Devil's Punchbowl Earthcache EarthCache
Devil's Punchbowl Earthcache
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Across from Steamboat Rock State Park, along Washington State
Highway 155, is a small inlet on Banks Lake known as the Devils
Punch Bowl. This stretch of highway has a turnout with great views
of Steamboat Rock and some other rocks that made us need to pull
over. My Dad and I have gone on several outings to visit sites
created by the Great Ice Age Floods. This site surprised us. Stop
by and see what you think about this rock that stopped us in our
tracks.
Much has been written about the Great Ice Age Floods. We have
several books and DVD's that tell the history of what happened to
this area thousands of years ago. One of our favorite DVD's is Ice
Age 2: The Meltdown by Blue Sky Studios. Though not entirely
historically accurate, it gives a great sense to the height of the
glaciers and the force behind the water that is lacking in other
DVD's. I feel it gives a great and different perspective to one of
the many ice dam breaks that helped form this beautiful landscape.
For a great in depth overview of the Great Ice Age Floods visit the
Ice Age Floods Institute at: http://www.iafi.org/floods.html
Anyway, all the books and other materials say that you will find
only one type of rock throughout the area uncovered by the forces
of the water in the Grand Coulee. How did that basalt get here?
During late Miocene and early Pliocene times, one of the largest
basaltic lava floods ever to appear on the earths surface engulfed
about 63,000 square miles of the Pacific Northwest. Over a period
of perhaps 10 to 15 million years lava flow after lava flow poured
out, eventually accumulating to a thickness of more than 6,000
feet. As the molten rock came to the surface, the earths crust
gradually sank into the space left by the rising lava. The
subsidence of the crust produced a large, slightly depressed lava
plain now known as the Columbia Basin (Plateau). The ancient
Columbia River was forced into its present course by the
northwesterly advancing lava. The lava, as it flowed over the area,
first filled the stream valleys, forming dams that in turn caused
impoundments or lakes. In these ancient lake beds are found fossil
leaf impressions, petrified wood, fossil insects, and bones of
vertebrate animals. With the end of the outpouring of lava,
tremendous forces deep within the earth began to warp the plateau
in several places. A general uplift of the mountainous region in
the north caused the entire plateau to tilt slightly to the south.
This tilting and associated stairstep rock folds, called
monoclines, in the vicinity of Coulee City and Soap Lake, played an
important role in the formation of the Grand Coulee.
More than likely, if you find yourself at this site, you're
probably aware of the forces behind what shaped this gorge during
the Great Ice Age Floods. If you are driving down from the north,
you may have noticed some of this type of rock in some of the
highway cutouts along the way from the Grand Coulee Dam in Electric
City. If you are driving up from the south, up to now all the rock
that you've seen has been the same, the reddish brown basalt lava
that cooled into the columns that line the Grand Coulee. At this
site there is a new type of rock here. The bedrock that the lava
flows were laid upon. From the pull out you can see across the
highway at an outcropping of this new type of rock. You do not need
to cross the highway to examine this rock, because they blasted
this rock to make room for the highway, and large chunks line the
pull out. If you choose to cross the highway be mindful of traffic,
which could be heavy depending on the season. If the visitor center
at the Grand Coulee Dam is open, they have a great display about
the rocks found in this area. I hope you enjoy this site.
To get credit for this Earthcache send an email to the owner with
the answers to the following:
1. How is this rock different from the basalt rock that forms the
coulee? Color, texture, etc.
2. Do you know what type of rock this is? What's it called.
3. How did it get here. Is it part of the bedrock, or could it have
been rafted here in the floods?
4. What is the title on the sign that is in the pull out.
You can post a picture as long as it doesn't show the answers,and
please do not put your answers in your log or it will be
deleted.
Thank you.
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