Topic 14 Regents Earth Science Landscapes Topic 14 Regents Earth Science

Uplifting or Leveling Forces Originate below or in lithosphere and raise land, build mountains, cause continental growth Energy comes from radioactive decay and heat left over from Earth’s formation Examples: volcanic action earthquakes plate 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 land Sources 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 slopes Controls stream drainage patterns Most resistant form cliffs, plateau tops, escarpments, tops of waterfalls RESISTANT 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?

Stream Drainage Patterns

Radial and Dendritic Patterns

Annular Stream Pattern

Trellis Stream Pattern