Exogenic Processes and Degradation Overview

Exogenic Processes

• Exogenic processes are external processes occurring near Earth's surface.
• They are part of the rock cycle, transforming rock into sediment.
• These processes involve degradation (weathering, mass wasting, erosion, and transportation) and aggradation (deposition).

Degradation Processes: Weathering, Mass Wasting, Erosion & Transportation

• Weathering: Physical breakdown and/or chemical alteration of rocks near Earth's surface.
• Types of Weathering: Mechanical and Chemical.
• Mechanical Weathering: Large rocks break into smaller fragments without changing mineral composition.
• Frost Wedging: Water in cracks expands when it freezes, causing rocks to break.
• Insolation Weathering: Thermal stress from expansion and contraction of rocks due to temperature changes.
• Unloading or Pressure Release: Overlying rock eroding, causing the outer layer to expand more than the layers underneath.
• Chemical Weathering: Decomposes rocks through chemical changes.
• Oxidation: Oxygen dissolved in water oxidizes some materials, creating reddish-brown rust.
• Hydrolysis: Water is the most important chemical weathering agent, dissolving minerals into ions that react with water, forming clay minerals.
• Carbonation and Solution: Carbon dioxide dissolves in water forming carbonic acid, reacting with carbonate rocks forming a soluble product (calcium bicarbonate).

Mass Wasting

• Mass wasting is the movement of rocks, soil, and regolith.
• It is a degradation process following weathering.
• Gravity, steepness of slope, water content, and vegetation influence mass wasting.
• Oversteepening is a factor affecting mass wasting.
• Examples include rock fall, debris fall, slides (translational and rotational), and flows (slurry and granular).

Erosion

• Erosion is a degradation process, transporting weathered sediments to different places.
• Agents of erosion include water (splash, rill, gully, valley, bank, coastline), glaciers (plucking, abrasion), and wind.

Aggradation Processes (Deposition)

• Deposition is the aggradation (accumulation) of weathered sediments.
• Deposition leads to landform creation.
• Depositional features include spits, deltas, alluvial fans, moraines, and sand dunes.

Transportation

• Materials are transported in four distinct ways: solution, suspension, traction, and saltation.

This quiz explores exogenic processes that shape Earth’s surface through degradation and aggradation. You will learn about various types of weathering, including mechanical and chemical processes, and the role of erosion and sediment transportation. Test your knowledge on how these processes contribute to the rock cycle.