The first reefal episode (Earliest Plagian) in the Cantabrian Zone (NW Spain) and its relationship with the Lochkovian-Pragian Boundary Event

Abstract

In the Cantabrian Zone (NW Spain), as in other North Gondwanan regions, the first Devonian stage of reef development (just a few metres above the Lochkovian-Pragian boundary) is of minor importance and it is represented by small biostromal patches composed of branching rugose corals (disphyllids), branching tabulate corals (thamnoporids) and laminar to tabular, sometimes domical, strornatoporoids (coenostromatids, labechiids, atelodictyids, actinostromatids) and tabulate corals (favositids, micheliniids). These biostromal units are located in the middle part (Mernber C) of the Lebanza formation (Palencia province: Palentine Domain, SE Cantabrian Zone) and in the upper part or the Nieva formation (Asturias province: Asturo-Leonese Domain, N Cantabrian Zone).