1. Sedimentary Rocks
Interpretations

2. What do Sedimentary Rocks Record?
Source of sediment
Erosion and Transport Agent
Distance of Transport
Depositional Environment
Paleogeography/Tectonic Setting

3. Interpretation of Composition
Detrital Rocks:
Source of sediment
Exposure to Weathering (Distance of Transport) (Type of Climate)

4. Note About Detrital Rock Color & Composition
Grain Size Smaller is often darker
Composition Carbon - black or brown Quartz - tan, clear, white Orthoclase - orange
Depositional Environment Iron on land - red Iron in deep, oxygen poor water - green

5. Interpretation: Grain Size
Gravel
Sand
Silt
Clay
High Energy
Low Energy
River, Beach
River, Beach, Desert
Delta, Shallow Ocean
Deep Ocean, Lake, Swamp

6. Detrital Rock Names (Based Primarily on Grain Size)
Gravel Sized:
Conglomerate
Sand Sized: Sandstone
Mud Sized:
Mudstone
Siltstone
Shale

7. Interpretation: Sorting
Poorly Sorted
Well Sorted
Transport Agent
Gravity and Glaciers (and Rivers)
Water and Wind

8. Clast Supported Conglomerate (River Deposits)

9. Matrix Supported Conglomerate (Glacial/Landslide Deposits)
2.2 Gyr Conglomerate
“Modern” Glacial Sediments

10. Interpretation: Grain Roundness
Interpretation: Distance of Transport
Short
Far

11. Limestone
Crystalline
Limestone
Fossiliferous Limestone
Chalk

12. Formation of Limestone
Calcite Precipitates in
Warm Water
Water Under Low Pressure (Shallow) Or
It is secreted by biological organisms
Clams, Mussels, Scallops, etc.
Corals
Foraminifera

13. Limestone Represents:
Shallow Tropical Ocean

14. Chalk (Coccolithophores)

15. Black Sea

16. Travertine (Limestone)

17. Chert (Flint, Jasper, Agate…)

18. Diatom Steletons

19. Chert Represents
Deep Ocean

20. Evaporites: Bonneville Salt Flats, Utah
Rock
Gypsum
Rock Salt
Isolated,
Arid,
Salty
Sea/Lake

21. Peat and Coal
Swamp, Bog

22. Intermission: Quiz What can you say about the history of this rock?
Deposited in a beach/river or desert, very far from the source of the sediment.
Quartz Sandstone

23. Intermission: Quiz What can you say about the history of this rock?
Deposited in a quiet water environment (deep ocean, lake, lagoon). Dark color implies oxygen-poor environment, rich in organic material.
Shale

24. Intermission: Quiz What can you say about the history of this rock?
Deposited in a shallow tropical ocean.
Limestone