Sedimentary Rocks and Clastic Formation

Sedimentary Rock

• Two major types of sedimentary rocks:
  • Chemical: Formed by mineral precipitates from chemical or biochemical processes       - Clastic (Detrital): Formed from eroded rock fragments (mineral or rock)
• Clastic rocks dominate Earth’s crust

Characteristics of Clastic Rocks

• Composed primarily of silicate fragments called "clasts"
  • Examples: quartz, granite, basalt
• Formation process: weathering & erosion, transport, deposition, and lithification

Clastic Rock Components

• Clasts (c)
• Matrix or groundmass (m)

Porosity

• Important property for hydrocarbon reservoirs (oil and natural gas)
• Pores can be filled with fluids
• Pore types:
  • Macropores: larger than 5 microns
  • Micropores: smaller than 5 microns

Pore Classification

• Catenary pores: allow fluid flow in subsurface conditions
• Cul-du-sac pores: can be filled with fluids but do not allow flow
• Closed pores: generally empty, do not allow fluid flow

Clastic Rock Formation Cycle

• Weathering & erosion > Transport > Deposition > Lithification

Weathering and Erosion

• Physical alteration of rocks exposed to atmospheric influences
• Physical weathering: breaks bedrock into smaller fragments, mineral composition remains unchanged
• Chemical weathering: reactions between water, dissolved ions, and solid rock that produce new materials

Sediment Transport

• Various transport mediums:
  • Landslides and rockfalls       - Eolian transport (winds and air currents)
  • Glacier transport (glaciers)
  • Stream and river transport (continental water)

Explore the fascinating world of sedimentary rocks, focusing on the classification and characteristics of clastic rocks. Learn about the formation processes, porosity, and the different types of pores that influence fluid flow. This quiz will enhance your understanding of how clastic rocks dominate Earth's crust and their significance in hydrocarbon reservoirs.