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Chapter 7 Key Terms
Topography
Landform
Elevation
Fold Mountain
Erosional Mountain
Moraines
Isostasy
Relief
Actual Height
Depositional Mountain
Plateaus
Sediment
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Chapter 7
MOUNTAINS AND HILLS
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What is a mountain?

Why does Mt. Everest seem to be getting taller?

Movement of the India plate into the Eurasian plate causes an
increase of almost 2.4” per year

If that is correct and constant, how much may Mt. Everest
have risen from when it was first measured (1856) until now?
 31.8

feet
How old are the Himalayas if Mt. Everest is 29,035 ft. tall?
 145,175
years
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Topography

“Topo” – shape

Study of surface shape and features of the Earth (variations in
elevations)
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Topography

Oceanic crust is fairly thin and dense
 Basins

– low level areas on earth’s surface (oceans & seas)
Continental crust has lighter, less-dense rocks
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Isostasy

“Iso” – equal ; “stasis” – to stand still

The balance of the weights of rocks, water and ice with the
upward force of the mantle

Determines the topography
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Landforms

Structures on the earth’s surface
 Mountains,

hills, lakes, beaches, deserts…
Orogeny
 “Oro”
– mountains ; “Gene” – beginning (the way to make)
 Study of mountain formation
Definition:
 Mountain – natural elevation of the earth’s surface rising more
or less abruptly to a summit

 Also
applies to a hill
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Landforms

Heights are usually given in meters or feet above sea level
 Elevation
Actual height – height above lowest elevation of surrounding
terrain/base
 Relief – difference in height between highest and lowest
elevations of the terrain
 Tallest mountain in the world?

 By
elevation: Mt. Everest (29,034 ft)
 By actual height: Mauna Kea (33,000 ft)
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Groups of Mountains

Mountain Range
A
series of mountain peaks in the
same geographical area

Mountain System
 Group
of mountain ranges connected
over a large area

Longest mountain system
 Mid-Atlantic
long)
Ridge (over 10,000 miles
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Mountains

Geologists classify mountains based on how they think
mountains formed
Landforms
Tectonic
Nontectonic
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Tectonic Mountains

Mostly found near convergent tectonic plate boundaries

However, they can also be found at divergent zones
 Mid-Atlantic

Ridge
These landforms are classified by the forces that cause them
 Convergent
 Divergent
 Uplift
 Subsidence
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Landforms
Nontectonic
Tectonic
Convergent
Divergent
Uplift
Subsidence
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Convergent Landforms

Sediment
 Deposits
 Layers

of eroded earth materials that eventually harden
are called strata
Fold Mountains
 Formed
3
from folded rock strata
basic types of folds
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Fold Mountains

Anticlines – an arch of rock layers
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Fold Mountains

Synclines – a trough of rock strata (downward fold)
 Both
anticlines and synclines are formed by compression forces
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Fold Mountains

Anticlines – an arch of rock layers

Synclines – a trough of rock strata (downward fold)

Monoclines – an area of smoothly folded strata above a fault
that forms a single “step”

Complex tectonic mountains
 Most
mountains will have multiple of these fold throughout them
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Divergent Landforms

Rift valleys
 Series
faults
of steep-walled valleys lined with high cliffs rising from
 Grabens
 Low
 Most
areas where rocks cracked and dropped downward
rift valleys are underwater
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Uplift Landforms

Plateaus
 Broad
region of relatively undisturbed sediment that has been lifted
 Usually
 Made

level or gently tilted
of sediment or lava
Domes
 Landform
bowl
 Usually
with sedimentary strata that looks like an upside-down
forms when magma pushes small area upward
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Subsidence Landforms

Basins
 Bowl
shaped structure formed when a deep magma chamber
emptied causing the rock strata above to sag
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Tectonic Landforms
Landforms

Fold Mountains
Anticline
 Syncline
 Monocline


Rift Valleys


Grabens
Uplift
Plateaus
 Domes


Nontectonic
Tectonic
Subsidence

Basins
Convergent
Divergent
Uplift
Subsidence
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Non-Tectonic Landforms

Erosional
 Forms

when land is taken/eroded away by some force
Depositional
 Formed
 Forms
by process called sedimentation/deposition
when sediment is “deposited” in certain places
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Erosional Landforms

Mesas and Buttes
 Flat-topped
 Talus
hills that have steep cliff-like sides
are piles of broken rock at the base of these formations
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Erosional Landforms

Pinnacles
 Tall
spires of rock that are remnants of a plateau
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Depositional Landforms

Wind formed
 Sand

dunes – hills of sand that vary in size
Glacier formed
 Glacial
till – pieces of bedrock broken out and crushed by a glacier
 Moraines
– long, low ridges of glacial till formed at the front and sides
of a glacier
 Drumlins
– low hills formed as glaciers dragged over piles of till
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Volcanoes

Volcanoes also play a part in deposition
 Considered
both tectonic and depositional landforms