weathering

Agents of physical weathering

Temperature changes, pressure changes, plant and animal actions, water, wind and gravity.

wind, moving water, and gravity

3 agents of physical weathering that can cause abrasion.

Ice wedging

Also known as frost wedging can cause rocks to physically break apart. Cracks in rocks expand as water seeps in and freezes. water expands as it freezes to become ice. can cause even the largest rock to split apart.

Animal action

Can cause physical weathering by digging burrows into the ground allowing rock to be exposed. Examples: ground squirrels, prairie dogs, ants and earth worms, pocket gophers.

Pressure changes

Physical weathering can be caused when rocks formed under pressure deep within the Earth become exposed at the surface. When overlaying material is removed above the rocks, the pressure decreases. The rock expands causing the outermost layers of rock to separate from the underlying rock. causes exfoliation.

oxidation

The process by which other chemicals combine with oxygen. Oxygen in the air or water can cause chemical weathering. Oxygen reacts with the compounds that make up rock and cause a chemical reaction. color change.

Physical weathering

The process by which rock is broken down into smaller pieces without a change in composition

Exfoliation

The process by which the outer layers of rock slowly peel away due to pressure changes. Enchanted Rock in Texas is an example.

Temperature change

a rise in temperature causes a rock to expand and a decrease in temperature causes a rock to contract.

wind

abrasion occurs when wind lifts and carries small particles in the air. wind blown sand can blast away at surfaces and slowly wear them away.

Reactions with acids in groundwater

as groundwater moves through cracks in rock acid in the water can cause the rock to dissolve. can create extensive cave systems that are carved out over time undr Earthe's surface.

color change in rock

can mean a chemical reaction has taken place. rocks containing iron can easily undergo chemical weathering. Iron in rocks and soil combine quickly with oxygen that is dissolved in water, result is reddish orange, which is rust.

Chemical weathering

causes changes in both the composition and appearance of rocks. breakdown of rocks by chemical reaction.

acid in atmosphere

created when chemicals combine with water in the air. Rai is normally slightly acidic.

stalagmites

found in caves formed upward from ground, deposited by dissolved chemicals in dripping water.

stalactites

hang down, common feature in cave as dissolved chemicals are deposited by dripping water underground.

acids in living things

lichens and loses often grow on rocks and trees, as they grow they produce weak acids and weather the rock's surface and chemical reactions occur, can form cracks as acid seeps deeper and can eventually break apart.

Plant growth

over time a plant can grow larger and roots can grow inside small cracks and put pressure on a rock. more pressure causes the rock to expand. can lead to physical weathering.

Agents of chemical weathering

oxygen in the air and acids.

soil in southeastern U.S. and rock formations in Southwest U.S.

red color in soil and rock due to presence of rust, brought about by oxidation.

gravity

rocks can be broken down in a landslide, causing abrasion.

moving water

rocks can become rounded and smooth, abrasion occurs as rocks are tumbled in water, hitting other rocks.

abrasion

the breaking down and wearing away of rock materialby the mechanical action of other rock.

acid precipitation

when fossil fuels are burned other chemicals combine with water in the atmosphere to produce stronger acids. when stronger acids fall to Earth it is called ________. can cause rocks to break down and change composition.