EXOGENIC AND ENDOGENIC PROCESSES

• What are exogenic processes in geology?

  • Geologic processes that occur on the surface of the Earth
  • Examples: weathering, erosion, and sedimentation/deposition
• What is weathering in geology?

  The breaking down of rocks and minerals on the surface of the Earth
• What is erosion in a geological context?

  The geological process in which earthen materials are worn away and transported by natural forces such as wind or water
• What is deposition in geology?

  The laying down of sediment carried by wind, flowing water, the sea, or ice
• What is the relationship between erosion and deposition?

  Erosion is the process, deposition is the product
• What are the two main types of weathering?

  • Mechanical or Physical weathering
  • Chemical weathering
• What is mechanical or physical weathering?

  The breakdown of rocks into pieces without any change in their chemical composition
• How does pressure cause mechanical weathering?

  • Tectonic forces cause rocks like granite to rise and form mountain ranges
  • When pressure diminishes, the rock expands, cools, and becomes brittle and fractured
• How does temperature affect rock weathering?

  • High temperatures cause rocks to expand and fracture
  • Freezing temperatures also cause expansion and fracture
• What is frost wedging?

  The process where water accumulates in cracks, freezes, expands, and breaks the rock apart
• How does abrasion contribute to rock breakdown?

  • Caused by impact and friction
  • Primarily occurs during collision of rocks, sand, and silt due to currents or waves
  • Leads to sharp edges and corners wearing off, becoming rounded
• How do plant roots contribute to rock weathering?

  Roots grow into cracks, expand, and eventually break the rock
• How do human activities affect weathering?

  • Digging
  • Quarrying
  • Deforestation
  • Cultivating land
• Name some burrowing animals that contribute to weathering.

  Rats, rabbits, and squirrels
• What is chemical weathering?

  The breakdown of rocks into pieces with changes in their chemical composition
• In which specific minerals does dissolution occur during chemical weathering?

  Halite and calcite
• What is hydrolysis in chemical weathering?

  • Rock forming minerals react with water
  • Forms different kinds of clay minerals
  • Examples: amphibole, pyroxene, feldspar
• What are endogenic processes in geology?

  Processes that occur or are created under the Earth’s surface
• What is oxidation in chemical weathering?

  The response of oxygen in minerals, such as rusting
• What is primordial heat?

  • Internal heat accumulated during a planet's first few million years
  • Result of potential energy released during matter collapse into a gravity well
  • Kinetic energy of accreted matter also contributes
• What is radiogenic heat?

  • Heat energy produced from spontaneous nuclear disintegration
  • Radioactive isotopes are responsible
  • Approximately 50% of Earth's internal heat originates from this process
• What is $^{238}U?$


  Uranium-238
• What is $^{235}U?$


  Uranium-235
• What is $^{232}Th?$


  Thorium-232
• What is $^{40}K?$


  Potassium-40
• What are the three primary methods of heat transfer in Earth’s interior?

  • Conduction
  • Convection
  • Radiation
• What is conduction in heat transfer?

  A process by which thermal energy is transmitted between neighboring atoms or molecules
• What is convection in heat transfer?

  The transfer of heat by movement of mass, predominantly fluid
• What is radiation in heat transfer?

  The transfer of heat in the form of waves or particles without direct contact
• What is magmatism in geology?

  • The movement of magma to form igneous rocks
  • Responsible for mountain formation
  • Forms additional mass and volume at Earth's convergent and divergent boundaries