Chitinozoan biostratigraphy in the Dob's Linn Ordovician-Silurian GSSP, Southern Uplands, Scotland

Abstract

The Dob's Linn section has recently been confirmed as the Global Stratotype Section and Point (GSSP) for the Ordovician-Silurian boundary. Within the framework of the present study, the Dob's Linn sections yielded, for the first time, chitinozoans with biostratigraphical and correlative value. In the North Cliff trench, the Armoricochitina reticulifera Biozone has been recognised, allowing correlation with the Newport Sands section of the Cardigan area in Wales, which has good graptolite control. In the GSSP trench around the Ordovician—Silurian boundary, a fauna dominated by Cyathochitina and Ancyrochitina spp. has been recovered; the chitinozoans were in ascending order attributed to the Ancyrochitina ellisbayensis, Ancyrochitina laevaensis and Belonechitina ?postrobusta biozones, allowing correlation with several other sections in Laurentia (Ellis Bay) and Baltica, and the global chitinozoan biozonation for the Silurian System.