Sedimentary Rocks Rocks
Schwichtenberg
Sedimentary Rocks Pieces of solid material that have been broken
down over time by wind, water, gravity, and other natural processes
Sediments get cemented together – depends on weathering & erosion
How Are Sedimentary Rocks Classified?
Based on how they were formed
Three Main Groups of Sedimentary Rocks
1. Clastic (Detrital) Sedimentary Rock- Most common type of sedimentary rock- Clasts Present - Formed from loose sediment deposits on earth’s
surface
Three Main Groups of Sedimentary Rocks
2. Chemical Sedimentary Rock- Rocks formed by chemical weathering- Clasts not present- Change from one form to another- Change Mineral Content
Three Main Groups of Sedimentary Rocks
3. Organic Sedimentary Rock- Rocks formed from once living things- Organic Material – contain carbon
How are Sedimentary Rocks Classified?
Clastic vs. Chemical
clasts present clasts not present
particles visible particles not visible
Clastic (Detrital)Course
Conglomerate Breccia
Detrital Sedimentary Rock
Chemical Sedimentary Rock
Two Types of Weathering
Chemical Weathering
Occurs when minerals within a rock are dissolved or become chemically changed
Physical Weathering
Minerals that are chemically unchanged break along fractures or grain boundaries
Physical properties are changed
Results of Weathering
Clastic Sediments Rock & Mineral Fragments
Boulder Cobble Pebble
Sand Silt Clay
Sediment Particle Size Rock ExplanationBoulder Watermelon Breccia
/ConglomerateRounded to Angular
Cobble Orange Breccia /Conglomerate
Rounded to Angular
Pebble Grape Breccia /Conglomerate
Rounded to Angular
Sand Sandstone Sand Sized Grains
Silt Fine Grained mud
Siltstone Fine Grained
Clay mud Shale Fine Grained
Sediment Particle Size Rock ExplanationBoulder Watermelon Breccia
(Conglomerate)Rounded to Angular
Cobble Orange Breccia (Conglomerate)
Rounded to Angular
Pebble Grape Breccia (Conglomerate)
Rounded to Angular
Sand Sandstone Sand Sized Grains
Silt Fine Grained mud
Siltstone Fine Grained
Clay mud Shale Fine Grained
LARGEST
SMALLEST!
Erosion
Transport & Movement of sediments
Jebel Kharaz, Jordan
Four Main Methods of Erosion
1. Wind
2. Water
3. Ice/Glaciers
4. Gravity
Formation of Sedimentary Rocks
1. Deposition - When sediments are laid down on
surfaces or sink to bottom of bodies of water
- Sediments are settling out
Formation of Sedimentary Rocks
2. Burial
- Repeated deposition & layering over time
- Banding may occur
Formation of Sedimentary Rocks
Lithification3. Compaction
4. Cementation
Lithification
3. Compaction
- Squeezing out of fluids from intense pressure
- Causes a physical change
Lithification
4. Cementation
- Sediments come together to form a solid rock
HOW?Cementing materials carried in solution by water through pore spaces and between particles.
Have compaction and temperatures rise.
Causes a chemical & mineral change and particles join
Cementation
Sequence How Sedimentary Rock is Formed From Clastic Sediments
Sequence How Sedimentary Rock is Formed From Clastic Sediments
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