1. Sedimentary Rock There are 3 main kinds: 1. Chemical
- Sedimentary rocks are formed from mineral grains that have precipitated as a result of evaporation or by chemical action.
Examples include:
Rock salt (halite) and limestone

2. Halite, Rock Salt, and Limestone
Not in your notes.

3. Rock Gypsum – A chemically formed sedimentary rock
Not in your notes.

4. Sedimentary Rock 2. Organic - Sedimentary rocks form from
the remains of plants and
animals.
Examples include:
Coal; some limestone, and coquina

5. Coal
Organic Limestone
Not in your notes.

6. coquina
Not in your notes.

7. Sedimentary Rock 3. Clastic - Sedimentary rocks are formed
from fragments of other rocks.
Examples include:
Shale, sandstone, and conglomerate

8. Clastic Sedimentary Rock
Fragments can be as large as pebbles or as fine as silt.
The fragments are carried by wind, waves, or glaciers and then deposited as kinetic energy is lost.
Finer particles can be carried further before being deposited.

9. Clastic Sedimentary Rock
Water-deposited sediment:
Natural cements (silica, calcite, iron oxide) are deposited among the fragments.
These cement the fragments together.

10. Clastic Sedimentary Rock
Rounded pebbles and gravels become conglomerate.

11. Clastic Sedimentary Rock
Coarse, angular fragments form breccia. The fragments did not travel far enough from their source to smooth their rough edges.

12. Clastic Sedimentary Rock
Sands form sandstone.
It is mostly grains of quartz.
Up to 30% is air space.

13. Clastic Sedimentary Rock
Silts and clays form shale.
Shale is impermeable to water.

14. Clastic Sedimentary Rock can also form from:
Wind-deposited sediment:
The pressure from the weight of upper layers of sediment can cause fragments to stick together.

15. Uniformitarianism - Modern and Ancient Dunes

16. Identifying Sedimentary Rock
Stratification means deposited in visible layers.
A layer change occurs when the type of deposited sediment changes.
soil pit

17. On a larger scale …
Not in your notes.

18. The layers in sedimentary rock are separated by “bedding planes.”
These planes are usually horizontal.
Cross-bedding occurs when sediment is deposited unevenly.

19. Cross-bedding on a larger scale.
Not in your notes.

20. Identifying Sedimentary Rock
Fossils
As dead plants and animals are buried by sediment, their softer parts rot and their harder parts remain.
Fossils are the remains of dead plants and animals as well as impressions within rock.

21. Not in your notes.

22. Identifying Sedimentary Rock
Ripple marks are formed by the action of winds or water on sand. Many of the marks are preserved when the sand becomes sandstone.

23. Identifying Sedimentary Rock
Mud cracks develop when wet clay dries and shrinks.
They can become filled with other sediment and eventually form sedimentary rock.