Weathering, Caves, and Karst Topography

Flashcards covering key terms related to weathering, climate influences, cave formation, and karst topography, based on textbook sections 15.4, 15.5, 15.6, and 15.7.

Chemical Weathering

Breakdown of rocks through chemical reactions, often involving water, acids, and gases.

Physical Weathering

Mechanical breakdown of rocks into smaller pieces without changing their composition.

Climate

The long-term average of temperature and precipitation in an area, which affects the type and rate of weathering.

Elevation

Height above sea level; affects temperature and precipitation patterns, influencing weathering.

Slope Aspect

The direction a slope faces (e.g., north- or south-facing); influences sun exposure, temperature, and moisture.

Slope Steepness

The angle of a slope; steeper slopes shed water and material faster, affecting weathering.

Windward Slope

Side of a mountain facing prevailing winds; usually receives more precipitation.

Leeward Slope

The side sheltered from the wind; drier and experiences less weathering.

Vegetation

Plants that influence weathering through root growth (physical) and acid secretion (chemical).

Root Wedging

A form of physical weathering where plant roots grow into cracks in rock and expand them.

Organic Acids

Acids released by roots and organisms that chemically break down minerals in rocks.

Lichens

Symbiotic organisms (fungus + algae) that break down rock through acid secretion.

Carbonic Acid

A weak acid formed when CO₂ from roots or air dissolves in water; breaks down carbonate rocks.

Time

The duration over which weathering occurs; more time = more extensive weathering.

Spheroidal Weathering

Weathering that rounds rock edges and corners, producing spherical shapes.

Weathering Rind

The outer, weathered layer of a rock that thickens over time as weathering progresses.

Differential Weathering

When different minerals or rock parts weather at different rates, creating uneven surfaces.

Oxidation

A chemical reaction between minerals and oxygen (often from air or water) that forms oxides, like rust.

Salt Crystallization

Physical weathering caused by salt crystals forming and expanding in rock cracks.

Carbonate Crystallization

Weathering process where calcium carbonate dissolves and later crystallizes, weakening materials like mortar.

Biotic Weathering

Weathering caused by living organisms, including root growth, burrowing, and acid production.

Root Zone

The area underground where plant roots extend; significant for both physical and chemical weathering.

Jointing

Natural fractures in rock that make it more vulnerable to weathering.

Hoodoo

Tall, thin spire of rock formed by weathering and erosion along joints in sedimentary rocks.

Cave

A natural underground space formed by the dissolution of rock, especially limestone, by acidic water.

Limestone

A sedimentary rock mainly composed of calcite (CaCO₃) that is highly soluble in acidic water, making it prone to cave formation.

Calcite

A mineral (CaCO₃) that dissolves in weakly acidic water, common in limestone.

Acidic Water

Water that contains dissolved carbon dioxide (CO₂) or other acids, allowing it to dissolve rocks like limestone.

Groundwater

Water located beneath Earth’s surface that can dissolve rock to form caves when it becomes acidic.

Water Table

The level below which the ground is saturated with water; caves often form just below this level.

Dissolution

The chemical process of dissolving a solid (like limestone) in a liquid, typically acidic water.

Lava Tube

A type of cave formed in volcanic regions where flowing lava leaves behind a hollow tunnel.

Stalactite

A dripstone feature that hangs from the ceiling of a cave, formed by precipitation of calcium carbonate.

Stalagmite

A mound or column that rises from the floor of a cave, formed by dripping water depositing calcium carbonate.

Column

A feature formed when a stalactite and a stalagmite grow together and meet.

Flowstone

Smooth, layered cave formations created as mineral-rich water flows over walls or floors and deposits calcium carbonate.

Travertine

A banded form of calcium carbonate commonly deposited in caves by dripping or flowing water.

Skylight

An opening in the roof of a cave, often formed by collapse, that allows light to enter from the surface.

Karst Topography

A landscape shaped by the dissolution of soluble rocks (like limestone), featuring sinkholes, disappearing streams, and caves.

Soluble Rock

Rock that can dissolve in water, such as limestone, dolomite, gypsum, and rock salt.

Sinkhole

A surface depression or hole caused by the collapse of a cave roof or by dissolution of rock beneath the surface.

Disappearing Stream

A stream that flows into a sinkhole or underground cave system, vanishing from the surface.

Underground Drainage

Water flow that occurs below the surface through cave systems in karst terrain.

Karst Hazard

A risk associated with living or building on karst terrain, such as sinkhole collapse due to groundwater removal.

Reddish Soil

Clay-rich soil produced by chemical weathering in humid karst environments, often containing limestone fragments.

Limestone Exposure

Surface appearance of weathered limestone that shows signs of dissolution, grooves, or fossils—often a clue for karst.

Fossiliferous Limestone

Limestone containing fossils, common in karst regions and useful for identifying past marine environments.

Karst Distribution

The geographic spread of karst terrain, shown by maps indicating areas with soluble rocks like limestone and gypsum.