Flashcards
Absolute dating & Isotopic dating
Flashcards do conjunto (7)
- 1What is dendrochronology?Study tree rings (~12 Ka)
Dark = winter
Light = summer
One ring = one year - 2What is fission-track dating?Dating by "counting up" the amount of radiation damage in a crystal.
(Older rocks have more damage) - 3What is amino acid racemization?Dating by measuring the amount of degradation of amino acids in organic materials.
More amino acid degradation = older - 4What is ice sheet dating?Counting ice layers
1 layer = 1 year - 5What is isotopic dating?Also known as radiometric dating.
Measuring how radioactive the atoms are in a particular rock.
Parent isotopes decay into daughter isotopes. - 6Which rocks do radiometric dating work for?Igneous rocks gets you date of cooling/crystallization.
Metamorphic rocks gets you date of alteration (cooking).
Sedimentary gets you age of cement minerals. - 7What is a half-life?The amount of time needed for 1/2 of any amount of parent to decay into a daughter isotope.