Rocks Flashcards
physical/mechanical weathering
biological (roots), exfoliation, frost wedging
chemical weathering
oxidation, hydrolysis (water change structure), dissolution
factors controlling weathering
type of rock/mineral, rock structure, rainfall/temp, vegetation
formation of soil
in situ weathering
controls of soil formation
time, topography, organisms, composition of bedrock
soil composition
minerals (45%), water (25%), gases (25%), organic matter (5%)
layers of soil
organic matter then top soil, subsoil, weathered rock, solid rock
when does erosion happen
after weathering
types of erosion
water, ice, wind
depositional environment
lake, swamp, beach, river
allochthonous
material from outside environment that blows to sea
autochthonous
matter in ocean
principle of superposition
oldest at bottom
principle of horizontality
rocks layered horizontally
geological archives
continuous accumulation of sediment, lakes/basins
what do sediments contain
proxies
biological proxies
pollen/diatoms
chemical proxies
isotopes
physical proxies
colour/grain size
classifying sediments
clastic (over 2mm, conglomerate/breccia), organic (coal), chemical
conglomerate/breccia
con is rounded coarse, breccia angular coarse
formation of limestone
organisms with calcite shells accumulate together
flintstone formation
diatoms have silica shells, when they die it accumulates as chert
metamorphic diagenesis
occurs in sediments at less than 100C or less
