Ch. 8Lesson 2How are

sedimentary rocks formed?

Activity-Sedimentary Sandwich

Layer of sandwich

Layer of geologic time scale- description

Bottom slice of bread (sand)

Precambrian Era- jellyfish fossils

Peanut butter (mud)

Paleozoic Era- fish, insect fossils

Jelly (old decaying plants)

Mesozoic Era- dinosaur fossils

2nd slice of bread

Cenozoic Era- flowering plants fossils

Precambrian Era

Paleozoic Era

Mesozoic Era

Cenozoic Era

Sedimentary Sandwich

sedimentaryrock

form when layers of

materials & rock particles settle on top of each other

& harden

plant & animalfossils

examples:

conglomerate

sandstone

A fossil of a dragonfly, from Germany, about 150 million years ago.

sandstone

limestone

mudstone

sediment•eroded material that settles on land or on bottoms of lakes, rivers & oceans

Weathering and erosion have created this rippling red sandstone landscape. Sedimentary rocks such as sandstone

weather easily compared to some other types of rock.

After an animal dies, its skin, muscles and other soft body parts decay. Its skeleton,

shell, or other body parts are left.

Sediments such as sand or mud settle on top of the remains.

More layers form. Eventually, materials in the remains may be

replaced with minerals in the sediment that harden into rock.

Over many years, the rock layers weather and erode. The fossil

appears at the surface.