|1997||White Elephant Pegmatite
Wind River Canyon
Yellowstone basalt flows
Little Cottonwood Canyon
Marysvale Volcanic District
Block Glide in Pennsylvania
These are photos from the White Elephant Pegmatite in the Black Hills of South Dakota. The top one shows tourmaline crystals (black) radiating through lepidolite, feldspar, and quartz. The person is Scott Steele. The bottom one shows lepidolite crystals in radiating patterns, also crystallized with tourmaline, feldspar, and quartz. I took these photos while at field camp on June 7, 1997. Click here for a photo of the mine from the nearby highway, and here for a photo of a tourmaline/lepidolite sample collected there, and here for a photo of a section through some graphic granite collected there.
Also, here is a link to a photo of me in the mine with some other students.
||These two photos were taken during a trip to Wind River Canyon, south of Thermopolis in Wyoming in mid-June, 1997. Wind River Canyon is an excellent place to see the stratigraphy of central Wyoming, with exposures from the Archean to the Mesozoic Era. The first photo shows students looking at an outcrop of the Triassic Chugwater Formation along the road between Wind River Canyon and Thermopolis. The second shows an outcrop of the craton, which is the Archean basement rock exposed at the southern end of Wind River Canyon. The rock is amphibolite.|
|These are two photos of Elk Basin, an oil field along the axis of an anticline on the Montana-Wyoming border. They were taken on June 17, 1997, facing north. The anticline is formed on the ramp of a deep subsurface thrust fault (a ramp anticline). This is the second mapping area at Penn State's field camp. Most of the rocks on the surface are Mesozoic in age. The top photo shows the axis of the anticline with the oil refinery in the center, and the bottom one shows the dipping strata and cuestas of the western limb.|
||I took these photos June 26, 1997 while visiting Yellowstone National Park for Penn State's geology field camp course. These photos show interesting jointing structures caused by varying rates of cooling within relatively young basalt flows within the park. The jointing creates elongated columns of rock that are polygonal in horizontal section. These are called collonades, and they result from the slowest rate of cooling because they occur at the bottom of the basalt flow. Above the collonades are smaller yet similar (in shape) structures called entablature. The entablature structures disappear at the top of the flow because the top cools rapidly. These basalt flows have undergone hydrothermal alteration which has changed their color to yellow. Hence the name of the park.
The first photo shows two rows of collonades (from separate flows) across the valley from where we were parked. The second photo shows a close-up of the collonades where we were parked, and it gives a good sense of scale. Note the thickness of the flow from the trees at the top of the cliff in the background. That's Duff Gold in the foreground. The third photo shows both the collonades and entablature. The fourth photo shows the very bottom of the flow, just below the collonades, where the crushed and baked remnants of vegetation are visible. The structures here are often called "clinkers".
||I took these photos in July of 1997 while doing some geologic mapping projects for Penn State's geology field camp course. We stayed Alta Peruvian Lodge in the town of Alta, Little Cottonwood Canyon, Utah. The canyon is a glacially carved valley in the Wasatch Mountains, east of Salt Lake City. The top photo shows Little Cottonwood Canyon from the Honeycomb Cliffs on the eastern end of the canyon, facing west. The second photo shows the students on the north side of the valley, between Boundary Peak and Cardiff Peak (in the background). The bottom photo shows a roche moutonee, carved into the Ophir Formation by a Pleistocene glacier, on the north side of the canyon. The white rock in the background is a felsite dike.|
|These are two more photos from Little Cottonwood Canyon (see above). These show xenoliths ('strange rocks', the dark spots in the photos) in the Alta Stock, a Tertiary Granodiorite pluton at the eastern end of the canyon. In the bottom photo one xenolith is cut by an aplite/pegmatite vein.|
||These are photos from the Marysvale Volcanic District of central Utah, taken during field camp. The first shows the Big Rock Candy Mountain, replacement deposits of the Bullion Canyon Volcanics, along route 89. Potassic hydrothermal alteration has caused the normally dark volcanic rocks to appear yellow and other bright colors. The second shows an outcrop of the Joe Lott Tuff, a lithified rhyolitic pyroclastic flow, along route 4. Click here for a photo of a hand sample from this outcrop. The first two photos were taken on July 24, 1997. The last shows an outcrop of the Red Hill Tuff, taken July 25, 1997.|
|This photo shows a type of landslide known as a block glide at Mile Marker 23 along US 220/I-99 in Blair County, Pennsylvania. Landslides of any kind are comparatively rare in Pennsylvania. Part of a hill of shale was removed to make the road, forming a dip slope. The upper block detached along a bedding plane and is sliding down the hill, forming a jumbled pile of rock at the toe of the slide. Photo taken September 5, 1997.|