The Late Ordovician–Silurian succession in the Marimanha Massif, central Pyrenees, Spain, and comments on the frst the occurrence of the conodont Kockelella walliseri in North Gondwana

Abstract

Purpose The study of the Upper Ordovician to Silurian stratigraphic succession in the metamorphic rocks of the Marimanha Massif (central Pyrenees) includes a regional pre-Upper Ordovician unconformity, a locally described pre-Hirnantian unconformity and a pre-Wenlock, Silurian hiatus. Silurian metamorphic carbonates correspond to a condensed succession that comprises pelmatozoan and cephalopod-bearing marbles, with reduced siliciclastic input. The occurrence of Silurian condensed carbonate succession is unusual in the deep-water anoxic shale sedimentation with mainly pelagic faunas observed in the northern margin of the central part of Gondwana. Methods The present study includes 6 stratigraphic sections and 8 samples with poorly preserved Silurian conodont among 30 collected samples. Results Marbles yield Sheinwoodian (Wenlock) conodonts such as Kockelella cf. corpulenta, K. ortus, K. ranuliformis and K. walliseri, and the Ludlow K. cf. variabilis. The occurrence of K. walliseri is the frst record in the southern Europe and North Africa. This species was described from shallow-water facies in low latitudes of Laurentia, Baltica and eastern Gondwana. Conclusions The Upper Ordovician to Silurian sedimentary gaps in the studied succession are relate to the Late Ordovician rifting and the Hirnantian glaciation described in north Gondwana. Wenlock carbonate sedimentation occurred in a local shallow-water topographic palaeo-high. Conodont content suggest relatively shallow and warm water environment and a moderate to low latitude location in relation to the Silurian northward drift of areas derived from the Gondwanan margin as the Pyrenees.