GEY 101 - Introductory Geology: Exploring Planet Earth
Sedimentary Rocks

What is a sedimentary rock?

Sedimentary rocks are important for economic considerations because they may contain

Turning sediment into rock

Many changes occur to sediment after it is deposited



Types of sedimentary rocks

Detrital sedimentary rocks

The chief constituents of detrital rocks include

Particle size is used to distinguish among the various types of detrital rocks

Common detrital sedimentary rocks (in order of increasing particle size)

Chemical sedimentary rocks

Consist of precipitated material that was once in solution

Precipitation of material occurs in two ways

Common chemical sedimentary rocks

Classification of sedimentary rocks

Sedimentary rocks are classified according to the type of material

Two major groups

Two major textures are used in the classification of sedimentary rocks

Sedimentary environments

A geographic setting where sediment is accumulating.
Determines the nature of the sediments that accumulate (grain size, grain shape, etc.)

Types of sedimentary environments

Sedimentary facies Different sediments often accumulate adjacent to one another at the same time.
Each unit (called a facies) possesses a distinctive set of characteristics reflecting the conditions in a particular environment.
The merging of adjacent facies tends to be a gradual transition.

Sedimentary structures

Provide information useful in the interpretation of Earth history.

Types of sedimentary structures

Fossils: Evidence of past life

By definition, fossils are the traces or remains of prehistoric life now preserved in rock.

Fossils are generally found in sediment or sedimentary rock (rarely in metamorphic and never in igneous rock)

Geologically fossils are important for several reasons

Additional Study Guide

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