Soils
In addition to weathering, eluviation, and illuviation, this is the final main component required for soil development.
What is organic material?
Mass wasting occurs when these specific "driving forces" (like gravity) are greater than resisting forces (like friction).
What is overall gravity?
All freshwater on Earth ultimately comes from this initial atmospheric source.
What is precipitation?
This term describes the percentage of total volume of rock or sediment that consists of pore spaces.
What is porosity?
Contrary to popular belief, this is the primary defining characteristic of a desert, rather than just high temperatures.
What is a lack of precipitation?
These glaciers, also known as mountain or valley glaciers, are typically smaller, thinner, and younger than continental ice sheets.
What are Alpine glaciers?
This is the primary force responsible for the erosion and deposition of sediment along most coastlines.
What is wave action?
Soil properties like porosity and permeability are mainly controlled by the relative proportions of these sized particles.
What are clay, silt, and sand (or "all of the above")?
These are the two primary characteristics used to classify mass wasting events.
What are type of material and type of motion?
This is the largest source of freshwater that is actually "readily available" and easily obtained for human use.
What is groundwater?
This term describes a material's ability to transmit a fluid.
What is permeability?
This large-scale atmospheric circulation cell is responsible for creating many of the world's major subtropical deserts, like the Sahara.
What is a Hadley Cell?
This is the specific term for the stratified (layered and sorted) sediment deposited by glacial meltwater.
What is outwash?
This term describes the zigzag movement of sediment along a beach caused by waves hitting the shore at an angle.
What is longshore drift?
While sand and silt are often composed of quartz and feldspar, clay-sized particles are generally composed of this mineral group.
What are clay minerals?
This specific action, which involves changing the steepness of a slope, can destabilize it and trigger a slide.
What is re-grading a slope (over-steepening)?
Of the world's total water volume, this is the approximate percentage that is readily available, liquid, and non-salty.
What is less than 1%?
This is the specific term for an impermeable layer (like clay) that hinders or prevents water movement.
What is an aquitard?
This desert-forming phenomenon occurs on the leeward side of a mountain range, where the air is dry because moisture was lost on the windward side.
What is a rain shadow?
While rivers generally carve V-shaped valleys, glaciers are famous for carving valleys with this distinct shape.
What is U-shaped?
This specific shoreline feature is a ridge of sand that connects an island to the mainland or to another island.
What is a tombolo?
While sand and silt are often made of quartz, these particles are generally composed of specific "clay minerals."
What are clay-sized particles?
This force acts parallel to the slope and is the primary driver behind mass wasting.
What is shear stress (or the downslope component of gravity)?
This is the primary "engine" or energy source that drives the entire global water cycle.
What is the Sun?
This is the specific boundary line that separates the "Zone of Aeration" (unsaturated) from the "Zone of Saturation."
What is the Water Table?
This is the specific term for the "lifting" and removal of loose, fine-grained material by the wind, often leaving behind a stony surface called desert pavement.
What is deflation?
These cracks or fissures extend from the surface of a glacier down to the base of the "brittle zone."
What are crevasses?
These man-made structures are built perpendicular to the shoreline to trap sand and prevent beach erosion from longshore currents.
What are groins?
This term describes the downward movement of dissolved or suspended material within the soil profile, often aided by water.
What is eluviation or leaching?
Adding a small amount of water increases this property in sand, but adding too much water destroys it, leading to slope failure.
What is cohesion?
This process describes the combined release of water vapor into the atmosphere from both the Earth's surface and from plants.
What is evapotranspiration?
This term describes a geological unit that is both porous and permeable enough to store and transmit significant amounts of water.
What is an aquifer?
This term describes the process where fertile land becomes desert, often creating a "positive feedback loop" as vegetation loss leads to further drying.
What is desertification?
A glacier's margin (terminus) will advance when this condition is met regarding accumulation and ablation.
What is "total accumulation is greater than total ablation"?
During the peak of the last glacial period, global sea levels were approximately this much lower than they are today.
What is 100 to 120 meters (approx. 330–400 feet)?