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Published byColleen Woodell Modified over 9 years ago
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32. Flood basalts Dan Barker April 2009 Creag Mhor, Isle of Mull, Scotland
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About 55 million years ago, while the North Atlantic opened up, enormous outpourings of basalt lava covered western Scotland, Northern Ireland, and eastern Greenland. Creaga Ghaill, Mull.
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Thick stacks of lava flows built up in a few million years. Most flood basalts erupt from long fissure systems, not from a central vent. Bearraich. Mull
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Floddigarry, Isle of Skye
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Struan, Isle of Skye
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The same thing happened in NE Africa, starting about 40 million years ago. 89 km south of Asmara, Eritrea
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The Simien Mountains, Ethiopia, are a spectacular remnant of these flood basalts.
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Wrangellia Basalts, Vancouver Island, BC, formed 230 million years ago on an oceanic plateau in the SW Pacific, before colliding with North America.
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Another view of the Wrangellia Basalts,Vancouver Island, BC
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North America's youngest flood basalts cover about half of Washington State. Columbia River Basalts, Snake River.
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Eruption of the Columbia River Basalts, WA, peaked about 16 million years ago, and 95% of the volume erupted in less than 1 million years.
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Many Columbia River Basalt flows show prismatic joints, from interactions with surface water. Palouse River WA
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There was enough time between flows for thick soils to develop. From Wishram Heights WA
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The Dalles WA
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Wanapum Basalt at the Dalles
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Columbia River Basalts warped by an anticline, WA
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