A test of the40Ar/39Ar age spectrum technique on some terrestrial materials

摘要: Abstract 40 Ar/ 39 Ar age spectra were determined for 10 terrestrial rock and mineral samples whose geologic history is known from independent evidence. The six whole samples, including biotite, feldspar, hornblende, muscovite, granodiorite, that have experienced post-crystallization heating did not reveal the of crystallization in any obvious way. Minima spectra, however, give reasonable maximum ages reheating high-temperature maxima can be interpreted as minimum ages. High-temperature microcline albite been reheated are approximately 10% younger than age. Apparently there no domains these feldspars retained radiogenic quantitatively. Spectra two diabase contain significant quantities excess argon might mistakenly do emplacement. spectrum technique may a potentially valuable tool study areas with complex histories, but interpretation seems to more difficult suggested by some previous studies.