Volcanic evolution of the Pacific Northwest: 55 million year history

Active volcanoes in the Pacific Northwest result from a varied tectonic setting. Ocean-ridge rifting produces submarine volcanism offshore. Northwest subduction of the young Juan de Fuca Plate creates the arc of Cascades volcanoes. Hot-spot volcanism drives the Yellowstone caldera system. Continental extension plus a northward migrating triple junction add to the complex volcanic history. To look at the development of volcanism in the Pacific Northwest we will go back 55 million years to a time prior to stretching of the continent by Basin-and-Range extension and when Mesozoic subduction, compression, and crustal thickening had waned. At the end of the Cretaceous, […]

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Mars’ Largest Volcano – Olympus Mons

This is Mars. Three billion years ago it had active volcanoes. One still remains, the largest volcano in the solar system. The cliffs leading to it are over nine kilometers high. Mt. Everest would sit comfortably in their shadow and those are just the foothills. This is the awe-inspiring Olympus Mons. It covers an area the size of Arizona. Its crater alone is 85 kilometers wide. Yet a structure this size would require millions of years to form, time that volcanoes on Earth never get. On Earth, the crust is always moving. Deep below a single hot spot pushes magma […]

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