This is only an outline of the lecture. You will need to go to class
       to fill in the outline, although much of the relevant information is
       also in the text.
 
 

Sediment is
 
 
 
 

Sediment is created by
 
 

Mechanical break up of rock may be caused by
 
 
 
 

Chemical decomposition includes
 
 
 

 These changes soften the rock, making mechanical break up easier.

The products of weathering include

1)

2)

3)

4)

Clastic sediment consists of
 
 
 
 

These pieces are divided into:

1)
2)
3)
4)

Some minerals weather faster than others.  These more susceptible minerals may oxidize, dissolve or change to clay.  Therefore, we don't often find them in the sediment downstream.

We can list the silicate minerals from less resistant (more susceptible) to more resistant:

less resistant
 
 
 
 
 
 
 

more resistant

As a result, we find that smaller size sediment is made mainly of the more resistant minerals:
 
 

Sediment is transported by
 
 
 
 

Sediment transported by landslide or glacier will be of all sizes:
 
 
 

Water
 
 
 
 

Wind
 
 

Glaciers and landslides
 
 
 
 

Water sorts sediment moderately well by size.
 
 
 

The size it can carry depends on its velocity and turbulence.
 
 
 

Wind sorts sediment very well.
 
 

Grains become rounded during transport.

Landslides and glaciers do not round
 
 
 
 

A river rounds gravel very well
 
 
 
 
 

Sand grains carried by wind
 
 

Stratification is layering.  In water, sediment is deposited horizontal layers, one on top of another.
 
 
 

The layering results from changes in grain size through time, which is caused by
 
 
 

Graded bedding means that the grain size changes within each layer.  Usually it changes from large to small (from bottom to top).
 
 
 
 
 
 
 
 

 Crossbedding means there are beds within beds, and the little beds are not horizontal.  The most common cause of these is sand dunes.
 
 

 In sedimentary rocks,
 
 
 
 
 
 
 

Recrystallization is very minor in clastic rocks, but important in formation of limestones (below).

Limestone mostly is formed by living organisms.
 
 
 
 
 

Shells that form limestone are made of calcite or aragonite.
 
 
 
 
 

You will see two varieties of limestone in lab:
 
 
 
 

Limestone reacts with acid, so you can use the acid test to identify it.
Shells become limestone by
 
 

Evaporites precipitate (crystallize) from water as the water evaporates.

The most common evaporite rocks are
 
 
 
 
 
 
 

Evaporites usually form as hard rocks, originally.  They don't have to be "lithified."

Chert is made of
 
 
 

When the shells accumulate in layers on the seafloor, the opal crystallizes to
 
 
 
 
 
 
 
 
 

Chert is harder than glass, like other forms of quartz.
 
 

Coal is made from
 
 
 
 
 
 

Instead, it heats and compresses in the absence of oxygen,
 
 
 
 
 
 
 

Thus, coal is called a hydrocarbon.
 
 

In summary, wind sorts sediment best, then water, then ice.
 
 
 
 
 
 

Ice can carry the largest sediment, then water, then wind.

Sediment is typically stratified, or layered.  Sand dunes have cross stratification.  Running water often produces graded beds.

You can use these clues to figure out what process deposited the sediment.
 
 

Sediment in the ocean is more coarse near land, and becomes very fine in the deep ocean.
 
 
 
 
 
 
 

In the deep ocean, there is no sand or gravel.
 
 
 

Otherwise the deep ocean has mostly organic sediment: