1. Sediment Sediment Sediment Sediment Sediment Sedimentary rock
Notes #11

2. Sedimentary Rocks
Form when sediments (bits and pieces of any other rocks) are compacted and cemented together.
**Normally layered**

3. Sediment
The following processes are necessary for the formation of sediment:
Weathering – breaking down of rock material by physical or chemical means
Erosion - The transportation of weathered sediment by water, wind, ice, gravity, etc.
** Mountains that have been uplifted are typically the source of weathered and eroded sediments**

4. 2 1

5. The following processes are necessary for the formation of sedimentary rock:
3. Deposition – dropping off of sediment
- Usually occurs in a body of water (oceans).
- This happens when the agent of erosion slows down or stops
- Burial of each layer beneath

6. - Results in de-watering
4. Compaction – Squeezing of sediment by the weight of overlying sediment
- Results in de-watering
5. Cementation - gluing together of sediment by minerals
- Quartz or calcite is dissolved in water, when the water leaves the sediment, the minerals remain gluing the sediment together.
***This process by which sediments get compacted into rock is called lithification.

7. 3 4 5 2 1

8. Two main classes of sedimentary rocks clastic and chemical
Clastic rocks are made up of pieces of other rocks.
Chemical rocks are made from evaporation of water and/or chemical precipitation

10. Clastic Rocks
Made of pieces from less than cm to 1 m or more in size.
Classified based on particle size
Clay, silt, sand, pebbles, cobbles, boulders
Composition does not matter
Made of mostly quartz, feldspar, and clay minerals due to their resistance to weathering

11. Conglomerate - pebbles

12. Breccia – angular pebbles

13. Sandstone – notice the layers

14. Siltstone – a little finer grained

15. Shale – usually dark grey or black

16. Grand Canyon of Arizona

17. Notice: layers and sediments

18. Chemical Rocks May have crystalline texture
Classification based solely on composition - monomineralic
Grain size does not matter
Dissolved minerals precipitate out of salt water solution (ocean water is salty) and are called “evaporites”

19. Evaporites Steps for evaporite formation
1. Minerals dissolve in water (weathering)
2. Water evaporates (deposition)
3. Dissolved minerals precipitate out leaving salt minerals behind. (cementation)
Precipitation is the opposite of dissolution

20. Halite – rock salt - NaCl

21. The Dead Sea in Jordan 8.6 X saltier than the ocean
Water is saturated so salt precipitates on everything

22. The water in the Dead Sea is so dense with salt, that you float much higher than in a lake or the ocean.

23. The Great Salt Lake in Utah (ancient lake Bonneville) is another example

26. Rock Gypsum – Made of gypsum CaSO4

27. Dolostone – made of dolomite

28. Made of SiO2 – “diatomaceous ooze”
*Not in ESRT*
Made of SiO2 – “diatomaceous ooze”

29. Limestone – crystalline, made of calcite

30. There is a third sub category called Bioclastic meaning life-pieces
Made mostly of fossils, shells, or organic material
Fossiliferous limestone

31. Fossils are evidence of past life. Only found in sedimentary rocks
May be shells, teeth, claws, bones, etc.
Typically hard parts

32. Coquina – broken pieces of shells

33. Bituminous Coal – fossilized plant remains

34. Horizontal sorting during deposition
As streams enter a body of water they slow down and drop off their sediment load.
The larger particles fall first and the smaller particles may travel farther into the ocean.
Conglomerates and breccias
siltstone

35. Sedimentary Structures
STRATIFICATION - sediment layers are stacked on top of each other. The Grand Canyon in AZ is a perfect example.

36. Sedimentary Structures
CROSS-BEDDING - It reflects the transport of gravel and sand by changing currents

37. Sedimentary Structures
RIPPLE MARKS - are produced by flowing water or wave action

38. Sedimentary Structures
MUD CRACKS - form when a water rich mud dries out

39. I know it is a sedimentary rock because
It has fossils
(organic remains)
2. It has pebbles
3. It has clasts
4. It is layered