Welcome to a photo tour of one of the most geologically fascinating places on Earth. Last July, 20 teachers joined planetary scientists and educators on a five-day trip through the volcanic regions of Washington and Oregon
The journey was the first part of an eight-day workshop examining the region's volcanoes and its relationship to the discoveries made on the Moon, Venus, Mars and Io. Following the field trip, the group then returned to the University of Washington where used their new knowledge to develop hands-on activities for their classrooms.
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| Mount Rainier is a large stratovolcano of andesitic rock in the Cascade Range of western Washington. Although the volcano as it now stands was almost completely formed before the last major glaciation, geologic formations record a variety of events that have occurred at the volcano in postglacial time. |
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| The 1980 eruptions of Mount St. Helens marked the re-awakening of a relatively young (40,000 years) volcano that had been dormant since 1857. Beginning in the summer of 1983, visitors have been able to drive to Windy Ridge, only four miles northeast of the crater. (USGS report) |
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| We set out across the pumice plain to see the prairie lupine that have returned to the mountain and learn what scientists have discovered about the area's recovery. |
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| Near Meta Lake we stopped to view a car damaged by the May 18 blast. The vehicle belonged to a family who were killed at their small mine, on the ridge 1 1/2 miles to the west. |
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| From the summit of Paulina Peak (7,985 ft.), we had a sweeping view of the two lakes that fill the Newberry caldera, as well as the peaks of the Cascade range. Newberry Volcanic National Monument covers more than 50,000 acres of lakes and lava flow. |
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| Newberry caldera map provided by the U.S. Forest Service. |
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| Obsidian of the lava flow, like that pictured above, contains about 73 percent silica, the same as most window glass does. In a hot, molten state, silica's atoms tend to stick together and create webs of molecules that slow down the movement of all atoms. The surface of this lava flow cooled off before its atoms had time to organize into crystals, so we are left with glass instead. (U.S. Forest Service) |
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| A new trail allowed us to explore the Big Obsidian Flow, created 1,300 years ago. The flow covers 700 acres. Obsidian was highly prized for its razar-sharp edge. The Indian name for obsidian is "Isukws" (pronounced eshookwsh). The Indian name is provided courtesy of Confederated Tribes of the Warm Springs Reservation of Oregon. (U.S. Forest Service) |
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| Pumice is so light you can easily lift a massive rock with one hand, as Alex Koerger demonstrates. |
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| Crater Lake is the seventh deepest lake in the world and the deepest in the United States. Generous amounts of winter snow — an average 533 inches per year — supply the lake with water. There are no inlets or outlets. Evaporation and seepage prevent the lake from becoming any deeper. (U. S. National Park Service) |
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| The Pinnacles, eerie spires of eroded ash flow tuffs, rise from the edges of Sand and Wheeler Creeks. The formations are erosional remnants of a pyroclastic flow. (More information is available on the Crater Lake page of Volcano World.)
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| The cinder cone on Wizard Island rises 760 feet (233 meters) above the lake and is surrounded by black volcanic lava blocks. A small crater, 300 feet (90 meters) across and 90 feet (27 meters) deep, rests on the summit. The crater is filled by snow during the winter months, but remains dry during the summer. (USGS) |
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| The Devil's Back Bone is an andesite feeder dike for lava flows in ancestral Mt. Mazama. It's exposed because of the collapse of the summit to make the "caldera lake," referred to incorrectly as Crater Lake. |
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| Explosive silicic eruptions occurred at several vents around 70,000 years
ago. The most impressive was at Pumice Castle on the east wall, where layers
of a dacitic Plinian fall deposit became densely welded near their vent. |
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| Dr.Allan Treiman, planetary geochemist with the Lunar and Planetary Institute, shows the class a sample of a Josephine ophiolite. A ophiolite is just a chunk of the seafloor that got shoved up above sea level. These are named for Josephine County, Oregon, where they are found. |
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| Instructor Allan Treiman, a planetary geochemist, and teacher Alex Koerger
chip samples from an exposure of sheeted dikes in the Josephine Ophiolite.
The entire sheeted dike complex, from the lower transition with the gabbro
to the upper gradational contact with extrusive volcanic flows and pillows,
is preserved essentially intact on both flanks of Monkey Creek Ridge.
However, it can be tough to identify the sheeted dike complex as the sheeted
dike complex because of the chemistry of the rocks. |
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