What is a mountain?
A: A mountain is an elevated portion of the Earth's crust, generally with
steep sides that show significant exposed bedrock.
A mountain differs from a plateau in what ways?
A: A plateau has a limited summit area, and is larger than a hill,
typically rising at least 300 meters (1000 feet) above the surrounding land
A few mountains are isolated summits, but most occur in
what?
A: Mountain ranges.
How are mountains formed?
A: Through tectonic forces, erosion, or volcanism, which act on time scales
of up to tens of millions of years.
Once mountain building ceases, mountains are slowly
leveled through the action of what?
A: Weathering, slumping and other forms of mass wasting, as well as through
erosion by rivers and glaciers.
High elevations on mountains produce what type of
climates compared to sea level at similar latitude?
A: Colder.
Why do these colder climates strongly affect the
ecosystems of mountains?
A: Different elevations have different plants and
animals.
Because of the less hospitable terrain and climate,
mountains tend to be used less for what?
A: Agriculture and more for resource extraction, along with recreation.
What is the highest mountain on Earth?
A: Mount Everest in the Himalayas of Asia, whose summit is 8,850 m (29,035
ft) above mean sea level.
What is the highest known mountain on any planet in the
Solar System?
A: Olympus Mons on Mars at 21,171 m (69,459 ft).
Whether a landform is called a mountain may depend on
what?
A: Local usage.
Mount Scott outside Lawton,
Oklahoma, USA, is only how
tall?
A: 251 m (823 ft) from its base to its highest point.
In the United Kingdom and the Republic of
Ireland, a
mountain is usually defined as what?
A: Any summit at least 2,000 feet (610 m) high.
At one time the U.S. Board on Geographic Names defined
a mountain as being how tall?
A: 1,000 feet (305 m) or taller but has abandoned the definition since the
1970s.
Any similar landform lower than this height was
considered what?
A: A hill.
Today, the United States Geological Survey (USGS)
concludes that these terms do not have what?
A: Technical definitions in the US.
What are the three main types of mountains?
A: Volcanic, fold, and block.
All three types are formed from what?
A: Plate tectonics: when portions of the Earth's crust move, crumple, and
dive.
Major mountains tend to occur in what?
A: Long linear arcs, indicating tectonic plate boundaries and activity.
Volcanoes are formed when a plate is what?
A: Pushed below another plate, or at a mid-ocean ridge or hotspot.
At a depth of around 100 km, melting occurs in rock
above the slab (due to the addition of water), and forms what?
A: Magma that reaches the surface.
When the magma reaches the surface, it often builds a
what?
A: A volcanic mountain, such as a shield volcano or a stratovolcano.
Fold mountains occur when two plates do what?
A: Collide.
Block mountains are caused by what?
A: Faults in the crust.
Erosion causes the surface of mountains to be younger
than what?
A: The rocks that form the mountains themselves.
Climate in the mountains becomes colder at high
elevations, due to what?
A: An interaction between radiation and convection.
Sunlight in the visible spectrum hits the ground and
does what?
A: Heats it.
The ground then does what?
A: Heats the air at the surface.