Resumen de El circo de Las Cañadas y sus dependencias
Enough information has been obtained to delineate the series of volcanic rocks and the tectonic and erosive phenomenons which have originated the Cirque of theCañadasand its dependencies from the investigation of the geological structures crossed by horizontal galieries arilled in the slopes of Tenerife island in order to find underground water. The author has studied about 100 kilometres of a total of 800 of galleries drilled, principally around the volvanic shield which forms the central body of the island. The cronologic order of the volcanic, tectonic and erosive phe- nomenons can be established as follow: Existence of a block of basalts with salic boss which were laying on a base pre-Tertiary era of green rooks, diabases, nepheline syenites; explosions which reduced to debrises the central body of the island; three series of oe volcanic rocks, phanolites, bassalts and new phonolites are su- perposed on these debrises; in the central body of the island a long period of volcanic tranquility allows the formation of a great erosiveCaldera,Las Canadas; new basaltic series defill the erosivecalderato great extent; unstable masses of the slopes of the island slip over the old debrises soacked in the underground water and they gaveorigento the Orotava and Gilimar valleys; in the middle of theCalderaand on theserieof basalts, the trachy-phonolotic erptions took place and formed the volcanic complex of the Picas of Teide and Viejo. At the present a new basaltic phase has been initiated.
This investigation is considered as preliminary.
