Landscape Evolution Models

Landscape Evolution Models

1. Geomorphology

   • Studies
     • Earth's landforms
     • Processes that shape Earth
   • Concept of evolving landforms

2. Landscape evolution

   • Interactions between
     • Landforms
     • Processes that shape the land over geological time scales

3. Taxonomy of Landscape Evolution Models

   • Landform
     • Feature of topography, shaped by surficial processes
   • Landscape
     • Aggregate of landforms

4. Categories of Landscape Evolution Models

   • Qualitative
     • Describe long term changes in size, shape and relief of landforms
     • Based on good field observations
     • Classic paradigms of long-term landscape evolution
       • Base Level, Erosion, and Landscape Genesis
         • Ideas extracted from observations of
           • Great Unconformity of Grand Canyon
           • Water washing off material of steep hill slopes
           • Rivers attempting to lower their gradients
       • Form and Process
         • Modern process geomorphology
           • Interaction between form and process: equality of action
           • Rates of erotion, land sculpture and drainage adjustment
       • The Geographic Cycle
         • All landscapes are palimpsests, overwritten by numerous tectonic and climatic processes
         • How mean elevation and mean relief change as a landscape erodes
       • Slope Replacement
         • Long-term landscape evolution occurs in stages from youth to old age
         • Mechanism for hillslopes evolution
       • Pediplanation
         • "Landscape assumes the form of a series of nested, retreating escarpments"
         • When a pediment forms, it persists indefinitely until consumed by younger retreating escarpments
       • Dynamic Equilibrium
         • Landscapes are in a state of dynamic equilibrium
           • “Given the same driving and resisting forces over a long period, a time independent characteristic landscape will emerge”
         • Climate, tectonics and rock type change as subaerial erosion progresses
       • Process Linkage
         • "Direct and indirect ways in which individual components of a watershed mutually respond to an external driving force"
           • Tectonics and climate
         • There isn't an unique response to an stimuli
         • Landscape change depending on creation and routing of sediment
       • Geodynamic and Surficial Process Feedbacks
         • Shape of a mountain range depends on the uniformity of erosion upon the range
         • Evolution of landscape is a reaction, not an interaction, with climate or tectonic changes
   • Physical
     • Scale representations of landforms
     • It's difficult to correctly scale material properties
     • Isolate one part of the Geomorphic System
       • Drainage Networks
         • Hypotheses of drainage networks evolution
           • Network growth by overland flow
           • Headward growth of established channel heads
           • Dominance of rapidly elongated channels
       • Hillslopes
         • Understand landslides, earthflows, and debris flows
         • Simulations of weathering and rock disaggradation
         • Some models are controlled field monitoring studies designed to isolate one process acting over a limited area
       • Alluvial and Bedrock Channels
         • Purpose: understand processes and behaviors of alluvial channels
         • Focus on bedrock channels: understand their behavior on tectonically active settings
           • Processes and rates of channel bed erosion
         • Variables: gradient, width, depth, flow velocity, grain size depending of the discharge
       • Process Sedimentology
         • Synthesize basin stratigraphy
         • Purpose: deconvolve the record of base level, sediment supply, and subsidence from a resulting synthetic stratigraphy
   • Surficial Process Models
     • Principles of physics and chemistry
     • Inspired and verified by field observations
   • Numeric Models
     • Surrogate Models
       • Aims to track a metric of the landscape
       • Uses physically based equations or relations between landscapes and processes
     • Multi-Process Landscape Models
       • Considers several interacting geomorphic processes
       • Mathematically describes several processes
     • Coupled Geodynamic-Surface Process Models
       • Predicts topographic and landscape evolution based in the deformation of Earth's Crust
     • Different Aproaches
       • Computational Intense
       • Looking to capture all interactions of geomorphic and geodynamic processes

5. Estudiante: María Isabel Olarte García