(MODULE 4) SEDIMENTARY ROCKS Flashcards
how are sedimentary rock formed from igneous rock?
igneous rock undergoes weathering and erosion which turns it into sediments. those sediments undergo lithification (cemented or consolidated) and formed into a sedimentary rock
___ is the collective name for loose, solid particles of mineral originating from weathering and erosion (detrital) and precipitation (chemical)
sediment
the chemical, physical, and biological changes that take place after sediments are deposited.
diagenesis
diagenesis includes:
1.
2.
- recrystallization
- lithification
development of more stable minerals from less stable ones.
recrystallization
sediments are transformed into solid rock by either compaction or cementation
lithification
natural cements include ___, ___, and ___
calcite, silica, and iron oxide
during this type of lithification, pressure compacts and rearranges loosely packed, fine clay-size particles to create sedimentary rocks.
compaction
during this type of lithification, silica- and calcite-rich material fill the pore space of course-grained particles and clues them together.
cementation
eroded mineral grains
transported sediment as solid particles; fragments of preexisting rocks
detrital sedimentary rocks
minerals precipitated from low-temperature solution
sediment that was once in solution
chemical sedimentary rocks
consolidation of organic remains of plants
formed from the carbon-rich remains of organisms
organic sedimentary rocks
- ___: compressed but still has water in it
- ___: compressed to the point where the water is squeezed out
- compression
- consolidation
clay-sized particles in thin layers (laminea) which split into layers (fissility)
also the most common sedimentary rock
shale
sedimentary rock which breaks into chunks or blocks
mudstone
composed of silt-size particles. lacks fissility.
siltstone
composed of sand-sized particles, quartz is the predominant mineral
sandstone
consists of rounded gravels; often has a similar appearance to concrete
conglomerate
composed mainly of large angular particles and fragments which have not been rounded
breccia
common detrital rocks (sedimentary rocks from weathering)
1.
2.
3.
- shale
- sandstone
- conglomerate & breccia
common chemical rocks (precipitated from a low temperature aqueous environment)
1. ___
2. ___
3. ___
4. ___
- limestone (biochemical, inorganic)
- dolostone
- chert
- evaporites
chemical rocks
cementation of shells and shell fragments accumulated on shallow sea floor near shore
coquina
chemical rocks
light-colored, porous, very fine-grained variety of bioclastic limestone that forms from the seafloor accumulation of microscopic marine organisms that drift near the sea surface.
chalk
chemical rocks
type of limestone seen in caves
travertine
chemical rocks
formed by cementation of sand-sized ooids or small spheres of calcite
oolithic limestone
chemical rocks
how do you differentiate dolostone and limestone?
limestone fizzes when poured with acid, dolostone doesn’t react visibly
chemical rocks
compact and hard rocks made of microcrystalline quartz
chert
chemical rocks
a form of banded chert
agate
chemical rocks
evaporation triggers deposition of chemical precipitates, forming
evaporites
how is coal formed?
- accumulation of plant remains in a swampy environment makes peat
- peat is buried and transformed into lignite (soft brown coal)
- further burial forms bituminous coal, the source of coal energy
- metamorphism makes anthracite coal
two major textures are used in the classification of sedimentary rocks:
1.
2.
- clastic
- non-clastic
pattern of fragments and particles, detrital rocks fall under this classification
clastic texture
pattern of interlocking crystals, resembling igneous rock
non-clastic texture
