GEOG 205 - FINAL EXAM

What is geomorphology?

The study of surface landforms, processes, and landscape evolution of the Earth.

What do surface processes produce?

Materials and landforms.

What do landform and material products record?

Earth’s surface history.

Name the subdiscipline that studies rivers.

Fluvial geomorphology.

Name the subdiscipline focused on slopes.

Hillslope geomorphology.

Name the subdiscipline focused on ice-related processes.

Glacial geomorphology.

Which subdiscipline studies tectonic forces?

Tectonic geomorphology.

Which geomorphology subfield is quantitative and often overlaps with civil engineering?

Quantitative geomorphology.

Which subdiscipline studies coastlines?

Coastal geomorphology.

Which subdiscipline focuses on deserts?

Desert geomorphology.

Which subdiscipline combines biology with geomorphology?

Biogeomorphology / landscape ecology.

Which subdiscipline examines limestone landscapes?

Karst geomorphology.

Why is setting important in geomorphology?

Biophysical factors affect processes and the rate at which they occur.

Define “process” in geomorphology.

A set of actions or mechanisms that operate in order to produce a phenomenon in response to a driving force.

Define “form” in geomorphology.

A characteristic landform over which processes occur; forms are results of processes.

Give an example of a geomorphic process.

Wind.

Why does wind occur?

Because of atmospheric pressure differences.

How can wind influence the landscape?

By causing processes such as tree blowdown, which alters the landscape.

What is catastrophism?

The belief that changes occur due to sudden, catastrophic, large-scale events happening over short periods.

Who proposed catastrophism?

Georges Cuvier.

Give examples of catastrophic events.

Floods, earthquakes, eruptions, impacts.

What is uniformitarianism?

The idea that changes occur through continuous, smaller-scale processes over long periods.

Who proposed uniformitarianism?

James Hutton.

What phrase summarizes uniformitarianism?

“The present is the key to the past.”

What processes drive uniformitarian change?

Erosion, deposition, compaction, uplift.

What is gradualism?

The refinement of uniformitarianism describing small steps over long periods.

Who proposed gradualism?

Charles Lyell.

What is a modern critique of Davis’s geomorphology model?

It oversimplifies complex processes and assumes steady-state conditions.

What did William Morris Davis emphasize?

Landscape evolution based on form.

Why is Davis’s model problematic scientifically?

It assumes erosion/deposition balance and ignores tectonics and climate variation.

What did Horton and Strahler contribute?

A shift from form-based to process-based geomorphology with numeric quantification.

What is measured in a meandering stream?

Radius of curvature and meander wavelength.

What are examples of channel geometry metrics?

Gradient, channel width, drainage.

Why are scales important in geomorphology?

Processes operate on different time and space scales.

What does “nested scales” mean?

Small-scale processes operate within the context of larger-scale processes.

Name a real-world application of geomorphology.

Hazard assessment and predictive modelling.

What hazards can geomorphologists help predict?

Landslides, floods, river changes, and coastal hazards.

What does geomorphology contribute to water studies?

Understanding water quality and water availability.

What glacial-related application does geomorphology help with?

Determining how glacial landforms act as aquifers.

What planetary field uses geomorphology?

Planetary landform studies.

What climate-related use does geomorphology have?

Reconstructing climate records and process understanding.

How is geomorphology useful for agriculture?

Understanding soil formation and land processes.

Define a geomorphic system.

A set of interrelated objects and processes linked by flows of matter and energy.

What is an isolated system?

A system where no matter or energy crosses boundaries.

What is a closed system?

A system where matter cannot cross boundaries but energy can.

What is an open system?

A system with both matter and energy crossing boundaries.

What is steady-state in an open system?

Equilibrium where inputs and outputs balance.

Define feedback in a system.

Outputs that influence aspects of the system.

What is negative feedback?

A process that discourages change and stabilizes the system.

Give an example of negative feedback.

Coarse sediment deposition lowers gradient, reducing erosion.

