lindahl is thanked for generously allowing access to thin-section production facilities. Ingvor and Åke Pettersson are thanked for providing transport possibilities to Kinnekulle in April 2013, and Iris Lindskog is thanked for enabling the associated fieldwork. Stig M. Bergström, Arne Thorshøj Nielsen and an anonymous reviewer are thanked for valuable comments on the manuscript. This paper is a contribution to IGCP 591 – “The Early to Middle Paleozoic Revolution”.