Earth Science Unit 3 chapters 7 and 8

Weathering

The breaking down of rocks and other materials on the Earth's surface.

bedrock

Rock that makes up Earth's crust; also the solid rock layer beneath the soil

physical (mechanical) weathering

any process that causes a rock to crack or break into smaller particles

abrasion

physical weathering- grinding away of rock by friction with other rocks.

frost wedging

physical weathering: repeated freezing and thawing of water in cracks in rocks

exfoliation

when rock expands and cracks into slaps that break loose from bedrock

biologic activity

the actions of plants and animals can cause weathering.

chemical weathering

a natural process that occurs under conditions at earths surface, forming new compounds

chemical change

results in the new formation of a new substance

oxidation

chemical weathering. chemical reaction of oxygen with another substance. materials in a rock can ------ and break the rock down

carbanation

the reaction of carbonic acid with other substances

carbonic acid

a weak acid that can react with rocks like limestone (contains calcite) and break them down. carbon dioxide dissolves in rainwater to make his acid. rainwater entering the ground pics up more carbon dioxide from decaying plant remains

Sulfur and Nitric Acids

these oxides from burning fossil fuels can form acid when combined with atmospheric moisture- forms of acid precipitation. these acids can break down rocks like limestone and marble.

water

reacts with minerals in a rock
speeds up chemical reactions
can dissolve substances

organic waste

acid from decaying ---------------- can dissolve certain rock materials

How are limestone caves created?

when the ---------------- is slowly weathered away by acidic water and the ----- are carved out by the flowing water underground

softer parts of a rock

weather more quickly than harder parts

cold and moist climates

more physical weathering

warm and moist climates

more chemical weathering

warm and dry climate

little weathering

breaking rock into smaller fragments

exposes more surface area which equals FASTER WEATHERING

rocks closer to earths surface

faster weathering

more pollution

more acids. faster weathering.

soil

mixture of weathered rock and organic matter. formed over long period of time by weathering and biological activity.

organic matter (humus)

the decayed remains of living organisms in which plants can grow

infilitation

water seeping into the ground. water can carry dissolved minerals deeper into the soil

soil horizons

mature well developed soils show layering

side profiles

side views of soil

best soil contains

air and moisture within a mix of weathered rock and humus

Residual Soil

soil that is formed in place and remains there

transported soil

soil that is formed in one location and moved to another location

new york state soils

brought over from Canada by last ice age

leaching

washing away of soluble minerals

forest soils- pedalfers

soils rich in iron and aluminum- thin layer of humus, much leaching

desert soils- pedocals

soils rick in calcium carbonate- dry soil, very little leaching

grassland soils

much humus ADEQUATE moisture, agricultural centers of the world, little leaching

erosion

the movement of sediments by water, air, glaciers, or by gravity acting alone

gravity

driving force behing all erosinal processes

rocks eroded by gravity are usually

angular and rough

mass movement

the motion of sediments or rock down a slope without the influence of running water, wind and or glaciers

angle of repose

The greatest angle at which loose material will rest on a surface.

rock fall

mass movement when fragment of rock falls down a steep hillslide

mudflow

when rain mixes with soil to form mud which flows

agents of erosion

factors that cause erosion—water, wind and ice

water erosion

most important agent of erosion. rocks eroded by ------ are smooth

wind erosion

--- transports small loose particles like sand or smaller. occurs within 1 meter off ground. rocks are angular and can be pitted of frosted. abrasion by ------ sand have flat surfaces

ventifacts

Wind worn rocks that have flat surfaces

glacier erosion

they push drag and carry rocks soil and sediments as they flow. when they erode rocks they have striations/grooves

Stirations

caused by glacier dragging rocks along surface of other rocks

Deposition

the settling or release of sediments carried by an agent of erosion

agents or erosion are also

agents of deposition

Vertical sorting (graded bedding)

when particles in a wide range of sizes settle at the same time big particles settle first small particles settle last. each layer represents a single event of deposition

the rounder the particle

the faster it will settle

flat and irregular particles settle more slowly BECAUSE

their large surface area produces more friction

sorting

separation of sediments according to shape, density, or size

horizontal sorting

when river with sediment slows and sediments are deposited and big particles first small particles last

dunes

wind blows sand into hills or ridges of sediment

glaciers directly leave behind

unsorted and miced sediment

melted water from a glacier

may indirectly sort out sediments

dynamic equilibrium

a state of balance between continuing processes