December 14, 2012 – CALIFORNIA – Scientists have discovered one of the world’s weirdest volcanoes on the seafloor near the tip of Baja, Mexico. The petite dome — about 165 feet tall (50 meters) and 4,000 feet long by 1,640 feet wide (1,200 m by 500 m) — lies along the Alarcón Rise, a seafloor-spreading center. Tectonic forces are tearing the Earth’s crust apart at the spreading center, creating a long rift where magma oozes toward the surface, cools and forms new ocean crust. Circling the planet like baseball seams, seafloor-spreading centers (also called mid-ocean ridges) produce copious amounts of basalt, a low-silica content lava rock that makes up the ocean crust. But samples from the newly discovered volcano are strangely rhyolite lava, and have the highest silica content (up to 77 percent) of any rocks collected from a mid-ocean ridge, said Brian Dreyer, a geochemist at the University of…