What is so special about the Cascade-Siskiyou National Monument?

This national monument spans the border between Oregon (Jackson County) and California (Siskiyou County) immediately east of the I-5 freeway. It was first established in 2000 by President Bill Clinton and expanded in January 2017 by President Obama as one of his last actions before leaving office. The monument is managed by the Bureau of Land Management (BLM) from the...

The Great American Biotic Interchange

With its many excellent fossil sites, Argentina has lots of evidence for how life evolved through time. One of the largest effects on how organisms evolved was the position of the continents. For example, when the continents were united into the "super continent" called Pangea at the end of the Paleozoic, land animals could migrate for huge distances. In contrast,...

Earthquakes tell the story of changing tectonic plates along the Andes

We are now in Córdoba city (capital of the province of Córdoba), which is nearly 600 km (360 miles) east of the Cordillera Principal (high Andes). To the east of Córdoba are the flat plains of the pampa; to the west are the Sierras de Córdoba that, together with the other ranges lying eastward of the Cordillera Principal, are referred...

Argentina—a paradise for fossils of dinosaurs and proto-mammals

We visited Parque (park) Ischigualasto, which means "the place animals go to die" in the local indigenous language. The native people saw many bones in the region, which was the reason for this name. Later, of course, these bones were recognized as animals that have long been extinct. We also visited the Museo de Ciencias Naturales (museum of natural sciences)...

The second highest mountain range in the world—and still rising

After the Himalayas, the Andes Mountains are the second highest range in the world—but you have to go to the right place. Many parts of the Andes are beautiful but have elevations more similar to other, relatively low-elevation subduction-zone ranges like the Cascades in the Pacific NW (USA). But at 6964 meters (22,841 feet), Alconcagua is the highest peak in...

Climate, culture and history of the Quebrada de Humahuaca

Because the Quebrada de Humahuaca is such a long north-south valley with readily available water from the river (Rio Grande) that cut it, it has been a well-used route connecting Peru, Bolivia and Argentina for thousands of years. The region was also important in the revolution for independence from Spain (1810). To the west, the highest part of the Andes,...

La Quebrada de Humahuaca—colorful landscape in NW Argentina

A quebrada is a valley or canyon formed by the action of flowing water. The Quebrada de Humahuaca is located in the northwesternmost corner of Argentina, on the eastern side of the Andes, where active uplift of the land has caused rivers to cut down and create quebradas of many sizes and shapes, resulting in a stunning landscapes of shear...

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...

Pyla dune—the highest sand dune in Europe

The last three posts touched on how the landscape of Bordeaux affects wine characteristics. But there are landscape features that are just fun for their own sake. Billed as the highest dune in Europe, we had to visit Pyla Dune, a geologic feature along the Atlantic coast south of Arcachon, a popular seaside that is an easy 52-minute train ride...

Biking between two rivers—the Entre-Deux-Mers region

The Entre-Deux-Mers region is located between the Garonne and Dordogne Rivers that feed into the Gironde estuary. The name, though, is "between two seas" or "between two tides" because the rivers have a tidal influence. The Gironde has a large tidal range and during the largest tides, a tidal bore (single wave) will move upstream in the rivers. One of...

The terroir of Saint Emilion

The terroir of the Saint Emilion AOC (see roundish purple region on the Right Bank in previous post) differs from that of the Médoc (of course). The climate has less of a maritime influence, and the limestone bedrock is close to the surface, with only thin, mostly clay-rich soils. We visited just one Chateau—Troplong Modot. Notice that the rocks in this...

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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