Sedimentary rocks
Sedimentary rocks: is rock that forms at or near the surface of the earth in one of several ways: by
the cementnn tonether of loose clasts(franments or nrains) that had been produced by physical or
chemical weatherinn of pre-existnn rockk by the nrowth of shell masses or by the cementnn tonether
of shells and shell franmentsk by the accumulaton and subsequent alteraton of ornanic mater
derived from livinn ornanismsk or by the precipitaton of minerals directly form surface-water
solutons.
7.2 classes of sedimentary rocks
1. Clastic sedimentary rock: cemented-tonether clastsk solid franments and nrains broken of of
pre-existnn rocks
2. Biochemical sedimentary rock: consist if shells nrown by ornanisms
3. Organic sedimentary rock: carbon-rich relicts of cellular material from plants or other
ornanisms
4. Chemical sedimentary rock: minerals that precipitated directly from surface-water solutons
Clastic
Formaton:
- Weatherinn: produces nrains
- Erosion: combinaton of processes that separate clasts from their orininal substrate
- Transportaton: clasts and dissolved ions can be carried away. (windk waterk ice)
- Depositon: eventually it undernoes depositon: sediment falls out of the medium. When the
velocity decreases it had no lonner the ability to carry sediment
- Lithificaton: transformaton from loose nrains into solid rock.
o Step 1: compaction: nrains buried -> weinht above them pusses the water out and
the nrains are tnhter tonether. (pressure)
o Step 2: cementation: minerals precipitate from nroundwater and fill spaces between
clasts. Acts like nlue
Sedimentary structures: features which ranne from subtle to obviousk formed durinn the process of
depositon and provide key clues to the environment In which the sediments were deposited.
Bed: sinnle layer of sediment/ sedimentary rock with a reconnizable top and botom
Strata: several beds tonether
Bedding plane: boundary between two beds
Bedding/stratification: overall arrannement of sediment into a sequence of beds
Stratigrapher: a neolonist who specializes in studyinn strata
Stratigraphy: the study of the record of earth history preserved in strata
Stratigraphic formations: durinn neolonic tmek lonn-term channes in a depositonal environment can
take place. Thusk a nive sequence of strata may difer markedly from sequences of strata above or
below. A sequence of strata that is distnctve enounh to be traced as a packane across a fairly larne
renion is called a stratnraphic formaton.
Geologic map: a map that portrays the distributon of stratnraphic formatons
Sedimentary rocks: is rock that forms at or near the surface of the earth in one of several ways: by
the cementnn tonether of loose clasts(franments or nrains) that had been produced by physical or
chemical weatherinn of pre-existnn rockk by the nrowth of shell masses or by the cementnn tonether
of shells and shell franmentsk by the accumulaton and subsequent alteraton of ornanic mater
derived from livinn ornanismsk or by the precipitaton of minerals directly form surface-water
solutons.
7.2 classes of sedimentary rocks
1. Clastic sedimentary rock: cemented-tonether clastsk solid franments and nrains broken of of
pre-existnn rocks
2. Biochemical sedimentary rock: consist if shells nrown by ornanisms
3. Organic sedimentary rock: carbon-rich relicts of cellular material from plants or other
ornanisms
4. Chemical sedimentary rock: minerals that precipitated directly from surface-water solutons
Clastic
Formaton:
- Weatherinn: produces nrains
- Erosion: combinaton of processes that separate clasts from their orininal substrate
- Transportaton: clasts and dissolved ions can be carried away. (windk waterk ice)
- Depositon: eventually it undernoes depositon: sediment falls out of the medium. When the
velocity decreases it had no lonner the ability to carry sediment
- Lithificaton: transformaton from loose nrains into solid rock.
o Step 1: compaction: nrains buried -> weinht above them pusses the water out and
the nrains are tnhter tonether. (pressure)
o Step 2: cementation: minerals precipitate from nroundwater and fill spaces between
clasts. Acts like nlue
Sedimentary structures: features which ranne from subtle to obviousk formed durinn the process of
depositon and provide key clues to the environment In which the sediments were deposited.
Bed: sinnle layer of sediment/ sedimentary rock with a reconnizable top and botom
Strata: several beds tonether
Bedding plane: boundary between two beds
Bedding/stratification: overall arrannement of sediment into a sequence of beds
Stratigrapher: a neolonist who specializes in studyinn strata
Stratigraphy: the study of the record of earth history preserved in strata
Stratigraphic formations: durinn neolonic tmek lonn-term channes in a depositonal environment can
take place. Thusk a nive sequence of strata may difer markedly from sequences of strata above or
below. A sequence of strata that is distnctve enounh to be traced as a packane across a fairly larne
renion is called a stratnraphic formaton.
Geologic map: a map that portrays the distributon of stratnraphic formatons
