Lab 3: Sedimentary Rocks Flashcards
Breccia
framework clasts are angular
gravel or larger angular clasts surrounded by sand/mud particles
poorly sorted
Chert
you can not see the individual grains at all - appears very smooth
cryptocrystalline quartz
conchoidal fracture
hardness = 7
Conglomerate
framework clasts are rounded
gravel or larger rounded clasts surrounded by sand/mud particles
poorly sorted
Dolostone
look for more beat up railway ballast rock (people wrecking it to make powder)
will weakly react with acid
calcite
Fossiliferous Limestone
look for visible fossils
will react with acid
calcite
Limestone
look for railway ballast rock
will react with acid
calcite
Mudstone
grains are too small to be seen with a hand lens
massive or blocky in nature
feels smooth
mud sized grains
micas and clays
Potash
look for mostly pink crystal texture
sylvite and halite
crystalline texture
Rock Salt
halite - literally just halite
white crystal texture
crystalline texture
Sandstone
speckled salt and pepper-like appearance
mixture of quartz and feldspar with lithics
sand-sized grains
moderately to well sorted
rounded
Shale
grains are too small to be seen with a hand lens
breaks into sheets or thin layers
(Fissile, cleavage is wrong)
feels smooth
micas and clays
mud-sized grains
biochemical sedimentary rocks
dolostone, limestone, fossiliferous limestone, chert
chemical sedimentary rocks
rock salt, potash
clastic sedimentary rocks
conglomerate, breccia, sandstone, mudstone, shale
controls on soil formation
parent material
time
climate**
plants/animals
topography
parent material
the type of material that soil grows on top of, which determines the rate of weathering and the soil fertility
time
the longer the soil has been forming the thicker it becomes and less it resembles the parent material
climate
most important**
temperature and precipitation are considered among the most influential factors in determine the rate and depth of weathering, particularly at larger scales where climatic differences are more pronounced
plants/animals
the physical/chemical properties of soil depend upon the type and abundance of plants and animals which interact with the soil in a variety of complex ways
topography
steep slopes impede soil formation due to a decrease in water retention and increase in erosion, thus soils grow much more readily on flat ground
o horizon
plant litter, and partly decomposed organic matter
a horizon
mainly mineral matter with some decomposed organics
topsoil
horizon O and A; they are unsuitable for the construction of infracture
E horizon
lEEching horizon. light coloured layer that water percolates through, moving dissolved components and finer particles to lower depths
