1. Earth Systems

2. The Earth’s resources were determined when the planet formed.
Earth is ~4.6 Billion years old
Almost all of the elements currently found on the planet were present during formation.
As the forming Earth cooled, heavier elements condensed due to gravity and settled based on mass.
Ex. Iron sank towards the center and silica settled towards the surface.
Gaseous elements became the atmosphere

3. The Earth’s Layers
This settling by mass resulted in distinct vertical layers
Core - the innermost zone of the planet made of nickel and iron.
Mantle - above the core containing magma
Crust - the outermost layer of the planet.

4. The Earth’s Layers
Asthenosphere- the outer part of the mantle, composed of semi- molten rock.
Lithosphere- the brittle outermost layer of the planet

5. Lithosphere Made up of several large plates and numerous small plates
Includes the upper mantle and crust
Contains soil on the upper crust which is what allows life on the planet to exist because they contain the elements required for life

6. Earth is dynamic and constantly changing
Earth’s geologic cycle consists of 3 major processes:
Tectonic Cycle
Rock Cycle
Soil formation

7. Convection and Hot Spots
Despite being 4.6 byo, the planet remains very hot at
its center
The heat causes hot magma plumes to well upward from the mantle producing hot spots
Hot Spots: places where molten material from the mantle reaches the lithosphere

8. Theory of Plate Tectonics
States that the Earth’s lithosphere is divided into plates, most of which are constantly in motion
Tectonic Cycle – The sum of the processes that build up and break down the lithosphere

9. Plate Tectonics The lithosphere is broken into plates:
Oceanic Plates: Lie primarily beneath oceans
Crust is dense and rich in iron
Continental Plates: Lie beneath land masses
less dense and has more silicon dioxide
Continental plates are lighter and will rise above oceanic plates

10. Plate Tectonics
Convection: the movement of hotter and less dense material to rise, and colder, denser material to sink which results in the transfer of heat.
Where oceanic and continental plates come together, subduction occurs
Subduction: Plates passing under one another

11. Consequences of Plate Movement
As a plate moves over a geologic hot spot, heat from the rising mantle plume melts the crust and forms a volcano
Volcano: a vent in the Earth’s surface that emits ash, gases, and molten lava.

12. Plate movement over a hot spot
Hawaiian islands are an example of how land can form over hot spots due to volcanic eruption
Geologically, this is how all land originally formed
The eruption and cooling of molten lava

13. Types of Plate Contact
Divergent plate boundaries- when plates move apart from one another.
Convergent plate boundaries- when plates move toward one another and collide.
Transform fault boundaries- then plates move sideways past each other.

14. Divergent Boundaries Occur between oceanic plates
Plates move away from each other, new magma rises and cools to form new lithosphere
This is called seafloor spreading

15. Convergent Boundaries
If oceanic collide with continental, a coastal mountain range will form because the lighter continental plate will rise on top of the heavier oceanic plate which will subduct
If 2 continental plates collide, both margins will rise forming a mid-continental mountain range

16. Transform Fault Boundaries
Transform boundaries are where plates slide against each other
Faults- a fracture in rock across which there is movement.
Earthquakes- occur when the rocks of the lithosphere rupture unexpectedly along a fault.

17. The Rock Cycle
Rock cycle- the constant formation and destruction of rock.

18. The Rock Cycle Igneous rocks- rocks that form directly from magma.
Sedimentary rocks- form when sediment such as mud, sands, or gravels are compressed by overlying sediments.
Metamorphic rocks- form when sedimentary, igneous or other metamorphic rocks are subjected to high temperatures and pressures.

19. Weathering and Erosion
Weathering- when rocks are exposed to air, water, certain chemicals or biological agents that degrade the rock.

20. Weathering and Erosion
Physical weathering- the mechanical breakdown of rocks and minerals.
Chemical weathering- the breakdown of rocks and minerals by chemical reactions.

21. Erosion
Erosion- the physical removal of rock fragments from a landscape or ecosystem. Wind, water, ice transport and living organisms can erode materials.
Deposition- the accumulation or depositing of eroded material such as sediment, rock fragments or soil.

22. Soil Soil is important because it Is a medium for plant growth
Serves as a filter for water
A habitat for living organisms
Serves as a filter for pollutants

23. The Formation of Soil Factors that determine the formation of soil:
Parent material- what the soil is made of influences soil formation
Climate- what type of climate influences soil formation
Topography- the surface and slope can influence soil formation
Organisms- plants and animals can have an effect on soil formation
Time- the amount of time a soil has spent developing can determine soil properties.

24. The Formation of Soil
Parent Material- the rock material from which soil is derived.

25. Soil Horizons
As soils form, they develop characteristics layers.

26. Soil Horizons
O horizon- (organic layer) composed of the leaves, needles, twigs and animal bodies on the surface.
A horizon- (topsoil) the zone of organic material and minerals mixed together.
B horizon- (subsoil) composed primarily of mineral material with very little organic matter
C horizon- (parent material) the least weathered horizon and is similar to the parent material.

27. Physical Properties of Soil
Texture- the percentage of sand, silt and clay the soil contains.

28. Physical Properties of Soil
Porosity- how quickly the soil drains (which depends on its texture)