Post on 16-Dec-2015
transcript
Lecture 8
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)
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
Clastic
Classification depends on grain size
Size (mm) particle name
>256
64-256
4-64
2-4
.0625-2
.0039-.0625
<0.0039
Clastic
Classification depends on grain size
Size (mm) particle name rock name
>256 boulder
64-256 cobble
4-64 pebble
2-4 granule
.0625-2 sand
.0039-.0625 silt
<0.0039 clay
Clastic
Classification depends on grain size
Size (mm) particle name rock name
>256 boulder
64-256 cobble
4-64 pebble
2-4 granule
.0625-2 sand sandstone
.0039-.0625 silt
<0.0039 clay
Clastic
Classification depends on grain size
Size (mm) particle name rock name
>256 boulder
64-256 cobble conglomerate
4-64 pebble or breccia
2-4 granule
.0625-2 sand sandstone
.0039-.0625 silt siltstone
<0.0039 clay shale