Extent of Pliocene hyaloclastic deposits and related lava flows in the Columbia Gorge, Oregon and Washington
This dataset contains polygons representing deposits of hyaloclastic debris that were generated between about 3.5 and 3.0 million years ago when a series of basaltic lava flows entered the canyon of the ancestral Columbia River. The lava flows were erupted from volcanoes in the area of the Hood River graben of …