Monday, May 10, 2010

Having a Blast in the Fort Rock Basin - Part 1, Hole-in-the-Ground


Last summer we took a drive through the beautiful Fort Rock Basin located in Central Oregon's Lake County to investigate its interesting volcanic topography. Home to a massive pluvial lake from as early as 50,000 to 100,000 years ago, this once-highly seismic area is a great place to observe the dramatic effects of some of nature's most primal forces.  

The first stop along our route brought us to a large maar known as "Hole-in-the-Ground".  After driving through the Cascade mountain range to get to Lake County, it would be easy to dismiss a "small" rise in the landscape of a mere 110 feet (210 on its highest side) and surrounded by towering Ponderosa pines, it might be possible to miss it entirely.  However, upon cresting the rise and seeing the nearly mile-diameter crater in front of you, its sides sloping away steeply to the basin roughly 600 feet below, the importance of what you're standing on begins to leave an impression.

From Wikipedia: The crater formed during the late Pleistocene, between 13,500 and 18,000 years ago, at which time the Fort Rock Basin was a lake and the location was near the shore. Basaltic magma intruding near the surface flashed ground water to steam, which blew out overlying rock and soil, along with some juvenile material. As material slid into the hole formed, it closed the vent and the process repeated, eventually forming the huge hole

A hole in Hole-in-the-Ground

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