This document discusses Earth materials and processes. It focuses on the geologic cycle and its subcycles, including tectonics, rocks, hydrology, and biogeochemistry. Key points covered include the two types of crust (oceanic and continental), plate tectonics and the three types of plate boundaries (divergent, convergent, transform), and associated landforms. Critical cycles like the hydrologic cycle and biogeochemical cycles are also introduced.

1. Ch. 2 Earth Materials &
Processes

2. Earth Materials & Processes
Focus:
Geologic materials and processes most important to the study of the
environment
Objectives:
– Acquire a basic understanding of the geologic cycle and its
subcycles (tectonic, rock, hydrologic, biogeochemical)
– Review of some of the important mineral and rock types and
their environmental significance
– Appreciation/significance of geologic structures
– Appreciation of the landforms, deposits, and environmental
problems resulting from wind and glacial processes

3. Earth Materials & Processes
1. Geologic cycles & processes (espec. Tectonics)
2. Rocks & Rock Materials
– General properties
– Types/classification (general)
– Geologic structures
3. Surficial Processes: Ice & Wind

4. Earth (Geologic) Processes
Combinations of Internal and Surficial Processes affect and
shape the environment:
– Mountain Building Processes (Internal processes)
• Volcanism
• Faulting
• Folding
– Erosional/Depositional Processes (Surficial: driven by solar energy):
• Water/Rivers
• Glaciers
• Wind
• Landslides

5. Geologic (Earth) Cycles
• Tectonic (plate tectonics)
• Rock Cycle
• Hydrologic Cycle
• Biogeochemical Cycles
– Carbon, Nitrogen,
Phosphorous, etc.

6. Tectonic Cycle
• Tectonic = Large-scale internally driven
dynamic earth processes
• Shape and deform the earth’s crust (landforms)
– Mountain building
– Continents
– Basins

7. The earth is a differentiated planet with
dynamic internally-driven processes

8. Essentially all parts are in motion, producing:
“Plate” motions in the lithosphere: Plate Tectonics

9. Continuous cycling of “lithospheric” material through:
• Formation of new “oceanic” crust at “spreading centers”
• Destruction of older “oceanic” crust at “subduction” zones
• “Islands” of thick, relatively stable, “continental” crust
• These “zones” define plate boundaries

10. Surface/Crustal Manifestation of
Plate Tectonics

11. Observations/Correlations:
• Types and spatial distribution of plate boundaries
• Correlation between plate boundaries and volcanoes (+ earthquakes)

12. Two Types of Crust/Lithosphere:
• Oceanic
Crust (O)
• Continental
Crust (C)
r = 2.8
r = 2.9
r = 4.5
Core
r = 10.7

13. Two Types of Crust/Lithosphere:
• Oceanic (O):
• forms 70% of earth’s crust
• constitutes sea-floor bedrock; ~30 km thick
• made of primary volcanic “basalt”; density=2.7-3.0
• Young; No old oceanic crust
• Continental (C):
• Thicker (~100 km)
• Composition: Less dense sediment/granite
• “floats” on denser mantle material
• Older
• Mantle
– Primary material (from which basalts are derived)
– Underlies crust

14. Plate Boundaries
Most major tectonic activity (volcanoes,
earthquakes, etc.), and major topographic
features occur (or were formed) at plate
boundaries

15. Main Types of Plate Boundaries
• Divergent (splitting apart)
• Convergent (colliding)
• Third Type = Transform
(e.g., lateral offset)

16. Types Plate Motion, Plate Boundaries, and
Examples of Associated Landforms/Features
• Divergent (separating):
O-O sea-floor spreading/mid-ocean ridges
C-C Continental “rifts”: Red Sea, Rio Grande & Mississippi
river valleys, E. African (Kenyan) Rift Valley
• Convergent (colliding):
O-O Island arc Subduction; Japan, Aleutians
O-C Continental margin Subduction; Cascades, Andes
C-C Continental collision; Himalayas, Alps, Appalachians
Others: Obduction; Accreted terrain

17. Divergent Plate Boundaries (splitting)
Oceanic Rifts/Ridges
Continental Rifts:
– Red Sea; E. Africa
– Flood lavas (basalts)

18. Convergent Plate Boundaries (Colliding)

19. Continent-Contintent
Convergence
• Himalayas
• Alps
• Urals
• Appalacians

21. Other Types of Convergence &
Convergent Features
Oman
Obduction
•Coast Ranges
•Klammath Mtns
•Oman
•Newfoundland
Accreted Terrain:
•Olympic Mtns.
•Etc.

22. Lateral offset of
divergent boundaries
– Offsets of mid-ocean ridges
– San Andreas fault
Transform Boundaries

23. Other Important Types/Features
• Hot Spots:
– Hawaiian Islands
– Yellowstone, Snake River Plain, Columbia River
Plateau
• Flood Basalt Provinces (within continents)
– Columbia River Basalts
– India, S. Africa, Greenland, Brazil, Germany, etc.

24. Hawaiian
Hot Spot

25. Also correlated with distribution of volcanoes and earthquakes (see book)

26. Plate Tectonics of the Western US
Major tectonic activity (volcanoes, earthquakes, etc.), and geographical features
occur at plate boundaries and/or hot spots.

27. Hydrologic Cycle

28. Carbon
Cycle

29. Rock Cycle
• Stay Tuned

30. Summary
• Earth is differentiated and dynamic
• Manifestation of dynamic earth processes in lithosphere =
plate tectonics
• Two types of crust: oceanic & continental
• Centers/Zones where crust is formed (spreading) or
destroyed (subducted) or accreted define plate boundaries
• Two types of plate boundaries:
– Divergent (splitting/spreading)
– Convergent

31. Summary con’t
• Major “tectonic”/topographic features/events are
localized at plate boundaries (volcanoes, earthquakes,
mountains, trenches, hydrothermal vents)
• Other related features:
– Transform boundaries (faults)
– Hot Spots (oceanic & continental)
• Hydrologic Cycle: Water transport & storage system
• Biogeochemical Cycles: Counterpart for chemicals ±
biologic systems/storage