Landscapes

Topic 14

Regents Earth Science

Uplifting or Leveling Forces

Originate below or in lithosphere and raise land, build mountains, cause continental growthEnergy comes from radioactive decay and heat left over from Earth’s formationExamples: volcanic action

earthquakesplate movement

Leveling or Destructive Forces

Operate at/near earth’s surface and break down rocks, transport material from higher to lower elevations, and level off/lower the landSources of energy: gravity

the sun Examples: weathering deposition

erosion subsidence

Time and Landscape Stages

Youth

Uplfting forces dominant

High elevations

Steep slopes

Rugged surfaces

Mature

Leveling forces dominant

Lower elevations

Less rugged/more rounded surfaces

Steepness decreases

Old

Smooth

Flat

Low elevations

In which order should the diagrams be placed to show the most likely sequence of river and landscape development.

Effects of Climate on Landscape Development

Arid Landscapes

Steep slopes

Sharp, angular features

Thin, sandy soils

Little/no vegetation

Streams are intermittent (temporary)

Internal drainage

Alluvial fans

Humid Landscapes

Smooth, rounded slopes

Thick soil

Abundant vegetation

Permanent streams

Streams flow to ocean

Glaciers and Landscapes

Steep slopes/little soil

Wide, u-shaped valleys

Soils contain unsorted particles

Many lakes

Disrupted stream patterns

Effect of Bedrock on Landscapes

Controls shape and steepness of slopesControls stream drainage patternsMost resistant form cliffs, plateau tops, escarpments, tops of waterfallsRESISTANT rocks stick out/they do NOT weather or erode NONRESISTANT rocks are easily/quickly weathered and eroded

Resistant Strata

Which layer is the most resistant?

How can you tell?

Which layer is the least resistant?

How can you tell?

Stream Drainage Patterns

Radial and Dendritic Patterns

Annular Stream Pattern

Trellis Stream Pattern