Earth Science Notes3

New York State is a state with different landscape regions. Landscape is the topography of the state. This exists at the interfaces between any two spheres of Earth. It incorporates stream drainage patterns as well. We measure landscapes by taking the map profiles and gradients of different areas of the state to help us to identify the movements beneath us. There are three main types of landscapes – plains have sedimentary rocks and a low elevation with a gentle slope, mountains have igneous rocks or metamorphic rocks at their cores and have an elevation in the thousands of feet with steep slopes, and plateaus have undistorted rock structures with a steep slope and a gentle slope.

 

 New York State’s landscape regions can be identified on the map in your reference tables. Based on these names, what can you say about the slope and rocks in these areas? The boundary of each region can be easily identified by changes in slope, the course of a river, cliffs, ridges, or other physical changes in the rocks in the area.

 

 Landscapes are formed by several factors. These include:

1)      uplifting versus leveling – if uplifting is faster, mountains form; if leveling is faster, mountains fall and valleys form; if they are equal, plains form.

2)      Time – young mountains tend to be high because uplifting is faster, but as the mountain grows, leveling eventually catches up and reduces the mountain so that by old age the mountain is level with the ground.

3)      Climate – arid regions have nothing holding sediment in place so these regions have steep slopes and sharp sediment as opposed to humid climates where there is lots of vegetation holding sediment in place and allows for rounded features and more defined slopes.

4)      Glaciers – these transport soils to other areas and shape valleys as well as produce streams for an area.

5)      Streams – in arid regions there is a great deal of infiltration while in humid areas runoff is common.

Soils – permeable soil, porous soil, and sorted soil allows for infiltration while the opposite soils do not.

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The type of bedrock in an area will determine how quickly the landscape is eroded, which in turn will affect streams in the area and gradient. If all the rock in an area erodes equally, the landscape will be shaped by tectonic forces. If there are rocks with varying erosional rates, the landscape will be dotted with various features at random locations. For example, areas with sandstone and shale will see sandstone erode faster than shale. This leads to the formation of cliffs, called escarpments, between the two layers. Ridges form when more resistant igneous or metamorphic rocks are left behind in areas where less resistant rocks are eroded.

 

 Areas where folded, faulted, or tilted rocks are areas where valleys tend to form because more surface area of the rocks have been exposed and could be eroded away faster. The rate of erosion in an area will determine a stream’s pattern in the area. There are several patterns that are important to New York State. Dendritic (random) patterns are formed in areas with very little difference in erosional patterns. Trellis (blocks) are formed in areas with a great deal of erosional rates. Radial patterns are formed on domed structures with little difference in erosional rates. Annular patterns are fromed in areas where domes are located and have a great deal of difference in erosional rates. The bedrock in an area also will determine what type of soil is formed there. Remember what was said about soil profiles and glaciers transporting soil.

 

 Landscapes can be altered over time by different factors. For example, people can affect an area through construction projects, land pollution, water pollution, air pollution, etc. Certain landscapes attract people more than others. Shores are attractive but are areas of floods and changes in tides. Areas with a lot of soil have soil creep if they are hilly. Therefore, it is important for people to conserve the environment as best as possible to preserve the resources in the area.

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