Tortuga, Isla (Mexico)

Status Unknown Eruption Unknown 224m
Shield (Rift zone / Continental crust (> 25 km))

A youthful shield volcano forms Isla Tortuga, which lies in the Gulf of California, 40 km off the Baja coast. There is a circular, 1-km-wide caldera, west of the center of the oval 4-km-long island. Circumferential faults cut the rim of the more than 100-m-deep caldera, which is floored by a solidified lava lake and contains youthful-looking spatter cones. The volcano was constructed during two north-migrating periods of activity that began with submarine eruptions and included formation of a circular tuff-ring complex enclosing the caldera. The sides of a small volcanic horst in the center of the caldera display lava flows overlying a 2-m-thick halite bed, formed when sea water filled the caldera, creating an evaporite basin. Recent lava flows cover most of the flanks, and fumarolic activity has continued into historical time. A submarine cone with a 2-km-wide summit caldera lies about 5 km ESE of the island on the flanks of the edifice.

Isla Tortuga is 4-km-wide volcanic island located in the Gulf of California, 40 km off the coast of Baja California. The flat-topped summit of the 210-m-high shield volcano contains a 1-km-wide caldera. Recent lava flows cover much of the surface of the volcano. This 1989 view is from the west. No historical eruptions are known from Tortuga, although fumarolic activity continues.

Photo by Marjorie Summers, 1989 (Smithsonian Institution).

Last updated 2019-08-04 00:28:03