Title: Sediment and Sedimentary Rocks
1- Sediment and Sedimentary Rocks
Big rocks into pebbles, Pebbles into sand. I
really hold a million, million Rocks here in my
hand. Florence Parry Heide
Created from the scraps of old rocks
2Sedimentary RocksTerms
- Regolith rock and mineral fragments produced by
weathering - Sediment regolith that has been transported by
wind, water or ice - Soil portion of regolith that supports plant life
3Sedimentary Rocks Characteristics
- Loose, solid particles
- sediments
- Unconsolidated
- Classified based on size of individual fragments
4Four Fundamental Components of Sedimentary Rocks
- Grains/Clasts sand, gravel or fossils
- Matrix fine grained clay-sized sediment
- Cement chemically precipitated mineral material
- Porosity space with no mineral matter
Cement
Clasts, matrix and iron oxide cement (reddish
brown colour)
5Types of Sedimentary Rocks
- 2 main types of sedimentary rocks (based on
composition) - Clastic
- Inorganic sediments
- rocks made up of broken and worn particles of
rocks and minerals - Non-Clastic
- Organic sediments
- sediment precipitates from solution in water
originating from chemical and organic processes
Breccia
Chert from Will County, Illinois
6Characteristics of Clastic Sediment
- Clastic sediment is divided into four main size
classes (based on texture as well) - Gravel
- Sand
- Silt
- Clay
Bedrock outcrop
River gravel
Beach sand
Clayey silt
Marine clay
7Properties of Clastic Sedimentary Rock
- Processes
- Lithification / Diagenisis
- Compaction
- Pressure from recent, overlying sediment
- Cementation
- Hardening
- Stratification
- Layering
8How Clastic Sedimentary Rock Form
- Clastic sedimentary rocks originate because of
- Weathering
- Erosion/Transportation
- Deposition/Burial
- Lithification / Diagenesis
9Weathering
The rocks that make high ridges are much more
resistant to weathering than the surrounding
rocks
10Erosion and Transport
This stream carries sediment that has weathered
from nearby mountains at Polychrome Pass, Alaska
11Deposition/Burial
These pebbles were deposited in a stream that
once flowed over this area in Indiana, USA
thousands of years ago. Now they are part of a
clastic sedimentary rock called conglomerate