Radiometric dating solar system
Thermal processes that may occur during meteorite impact in the lifetime of the specimen can reset some of the atomic clocks, mixing components and releasing important gases such as "You refer to extinct nuclides 14C, 26Al, and 129I.
Only the latter two "extinct" nuclides are used in dating.
Trees undergo spurts in growth in the spring and summer months while becoming somewhat dormant in the fall and winter months.
When a tree is cut down, these periods are exhibited in a cross section of the trunk in the form of rings.
26Al and some other nuclides not mentioned are also used in this way.These rates are usually expressed as the isotope's half-life--that is, the time it takes for one-half of the parent isotopes to decay.After one half-life, 50 percent of the original parents remains; after two, only 25 percent remains, and so on."Near the end you imply that low petrologic type chondrites are the most easily dated.