Our Beautiful Planet

Crater Lake album

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Pumice Castle at Crater Lake from the Pumice Castle viewpoint northeast of Sentinel Rock viewpoint. Next picture is a zoomed-in view from this vantage point. Image taken late July 2008. This image is 42% size of original.

Information from the park sign: Mount Mazama, the great volcano that preceded Crater Lake, was built up by successive eruptions of lava over many thousands of years. Some lavas oozed or poured from the volcano's top or sides. Some erupted as red-hot rocks that flooded down the slopes. Others exploded into the air and fell as cinders or globs.

You can see the variety of Mt Mazama's lavas on the steep caldera wall. Pumice Castle, with its pinkish-brown [? looks orange to me] "turrets," is the most eye-catching feature. It's made of layers of pumice and other rocks coughed up by Mt Mazama—some so hot they welded together. These air fall deposits were buried and compacted by other lavas, then exposed when Mt Mazama collapsed. A firm foundation of andesite lava has kept Pumice Castle intact, while surrounding pumice deposits have eroded away.

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Crater Lake album

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last updated: August 6, 2011