IS THE MAFIC-ULTRAMAFIC MASSIF OF CABO-ORTEGAL (NORTHWEST SPAIN) A NAPPE EMPLACED DURING A VARISCAN OBDUCTION - NEW GRAVITY INTERPRETATION

Based on gravity data, the high grade igneous mafic/ultramafic rocks and metasediments at Cabo-Ortegal have recently been interpreted as a Precambrian autochthonous basement which extends far below the low-grade Paleozoic series (Van Overmeeren, 1975). The same gravity data, however, also agree with another model which is consistent with an allochthonous position of the high-grade rocks. On the basis of this new gravity model and of recent geological data (mainly the evidence of ophiolitic melanges in the low-grade Paleozoic series, the Paleozoic age of the high grade mafic/ultramafic rocks and also the general considerations about the Variscan belt), we suggest that the Cabo-Ortegal massif forms part of a large nappe emplaced during a Variscan obduction. © 1979.