Palaeomagnetic, geochronological and geological constraints on the tectonic evolution of the Mejillones Peninsula, northern Chile

Data from an Early Palaeozoic high grade metamorphic complex (Jorgina Formation) and Jurassic layered basic intrusion (Moreno Complex) are reported. 40Ar-39Ar dates from the Jorgina Formation and the Moreno Complex of between 170 and 158 Ma suggest that intrusion and magnetization of the Moreno Complex and the metamorphism and remagnetization of the Jorgina Formation were related to batholith emplacement. Stable components of magnetization from all units defined site-mean directions with a scattered distribution, interpreted as being due to minor, localized, non-uniform, block-fault related rotation after 158 Ma. No significant large-scale latitudinal translation of crustal blocks has taken place in this part of northern Chile since the Late Jurassic. Forearc wide block-fault rotation models are not applicable to the Pacific margin of northern Chile. -from Authors