Principles and Unifying Concepts of Geomorphology Week 1

Vocabulary flashcards covering core definitions, processes, systems, and energy/force balances from introductory geomorphology notes.

Geomorphology

The study of the processes shaping Earth’s surface and the landforms and deposits produced by these processes.

Form

In geomorphology, the physical state of the landscape including constitution (material properties), configuration (geometry and spatial relationships), and mass flow (rates of erosion, mass transport, deposition).

Process

Anything that produces change at the Earth’s surface.

Endogenic processes

Internal processes generated within the Earth, such as mantle convection, plate tectonics, and volcanism.

Exogenic processes

External processes generated from outside the Earth, such as erosion, transport, and weathering.

Geosphere

The system encompassing Earth’s crust and the global tectonic system that ultimately controls elevation patterns.

Hydrosphere

The system encompassing oceans, atmosphere, surface and subsurface waters that erode, transport, and deposit mass.

Biosphere

The living parts of ecosystems (plants, animals, fungi) that help shape and are in turn shaped by landscape dynamics.

Felsic

Silica-rich geological material that is less dense, with a density of $2700\,kg/m^3$.

Mafic

Iron-rich geological material that is more dense, with a density of $3000\,kg/m^3$.

Ultra-mafic

The densest geological material, possessing a density ranging from $3300\,kg/m^3$ to $4500\,kg/m^3$.

Isostasy

The gravitational equilibrium between parts of the Earth’s crust such that the crust floats on the mantle based on density differences.

Hypsometry

The mathematical relationship between surface area and elevation on Earth.

Climate

Long-term spatial and temporal patterns of precipitation and temperature on Earth’s surface.

Insolation

Incoming solar radiation that is distributed unevenly over the globe and provides the energy driving climate.

Albedo

The reflectivity of Earth’s surface, where lighter regions reflect more light and darker regions reflect less.

Hadley cells

Equatorial, low-latitude atmospheric circulation cells where warm, moisture-laden air rises at the equator and cold, dry air descends at $30\text{--}35^\circ$ latitude.

Ferrel cells

Temperate region atmospheric circulation cells where warm, moist air rises to produce a rainfall belt between $40\text{--}60^\circ$ latitude.

Polar cells

Polar region atmospheric circulation cells where cold, dry air descends at high latitudes.

Upwelling

The upward movement of warm water in ocean circulation.

Downwelling

The downward movement of cold water in ocean circulation.

System

A collection of related components.

Landscape

A suite of landforms that share common genesis, contiguous location, geology, and history.

Law of conservation of energy

The physical principle stating that energy is neither created nor destroyed, only transformed or transferred from one form to another.

Potential energy

Energy associated with position and configuration.

Kinetic energy

Energy associated with motion.

Gravitational potential energy

Potential energy associated with elevated positions in Earth's gravity field.

Mass-balance equation

The conservation of mass expression $I - O = \Delta S_T$, where $I$ is mass input, $O$ is mass output, and $\Delta S_T$ is change in storage.

Drainage basin

The fundamental unit for geomorphic analysis of river systems.

Driving force

Energy exerted on Earth’s surface or applied to Earth materials, primarily driven by gravity, climate, and internal heat.

Resisting force

Anything that counteracts a driving force, primarily determined by lithology and structure.

Buoyancy

Upward force exerted by a fluid that opposes the weight of an immersed object, with magnitude proportional to the density difference.

Isostatic compensation

The mechanism where for every $1\,m$ of surface erosion, approximately $80\,cm$ of crustal uplift occurs to maintain buoyancy equilibrium with the mantle.

Frequency

How often a geomorphic process or event occurs.

Magnitude

How impactful a geomorphic process or event is.

Recurrence interval (RI)

The average time between events of a similar magnitude.

Dynamic steady state

A condition where a landform or process changes over time but oscillates around a central tendency (mean value).

Thresholds

Physical or chemical conditions that, when reached or exceeded, trigger a change in state or a shift to a new range of average conditions.

Complex response

A cascade of changes within a system, often involving delayed responses, triggered by crossing a threshold.

Static

No change

Steady-state

change occurs but remains balanced over time, leading to a consistent condition within the system.

directional

results in change completely over time (millions of yrs)

Law of Conservations equation

I-O = change in storage