Weathering, Erosion, and Geologic Time

Provide two agents of physical weathering and give an example of how they could weather rock.

1. Ice wedging - water can get into cracks of rock, freeze, and expand, making the rock break over time. 2. Wind - it can weather a rock by blowing over it for a long time.

If there was an isotope named Ginger-18, and its half like was 2 mil. years, and you found a dinosaur bone with 25% of the isotope remaining, how old is the dino bone?

4 million years old

What does radiometric dating allow us to determine?

Both the relative age of a rock or fossil and its exact age.

What does the Geologic Time Scale represent?

It represents a timeline of Earth's history and major events.

Explain how chemical weathering differs from mechanical weathering.

Mechanical weathering breaks down rocks by force. Chemical weathering breaks down rocks by chemical reactions.

Explain how relative dating of fossils differs from absolute dating of fossils.

Relative dating determines what order things come in. Absolute dating tells the exact age.

Describe the difference between weathering, erosion, and deposition.

Weathering breaks rocks down, erosion carries the sediment it produces away, and deposition is when the sediment is dropped off into slower moving water.

Describe a major difference between a young mountain and an old mountain.

Young mountains are sharper because they haven't had as much time to weather.

The sediment that is produced through ___ weathering is different than the original rock itself.

chemical

Frozen water in the form of ___ is an extremely powerful physical weathering agent.

glaciers

What force causes rocks and sediment to erode down slopes?

gravity

___ wedging occurs when water freezes inside a crack in a rock, causing the rock to break apart.

ice

Where would you find the fastest moving water in a meandering river?

on the outside bank of a meander

An example of ___ weathering is when a large rock falls down a slope and breaks into small pieces.

physical

The method of putting events in the order in which they happened is known as ___.

relative dating

Which of the following are characteristics of older mountains?

rounded, rolling hils

Weathering breaks rocks into bits and pieces called ___.

sediment

What do you think happens where a river empties into the ocean?

the river deposits sediment

The process of breaking down rock is called ____.

weathering

Provide two agents of chemical weathering and give an example of how they could weather rock.

1. Acid rain can weather statues by chemically changing it so that the new sediment is different from the old one. 2. Statues, when exposed to oxygen in the air, can rust, and the rust is different from the old material.