Erosion and Deposition Answers

Ethan determines that layer B is 3.5 million years old. Due to the , he can estimate that layer A is years old.

The principle of cross-cutting relationships states that certain features, such as faults, are than the rock layers they cut through. These features are breaks in Earth’s surface where rock has moved sideways, upward, or downward. formations are made of molten rock that has cooled. Those on Earth’s surface are called . Those beneath Earth’s surface are called .

The principle of cross-cutting relationships states that certain features, such as faults, are than the rock layers they cut through. These features are breaks in Earth’s surface where rock has moved sideways, upward, or downward. formations are made of molten rock that has cooled. Those on Earth’s surface are called . Those beneath Earth’s surface are called .

Index fossils are the remains of organisms that lived on Earth for periods.

First, geologists use relative age to determine the of the layers of rock.

They then use index fossils to relate the layers to those in locations.