hydrocarbons, nonconformities, and geologic dating

source rock

organic rich shale heated to oil/gas window, transforming kerogen (by breaking it down) to hydrocarbons

reservoir rock

porous and permeable, where oil and gas exists/is extracted from

seal rock

impermeable, prevents migration

trap

geometry of seal and reserve rocks that contains the oil/gas; anticline, faults

porosity

amount of open space

permeability

degree pore spaces connect

location of oil and gas deposits

foreland basins, convergent boundaries

foreland basin

depressed region next to a mountain arc

coal types

ordered in increasing carbon content peat, lignite, bituminous, anthracitic

lithium extraction

mined from spodumene, then the brine (result of chemical weathering) is concentrated/precipitated through a series of pools, very water intensive

cobalt

primarily hydrothermal fluids in sedimentary rocks in the congo, can also be from weathering of mafic rock

steno’s laws

principles of superposition, continuity+horizontality, cross cutting relations, inclusions (are older than rock surrounding it) baked contact (contact metamorphism, pre-existing rock is older and invaded) fossil

unconformity

gap in geological sequence/rock record, indicating missing time

angular unconformity

horizontal rocks overlying tilted rocks

non-conformity

sedimentary rock overlying igneous/metamorphic rock

disconformity

sedimentary rock overlaying sedimentary rock

potassium-argon dating (radioactive)

requires: must contain K (feldspars, micas, amphiboles), at least 100,000 years old

t1/2 is 1.3 billion years

40k —> 40Ar, clock starts once the blocking temp. (500C) is reached, Ar can no longer diffuse out

radiocarbon dating

measure of the ratio of 14C and 14N, reflects specific atmospheric composition, thermal neutrons collide with C decaying it

t1/2 =5730