Palaeomagnetism of the Guaniguanico Cordillera, western Cuba: a pilot study

A palaeo- and rock-magnetic study was carried out on the Jurassic-Cretaceous Guaniguanico Cordillera (15 sites, 112 oriented cores) in order to define a preliminary magnetos tratigraphy and to obtain some constraints on the tectonic evolution of western Cuba. Rock-magnetic experiments indicate Ti-poor titanomagnetites as principal remanence carriers. Two magnetic phases seem to be present in a few samples: some spinels, which saturate at moderate magnetic fields and goethite, with higher coercivity. The presence of hematite (or mixture of spinels and hematite) is apparent in two units. In most cases the characteristic palaeodirections could be determined above 300degreesC. Eleven sites yield normal magnetic polarity and four reverse. The polarity zones can be tentatively correlated to chrons CM29-C24 in the reference geomagnetic polarity time scale. The mean palaeodirection calculated from all sites is Dm=335.7degrees, Im=43.1degrees, k=11, alpha(95)=12.3 and N=15. The corresponding palaeopole is Plat=66.4degrees, Plong=205.8degrees, K=13, and A(95),=11.1. This pole is not significantly different from North American Jurassic-Cretaceous poles. This suggests that no major latitudinal displacements and deformation have occurred since the Jurassic, in contrast to some previously proposed tectonic models. (C) 2001 Academic Press.