The mathematical study of diffusional zoning in olivines from Hungarian alkali basalts is discussed, assuming both constant T, and T changing with time. The Fe-Mg distribution profiles of the olivine grains were determined by electron microprobe and can be reasonably well matched by the concentration profiles generated by diffusion. On this basis the cooling rate, or the steady T directly before eruption, of some basalt samples are calculated; the cooling rates obtained range from 0.7-5.5oC per day, the original T being 1250o-960oC.-R.A.H.
|Number of pages||19|
|Journal||Acta Geologica Hungarica|
|Publication status||Published - Jan 1 1983|
ASJC Scopus subject areas