Mountain Building Stages
This is the first stage of mountain building, involving the accumulation of sediments and tectonic compression.
What is the orogenic (mountain-building) initiation stage?
An anticline bends rock layers in this direction.
What is upward or arch-shaped?
Metamorphic rocks are classified primarily by these two characteristics.
What are structure and metamorphic grade?
This region of the western U.S. is dominated by alternating mountains and valleys caused by normal faulting.
What is the Basin and Range Province?
This type of faulting is common in Basin and Range parks but rare in the Appalachians.
What is normal faulting?
These National Parks preserve evidence of each stage of mountain building.
What are examples like the Appalachians, Rockies, and Basin and Range parks?
This type of fold bends downward and creates a trough-like structure.
What is a syncline?
Foliation in rocks forms due to this type of stress.
What is directed or differential stress?
The Appalachian Mountains are divided into these major types of subregions.
What are physiographic provinces?
The Rockies—unlike the Appalachians—rose far inland from the plate boundary due to this unusual tectonic angle.
What is low-angle subduction?
This stage of mountain building involves erosion and is responsible for exposing older rock layers.
What is the final erosional stage?
This type of fault occurs when the hanging wall moves down relative to the footwall.
What is a normal fault?
Slate, phyllite, schist, and gneiss represent increasing levels of this.
What is metamorphic grade?
These mountains contain some of the oldest rocks exposed in the eastern U.S.
What are the Appalachian Mountains?
National Parks in volcanic areas (Module 5) differ from Module 6 parks because they form mainly from this process.
What is magma movement and eruptions?
This term describes the process of crustal blocks attaching to a continental margin, helping a tectonic plate grow.
What is accretion?
These factors determine whether rocks fold or fault.
What are temperature, pressure, and rock composition?
Metamorphism commonly occurs at these tectonic settings.
What are convergent plate boundaries?
The Great Smoky Mountains formed mainly through this type of tectonic process.
What is continental collision and repeated orogenies?
This characteristic of Appalachian rocks indicates they’ve undergone multiple deformation events.
What is complex folding and high-grade metamorphism?
The Rocky Mountains mainly formed during this major orogenic event.
What is the Laramide Orogeny?
This type of stress most commonly produces folding rather than faulting.
What is compressional stress?
This National Park shows clear evidence of metamorphism associated with ancient Appalachian events.
What is Great Smoky Mountains National Park?
Compared to the Rockies, the Appalachians are mainly this in terms of age.
What is older?
Compared to western U.S. parks, Appalachian parks mainly showcase this type of geologic history.
What is ancient, heavily eroded mountain building?