samman naeem
Sedimentary Rocks
Dead Horse Point, Utah
Dr. R. B. Schultz
What are sedimentary rocks and what do they represent?
Sedimentary rocks are those that represent the material record of environments in the form of rock layers or strata that once existed on earth.
There are two (2) types of sedimentary rocks, based on their textures:
Clastic (also called “Detrital”)-- form from deposition of solid grains; classified based on grain size: conglomerate, sandstone, and shale
Chemical -- form from minerals precipitating out of water and usually involves some sort of chemical reaction; classified based on mineral content: limestone, bituminous coal are examples.
Why are sedimentary rocks important?
Sedimentary rocks contain information about what earth surface environments were like in the past.
Possess natural resources including important fossil fuels.
Where are sedimentary rocks found?
Sedimentary environments (also referred to as depositional environments) are places environments where sediments accumulate usually in nearly horizontal layers.
There are three (3) very general sedimentary environments:
Continental (on a landmass)
Near shore/shallow water (a transition between continental and ocean)
Deep marine water
Importance of
Sedimentary Rocks
Bauxite: ore of aluminum
How can we detect what type of depositional environment a sedimentary rock formed in?
Controls on sedimentary environments:
Sedimentary rocks may contain fossils
Fossils tell us what type of environment the rock around the fossil formed in
What are some specific types of depositional environments?
Continental Sedimentary Environments
Glacial: deposits may have wide range of grain sizes (poorly sorted).
Fluvial (river): mostly sand, better (not perfectly) sorted)
Lacustrine (lake): muddy, thin layers on lakebed
Aeolian (wind blown): silt and sand dunes produces thick crossbeds; best sorted
Marine (Nearshore) Sedimentary Environments (Transitional)
Deltas:
Dead Horse Point, Utah
Dr. R. B. Schultz
What are sedimentary rocks and what do they represent?
Sedimentary rocks are those that represent the material record of environments in the form of rock layers or strata that once existed on earth.
There are two (2) types of sedimentary rocks, based on their textures:
Clastic (also called “Detrital”)-- form from deposition of solid grains; classified based on grain size: conglomerate, sandstone, and shale
Chemical -- form from minerals precipitating out of water and usually involves some sort of chemical reaction; classified based on mineral content: limestone, bituminous coal are examples.
Why are sedimentary rocks important?
Sedimentary rocks contain information about what earth surface environments were like in the past.
Possess natural resources including important fossil fuels.
Where are sedimentary rocks found?
Sedimentary environments (also referred to as depositional environments) are places environments where sediments accumulate usually in nearly horizontal layers.
There are three (3) very general sedimentary environments:
Continental (on a landmass)
Near shore/shallow water (a transition between continental and ocean)
Deep marine water
Importance of
Sedimentary Rocks
Bauxite: ore of aluminum
How can we detect what type of depositional environment a sedimentary rock formed in?
Controls on sedimentary environments:
Sedimentary rocks may contain fossils
Fossils tell us what type of environment the rock around the fossil formed in
What are some specific types of depositional environments?
Continental Sedimentary Environments
Glacial: deposits may have wide range of grain sizes (poorly sorted).
Fluvial (river): mostly sand, better (not perfectly) sorted)
Lacustrine (lake): muddy, thin layers on lakebed
Aeolian (wind blown): silt and sand dunes produces thick crossbeds; best sorted
Marine (Nearshore) Sedimentary Environments (Transitional)
Deltas: