Ordovician geodynamics: The Sardic Phase in the Pyrenees, Mouthoumet and Montagne Noire massifs - International Meeting, September 4-9th 2017, Figueres, Catalonia. Program and Abstracts volume - Excursion guide

Foreword

The presence of a Middle-Ordovician gap punctuating the stratigraphy of southwestern Sardinia (Teichmüller, 1931; Stille, 1939) has represented during the last decades a standard for correlation in southwestern Europe and northwest Africa. Any “similar” gap stratigraphic marking the absence of Furongian (“late Cambrian”)-to-Late Ordovician fossils has been used to invoke the correlation of the Sardinian event in the Alps (e.g., Stampfli et al., 2002), the eastern Pyrenees and the Montagne Noire (this vol.). After increasing research, the correlated gaps have finally displayed different time spans, such as the Furongian virtual absence of sedimentary strata in the Moroccan Anti-Atlas (except in the El Graara massif) and the Ossa-Morena Zone of Spain (recently re-interpreted as a break-up or rift-drift unconformity and named Toledanian Phase in the Central-Iberian Zone of the Iberian Peninsula) or the lack of Dapingian (Middle Ordovician) fossil-bearing strata in the Anti-Atlas. Therefore, the “Sardic Phase” is in need of re-evaluation outside Sardinia: any correlation should be based on a multidisciplinary approach based on recognition of stratigraphic gaps, geometrical reconstruction of sedimentary bodies and onlapping features capping inherited palaeoreliefs, structural studies of deformation predating any distinct gap and geochemical analysis of contemporaneous volcanic activies.

The presence of the Sardic Phase and associated Middle Ordovician stratigraphic gaps has been reported in the Eastern Pyrenees, the Mouthoumet massif and the Cabrières klippes of the southern Montagne Noire (Catalonia and Occitanie, southwestern Europe). Late Ordovician fault-controlled subsidence and the record of rifting volcanism were coeval, in some areas, with the onset of the Hirnantian glaciation. As a result, the Upper Ordovician of SW Europe offers a complex mixture of erosive unconformities and intrusion of acidic plutons (Pyrenees), followed by the breakdown of platforms in horsts and grabens and the onset of rifting branches (Mouthoumet and Montagne Noire), onlapping patterns and final sealing of Sardic palaeotopographies during Silurian and Early Devonian times.

This meeting addresses the dynamics of Cambrian-Ordovician sedimentary basins in southwestern Europe and Northwest Africa and aims to bring together a wide range of studies focusing on geodynamics, tectonics, volcanism, sedimentary geometries, event stratigraphy and chronostratigraphic correlation. We aim to balance the study of geodynamic processes recorded throughout North Gondwana with worldwide analogues.

J. Javier Álvaro, Josep Maria Casas, Sébastien Clausen

List of participants

ÁLVARO, J. Javier. Instituto de Geociencias (CSIC-UCM), José Antonio Novais 12, 28040 Madrid, Spain

CAPDEVILA, Ramon. 48 Avenue de Bédillières, 34120 Lézignan-la-Cèbe, France

CASAS, Josep Maria. Dpt. de Dinàmica de la Terra i de l’Oceà-Institut de Recerca Geomodels, Universitat de Barcelona, Martí Franquès s/n, 08028 Barcelona, Spain

CHICHORRO, Martim. GEOBIOTEC, Departamento de Ciências da Terra, Universidade Nova de Lisboa, Portugal

CLARIANA, Pilar. Instituto Geológico y Minero de España (IGME), Ríos Rosas 23, 28003 Madrid, Spain

CLAUSEN, Sébastien. UMR 8198 EEP CNRS, Université de Lille 1, Bâtiment SN5, Avenue Paul Langevin, 59655 Villeneuve d’Ascq Cedex, France

COCCO, Fabrizio. Dipartimento di Scienze Chimiche e Geologiche, via Trentino 51, 09127 Cagliari, Italy

COLMENAR, Jorge. Earth & Planetary Systems Science Section, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Copenhagen K, Denmark

DÍAS DA SILVA, Ícaro F. Instituto Dom Luis, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Edif. C8, Piso 3, 1749-016 Lisboa, Portugal

DÍEZ-MONTES, Alejandro. Instituto Geológico y Minero de España, Azafranal 48, 1ºB, 37001 Salamanca, Spain

EGUÍLUZ, Luis. Dpto. Geodinámica, Universidad del País Vasco (UPV-EHU), Spain

GONZÁLEZ-CLAVIJO, Emilio. Instituto Geológico y Minero de España, Azafranal 48, 1ºA, 37001 Salamanca, Spain

LAUMONIER, Bernard. University of Lorraine, Nancy, France

LIESA, Montserrat. Dpt. de Mineralogia, Petrologia i Geologia aplicada, Universitat de Barcelona, Martí Franquès s/n, 08028 Barcelona, Spain

MARGALEF, Aina. Centre d’Estudis de la Neu i de la Muntanya d’Andorra, Institut d’Estudis Andorrans, Andorra

MARTÍNEZ, Francisco J. Departament de Geologia, Universitat Autònoma de Barcelona, 08193 Bellaterra. Barcelona, Spain

MINOUX, Sylvie. Groupe Français du Paléozoïque, 25 rue Oudry 75013 Paris

MONCERET, Eric. Société d’Etudes Scientifiques de l’Aude. 18 rue des Pins, 11570 Cazilhac, France

PUDDU, Claudia. Dpto de Ciencias de la Tierra, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain

QUESADA, Cecilio. Instituto Geológico y Minero de España (IGME); and Dept. Mineralogía, Univ. Complutense de Madrid, José Antonio Novais 2, 28040 Madrid, Spain

ROUSSELLE, Jacky. Groupe Français du Paléozoïque, 25 rue Oudry 75013 Paris

SÁNCHEZ-GARCÍA, Teresa. Dpto. Investigación Recursos Geológicos, Área Recursos Minerales y Geoquímica, Instituto Geológico y Minero de España, Ríos Rosas 23, 28003 Madrid, Spain

VALVERDE-VAQUERO, Pablo. Instituto Geológico y Minero de España, Ríos Rosas 23, Madrid, Spain

VIZCAÏNO, Daniel. Société d’Etudes Scientifiques de l’Aude. 7 Jean-Baptiste Chardin, Maquens, 11010 Carcassonne, France