All the weathered sediments are later transported (eroded away), mainly by rivers, to basins. In these basins these sediments will accumulate and later by the process of lithification (compaction, cementation and recrystallization) they will become rocks.

The heaviest sediment (gravel) will be the first one to be deposited and after the process of lithication that GRAVEL will become a rock called CONGLOMERATE. Medium weight particles of SAND will travel a bit farther into the basin and once these particles are lithified, they will form a rock called SANDSTONE. The lightest particles mainly MUD consisting of clay and SILT will be deposited and lithified forming a rock called SHALE.

In some locations, there are lateral gradations within a single layer, as illustrated in the figure above, where a conglomerate grades into a sandstone which grades into a shale. When this occurs, the grain size decreases as the distance away from the mountain front increases.

The ability of moving water, as in a river, to transport sediment depends on flow velocity and on the size of the sediment being transported. Generally, high velocities can transport both small and large grained material, while slower flows can transport only the smaller size fractions. If a mixture of gravel, sand and mud is carried by moving water, which material is deposited first as the velocity of the water decreases? Which is deposited last, when the water has slowed down almost to a halt?

First material de deposited __________________________________

Last material de deposited __________________________________

From these considerations, explain how those layers in which there is a change in grain size originated in the basin setting described.

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Limestone - All sedimentary rocks that are made principally of calcite are called limestone. Limestones have diverse appearances depending on their origins and on the character of substances they contain (often in minute quantities) other than calcite. All limestones will react to hydrochloric acid because they contain calcium carbonate. We will be studying three types of limestones.

A) the shells of sea creatures such as clams accumulate along a shoreline. They are later buried and cemented together to form rock;

Origin A results in specimen called _________________________________________

(B) the calcareous (made of calcium carbonate) hard parts of minute or microscopic marine animals and plants accumulate on the sea floor to become part of a calcareous mud. The mud, upon burial, becomes dewatered, compacted and reorganized to form a very fine-grained, crumbly rock;

Origin B results in specimen called _________________________________________

(C) changes in the temperature, pressure or chemistry of lake water cause some of the calcium carbonate that is dissolved within it to come out of solution and be precipitated onto the lake floor to form an extremely fine- grained, even-textured mud. This mud, upon burial, becomes dewatered, compacted and reorganized to form an extremely homogenous, fine- grained smooth rock with very low porosity.

Origin B results in specimen called _________________________________________

CHEMICAL - Chemical sedimentary rocks are formed by the saturation and precipitation of salts accumulated in lakes and seas.

Name of rock = SHALE

Type of rock = CLASTIC

Composition = Layers of mud and clay became lithified

Reaction to HCL = Non Reactive

Name of rock = SANDSTONE

Type of rock = CLASTIC

Composition = Layers of sand became lithified

Raction to HCL = Non Reactive

Name of rock = CONGLOMERATE

Type of rock = CLASTIC

Composition = Gravel became lithified

Reaction to HCL = Non Reactive

Name of rock = LIMESTONE

Type of rock = CHEMICAL

Composition = Minute parts and microscopic animals die and accumulate on the seafloor creating a calcareous (made of calcium carbonate) ooze that precipitates to form this rock.

Reaction to HCL = Reactive

Name of rock = COQUINA

Type of rock = BIOGENIC

Composition = Shells of sea creatures that are compacted and cemented together

Reaction to HCL = Reactive

Name of rock = CHALK

Type of rock = BIOGENIC

Composition = Calcareous mud produced by dead plankton that became lithified

Reaction to HCL = Reactive