Publication: Geología y estructura del Arco de Taganana (Tenerife, Canarias)
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Publication Date
1996
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Sociedad Geológica de España
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Abstract
En este trabajo se presenta la cartografía geológica del Arco de Taganana (localizado al N del macizo de Anaga, Tenerife) y se estudian sus características estructurales. Está formado por un complejo filoniano antiguo, que atraviesa a materiales de tipo aglomerático y de tipo masivo. Discordantemente y relacionados con diques y domos más recientes, se apoyan depósitos piroclásticos, coladas basálticas y aglomerados sálicos. La edad mínima de los materiales más antiguos se sitúa en torno al Mioceno medio-superior, aunque podrían ser anteriores al Mioceno medio. Los diques más recientes, son tanto de composición basáltica como de composición sálico-intermedia. Los basálticos presentan una dirección dominante E-W, verticales y los diques sálico-intermedios una orientación entre N700-N800E, subverticales. El complejo filoniano más antiguo muestra en conjunto una orientación NE-SW (entre N400-N600E), con buzamientos de 60°-80° al SE. Sobre la base de la observación de las deformaciones de los diques en el campo y la existencia de brechas miloníticas, se propone un basculamiento pre-Serie 1 Media del conjunto de diques más antiguos, por arrastre debido a una fractura mayor supuestamente localizada al N de Anaga, para explicar el actual buzamiento al SE del complejo filoniano antiguo
The geological map and the structural features ofthe «Arco deTaganana» (Northern Anaga, Tenerife) are the main subjects ofthis papero It is formed by an old dyke-swarm which cut breccias and massive materials. Separated by an unconformity and overlying these rocks, there are pyrocIastic 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 N700-N800E strike, with vertical dip, for the most abundant salic dikes and an EW strike for the basaltic ones. The old dyke-swarm shows a main strike comprised between N40° to N600E, with a 60° to 80° SE dip. Most of dykes are forrned 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 ofTaganana 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.
The geological map and the structural features ofthe «Arco deTaganana» (Northern Anaga, Tenerife) are the main subjects ofthis papero It is formed by an old dyke-swarm which cut breccias and massive materials. Separated by an unconformity and overlying these rocks, there are pyrocIastic 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 N700-N800E strike, with vertical dip, for the most abundant salic dikes and an EW strike for the basaltic ones. The old dyke-swarm shows a main strike comprised between N40° to N600E, with a 60° to 80° SE dip. Most of dykes are forrned 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 ofTaganana 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.