Themes of the Day:

• Erosion, Transport & Deposition of Sediments
• Depositional Environments
• Sedimentary Structures
• Lithification

Erosion, Transport & Deposition of Sediments

• Conditions Necessary for Erosion, Transport, and Deposition
• Strongly linked to weather and the hydrologic cycle
• Transporting media:
  • Water
  • Air/Wind
  • Ice
• Gravity is the ultimate driving force - tectonic and climatic forces contribute
• Sediment Changes During Transport
  • Size decreases
  • Shape becomes more rounded (less angular)
  • Sorting improves - e.g., Poorly sorted sediment becomes well sorted sediment

Depositional Environments

• Figure 8-4 - Block Diagram, Explanation
• Terrestrial
  • Rivers (channel, floodplain)
  • Lakes
  • Deserts
  • Glaciers
• Marine
  • Coastlines
  • Deltas
  • Shallow Marine
  • Deep Marine

Sedimentary Structures

• bedding (straification)
• cross bedding - e.g., Zion National Park
• ripple marks - e.g., in sand and in sandstone
• graded bedding
• mudcracks and raindrop impressions - cross section of mudcracks in a mudstone
• fossils/trace fossils/bioturbation

Lithification

• Compaction - decrease in pore space - often due to burial
• Cementation - mineral "glue" fills in remaining pore spaces
• Dissolution/precipitation by pore waters
• Recrystallization (but not too much)