AIM: How are Sedimentary Rocks Formed?

Do Now: Take out your ESRT and turn to page 7. Look at the chart called Scheme for Sedimentary Rock identification and answer the questions below.

1)What textures of Sedimentary rocks will we be working with?

2)What material (not composition) are Clastic rocks made from?

I. Formation of Sedimentary Rocks

- mostly made from pieces of other rocks (as well as

once living things and precipitates)

- Sediment is small pieces of rock

ConglomerateRock saltBioclastic Limestone

- the breaking down of rocks into little pieces (sediment)

- the transport of sediment by water, wind or ice (agents of erosion).

- When the sediment stops moving. They stop because the agent of erosion stops.

• Weathering

• Erosion

• Deposition

II. How are Sedimentary rocks made?What material do you need to make most Sedimentary

Rocks?

• Compaction and Cementation (Lithification) – squeezes and glues sediments together forming a rock. – Pressure of overlying material squeezes– Minerals dissolved in water act as glue

Sediments are

lithified into clastic

sedimentary rock

III. Classification of Sedimentary Rocks

A. Clastic (fragmental) – composed of weathered bits of rocks. - Categorized by particle (grain) size.

Siltstone (silt)

Shale (clay)Conglomerate and Breccia (Pebbles)

Sandstone (sand)

B. Crystalline (Chemical) (precipitates)–

- water evaporates and leaves material behind to form rocks.

- rocks have a milky or crystalline appearance

Limestone Rock salt

C. Bioclastic- composed of once living things (plants and shells).

Limestone Bituminous Coal

Limestone

Take a black cup of rocks from the back of the room

IV. Features of Sedimentary Rocks

1. Layers – continuous depositions of sediments causes a layering effect. (like sand art)

2. Fossils – imprints of ancient life.