Goicoechea (canton)
Geologically, Goicoechea canton is grounded on volcanic matter dating to the Quartenary Period. Rocks from the Pleistocene epoch predominate in the region. Dating to this period, there are rolling structures located between Villa Rancho Redondo and the Purral district. Volcanic structures, recently and presently established, formed during the Holocene epoch. They are associated to pyroclastics and other volcanic matter such as lava, lahars and pyroclasts. The earliest ones are located west of the canton, originating from Villa Rancho Redondo. The later ones originate from Purral and move east.