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about how billions of years ago was rocks formed on earth?
what is relative dating?
system of reasoning that is used to determine the chronological sequence or order f a series of gerologic events
what is radiometric dating?
uses radioactive decay of radioactive isotopes within minerals to calculate chronological age
explain the pleozoic eon:
about 550 million years ago= start
tranformed single cell to multi cellular life
simple to diverse
explain mesazoic eon:
explain cenozoic eon:
whats happening now
when did archbishops james ussher say was exact date of earth creation?
nightfall preceding 23 october 4004 BC
in 1700 what what did technique philosopher, naturalist and geologist use to get theories of deep time?
in 1900 what did geologist use to get the age of the earth?
what are the five funadmental geologic events ordered by relative dating?
erosion-removal of rocks
deposition-sediment being deposited
what are the seven stratigraphic principles used in relative dating?
principle of original horizontality
principle or original lateral continuity
principle of cross cutting relationships
principle of inclusions
principle of unconformities
principle of faunal succession (evolution)
eplain principle superposition:
youngest rock on top and oldest on bottom
explain principle original lateral continuity
erosion cutting downward
explain principle of original horizontality:
horizontal strata on top and deformed strata on bottom
explain principle of cross cutting relationships
igneous dike cuts across- has to be younger
explain principle of inclusion
granite at surface expoed to weathering
sandstone deposited on granite
explain principle of unconformity
rock layers deposited, folded, eroded and covered with new depostion
which period is the beginning of the peleozoic?
which period is beginning of the mesozoic?
what is radioactive decay
one neutron decays and turn into something else
radiometric dating uses _______ to estimate age of geologic samples
what is half life
time it takes to have half of original atoms
what provides important isotopic clocks
what is the key point about why patssium-argon are useful
used to date igneous rocks
how many isotopes are there
which isotope is most common
about how many years old is the oldest mineral
about 4.4 bya
about how old is the oldest rock
about 4.2 bya