What is positive feedback?

A process that amplifies change, causing a snowball effect.

Give an example of positive feedback.

Heavy rain → low infiltration → runoff → soil erosion → thinner soil → even less infiltration.

Define equilibrium in geomorphology.

Self-correcting balance between materials, processes, and geometry.

What is dynamic equilibrium?

Rapid landscape adjustments in response to changing processes.

Define a threshold.

A magnitude/intensity that must be exceeded for a reaction or change to occur.

What causes thresholds?

System imbalances or critical limits.

What is an extrinsic threshold?

A threshold caused by external forces.

What is an intrinsic threshold?

A threshold caused by internal system conditions.

Give a threshold example.

Hillslope moisture exceeding limits → slope failure/landslide.

What determines the rate of landscape change?

Driving forces (energy input) and resisting forces (material strength).

What is the rate of landscape change equation?

Uplift – erosion.

Why do Niagara Falls and the Grand Canyon erode at different rates?

Differences in resisting forces (bedrock strength).

Is soil creep fast or slow?

Slow.

How can soil creep be increased?

By increasing slope angle, reducing vegetation, or increasing moisture.

How can soil creep be slowed?

By stabilizing slopes, adding vegetation, or reducing moisture.

Why is time essential in geomorphology?

Geologic processes require varying time scales and are cyclical.

Define recurrence interval.

The average time between events of a given magnitude.

What is the chance of a “100-year flood” occurring in any year?

1/100.

Can two 100-year floods occur back-to-back?

Yes, with a probability of 1/10,000.

What is recovery time?

Time required for a system to stop feeling effects of an event.

What happens when recovery time is fast and events are rare?

The system returns to its same state.

What happens when a threshold is crossed?

The system changes to a new state.

What events are associated with long recovery times and system change?

High-magnitude or frequent events.

What is the magnitude–frequency relationship?

Frequent events are low magnitude; rare events are high magnitude.

Which events do the most geomorphic work?

Medium-magnitude, medium-frequency events.

What are exogenic forces?

Forces acting on the Earth’s surface.

What are endogenic forces?

Processes and forces acting internally within the Earth.

What is mass balance in geomorphology?

The balance between exogenic and endogenic forces.

What is the first-order controlling factor of exogenic drivers?

Climate influences rainfall, insolation, vegetation, weathering/erosion style, and hydrologic processes.

What does gravity influence as an exogenic driver?

It drives flowing water and ice and density-driven currents.

What are the primary sources of internal heat in endogenic drivers?

Radioactive decay and frictional heat from earth tides and rock deformation.

What is mantle convection?

Movement of hot, low-density mantle rising and cooler, denser mantle sinking.

What does internal heat transfer drive?

Plate tectonics and plate motion.

What is force defined as?

Mass times acceleration, expressed as a vector.

What is energy in geomorphology?

The capacity to do work.

What is work defined as?

Work = Force × distance; work occurs when a force displaces a mass.

What is a geomorphic driving force?

Application of energy to perform work on Earth materials.

What types of events are typically low magnitude?

Frequent events.

How often do high-magnitude events occur?

Much less frequently.

Which events do the most geomorphic work?

Medium-magnitude, medium-frequency events.

What is denudation?

Processes that wear away landforms and decrease elevation and relief.

What does denudation counteract?

Uplift, faulting, and folding.

What is weathering?

In-situ breakdown and alteration of rocks and sediments.

What type of process is weathering?

Exogenic—physical, chemical, and biological.

What is erosion?

Movement of sediment by agents such as wind, water, ice, and gravity.

What does erosion do to weathered products?

Moves and displaces them away from the source area.

What does weathering expose?

New fresh rock to surficial elements.

Is weathering in-situ or by movement?

In-situ.

Is erosion in-situ or movement?

Movement/displacement of sediment.

What is a key function of weathering regarding rocks?

Weakens rocks, making them more susceptible to erosion.