1. Sedimentary Rocks

2. Formation of Sedimentary Rocks
Sedimentary rock forms at or near the surface, when sediments are pressed and cemented together, or when minerals form from solutions.
Sedimentary rocks often form as layers, strata.
The process by which sediment becomes sedimentary rock is known as lithification.

3. What is sediment?
Sediments are loose materials such as rock fragments, mineral grains, and remains of some organisms caused from
Sediments come from weathered and eroded igneous, metamorphic, and sedimentary rocks.

4. Classifying Sedimentary Rocks
Sedimentary rocks are classified by their composition and by the manner in which they formed.
The three types of sedimentary rocks are:
Clastic
Chemical
Organic

5. Clastic Sedimentary Rocks
Clastic sedimentary rocks are made from the broken fragments of other rocks cemented together by a mineral.
Clastic sedimentary rocks can have coarse-grained, medium-grained, or fine-grained textures
Ex. Sandstone, breccia, conglomerate, shale

6. Shale = forms from the compaction of silt and clay-size mineral particles
Sandstone = formed where sand is laid and buried – beaches, dunes, and seafloors

7. Monument Valley in Arizona

8. Clastic Sedimentary Rock
Processes that help form sedimentary rocks:
Weathering = Breaking down of material by wind, water, ice, sunlight, & gravity
Erosion = Movement of sediments
Deposition = The process by which sediment is dropped or settles in new locations.
Compacted = Smaller sediments pushed together
Cemented = Dissolved minerals such as quartz or calcite act as a natural glue cementing larger sediments together

9. Chemical Sedimentary Rocks
Chemical sedimentary rocks form from solutions of dissolved minerals and water.
Minerals crystallizes out of solution
Ex. Halite, limestone, gypsum

10. Organic Sedimentary Rock
Rocks made of the remains of once-living things are called organic sedimentary rocks.
One of the most common organic sedimentary rocks is fossil-rich limestone.
Coal- forms underground from plant material buried under sediment & changed to coal over millions of years

11. Example of Organic Sedimentary Rock
Chalk is another organic sedimentary rock that is made of microscopic shells.
When you write with
naturally occurring
chalk, you’re crushing
and smearing the calcite-shell remains of once-living ocean organisms.

12. Organic Clastic Chemical coal erosion chalk weathering compaction
forms when sediments are pressed and cemented together, or when minerals form from solutions
already-existing rocks that are weathered and eroded
Organic
Clastic
Chemical
compaction
Broken fragments of other rocks
Made of the remains of once living things
Dissolved minerals come out of solution
cementation
chalk
coal
Halite
limestone
weathering
erosion