All the rivers run to the sea, yet the sea is not full:
unto the place from whence the rivers come,
thither they return again.
- Ecclesiastes 1:7
Sedimentary Rocks
Webpage for course (daytime)
Webpage for course (nighttime)
Lecture 8
Three types of rocks:
- Igneous
-Sedimentary
- Metamorphic
Sedimentary rocks are important because
Form and are common at earth’s surface
Preserve the history of Life (contain fossils)
Sedimentary rocks are important because
Form and are common at earth’s surface
Preserve the history of Life (contain fossils)
Show past environments, climates
Provide a geologic record of past history
Major sources of energy – oil, gas, coal
General History of a Sedimentary Rock
WEATHERING
TRANSPORTATION
DECOMPOSITION
DEPOSITION
LITHIFICATION
Mechanisms of Transportation and Deposition
Water - streams, rivers, etc.,
freshwater and marine
Wind
Gravity – downslope movement
Ice – glaciers
Some sedimentary rocks form of atoms dissolved
in water and precipitated elsewhere
Classification of sedimentary rocks
Clastic (Detrital in your book)
Nonclastic
Nonclastic
Example, coal
Nonclastic
Another example, rock salt
Clastic
Classification depends on grain size
Size (mm)
>256
64-256
4-64
2-4
.0625-2
.0039-.0625
<0.0039
particle name
Clastic
Classification depends on grain size
Size (mm)
>256
64-256
4-64
2-4
.0625-2
.0039-.0625
<0.0039
particle name
boulder
cobble
pebble
granule
sand
silt
clay
rock name
Clastic
Classification depends on grain size
Size (mm)
>256
64-256
4-64
2-4
.0625-2
.0039-.0625
<0.0039
particle name
boulder
cobble
pebble
granule
sand
silt
clay
rock name
sandstone
Clastic
Classification depends on grain size
Size (mm)
>256
64-256
4-64
2-4
.0625-2
.0039-.0625
<0.0039
particle name
rock name
boulder
cobble
conglomerate
pebble
or breccia
granule
sand
sandstone
silt
siltstone
clay
shale
Why the distinction conglomerate and breccia?
Conglomerate means slow, breccia means sudden
Nonclastic
Chemical
Biogenic
Coal
Coquina
Chalk
Diatomite
Diatoms
Nonclastic
Chemical
Rock Salt
Chert
Limestone
Dolomite
Biogenic
Coal
Coquina
Chalk
Diatomite
Coal as Energy