Sedimentary Rocks
There are three kinds of sedimentary rocks, all of which can be found at the surface in Kansas. As you read the descriptions of the different types, you'll notice that limestone can be either chemical or organic. It is necessary to examine the composition of the limestone closely, in order to properly categorize it.
CLASTIC sedimentary rocks
After magma cooled and the first igneous rocks were formed, they began to be worn down by the abrasive action of wind, water, and ice. This action is called weathering or erosion. The eroded materials were carried by water, wind, glaciers, or gravity to places where it was deposited as sediments. Layers of sediment built up, were compacted, and then were cemented by any of a number of minerals.
These sedimentary rocks are composed of sediments that are described as grains or particles. The grain sizes range from very fine to coarse; the size depends on the time and amount of weathering.
Grain size Rock Type
Clay Shale or Mudstone
Silt Siltstone
Sand Sandstone
Pebbles Conglomerate
Cobbles
Boulders
CLASTIC sedimentary rocks
After magma cooled and the first igneous rocks were formed, they began to be worn down by the abrasive action of wind, water, and ice. This action is called weathering or erosion. The eroded materials were carried by water, wind, glaciers, or gravity to places where it was deposited as sediments. Layers of sediment built up, were compacted, and then were cemented by any of a number of minerals.
These sedimentary rocks are composed of sediments that are described as grains or particles. The grain sizes range from very fine to coarse; the size depends on the time and amount of weathering.
Grain size Rock Type
Clay Shale or Mudstone
Silt Siltstone
Sand Sandstone
Pebbles Conglomerate
Cobbles
Boulders
CHEMICAL sedimentary rocks
Chemical sedimentary rocks are formed by minerals precipitated in water. These minerals sank to the bottom and formed layers of sediments. The most common chemical sedimentary rock we find in Kansas is limestone. This process continues today in shallow warm seas, hot springs, and saline lakes.
Chemical rocks can also be formed by evaporation. When the ancient seas retreated, large bodies of water were left land-locked. Eventually the water evaporated, leaving behind salt, anhydrite, or gypsum in beds that varied widely in depth (thickness). Some limestones, cherts, irons ores, and travertine (carbonate spring deposits) are also classified as chemical sedimentary rocks.
Chemical sedimentary rocks are formed by minerals precipitated in water. These minerals sank to the bottom and formed layers of sediments. The most common chemical sedimentary rock we find in Kansas is limestone. This process continues today in shallow warm seas, hot springs, and saline lakes.
Chemical rocks can also be formed by evaporation. When the ancient seas retreated, large bodies of water were left land-locked. Eventually the water evaporated, leaving behind salt, anhydrite, or gypsum in beds that varied widely in depth (thickness). Some limestones, cherts, irons ores, and travertine (carbonate spring deposits) are also classified as chemical sedimentary rocks.
ORGANIC sedimentary rocks
These rocks have an organic origin, representing bodies of plants and animals that decayed in water and were laid down in layers. They include the following:
- some limestones
- diatomaceous earth (marl)
- many iron ores
- coal
These rocks have an organic origin, representing bodies of plants and animals that decayed in water and were laid down in layers. They include the following:
- some limestones
- diatomaceous earth (marl)
- many iron ores
- coal