DEVELOPMENT OF LANDSCAPES

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DEVELOPMENT OF LANDSCAPES

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What is a Landscape?

• Landscapes are the general shape of the land
• Relief is the change in elevation from highest
  point to lowest point that characterizes the
  different landscapes.
• Types of landscapes
• Mountains largest relief
• Plateaus medium relief
• Plains little to no relief (flat)

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MOUNTAINS

• Mountains
• Greatest relief biggest change in elevation
  (from high to low point)
• Usually composed of metamorphic rock which is
  very resistant to weathering
• Physical weathering freeze-thaw in highest
  elevations
• Formed by tectonic uplift - so there are many
  faults and folds

• Adirondack Mountains

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PLATEAUS

• Allegheny Plateau

• Plateau has some elevation but are not as
  rugged as mountains
• Result from uplift of land features due to
  tectonic activity
• Generally composed of layers of sedimentary rock
• Usually less resistant to weathering because
  sedimentary rock is generally weak
• Rivers will carve out V shaped valleys

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PLAINS

• Plains the lowest and least relief
• Underlying bedrock may be sedimentary
• Generally very flat, little slope (gradient),
  wide flood plains and meandering streams

• Erie-Ontario Lowland

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FACTORS THAT AFFECT LANDSCAPES

• GEOLOGIC FACTORS
• Composition of the underlying rock will affect
  how it is weathered
• Metamorphic rock and igneous rock generally very
  resistant to weathering
• Sedimentary rock less resistant to weathering and
  generally affected by water

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Drainage Patterns

• Streams will develop patterns based on the
  geologic factors of the landscape
• The main patterns are
• Dendritic
• Trellis or Rectangular
• Radial or Annular

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Five main patterns of drainage

• The pattern of drainage in a basin is largely
  determined by the underlying geology.
• Streams typically follow the path of least
  resistance, forming valleys where rock is most
  readily eroded or following the steepest slope
  gradient.
• Dendritic drainage is characteristic of areas
  where the geology is relatively uniform, for
  example where rock layers are horizontal. Streams
  intersect with a characteristic V-pattern. The
  tip of the V points downstream.
• Trellis drainage is characteristic of areas with
  alternating parallel valleys and ridges. The
  streams will intersect at right angles along
  zones of weakness n the bedrock.
• Rectangular patterns distinguish regions where
  the bedrock exhibits well developed joints or
  fractures. The streams flow along the fractures
  as lines of weakness.
• Radial drainage patterns are typically found on
  the slopes of volcanoes, where streams flow
  downslope.
• Annular drainage results from a variety of
  bedrock in a dome shape that has had some
  faulting.

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FACTORS THAT AFFECT LANDSCAPES

• CLIMATE FACTORS
• Humid (moist), warm climate will favor chemical
  weathering and favors rolling, rounded landscapes
• Arid (dry) climates will create very steep slopes
  and angular formations

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Climate Zones

• Climate is defined by the average conditions of
  temperature (amount of insolation)and
  precipitation (amount of moisture)
• Climate factors influence landscape development
  
• Theses factors are
• latitude, altitude, nearness to large bodies of
  water, ocean currents and wind belts, and
  presence of mountains.
• The earth is divided into climate zones due to
  these factors and therefore contribute to the
  landscape development in each zone

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World Climate Zones
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North America Climate Regions
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LANDSCAPES OF NEW YORK

• New York State has unique landscape
  characteristics
• It is a combination of mountains, plateaus, and
  plains
• The geology of the land and the past tectonic
  activity have all contributed to the development
  of the landscape
• The climate is less of a factor because it is
  relatively uniform
• Being seasonal which allows for the freeze thaw
  of physical weathering in winter and the effects
  of chemical weathering in the hot, humid summers.
• The ESRT pp. 2 and 3 provides very specific
  information about the NYS landscapes

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ADIRONDACK MOUNTAINS

• In Northeast NY
• Mt. Marcy the highest peak in NY
• Composed of metamorphic rock
• About 1 billion years old

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ALLEGHENY PLATEAU AND THE CATSKILLS

• Allegheny Plateau is an extension of the an
  extension of the Appalachian Plateau formed by
  collision of North America with Africa forming
  Pangea (300 million years ago)
• Many glacial features such as the Finger Lakes
• Catskills are not true mountains
• Layers of sedimentary rock from the erosion of
  the Acadian Mountains about 400 million years ago.

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PLAINS (LOWLANDS)

• Borders of Lakes Erie and Ontario are rich with
  glacial till and drumlins. The large bodies of
  water moderate the climate and allow for a longer
  growing season

• Long Island (Atlantic Coastal Plain) is the
  moraine from the last glacier about 10,000 years
  ago
• Northern border is low lying hills and the
  southern border are the beaches formed from
  glacial water as outwash plains.

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TUG HILL PLATEAU

• Rather remote region
• Low population
• Highest snowfall in NYS

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HUDSON VALLEY

• Hudson River the main waterway
• Palisades tall columns of igneous rock formed
  about 200 million years ago during the breakup of
  Pangea
• Other features Taconic Mountains, Hudson
  Highlands, Manhattan Prong complex geology

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Drainage Patterns in NY

• The variety of landscapes in NYS also allowed for
  development of different drainage patterns.

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Watersheds in NY

• A watershed is a gathering place. It is a place
  where hills and plains and peoples lives are
  connected by falling rain, melting snow, and
  flowing water.
• A watershed is any area of land that drains to a
  common point.