12th
September
2007
GeoChallenge #5
posted in GSCI100, GeoChallenge, geology |The Challenge: Correctly identify and accurately describe the geologic feature or process illustrated by one of the headers to this website. Credit will only be given for one header description per student - once credit has been given no other student may receive credit for the same header. If competing descriptions are offered for the same header I’ll only give credit to the one that does the most thorough and accurate job of describing the geology. Post your descriptions as a comment on this GeoChallenge.
One of the pictures up above is of the Great Sand Dunes in Mosca, Colorado, in the San Luis Valley.
The dunes are a product of wind and rain eroding the San Juan and Sangre de Cristo Mountains. They result from a series of weather patterns that combine perfectly to form these dunes:
-The wind and rain that erodes the surrounding mountains
-Water flowing from the Sangre de Cristo’s keeps the sand in place
One of the pictures above is of The Grand Canyon, which was created by the Colorado River -a meandering river- over a period of 6 million years, is 277 miles long, ranges in width from 4 to 18 miles and attains a depth of more than a mile. Nearly two billion years of the Earth’s history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted forming incised meanders.
It is the Colorado River, but it’s Canyonlands, not the Grand Canyon. Close enough.
[…] number of GeoChallenges can be completed online in a reasonable amount of time (e.g., GeoChallenges #5, #9, and #15). All GeoChallenges must be completed by midnight on Friday, December 7th. No […]
One of the pictures above is a picture of dry mud cracks. It doesnt state where the picture is from, but you do know that it was once wet and that it dry to the point where it form deep cracks and made polygram shapes. This type of rock is classifiede as an clastic, mud-sized sedment.
One of the pictures shown is a volcano caldera, although im not sure on which specific volcano it is. It is usually caused by a collapse of the summit of a volcano, and usually is a result of a violent eruption. However, these can also be caused by the collapse of the top of a shield volcano as a result of magma drainage. Calderas are usually several kilometers in diameter, and can sometimes fill up with water resulting in a lake.
One of the pictures is of a common and widely occurring type of intrusive, felsic, igneous rock called granite. Granite has a medium to coarse texture. Granites can be pink to dark grey and sometimes even black. This particular picture looks like the granite found at Yosemite National Park.
One of the headers is a picture of a sandy beach.You can see many different erosional porcesses on a beach, like the loss of land due to physical processes such as: movement of sediment by waves, coastal flooding and alongshore currents.
This Geology picture was shot somewhere at a volcano. The big, black crater is a sign for the tremendous size of this volcano.
In general, Craters are constructional features that were built upward as ejected fragments collected around the vent to form a doughnut-like structure.
In addition to that this volcanic crater seems to be a caldera, because they tend to have very large and usually circular depressions like this one on this picture.
These are blue crystals, with many sharp points almost daggers. I think they are salt crystals. I think the blue salt crystals are from maybe the ocean or I just don’t know. It’s inbeded in rock it almost seems like. I don’t know if it formed within the rock after an ocean area dried, or if the salt was on the ground already and than hardened into the salt crystals.
Lindsey Miller
lemiller3@scatcat.fhsu.edu
This picture is a “playa”. It is a dry, barren area in the lowest part of an undrained desert basin, underlain by clay, silt, or sand, and commonly by coluble salts. It may be marked by an ephermeral lake.
One of those pictures is Molten hot magma that comes from inside the earth that collects in magma chambers. Its extrusive form is this lava flow.Its spews from an volcano when it erupts. Cool temperatures cause it too cool and it is responsible for many igenouse rocks.
The header shown here is pink granite one of the most common phaneritic igneous rock. can be found in u.s. in theese place; barre, vermont; mount airy, North Carolina; and St. Cloud, Minisota.
One of those pictures is a wave cut terrace. by looking at the picture you can see where the water has eroded away the land and made terraces. because of this erosion process by the waves you can see where the water levels of the ocean used to be at.
The picture of the park with all the “red rocks” is in Sedona, AZ. The type of rocks are sandstone and limestone. The sedimentary rocks in the picture were sculpted by erosion.