Phantom Ship Rock On foggy days or in low light conditions, this series of rocks that stick up out of Oregon’s Crater Lake give the appearance of being a wooden sailing ship, leading to its name. Crater lake sits in a Caldera at the center of Mount Mazama, formed 7000 years ago when the volcano underwent a huge eruption and the peak collapsed downward into the emptied magma chamber. Like all the other rocks you see, Phantom Ship Rock is made of igneous rocks; in this case, andesitic lavas. The lava in this structure is about 400,000 years old, predating the cataclysmic eruption by several hundred thousand years. Therefore, these rocks survived the giant eruption without being too heavily damaged, but they were exposed. The vertical “pipe” like pattern is a result of hydrothermal processes. During the volcano’s long lifetime, there have been many times when it wasn’t erupting, but when hot water was circulating through older volcanic rocks. Hot water flowing through these rocks led to the growth of new minerals, hardening them against erosion and creating the pattern that now plays tricks on our eyes. -JBB Image credit: Barb Mayer http://www.flickr.com/photos/11902536@N02/3939492962/ Science: http://pubs.usgs.gov/dds/dds-72/site/phant.htm http://www.learnnc.org/lp/multimedia/10570