La Breña - El Jaguëy Maar Complex

The La Breña - El Jaguëy Maar Complex belongs to the Durango Volcanic Field, Durango, Mexico consisting of two near-circular intersecting maars: the larger La Breña maar composing the bulk of the complex with the smaller El Jaguëy maar overlapping the north-eastern quadrant of the former. The complex is located at the north-western corner of the Meseta Central, near the boundary of the Sierra Madre Occidental. La Breña is 1400 m in diameter, with remnants of spatter and lava cones reaching up to 2040 m elevation, whereas El Jaguëy has a diameter of ~700 m with an inclined cone shape. Volcanic rocks in both maars contain 4.9-9.7% normative nepheline and are mostly basanites, with some classifying as hawaiites. Xenoliths are found within vents and flows of both mantle (spinel-lherzolite) and lower-crustal (felsic orthogneiss) origin, with the former up to 30 cm in diameter indicating rapid ascension to the surface from great depth. Stratigraphy of eruptive sequences indicates a transition from phreatic to strombolian activity. A genetic model for the complex can be found in Aranda-Gómez et al. (1992) and geochemical data including whole rock major and trace element, radiogenic isotopic, and mineral chemical can be found in Pier et al. (1992).