Isla San Luis
Mexico /
Baja California /
San Felipe /
World
/ Mexico
/ Baja California
/ San Felipe
World / Mexico / Baja California
island, volcano
Southernmost of the five Islas Las Encantadas. The summit elevation 180 m. Tuff cone.
It is one of the most recent eruptive centers in the Gulf of California, presents a complete magma evolution trend from basaltic andesites to rhyolites. The less-evolved lavas are palagonite tuffs, related to Surtseyan-type activity which characterized the emergent stage of the island. Subaerial lava flows and later high-energy hydromagmatic eruptions are dacites which make up the tuff rings of the southeastern corner of the island. Rhyolites are the latest erupted products and the development of the younger dome in the centre of the island was preceded by ash and pumice fallout containing quenched bombs with an obsidian crust and a pumiceous core. Basaltic andesites contain olivine (Fo87–80), calcium-rich plagioclase and sparse clinopyroxene microphenocrysts; the typical mineralogy of dacitic and rhyolitic lavas is plagioclase+two-pyroxenes. Major and trace elements vary regularly with MgO taken as a differentiation index. Isla San Luis lavas are enriched in LILE and depleted in Nb, Ta and Ti. Their characteristics are intermediate between tholeiitic and calc-alkaline lavas. They are also LREE enriched and the [(La/Yb)n] ratios steepen slightly with differentiation. Such an evolution is better explained by combined fractional crystallization and assimilation processes.
It is one of the most recent eruptive centers in the Gulf of California, presents a complete magma evolution trend from basaltic andesites to rhyolites. The less-evolved lavas are palagonite tuffs, related to Surtseyan-type activity which characterized the emergent stage of the island. Subaerial lava flows and later high-energy hydromagmatic eruptions are dacites which make up the tuff rings of the southeastern corner of the island. Rhyolites are the latest erupted products and the development of the younger dome in the centre of the island was preceded by ash and pumice fallout containing quenched bombs with an obsidian crust and a pumiceous core. Basaltic andesites contain olivine (Fo87–80), calcium-rich plagioclase and sparse clinopyroxene microphenocrysts; the typical mineralogy of dacitic and rhyolitic lavas is plagioclase+two-pyroxenes. Major and trace elements vary regularly with MgO taken as a differentiation index. Isla San Luis lavas are enriched in LILE and depleted in Nb, Ta and Ti. Their characteristics are intermediate between tholeiitic and calc-alkaline lavas. They are also LREE enriched and the [(La/Yb)n] ratios steepen slightly with differentiation. Such an evolution is better explained by combined fractional crystallization and assimilation processes.
Wikipedia article: http://es.wikipedia.org/wiki/Golfo_de_California
Nearby cities:
Coordinates: 29°58'11"N 114°24'28"W
- Isla Ángel de la Guarda 91 km
- Cedros Island 200 km
- Montague Island 209 km
- Isla Guadalupe 393 km
- San Clemente Island 525 km
- Santa Catalina Island 557 km
- Santa Cruz Island 693 km
- Santa Rosa Island 713 km
- Grand Island 1143 km
- Silver Island 1232 km
- San Luis Gonzaga Bay 23 km
- gonzaga bay 27 km
- Sea of Cortez / Gulf of California 51 km
- Punta San Fermin 62 km
- Llanura San Fermin 82 km
- Nuevo Mazatlan (Agua de Chale) 89 km
- Santa Maria Bay 91 km
- Sulfur Mine 'El Apache' 91 km
- Alluvial Fan 105 km
- Sierra de San Pedro Mártir National Park 157 km
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