Abstract

The geological map of the Metropolitan Area of ​​San Salvador has been updated through field work, dating tests and review of existing bibliography at a scale of 1: 50000. This has made it possible to categorize volcanic bodies and deposits according to recent advances in lithostratigraphy and geological mapping. The geological map follows the basic lithostratigraphy of the Bálsamo, Cuscatlán and San Salvador formations. The members of the Bálsamo Formation (Upper Miocene - Pliocene) represent the remains of extensive volcanoes of andesitic/basaltic composition with lava flows and epiclastic complexes of volcanic rocks. The Cuscatlán Formation (Pliocene-Pleistocene) comprises silicic ignimbrites, tuffs, as well as related epiclastic rocks, in addition to contemporary andesitic/basaltic effusive rocks. The San Salvador Formation (Upper Pleistocene-Holocene) includes recent products from the San Salvador stratovolcano and the Ilopango caldera. Geological mapping helps to understand the best conditions for the care of natural resources and sustainability.

Keywords: geological map; lithostratigraphy; lithology; volcanic facies; tephras; tuffs; rocks