Geomorphology Lab
NAME:_______________________________
NAME:______________________________
Please do this exercise with only one or two Lab Partners, and not as a larger group.
Geomorphology covers a wide range of studies, all connected to the Rock Cycle. In today’s lab, you will be using the
following:
USGS 7.5” topographic maps:
Morena Reservoir Quadrangle
Monument Peak Quandrangle
Mt. Darwin Quandrangle
Stereoscope and Stereoscopic photographs
Pencil, eraser, ruler, calculater
Geomorphology is the study of many interconnected processes. These processes can be thought of as either erosive,
transportive, depositional, or some combination thereof.
Depositional processes create sedimentary rock, and require either wind or water.
Weathering is the chemical and physical disturbance of earth materials in place on exposure to atmospheric or surface
agents. The rock that is broken down by this process can subsequently be transported away by various agents of
erosion.
Mass Wasting Processes involve the downward movement of soil, regolith, and rock under the force of gravity. This is
visible in the landscape in slides, flows, topples, falls, and avalanches. The outcome of this can create Alluvial Fans in the
desert, and Landslides in the wetter areas. Subtle changes can occur such as Creep, and can be seen in the landscape
with leaning telephone poles and fence posts.
Aeolian processes pertain to the activity of the winds and more specifically, to the winds' ability to shape the surface of
the Earth. Winds may erode, transport, and deposit materials, and are effective agents in regions with sparse vegetation
and a large supply of unconsolidated sediments. Although water and mass flow tend to mobilize more material than
wind in most environments, aeolian processes are important in arid environments such as deserts.
Using the Monument Peak Quadrangle, please answer the following questions:
Please list 2 canyons that have an alluvial fan at their base:
What is the method of movement of materials in these canyons?
1
What kind of erosional and depositional a forces would you expect to find on the eastern side of this map?
Are they different from the same forces on the western slopes found on this map?
What is the slope from Garnet Peak (5840’) heading northeast into the stream to 3000’? What is the slope continuing
from 3000’ to 1800’? What does this demonstrate?
Look at the Stereoscope Station A, photo #18. What is the feature that you see? What process is involved in this?
Look at Stereoscope Station B, photo 12. What is the feature that you see? What process is involved in this?
Compare the maps with the Stereoscopic photo. What are the similarities? What are the differences?
Fluvial Processes include both rivers and streams, which are not only carriers of water, but also of sediment. The moving
water is able to pick up and carry sediment and transport it downstream, either as bed load, suspended load or
dissolved load. Rivers erode rock and create new sediment, both from their own beds and the surrounding hillsides. As
rivers flow across the landscape, they generally increase in size, merging with other rivers.
Using the Morena Reservoir Quadrangle Identify three creeks, and their associated canyons:
CREEK
CANYON
1.
2.
3.
2
How have fluvial forces changed the landscape?
What is the slope from Morena Butte (3919’) south to Hauser Creek?
Is this similar or different from the slope readings from Garnet Peak?
Go to the Stereoscope marked “C” , photo 1, and discuss what you see in the photo. What process contributed to the
formation of this area?
Compare the maps with the Stereoscopic photo. What are the similarities? What are the differences?
3
Tectonics effect on geomorphology can range from scales of millions of years to minutes or less. Earthquake faults can
lift and drag either slowly or quickly, with San Andreas, Elsinore, San Jacinto, and Rose Canyon Faults shifting and
contributing to the shape of Southern California.
Both volcanic (eruptive) and plutonic (intrusive) igneous processes can have important impacts on geomorphology. The
action of volcanoes tends to add to and change landscapes, covering the old land surface with lava of various types,
releasing pyroclastic material and forcing rivers through new paths. The volcanic cones built by explosive or effusive
activity also create significant new topography, which can be sculpted and shaped by erosion or weathering.
Go to the Stereoscope Station marked “D” and photo number 6, and discuss what you see in the photo. What process
contributed to the formation of this area?
Go to the Stereoscope Station marked “E” and photo number 11, and discuss what you see in the photo. What process
contributed to the formation of this area?
Using the Lunar Crater Quadrangle, what is the name of the range? Is this a mountain range?
Name the two craters
Is one more dominant than the other? How can you tell?
4
How is the butte formed? Is this a process that you’ve seen before? Where?
Compare the Lunar Crater map with the Stereoscopic photo. What are the similarities? What are the differences?
Biogeomorphology is the interaction of living organisms with landforms. Biogeochemical processes controlling chemical
weathering influence mechanical processes like burrowing and tree throw on soil development, as well as contributing
to processes that create sinkholes and caves associated with Karst topography.
Glaciers, while geographically restricted to Polar or Alpine environments, are effective agents of topographic change.
The gradual movement of ice down a valley causes abrasion and plucking of the underlying rock.
Go to the Stereoscope Station marked “F” and photo number 6RL, and discuss what you see in the photo. What process
contributed to the formation of this area?
Using the Mt. Darwin Quadrangle, name three active glaciers on Mt. Darwin
1.
2.
3.
5
Post –glacial forms include Patternoster Lakes, and U-Shaped Valleys. Can you find three of these on the map?
1.
2.
3.
Find 3 places where Glacial has changed to Fluvial process.
1.
2.
3.
Compare the Mt. Darwin map with the Stereoscopic photo. What are the similarities? What are the differences?
6