Geology Chapter: Deposition Terms

Deposition and Sedimentation Concepts

• Deposition: The process of dropping materials in new locations, integral to shaping landscapes.
• Sediments: Small fragments of rock that accumulate in various environments.
• Sedimentation: Synonymous with deposition; primarily refers to sediment settling out of transport mediums.

Erosional-Depositional System

• Erosional-depositional system: Continuous cycle of removing, transporting, and depositing sediments within a region.
• Water Influence: Deposition occurs when water carrying sediments slows or ceases.

Factors Influencing Deposition

• Particle Size: Larger particles settle first while smaller particles take longer to deposit.
• Particle Shape: Round particles settle faster than oval-shaped, which settle faster than flat particles.
• Particle Density: Denser particles settle more rapidly than less dense ones.

Sorting of Sediments

• Sorting: The process wherein particles are separated during deposition.
• Vertical Sorting: Sorting occurs from bottom to top within a sediment layer.
• Graded Beds: Layers of sorted sediment, typically found in quiet water environments.

Environmental Conditions for Deposition

• Location of Graded Bedding: Forms in shallow, calm water bodies and on the sea floor.
• Stream Velocity: Decreased velocity results in increased deposition of sediments.
• Horizontal Sorting: Happens as a stream slows, depositing sediments sequentially.

River and Delta Dynamics

• Sedimentation at River Mouths: When a river meets a larger body of water, its velocity drops suddenly, causing sedimentation.
• Delta Formation: A sediment deposit at the mouth of a river, contributing to land formation.

Processes of Precipitation

• Precipitates: Crystals that form from ion solutions.
• Precipitation Process: The conversion of ions into crystallized forms.

Glacial Deposits

• Direct Glacial Deposits: Unsorted sediments left directly by melting glaciers.
• Indirect Glacial Deposits: Sediments transported by water from melting glaciers, partially sorted.

Wind and Erosion

• Wind Deposition: Sediments deposited in well-sorted, fine layers due to wind patterns.
• Cross Bedding: Layer orientation changes due to varying wind directions.

Erosion and Dynamic Equilibrium

• Gravity's Role: Causes deposition at slope bases without sorting.
• Dynamic Equilibrium: A state where erosion and deposition balance evenly.

Floodplains and Features

• Flood Plain: Areas alongside streams where sediments spread after flooding.
• Moraine: Mounds of unsorted sediments left by glaciers, indicative of glacial movement.
• Drumlin: Oval mounds formed beneath glaciers, with the steep slope showing the glacier's origin direction.

Unique Landforms and Features

• Kettle Lakes: Formed by melting ice blocks leaving depressions that fill with water.
• Outwash Plains: Sorted sediments deposited by meltwater from glaciers.
• Beach: Coastal strips of sediments accumulated due to wave action.
• Sandbars: Form parallel to shorelines where strong currents deposit sediments.
• Barrier Islands: Narrow, elongated islands formed by sand from ocean waves, protect coastlines from erosion.

This quiz focuses on key terms related to deposition and sedimentation in geology. It covers definitions and processes including sediments and erosional-depositional systems. Test your knowledge on these fundamental concepts in earth sciences.