Unit 4 test Flashcards
What can convergent boundaries result in?
the creation of mountains, island arcs, subduction, earthquakes, and volcanoes
What can divergent boundaries result in?
seafloor spreading, rift valleys, volcanoes, and earthquakes.
What can transform boundaries result in?
earthquakes
How does an earthquake occurr?
when stress overcomes a locked fault, releasing stored energy
How is soil formed?
when parent material is weathered, transported, and deposited.
How is soil categorized?
by horizons based on their composition and organic material
Water holding capacity
the total amount of water soil can hold. Varies with different soil types.
What does water holding capacity contribute to?
land productivity and fertility of soils
How does the particle size affect soil?
affects the porosity, permeability, and fertility
Physical weathering
Mechanical breakdown of rocks and minerals
Abiotic causes of weathering
water, wind, temperature variations
Biotic causes of weathering
plant roots, burrowing animals
Chemical weathering
Releases essential nutrients from rocks
O Horizon = “Organic”
Decomposed organic material
Sometimes called humus (lower layer)
Most pronounced in forests
A Horizon = topsoil
Surface soil/topsoil
Organic mixed with mineral material
Most biological activity
E Horizon = “Eluviated”
In some acidic soils
Metals and nutrients are leached, or eluviated, from above (iron, aluminum, organic acids)
B Horizon = Subsoil
Mineral material – zone of accumulation of metals and nutrients
C Horizon
Least weathered
Similar to parent material
R Horizon
rocks unweathered parent material
Soil services
- Plant growth
- Cycling of nutrients
- Habitat
- Engineering medium
- Water storage and filtration
asthenophere
semi molten, flexible rock
lithosphere
solid upper mantle, outermost layer
hot spots
places where molten material from the mantle reaches the lithosphere
how is a volcano formed?
when a plate moves over a hotspot , heat melts the crust
