Download Worksheet_-_Geomorphology_of_Virginia

The Geomorphology of Virginia
Geomorphology is the study of landforms and the processes that are responsible for their
appearance. There are two major classes of geomorphic processes:
1.
2.
degradation – wearing down of material (erosion and transportation of sediment)
aggradation – building up of material (accumulated sediment)
A region with many similar landforms may be called a geomorphic province. Virginia includes 5
geomorphic provinces: the Coastal Plain, the Piedmont, the Blue Ridge, the Valley and Ridge
and the Appalachian Plateau.
Features of the Coastal Plain Province
The Coastal Plain slopes toward the ocean. It has very low elevation, with the maximum
elevation being 300 feet above sea level. The bedrock of the coastal plain is sedimentary rocks,
consisting of sands, gravels, clays, shell marls and diatomaceous sediments. The coastal plain
is cut by bays and estuaries. There are local swamps including the Great Dismal Swamp. There
may be cliffs up to 100 feet above the estuaries. Natural harbors, sandy beaches and barrier
beaches are common. The coastal plain extends westward to the Fall Line, which passes
through Richmond. The fall line is the point where streams begin to have rapids because of the
harder metamorphic rock underlying them.
Features of the Piedmont Province
The Piedmont region is to the west of the coastal plain. The term piedmont was first used in
Italy and has since been used to indicate a region that is at the base of a mountain or mountain
range. The Piedmont province of Virginia is about 30 miles wide at the Maryland border and
about 160 miles wide at the North Carolina border. The province is characterized by gently
rolling hills and valleys that extend one after another. The topography of the province is often
called the peneplane. This term indicates old age landforms with much erosion. The deeply
buried bedrock of the province is mostly igneous and metamorphic. It also contains basaltic
sills and dikes. There are deep deposits of sediment on top of the bedrock, ranging to 150 feet
thick. These deposits consist of limestone and marble, indications that this area was once
underwater. Other resources include the mineral kyanite and high-quality slate. Fossil records
show that the region was covered by a warm-water shallow bay. Dinosaur footprints have been
discovered in sedimentary rocks in the province.
Features of the Blue Ridge Province
The Blue Ridge Province is west of the Piedmont Province. It is a long narrow area that
extends from south-central Pennsylvania through Maryland, Virginia and western North Carolina
into Georgia. There are two distinct areas within this province. The first area is northeast of
the Roanoke River. It consists of an irregular mountain range, containing anywhere from one
single ridge to a group of closely spaced ridges with a width of 12-14 miles. It is a very rugged
area. The slopes of the ridges are covered with loose rock, called talus. The mountain ranges
have similar elevations, ranging from 1,200 feet near Maryland to almost 4,100 feet near Luray,
Virginia.
The second distinct area of the Blue Ridge Province is southwest of the Roanoke River. This
area is often called upland. It is nearly 70 miles wide and contains mountains of greater
elevations. There are 46 mountain peaks in this area that have elevations above 6,000 feet.
Most of the mountains have elevations from 2,300 to 3,200 feet. Streams in this area show
indications of rejuvenation, possibly caused by uplift of the region. The rock type differs from
area to area within this province. Sedimentary rocks are underlain by igneous rocks, indicating
a volcanic origin.
Features of the Valley and Ridge Province
The Valley and Ridge Province is west of the Blue Ridge Province. It consists primarily of
valleys separated by ridges. Streams drain to two different directions in this province. Streams
to the north drain into the Atlantic Ocean and streams in the south drain into the Gulf of
Mexico. The ridges (mountains) of this province are know as folded mountains. These were
formed under great heat and pressure during continental collisions. Some of the mountains
may have folded then “tilted” to one side. The rocks underlying the area are mostly
sedimentary (sandstones, conglomerate, and carbonates). Karst topography is found in this
region resulting in numerous caverns. There are some igneous intrusions. This province
includes the Shenandoah Valley. There are several valleys in this province; however, the bases
of the valleys in the south are approximately 1,000 feet higher than the bases of valleys in the
north. The topography of the province ranges from mountainous on the eastern border to
almost flat on the western border.
Features of the Appalachian Plateau Province
The Appalachian Plateau is the province in the southwestern corner of the state. It only
consists of 3 counties in Virginia so is often not shown on maps of the state. The area is
composed of a plateau; a flat region consisting of sedimentary rocks. Portions of these plateaus
may be uplifted so that the area has the appearance of mountains. Examination of the rock
layers will show that they are flat rather than folded. Portions of the plateau are rich in
resources such as coal (the most abundant), natural gas, and petroleum.
Name: _______________________________________________ Pd.: _______ Due Date: ___________________
The Geomorphology of Virginia Worksheet
Directions: Answer the following questions using the page in the booklet titled “The Geomorphology of Virginia”.
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1
Question
Define geomorphology.
2
List and describe the two major classes of
geomorphic processes.
3
What is a geomorphic province?
4
How many geomorphic provinces does Virginia
have?
List the provinces in order from east to west.
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8
What is the maximum elevation of the coastal
plain province?
What major rock type is found underlying the
Coastal Plain?
What is the fall line?
9
What is meant by the term “piedmont”?
10
What is a peneplane?
11
What does the presence of limestone in the
piedmont indicate about the area?
12
How do we know that the piedmont region
was once underwater?
13
How do we know that dinosaurs once lived in
Virginia?
14
What is talus?
15
How do we know that the Blue Ridge province
is volcanic in origin?
16
What type of mountains are found in the
Valley and Ridge province?
How did these mountains form?
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20
What type of rock is found in the Valley and
Ridge province?
How many counties in Virginia are in the
Appalachian Plateau province?
What type of rock is found in the Appalachian
Plateau province?
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