Earths Interdependent systems - Princeton Ch 4 Flashcards
Rift volcanoes
Occur when plates move away from each other. When a rift volcano erupts, new ocean floor is formed as magma fills in where the plates have separated
Subduction volcanoes
Occur where plates collide and slide over each other
A heavy ocean plate is pushed below the other and melts as it encounters the big mantle
Hot spot volcanoes
Do not form at the margin of plates.
Found over “hot spots” which are areas where magma can rise to the surface through the plates. (Ex. Hawaiian islands)
How old is the earth
Between 4.5 and 4.8 billion years old
What three things interact in the rock cycle and to create basic rocks
Time, pressure, and the earth’s heat
This type of rock results when rock is melted (by heat and pressure below the crust) into a liquid and then resolidifies. The molten rock (magma) comes to the surface of the earth, and when it emerges it is called lava; solid lava is this type of rock. Another example is basalt.
Igneous
These rocks are formed as sediment (eroded rocks and the remains of plants and animals) builds up and is compressed. One place this can occur is at a subduction zone where ocean sediments are pushed deep into the earth and compressed by the weight of rock above it. An example is limestone.
Sedimentary
This type of rock is formed as a great deal of pressure and heat is applied to rock. This can happen as sedimentary rocks sink deeper into the earth and are heated by the high temperatures found in the earth’s mantle. An example is slate. (The product of shale)
Metamorphic
Three soil categories from compact particle size to large pores (that can hold more water and don’t easily stick together)
Clay, silt, sand
As soil pH gets more _____, ions of heavy metals such as Hg or Al can leach into the ground water and harm plant and aquatic life.
Acidic
Soil Layers
OAEBCR O horizon A horizon E horizon B horizon C horizon R horizon
O horizon
Uppermost horizon; organic material (organism waste, decomposing organism, live organisms); humus
A horizon
Weathered rock and some organic material that has traveled down
Topsoil
Zone of leaching
E horizon
Eluviated horizon
leached of clay, iron, or aluminum oxides
Sand and silt sized minerals
B horizon
Relieved minerals leached out of the A horizon and organic materials
Zone of illuvation (the movement of dissolved material from higher soil layers to lower soil layers due to the downward movement of water caused by gravity)
C horizon
Bottommost layer of soil composed of larger pieces of rock that have not undergone much weathering
R horizon
Bedrock, below all other layers of soil
Loamy
Soil composed of roughly the same amount of all three textures (clay, silt, sand)
Best for plant growth
Problems of monoculture and prevention
Significant decrease in genetic diversity makes crops more susceptible to pests and diseases
Consistent planting of one crop in an area eventually leaches the soil of specific nutrients that the plant needs to grow
Prevention: crop rotation (diff crops are planted in the area in each growing season)
Detrimental effects of the green revolution
Chemical pesticides result in insects that are pesticide resistant
Over irrigated soils undergo salinization which leads to land degradation
Salinization
Soil becomes water-logged and when it dries out, salt forms a layer on its surface
Erosion has increased significantly caused by humans results from
Logging and slash and burn agriculture (deforestation)
Over cultivation of agricultural fields
Overgrazing
Urbanization
Best management practices to conserve soil
Use of animal waste (manure), compost, and the residue of plants to increase organic matter in soil
Organic agriculture, compost, manure, crop rotation, non-chemical methods
Contour plowing and strip planting
Trees and other wind barriers
Soil conservation act of 1935
Created the soil conservation service. Passed in response to the dust bowl. Created to conserve soil and restore the nation’s ecological balance. Was led by Hugh Hammond Bennett.
