Transcript 3.3 Sedimentary Rocks

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
- Sedimentary refers to “small pieces”
- these rocks are made from other rocks,
once living things and precipitates.
- sediments are small pieces of rock.
Bioclastic Limestone
Rock salt
Conglomerate
II. How do you make Sedimentary rock?
• Weathering - the breaking down of rocks
into little pieces
• Erosion
- the transport of little
pieces of rock by water,
wind or ice.
• Deposition - When the little pieces stop
moving. They stop because
the agent of erosion stops.
• Compaction and Cementation – squeezes and
glues sediments together forming a rock.
– Pressure of overlying material squeezes
– Minerals dissolved in water act as glue
*This process is also known as Lithification
III. Classification of Sedimentary Rocks
A. Clastic (fragmental) – composed of
weathered bits of rocks and minerals.
- Categorized by particle size.
Conglomerate and Breccia (Pebbles)
Sandstone (sand)
Siltstone (silt)
Shale (clay)
B. Crystalline (Chemical) (precipitates)–
- Forms when dissolved minerals precipitate
from watery solutions.
- Water evaporates and leaves material
behind to form rocks.
Limestone
Rock salt
C. Bioclastic Sedimentary rocks
- Composed of once living things (plants and
shells).
Limestone
Limestone
Bituminous Coal
With your partner, take 3 min to walk around
the room and find the 4 cards labeled Rock A,
B, C, D, E, F and G.
Identify the Texture of each group of rocks at
the card using your notes we just took.
IV. Features of Sedimentary Rocks
1. Layers – continuous depositions of
sediments causes a layering effect. (like
sand art)
2. Fossils – traces of remains of ancient life.