John Day Fossil Beds National Monument—stratigraphy

The John Day Fossil Beds is located in north-central Oregon. It was established as a national monument in 1974. The region has one of the world's most complete records of fossils during the Age of Mammals, a period of time also known as the Cenozoic Era (past 66 million years). There will be three blog posts: (1) stratigraphy—how layers of...

Mount Hood — Oregon’s highest peak

After smoky air deterred us from backpacking locations in northern California, we headed north to Mount Hood. There, the Timberline Trail promised an interesting trek around Oregon's highest mountain (3426 m / 11,240 ft), located about 80 km (50 miles) east of Portland. Mount Hood is the northernmost Cascade Range volcano in Oregon. See my post about Crater Lake for...

The geology of Yellowstone National Park, and its precursors in Oregon and Idaho

Yellowstone has the distinction of being the first national park in the U.S., and probably in the world. President Ulysses S. Grant signed the bill to protect more than one million acres—mostly in Wyoming—in 1872. Yellowstone was set aside because of its hydrothermal displays—the park contains more than 10,000 features, including the world’s greatest concentration of geysers, hot springs, mud...

South Sister—the third highest volcano in Oregon and one of its youngest

The Three Sisters volcanoes, located in the Three Sisters Wilderness west of Bend, Oregon, are part of the Cascade Range of volcanoes formed above the Cascadia subduction zone. "For magnificence of glacial scenery, for wealth of recent lavas, and for graphic examples of dissected volcanoes, no part of this range surpasses the area embracing the Sisters and McKenzie Pass", said...

Lassen Volcanic National Park—the southernmost Cascade Range volcano

The Cascadia Subduction zone extends along the entire coast of Washington and Oregon, but also along the northern coast of California. South of Mendocino, California, the plates change from converging with each other (the ocean plate loses and slides beneath the continental plate in the subduction zone) to sliding past each other along the San Andreas fault (a transform-type plate...

The Rogue Valley region in SW Oregon: displaying 300 million years of geologic time

Typically, I post blogs when traveling away from my home in Ashland, Oregon. But with COVID-19 keeping us all at home, it seems a good time to investigate the landscape of my local region. Ashland is a tourist town best known as the home of the Oregon Shakespeare Festival (OSF), an eight-month season of 11 plays—four by Shakespeare and seven...

Craters of the Moon National Monument—a little bit of Hawai’i in Idaho

If you ignore the arid climate and sagebrush vegetation in the Snake River Plain of Idaho, and just look at the landscape of lava, you can imagine yourself on the Big Island of Hawai'i. This photograph shows basalt-type lava in pahoe'oe and a'a flows, with cinder cones in the background. The area is still considered to be volcanically active, with...

Human interactions with the Lava Beds landscape

The Modoc group of Native Americans have lived in the region that is now the Lava Beds National Monument for thousands of years. They left little imprint on the land, but they did leave some rock art that is interesting to examine. Two caves—Big Painted Cave and Symbol Bridge Cave—contain pictographs that are painted onto the rocks with a charcoal-based...

Lava lava everywhere—Lava Beds National Monument, NW California

I've said there are just two Cascade Range volcanoes in California—Mt. Lassen and Mt. Shasta. But there is a third called Medicine Lake Volcano, as shown on the map below (from https://en.wikipedia.org/wiki/Cascade_Volcanoes). Lava Beds National Monument is located just north of the volcano, where numerous flows have completely covered the landscape during the past 500,000 years. Because it is a...

Climbing Mount McLoughlin—one of the lesser known Cascade volcanoes

Mount McLoughlin is located 63 kilometers (38 miles) east of Ashland, Oregon, where I now live. As shown on this map by the U.S. Geological Survey, Mount McLoughlin is located between the volcanoes of Mount Shasta and Crater Lake, which is the remnant of Mount Mazama that exploded to become a caldera 7,700 years ago. All of the Cascade Range...

Volcanoes past and present

The lake district is in the northwestern part of Patagonia, where the landscape has changed somewhat. In Argentina, the lakes are still on the dry side of the Andes, but the country border here jogs a little westward to capture more of the cordillera with its mountains and green forests. The nothofagus is still here—southern beech tree that evolved when...

About the Blogger

Karen (here with Mt. Shasta in background) is a geology professor emerita who aims to provide a "pocket geologist" for world travelers. Follow the blog to explore the landscapes of our planet and figure out what causes them to look the way they do.

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