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)

Three types of rocks:

- Igneous-Sedimentary- Metamorphic

Sedimentary rocks are important because

Form and are common at earth’s surfacePreserve the history of Life (contain fossils)

Sedimentary rocks are important because

Form and are common at earth’s surfacePreserve the history of Life (contain fossils)Show past environments, climatesProvide a geologic record of past historyMajor sources of energy – oil, gas, coal

General History of a Sedimentary Rock

WEATHERINGTRANSPORTATIONDECOMPOSITIONDEPOSITIONLITHIFICATION

Mechanisms of Transportation and Deposition

Water - streams, rivers, etc., freshwater and marine

Wind Gravity – downslope movementIce – 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) 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

Why the distinction conglomerate and breccia?

Conglomerate means slow, breccia means sudden

Nonclastic

Chemical Biogenic

CoalCoquinaChalkDiatomite

Diatoms

Nonclastic

Chemical

Rock SaltChertLimestoneDolomite

Biogenic

CoalCoquinaChalkDiatomite

Coal as Energy