GEOL 1 Lecture Notes - Lecture 17: Dendrochronology, Half-Life, Lightdark
2 Dec 2020
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Non-radiometric don"t use radioactive material, looking for things that form on. Forms in lake that freezes over winter. Restrictions: specific conditions, only gives info about small area, light bands are summer months, dark layers are winter months can"t have much biologic activity on floor of lake. Multiple trees can be overlapped to show broader number of years. Restrictions: only tells about one tree, assumption that trees produce one nring per year, trees can stop growing if disturbed, trees grow rings at different rates. Radiometric do use radioactive material, majority of techniques. Isotopes atoms of same element with different numbers of neutrons. Radioactive decay unstable isotope tries to become stable. Radiation combination of energy and particles given off by unstable isotope. Daughter atom present after radioactive decay, can also be radioactive and can produce second daughter. Decay series (chain) full sequence from parent to get to stable daughter. Half-life amount of time it takes for of parent atoms to decay.
