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Country: | México | |
| Subregion Name: | México | ||
| Volcano Number: | 1401-003 | ||
| Volcano Type: | Tuff cone | ||
| Volcano Status: | Holocene | ||
| Last Known Eruption: | Unknown | ||
| Summit Elevation: | 180? m | 591 feet | |
| Latitude: | 29.97°N | 29°58'0"N | |
| Longitude: | 114.40°W | 114°24'0"W | |
| Isla San Luis is the largest of the seven Encantada islands at the NW end of the Guaymas lineament in the northern part of the Gulf of California. The roughly 180-m-high island (also known as La Encantada Mayor, or Salvatierra) is located 3 km off the eastern shore of Baja California north of Punta Bufeo. The small 4.5 sq km island has an irregular shoreline with a narrow peninsula forming its SW tip. Initial basaltic-andesite and andesitic submarine surtseyan eruptions producing palagonite tuffs were followed by the effusion of subaerial dacitic lava flows and the formation of dacitic tuff rings. The latest eruptions formed two rhyolitic obsidian domes, the younger in a tuff cone at the center of the island and at the older at the NW tip of the island. Although the age of the domes is not known precisely, Medina et al. (1989) suggested that they could be less than a century old. | |||
