EXAM 2 weathering Mass Wasting

Alluvium

Sediment deposited by flowing surface water

Backslope

the upward-sloping excavated bank on the outer edge of a road ditch, trail, or cut section, connecting it to the natural ground level. - can prevent erosion

Bed load

sediment moving along the bottom of water

Calcification

accumulation of calcium carbonate in soils

Cenote

Spanish term for sinkholes at least partly filled by water

Chemical Weathering

the breakdown of rocks, minerals, and artificial materials at the molecular level through chemical reactions, altering their composition.

Colluvial Fan

A fan-shaped deposit of colluvium at the foot of a mountain slope produced by slope processes, especially debris flows and snow avalanches. Smaller and steeper

Colluvial hollow

common features of soil mantled hillslopes, accumulating sediment and and water, triggering landslides and debris flows which act as significant geomorphic agents.

Colluvium

Sediment deposited by gravity (see talus/scree slopes)

Columnar Basalt

polygonal columns formed in basalt by contraction upon cooling

Creep

the imperceptibly slow, steady, downward movement of soil or rock slope, driven by gravity, typically acting over years or centuries

Debris Flow

a rapid, dangerous, gravity-driven landslide consisting of water-saturated soil, rock, organic matter, and debris that flows down steep slopes like thick concrete

deep seated

massive slope failure - landslides below the roots ranging from 20 to hundreds if ft deep

Differential Weathering

when one rock type or mineral weathers (breaks down

and is either transformed or eroded) more quickly than surrounding rocks or minerals.

Dissociation

Breaking of a bond binding two atoms or molecules together, so that

they are split into separate ions

Dissolution

he change in state of a solid to a liquid by dissociation of ions.

Dissolved Load

Dissolved ions and minerals from chemical weathering being transported in water

Entrainment

the process by which surface sediment (such as sand, gravel, or soil) is incorporated into a moving fluid flow, including water, air, or ice.

Exfoliation

a form of mechanical weathering where curved or flat sheets of rock peel away from an exposed rock body, similar to an onion skin

Fall

Falls in geology are rapid mass-wasting events where rock or debris detaches from steep slopes, descending via free-fall, bouncing, or rolling

flow

the rapid, fluid-like downhill movement of water-saturated rock

Footslope & Toeslope

the lowest components of a hillslope, acting as depositional areas where sediment, water, and nutrients from higher elevations accumulate

Freeze-thaw

a weathering process in which the crystallization of ice creates a

physical pressure against confining rock or sediment, often dilating cracks or porous

media. With thaw, this pressure is released.

Grus

(in situ) accumulation of angular, coarse-grained fragments (particles of sand

and gravel) via the weathering and granular disintegration of a phaneritic igneous

rock; grus is typically formed in felsic, often granitic, rocks.

Hydrolysis

water breaks down chemical bonds in rocks - altering the composition

inselberg

an isolated hill, knob, or ridge that rises abruptly from gently sloping or level surrounding plains, often in arid or semi-arid regions. formed of erosion resistant rock

Insolation

Inbound Solar Radiation - a measure of how much solar energy

is received by a given square meter of the Earth’s surface in a specified period of

time

Karren

solution weathering features on the surfaces of rocks or (more broadly)

landscapes; fluting caused by dissolution of limestone, gypsum, rock salt, or other

soluble rocks/minerals

Karst

a distinct landscape formed by the dissolution of soluble bedrock—primarily limestone, dolomite, or gypsum—by acidic groundwater

Lateritization

the deep chemical weathering of sediment or rock, typically in

warm, humid (tropical) environments; during lateritization all ions except for Fe and

Al are typically leached out of the soil profile (some Si may remain initially). Thus,

laterites are composed almost entirely of Fe and Al oxides.

Leisegang banding

colored bands of cement observed in sedimentary rocks that typically cut across bedding.

Phyllosilicate

group of minerals characterized by their layered, sheet-like structure, where silicon-oxygen tetrahedra share three out of four oxygen atoms

Physical Weathering

the mechanical breakdown of rocks into smaller pieces without changing their chemical composition

Pocket Valley

a river valley which starts abruptly with a resurgent stream