1. Earth Systems

2. Geologic Time Scale 4 Distinct Eras
-used by scientists to describe the timing of Earth’s past events.
4 Distinct Eras
Precambrian(Earth formation)
2) Paleozoic(fish & reptiles)
3) Mesozoic(dinosaurs)
4) Cenozoic(mammals)
-separated by major extinctions.

3. GEOLOGY
Study of Earth’s interior & exterior processes as it relates to minerals and land formations.
3 Main Layers of Earth
1) Core- innermost zone
solid inner core of iron metal
liquid outer core
2) Mantle- thick, solid but fluid zone outside the core
3) Crust- outermost layer, mostly oxygen & silicates
*Lithosphere- land area of Earth consisting of the
crust and outer mantle.

4. Earth’s Layers

5. Rock Cycle process of rocks changing from one form to another Mineral
- naturally occurring, solid element/compound
Rock
- any solid material that makes up a continuous
segment of Earth’s crust.
- usually made of 2 or more minerals

6. Rock Types 1) Igneous - formed from cooled magma 2) Sedimentary
- combination of different sediments
pressed together
3) Metamorphic
- formed by high temp. & pressure
under the Earth
(Obsidian)
(Breccia)
(Gneiss)

8. Plate Tectonics Movement of Earth’s rigid plates
Caused by the flow of heat energy underneath.
Plate movement creates 3 boundary types:
1) Divergent plate boundary
- plates that move apart
2) Convergent plate boundary
- plates that push together
- create mountains, subduction zones
- can cause earthquakes & volcano formation
3) Transform Fault boundary
- plates that slide past each other

9. Plate Boundaries

10. RING OF FIRE

11. Earthquake
- abrupt movement along a fault

12. Volcano area where magma reaches the surface
releases solid objects, liquid lava, & gases
found near plate boundaries.

13. External Forces
1) Erosion
- carrying away of loose sediment &
depositing it elsewhere.
2) Weathering
- wearing down of rock by:
a) mechanical weathering
- physical actions
b) chemical weathering
- oxygen, carbon dioxide, water

14. Soil Soil Profile mixture of humus, rocks, air,
minerals, water, & organisms
- formed by:
- weathering of rock
- deposition of sediments
- decomposition of organic
matter

15. Soil Composition
- soil has a characteristic color, texture, structure, &
mineral content.
- Five soil composition types are:
1) Desert- mostly sand & pebbles
2) Grassland- rich humus & clay
3) Rain forest- acidic, light humus, some clay
4) Deciduous forest- humus-mineral mixture
5) Coniferous forest- acidic humus

16. Soil Types/Textures - texture determines permeability & porosity Types
1) clay- very fine particles
2) silt- fine particles
3) sand- medium size particles
4) gravel- coarse particles
5) loam- mixture of clay, silt, sand, gravel
Small particles = low permeability, high porosity
Large particles= high permeability, low porosity

17. Soil Types/Textures

18. Soil Erosion - movement of topsoil from one place to another Causes:
1) flowing water
2) wind
3) human activities (farming, logging, overgrazing)
Results:
1) loss of soil fertility & ability to hold water
2) sediment runoff causing pollution

19. Desertification - the process that changes a semiarid region into
an unproductive desert region.
Causes:
overgrazing, deforestation, erosion, salinization,
surface mining, soil compaction
Solutions:
1) Reduce loss of vegetation
2) Plant new vegetation that will reduce erosion

20. Excessive Irrigation - too much watering leads to: 1) Salinization
- salt accumulation due to evaporation of
unabsorbed water.
- excess salt becomes harmful to crops
2) Waterlogging
- saturating the ground causing excess salt
to concentrate at the roots
Solutions
- irrigate crops more efficiently
- plant salt tolerant crops

21. Soil Conservation Methods for reducing erosion:
1) Conservation-tillage farming
- farming with less soil tillage
- conventional-tillage leaves soil bare and
vulnerable to erosion.
2) Terracing
- cutting level layers into a slope for farming
3) Contour Farming
- plowing a field across the contour of a slope

22. 4) Strip cropping
- varying the type of crop planted from row to row
5) Alley cropping
- planting crops between rows of trees/shrubs
6) Wind breaks
- planting trees along the edge of fields