Upper Givetian and Frasnian (Middle and Upper Devonian) conodonts from Ampriu (Aragonian Pyrenees, Spain): global correlations and palaeogeographic relations

This report describes for the first time a part of the Middle and Upper Devonian conodont sequence of the Sierra Negra Subfacies in the Aragonian Pyrenees (Spain), establishing the basis for further sound correlations both across the distinct Pyrenean facies and subfacies and on other relevant world areas. The description of 20 conodont taxa and their stratigraphical distribution permits recognition of two separate time intervals. The older one corresponds to the lower Upper Givetian (Middle Devonian), hermanni to cristatus ectypus zones. The younger interval is uppermost Lower Frasnian to lower Middle Frasnian (Upper Devonian) and is equivalent to MN4MN6 zones. The combination of litho- and conodont biofacies supports the distinction between the Sierra Negra and Renanue Subfacies. Conodont biofacies for the studied interval are partially close to the ones from the Compte Subfacies, but lithofacies are clearly different. This faunal similarity fosters accurate correlation between subfacies and stimulates further research aiming at Devonian Pyrenean basin(s) reconstruction. Additionally, this faunal sequence permits direct comparison with regions located in northern Gondwana and in the Russian platform for part of the interval. Comparison with Laurasia, mainly with the Northwest Territories of Canada and the north-western United States, is also provided. Some taxa are also common with eastern and central Asia (China, Siberia, Tadzhikistan, Afghanistan), Australia and western USA (Nevada).