Geología y estructura del Arco de Taganana (Tenerife, Canarias)

Resumo

The geological map and the structural features of the «Arco de Taganana» (Northern Anaga, Tenerife) are the main subjects of this paper. It is formed by an old dyke-swarm which cut breccias and massive materials. Separated by an unconformity and overlying these rocks, there are pyroclastic deposits of basaltic composition, basaltic lava flows and salic breccias, all related to the emplacement of younger dykes and salic domes. New K-Ar data indicate an approximate mid.-upper Miocene age. This age must be considered as a minimum value because according to other prior data, the age of the «Arco de Taganana» could be older than mid. Miocene. Measurements from the younger dyke-swarm indicate a dominant N70°-N80°E strike, with vertical dip, for the most abundant salic dikes and an E-W strike for the basaltic ones. The old dyke-swarm shows a main strike comprised between N40° to N60ºE, with a 60° to 80° SE dip. Most of dykes are formed by basalts while the salic ones present ENE-WSW trends. Normal faults as well as breccia dykes («ghost dykes») are numerous. From these observations a mechanism to explain the structural features of the oldest dyke-swarm is considered here. It is proposed that the activity of a major fault, possibly located to the North of Taganana margin area, was the origin of the actual dip of the old dyke-swarm by a mechanism of dragging and rotating the northern side of the Anaga block before the setting of the middle Series I.