Isla Isabel Volcano, Mexico
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Isla Isabel Volcano, Mexico
A sea-cliff exposure at the southern end of Islota Pelon, located off the NW coast of Isla Isabel, shows a dramatic angular uncomformity between two generations of dipping tuff beds.
The large volcanic bomb perched on the rim at the top lies on dipping tuff beds in the interior of the tuff cone.
Wave erosion has left only the arcuate western rim of Islota Pelon, whose vent lies out of view to the right.
Buildings of a biological research station and fishermen's shacks line the shores of Playa Chica on the SE side of Isla Isabel.
The two spires at the upper left are the Islotes Las Monas, eroded remnants of an offshore tuff cone.
The lake-filled Laguna Fragatas maar can be seen at the left in front of the spires of the Islotes Las Monas.
The small 1.5-km-wide uninhabited Isla Isabel is a wildlife sanctuary.
Eruptive activity at Isla Isabel may have continued into the Holocene.
Isla Isabel, a complex of tuff cones and associated lava flows, forms a small 1.5-km-long island located in the Pacific Ocean 30 km off the coast of Narayit state, NW of the city of Tepic.
Despite its apparent location at the western end of the Mexican Volcanic Belt, Isla Isabel consists of alkaline basaltic rocks and tephra similar to those of other Mexican island volcanoes and in the Northern Mexican Extensional Province.
The island is a wildlife sanctuary whose rocks and vegetation are mantled with guano.
Spectacular exposures of the interior of the tuff cones forming the island can be found in sea cliffs of the main island and offshore islets.
The age of the most recent eruptive activity is not known, but morphology and a negative Argon-Argon age from a young sample suggests activity may have continued into the Holocene.
One youthful-looking unvegetated lava flow of unknown age is located on the NW side of the island.
Flat-topped Cerro El Faro tuff cone (upper right) lies across a low isthmus at the southernmost tip of Isla Isabel.
It is seen here across the Acantilado Mayor Bay from Cerro del Mirador, the high point of the small 1.5-km-long island.
Wave erosion has truncated the flank of Monte Transverso on the left.
An olivine-basaltic lava flow forms the flat isthmus connecting the two tuff cones.
Islota Pelón (upper left), just off the NW coast of Isla Isabel, is the outer rim of an elliptical, mostly submerged tuff cone whose SE rim (center) is located on the tip of the main island.
The poorly distinguishable narrow dark gray streak extending diagonally from the lower right is part of the Planicie lava flow, which extends to the bay at the center of the photo and is the product of the youngest eruption on Isla Isabel.
PHOTO SOURCE: Kim Luhr 1999, courtesy of the Global Volcanism Program, Smithsonian National Museum of Natural History, used with permission.
NOTE: The information regarding Volcano on this page is re-published from other sources. No claims are made regarding the accuracy of Volcano information contained here. All suggestions for corrections of any errors about Volcano photos should be addressed to the copyright owner noted below the photo.
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This page was last modified 16-Jul-2015, Copyright © 1995-2015 ITA all rights reserved.