40Ar-39Ar geochronological studies on submarine rocks from the Western Pacific area

40Ar-39Ar incremental heating dating has been applied to (1) one medium-grained hawaiite from the Suiko Seamount in the Emperor volcanic chain, (2) one alkali dolerite from a seamount in the Necker Rise, and (3) twelve rocks from the Line volcanic chain and its vicinity. 40Ar-39Ar ages were calculated from isochron plots. Only those experimental data for which the F test suggested acceptable fits to a straight line at 95% confidence level were used for age interpretation. The age of the Suiko Seamount (58.1 +- 0.6 m.y.) is in excellent agreement with a hot spot origin of the Emperor chain. The age for the Necker Rise sample (82.4 +- 3.2 m.y.) suggests that the formation of this rise is a different event from the formation of the northern part of the Line volcanic chain. Ages for the Line chain samples are very complex, ranging from 55 to 127.5 m.y. There does not seem to be the simple age progression which should be expected if the whole Line volcanic chain is of a hot spot origin. (Auth.)