Natural Monument of the Volcano of Cancarix, Spain: A Case of Lamproite Phreatomagmatic Volcanism

Abstract

The Natural Monument of the Volcano of Cancarix (south Spain) is of great scientific interest due to the particular lamproitic nature of the geological materials that constitute it. The Cancarix volcano and similar lamproite volcanoes in the southeastern parts of the Iberian Peninsula were emplaced during the Miocene in connection with transtensive structures at the north end of the Betic Cordillera. These structures reactivated older basement faults, which facilitated the ascending circulation of highly enriched Mg–K magma. Two episodes of material emission can be distinguished: (1) explosive volcanism due to the interaction between magma and groundwater from the karstic system of the host carbonate rocks, generating a phreatomagmatic complex as the final product (breccias and lavas); and (2) effusive volcanic activity with crystal-rich magma responsible for the lamproitic body. The tectonic structure, the main features of the phreatomagmatic ring, and the vertical columnar jointing at the edge of the volcanic constitute a wide spectrum of geological phenomena that justify its educational scientific value and its protection as a Natural Monument. Two geotrails present this natural space not only as an interpretive resource but also as an instructive reference for the conservation of a valuable part of Spain’s geological heritage. Further, the remarkable exhibition of materials along the two geotrails provides an excellent framework for promoting geology at different levels of knowledge.