sedimentation

• Mineralogy influences weathering

  Minerals crystallizing first in Bowen’s Reaction Series are more susceptible to chemical weathering
• Transportation

  Movement of weathered rock products by agents like streams, glaciers, wind, waves, and currents
• Deposition


  Settling of transported sediments in a new location
• Climate, topography, parent rock, chemical/mineral composition, and organic activity affect weathering
• Topography affects weathering

  Gently sloping areas favor chemical weathering, while steeper terrains favor mechanical weathering
• Chemical weathering


  • Breakdown of rocks with changes in chemical and mineral composition
• Mechanical weathering

  • Breakdown of rocks into smaller pieces with no changes in chemical and mineral composition
• Sedimentation


  Formation of sediments and their reaction to different surficial conditions
• Products of weathering are removed through erosion


  Agents include streams, glaciers, wind, waves, currents, and groundwater
• Weathering

  Breakdown of rocks into smaller pieces through mechanical or chemical processes
• Type of parent rock affects weathering

  Coarse-grained rocks and finer-grained rocks weather easily due to different factors
• Weathering can be mechanical or chemical
• Erosion


  Removal of weathered rock products from the source area
• Agents of erosion

  • Streams
  • Glaciers
  • Wind
  • Waves and currents
  • Groundwater
• Agents of erosion

  • Streams
  • Glaciers
  • Wind
  • Waves and currents
  • Groundwater
• Stream erosion


  Occurs along flood plains, alluvial fans, deltas, and valleys
• Wind erosion


  Indicated by the landforms loess and dunes
• Settling velocities increase with particle size and density, spherical particles tend to settle the fastest
• Transportation

  The movement of particles and solution by wind, water, and ice
• Physical transport

  Particles move when the force of the flow exceeds gravitational and cohesive forces, characterized by capacity and competence of the flow
• Chemical transport


  Dissolved ions present in water dependent on mineral solubility, ions deposited when chemical and physical changes are favorable
• Load


  The material normally transported
• No two depositional environments are exactly alike, differences in various factors distinguish them
• Erosion by waves and ocean currents


  Occurs in the undertow and longshore areas
• Glacial erosion


  Manifests as the formation of tills and moraine deposits along valley glaciers, ice caps, cirques, and hanging valleys
• Types of load

  • Bed load
  • Suspended load
  • Dissolved load
• Weathering

  Can be removed from the source area through the process of erosion
• Groundwater erosion


  Occurs particularly with fluctuating water table and along springs, influenced by the permeability and porosity of rocks
• Deposition


  Occurs when the transporting medium loses kinetic energy, particles settle due to decreased transport velocity and turbulence
• Cases of emerging environments are possibilities
• Types of depositional environments

  • Continental environment (fluvial, lacustrine, eolian)
  • Transitional environment (shorelines such as deltas and linear shorelines)
  • Marine environment (reef, shelf, pelagic areas)
• Factors that distinguish different depositional environments

  • Fauna and flora
  • Geology
  • Geomorphology
  • Climate and weather
  • Depth
  • Salinity
  • Temperature
• Sedimentary processes are affected by surface conditions leading to weathering, erosion, transport, and deposition
• Facies

  A mass of sedimentary rocks defined and distinguished by its geometry, lithology, sedimentary structures, paleoclimate patterns, and fossils
• By principle, there are no two depositional environments that are exactly alike
• Diagenesis


  All modifications in sediment characteristics that take place after the sediments have been deposited, including compaction, cementation, replacements, and recrystallization
• Understanding sedimentary processes can save lives and promote development