Geoscience Weathering and Erosion

What is mechanical weathering?

process of rocks crumbling down due to rain, wind, or other atmospheric conditions

examples of mechanical weathering?

abrasion, plant growth, animal actions, freezing/thawing, and release of pressure.

chemical weathering?

process that slowly breaks down rocks with chemical changes, including changes in the minerals.

examples of chemical weathering?

water, oxygen, carbon dioxide, living organisms, acid rain. 

Abrasion

Sand and other rock particles carried by wind and water grind away rock like sandpaper on wood

Plant Growth

Roots of trees and other plants grow in the cracks of rocks and pry them apart 

Animal Actions

Animals dig in the soil and loosen and break apart rocks

Freezing and Wedging is also known as

Ice wedging

Ice wedging

When water freezes it expands. Ice in the crack of a rock expands and makes the crack larger.

Release of Pressure is also known as

Unloading

Unloading/Release of Pressure

When rocks reach earth’s surface, reduced pressure can cause cracks and flakes in the rock 

What is chemical weathering?

the process that slowly breaks down rock with chemical changes, including changes in the minerals.

Water (Chemical weathering)

the most important cause of chemical weathering. When a rock dissolves in water, it mixes completely with the water

Oxygen

iron combines with oxygen and water in a process called oxidation. The result is rust. Oxidation of a rock makes it soft, crumbly and red or brown

Carbon Dioxide

dissolves in rainwater, becoming a weak acid called carbolic acid.

Living organisms

Plants, and other living organisms such as lichen, release weak acids that slowly dissolve rocks. 

Acid Rain

Burning coal, oil, and gas for energy produces pollution. This pollution combines with air and water to create acid rain and fast chemical weathering. 

The most important factors for the rate (speed) of weathering

Rock Type and Climate

A permeable rock weathers easily because

it contains many small, connected air spaces.

Wet climates with high temperature

speed up both mechanical and chemical weathering.

What are some examples of chemical weathering?

water, oxygen, carbon dioxide, living organisms, acid rain. 

Biological weathering

the breakdown of rocks through movements of plants and animals.

examples of biological weathering?

plants/roots growing through rocks, animal burrowing, and bacteria/moss.

difference between chemical and mechanical weathering?

Mechanical weathering is the physical breakdown of rock into smaller pieces.

Chemical weathering is the breakdown of rock by chemical processes.

difference between weathering and erosion?

Weathering is the physical or chemical breakdown of rock

Erosion is the removal of weathered pieces of rock to another place.

In what kind of climate do rocks weather faster?

Warmer

In what kind of climate do rocks weather slower?

Colder

How does temperature affect the rate of chemical weathering?

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Three forces of erosion

Water, wind, and ice

Deposition

the laying down of sediment carried by wind, water, and ice. 

Salt weathering

a type of physical weathering that is caused by growth and thermal expansion of salt crystals. 

examples of landforms that are created by erosion?

Valleys, water falls, and caves are landforms that are created by erosion. 

How do weathering, erosion, and deposition work together?

Weathering breaks down rock

Erosion moves rocks

Deposition places rocks in a new location.

lithification

the process by which sediments combine to form sedimentary rocks

What are some ways that water is involved in the rock cycle?

Water helps breaks down and transport the rocks

What makes some rocks look reddish brown?

Rust

How can life like plants, animals, or bacteria (all biosphere) be involved in the rock cycle?

Animal burrows and plants that grow into rocks are mechanically weathering

bacteria is chemical weathering which alters the minerals in the rocks. 

Explain how the surface of the Earth is shaped by weathering, erosion, and the water cycle.

Weathering breaks down small particles or sediments.

Erosion moves these particles by ice, wind, or water to create landscapes

The water cycle wears down rocks and creates features like riverbeds, mountains, and deltas over time

Explain how caves are created through weathering and erosion.

Caves are formed through chemical weathering, acidic water dissolved from carbon dioxide reacts with the other rocks.

Over time, the water seeps into cracks and dissolves the rocks, slowly enlarging spaces to form caves.

Erosion further shapes the cave by removing loosen rocks and expanding the passages

1. Describe the ways in which the erosional actions of wind, water, and glaciers are similar and the ways in which they are different.

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6 examples of landforms created through weathering and erosion.

• Caves

• Sea Stacks

• Arches

• Valleys

• Gorges 

• Sand Dunes

If no water existed on Earth, how would erosional processes be affected?

Erosion rate would decrease drastically, erosion would only be carried out by wind. 

Hyrdosphere

All water on earth

Geosphere

All rocks and minerals on earth

Atmosphere

All gases surrounding the Earth

Sedimentary rocks

Formed from particles of sand, shells, pebbles, and other fragments of materials

Metamorphic rocks

rocks that have changed from extreme heat and pressure

Biosphere

All living things on earth.

How do the Earth’s four sphere relate to weathering, erosion, rock cycle?

Geosphere has rocks that are weathered by the atmosphere wind, rain, and temperature changes

Water from hydrosphere weathers down rocks and has erosion by transporting the rocks

The biosphere can accerlate weathering

Igneous rocks

formed from the cooling and solidification of magma or lava

What are stocks in the water cycle?

Stores of Water

What are flows in the water cycle?

the transportation between the stocks 

All Stocks

• Ocean

• Lakes/Rivers

• Glaciers and Ice Caps

• Groundwater

• Atmosphere

• Soil Moisture

Ocean

massive body of saltwater

Flows

• Evaporation

• Condensation

• Precipitation

• Runoff

• Infiltration

• Transpiration

Transition between Ocean → Atmosphere

Evaporation

Transition between Atmosphere → Clouds

Condensation

Transition between Cloud → Snow

Freezing

Transition between Glacier (river of ice) → River

Melting

Transition between Cloud → Soil

Perciptation

Why does water have so many unique properties? 

Because of its it polar structure and its ability to create H-Bonds

Polarity

slight positive charge on the hydrogen atoms and a slight negative charge on the oxygen atom.

This polarity allows water to

interact with other charged or polar molecules.

Hydrogen Bonds

Water molecules are weakly attracted to each other due to hydrogen bonding

High Heat Capacity

can absorb a lot of heat energy before its temperature increases significantly

Cohesion

attraction between like molecules (water to water),

Adhesion

attraction between unlike molecules (water to other substances)

Surface Tension

The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules

Universal Solvent

capable of dissolving a wide variety of substances

River

A stream flowing into the ocean

Glaicer’s

huge sheet of ice that forms on land and slowly moves due to its weight and the pull of gravity.

Ground rock

• Water beneath the earth’s surface in soil or rocks

Atmosphere

Transport system for water vapor

Soil Moisture

Water stored in soil

Evaporation

Liquid water absorbs heat energy and transforms into water vapor

Condensation

Water vapors rises into the air and cools down into water droplets, forming clouds

Perciptation

Water droplets in the clouds become too heavy for the air to hold, they fall back onto the earth as snow, rail, hail, etc

Run Off

The remaining water that isn’t absorbed into the ground runs downhill until it hits a lake, stream, pond, etc

Infilitration

Water seeping into the ground

Transpiration

Plants release water vapor into the air