Aportaciones a la geoquímica de rocas básicas cámbricas de la Antiforma de Monesterio (zona de Ossa-Morena)

Abstract

Basic volcanic and subvolcanic rocks have been geochemically studied to provide new evidence for the location of the axis of the Cambrian rift of the Ossa-Morena Zone. The results of the analysis of various subvolcanic gabbros point to the location proposed by Giese and Bühn (7993), who studied lava-flows of a traverse of the Ossa-Morena Zone. This study has shown that gabbros of the northern limb of the Monesterio Antiform show an alkaline character, whereas those of the southern limb are clearly more subalkaline, showing MORB or volcanic-arc characteristics. Basic volcanics of the northern limb and some of the southern limb plot on within-plate environments, whereas those on the southernmost studied sector show a plate-margin emplacement enviroment. Finally, lava-flows and gabbros from the northern limb show an alkaline-transitional within-plate basalt character, those of the Jerez de los Caballeros sector indicate an alcaline or tholeiitic within-plate and MORB nature and those of the Lora del Rio area show a MORB or volcanic-arc nature