GEOCHEMISTRY AND U-PB ZIRCON AGE OF THE INTERNAL OSSA-MORENA ZONE OPHIOLITE SEQUENCES: A REMNANT OF RHEIC OCEAN IN SW IBERIA

• DOI: 10.4454/ofioliti.v35i2.390
• Publication Date: 2010-01-03
• Authors: Jorge Pedro; Alexandre Araújo; Paulo E. Fonseca; Colombo Celso Gae...; A. Ribeiro
• Keywords: SW Iberia; Rheic Ocean; Ophiolite; Ossa-Morena Zone; Lower Ordovician

The Early Paleozoic geodynamic evolution in SW Iberia is believed to have been dominated by the opening of Rheic Ocean. Ocean generally accepted resulted from drift peri-Gondwanan terranes such as Avalonia northern margin Gondwana during Late CambrianEarly Ordovician times. closure was final result a continent-continent collision between and Laurussia that produced Variscan orogen. Ossa-Morena Zone peri-Gondwana terrane, which preserves spread fragments ophiolites - Internal Zones Ophiolite Sequences (IOMZOS). patchwork IOMZOS shows complete oceanic lithospheric sequence with geochemical characteristics similar ocean-floor basalts, without any orogenic fingerprint and/or crustal contamination. were obducted imbricated high pressure lithologies. Based on structural, petrological whole-rock data, authors argue represent lithosphere Zircon SHRIMP U-Pb geochronological data metagabbros point an age ca. 480 Ma for IOMZOS, providing evidence well-developed ocean this period, reinforcing interpretation wide among