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Richards 1966

Richards, A.F. (1966). Geology of the Islas Revillagigedo, Mexico; [Part] 2, Geology and petrography of Isla San Benedicto. Proceedings of the California Academy of Sciences 33(12): 361-414.

San Benedicto lies at the intersection of four local ridges thought to be fissures where the Clarion fracture zone crosses a range of submarine volcanoes. Compared to others of the Revillagigedo archipelago, its very narrow insular shelf is poorly developed. Principal landforms are large eroded trachytic domes older than late Pleistocene, and two pyroclastic volcanoes of recent origin. The trachybasalt and trachyandesite flows on the island and northward offshore submarine ridge, and accessory sodic rhyolite ejecta from Volcan Barcena, 1952-53, are described. The increasing age and decreasing quantity of silicic lavas and active volcanism from east to west in the Revillagigedos appear related to convection under the East Pacific Rise, accounting for similarity of sodic rhyolites found on San Benedicto and elsewhere in the Pacific Basin.

Keywords
Clarion fracture zone, East Pacific, geologic, igneous rocks, Isla San, Benedicto, Isla San Benedicto and submarine ridges, maps, marine, geology, Mexico, North Pacific, Northeast Pacific, off Mexico, Pacific, Ocean, petrology, Revillagigedo archipelago, structural geology, volcanic ridges, volcanic rocks, volcanoes, volcanology, 05 Igneous and metamorphic petrology, 07 Oceanography, 16 Structural, geology

Journal
Proceedings of the California Academy of Sciences