▁but ▁diver ge ▁in ▁the ▁northern ▁part ▁( 6   mm / yr ) ▁and ▁a ▁very ▁slight ▁difference ▁in ▁spread ing ▁rates ▁across ▁the ▁central ▁part ▁of ▁the ▁ult ra - slow ▁SW IR ▁indicates ▁there ▁is ▁a ▁vague ▁triple ▁j unction ▁somewhere ▁south ▁of ▁Mad agas car . ▁ ▁T ect onic ▁evolution ▁The ▁R T J ▁was ▁born ▁when ▁the ▁Se ych elles ▁micro cont inent ▁dr ift ed ▁off ▁the ▁Indian ▁Pl ate ▁at ▁ 6 4   Ma ▁and ▁the ▁Car ls berg ▁R idge ▁opened . ▁ ▁Since ▁then ▁the ▁R T J ▁has ▁moved ▁east ward ▁from ▁south ▁of ▁Mad agas car ▁( mod ern ▁coordinates ) ▁to ▁its ▁current ▁location . ▁ ▁Since ▁ 6 5   Ma ▁the ▁R T J ▁has ▁been ▁migr ating ▁north - east ▁at ▁a ▁decre asing ▁rate : ▁originally ▁the ▁velocity ▁was ▁ 1 0   cm / yr , ▁at ▁ 4 3   Ma ▁ 2 . 6   cm / yr , ▁and ▁since ▁ 4 1   Ma ▁around ▁ 3 . 6 – 3 . 8   cm / yr . ▁ ▁The ▁stability ▁in ▁migration ▁rate ▁around ▁ 4 1   Ma ▁co inci de ▁with ▁the ▁b end ▁in ▁the ▁Hawai ian – Em peror ▁se amount ▁chain   — ▁hint ing ▁at ▁a ▁global ▁re organisation ▁of ▁t ect onic ▁pl ates ▁at ▁this ▁time . ▁ ▁Origin ally ▁considered ▁a ▁stable ▁R R R ▁( ridge - ridge -