Exam- Geologic Time Flashcards
Era of reptiles/dinosaurs
Mesozoic
Time it takes for half of an unstable isotopes to decay
Half life
Law that states sedimentary rocks are laid down in level layers
Horizontality
Stable isotope that results from the decay of the parent isotope
Daughter
How long ago the earth formed
4600 mya
Rocks that form from cemented sediments
Sedimentary
Longest and oldest era
Precambrian
Faults and magma intrusions are younger that the rock layers they cut through
Cross cutting
Unstable radioactive isotope of an element
Parent
Era of mammal
Cenozoic
Actual age in years of rock layers
Absolute age
Sequence of events, not actual age in years
Relative age
Era of fish and amphibian
Paleozoic
Which geologic time principal tells us that rock layers are older as you go down through a rock sequence
Superposition
A break in the rock record is a
Uncomformidy
Which scenario list the units of geologic time in order from largest to smallest
Eon era period epoch
Fossil type where once living material is replaced by Rock
Altered
Era we live in
Cenozoic
Break in rock record between two sedimentary rock layers
Discomformity
Isotope formed from a radioactive isotope
Daughter
Rocks are laid down in horizontal layers
Horizontality
Rock that forms from sediment cemented together helps us understand earths history
Sedimentary
Atoms of the same element with a different mass numbers due to very number of neutron
Isotope
The loss of radioactive particles result in an isotope changing over time the original isotope (parent) changes into a new isotope (daughter) is a loses particles
Radioactive decay
Time it takes for half of the parent to change into the daughter isotope by comparing the amount of parent versus daughter isotope remaining in the sample you can determine the age of the sample
Half-life
The idea that processes occurring on earth today where occurring in the past
Uniformitarism
Fragments in a rock layer are older than the rock layer that contains
Principle of inclusions
Evidence of teeth shells and sometimes even flush organism are found
Unaltered remains
When the tissue of the ones living organism is replaced by mineral matter
Altered remains
Form in a shell or other structure is buried in sediment then dissolved by groundwater evening impression of the external structure
Molds
Form when molds are later filled with mineral matter
Casts
