• The Earth is……
– Old
– A system
– A dynamic place
•Why is the Earth constantly changing?
• Geologic Processes
• Change can be dramatic or subtle
• Changes can occur at constant or variable rates
• Changes can be repetitive or not
• Repetitive change can be rhythmic or irregular
The Earth System
• The Earth consists of 4 major parts
• Solid Earth
• Atmosphere
• Hydrosphere
• Biosphere
• Changes to one part of the system has an impact on the other parts
The Dynamic Earth
• Mechanisms for change - internal earth processes
• The layered earth
• Outer core = internal heat engine
Internal Processes
• Mantle Convection
• Moving Plates
• Changes/Tectonism - occurs at plate boundaries Internal Processes
• Tectonism occurs at different rates
• Short-term catastrophic change
– Volcanic eruptions
– Earthquakes
– Tsunamis
• Long-term subtle change
– Plate movement
– Sea-floor spreading
– Mountain building
Surface Processes
Powered by the Sun and Other
EX: the Hydrologic Cycle
Sculpts surface and breaks down Earth Materials
Surface Processes
• Short-term catastrophic change
– Storms
– Floods
• Long-term subtle change
– Erosion/deposition
– Climate change
– Sea level change
Geologic Change
• Discuss the following question with the people next to you…
• What types of changes are more likely to have a long-lasting influence
on the earth system….
• Short-term catastrophic change or long-term gradual change?