, ▁so ▁it ▁is ▁essentially ▁stable ). ▁However , ▁in - s itu ▁ 1 8 7 Os ▁/ ▁ 1 8 8 Os ▁and ▁ 1 8 6 Os ▁/ ▁ 1 8 8 Os ▁of ▁modern ▁pl ume ▁related ▁mag mas ▁show ▁simultane ous ▁en rich ment ▁which ▁implies ▁a ▁source ▁that ▁is ▁sup ra - ch ond rit ic ▁in ▁P t / Os ▁and ▁Re / Os . ▁Since ▁both ▁parent al ▁is ot op es ▁have ▁extremely ▁long ▁half - l ives , ▁the ▁Os - is ot ope ▁rich ▁res er voir ▁must ▁be ▁very ▁old ▁to ▁allow ▁enough ▁time ▁for ▁the ▁daughter ▁is ot op es ▁to ▁form . ▁These ▁observations ▁are ▁interpreted ▁to ▁support ▁the ▁theory ▁Ar che an ▁sub duct ed ▁cr ust ▁contributed ▁Os - is ot ope ▁rich ▁mel ts ▁back ▁into ▁the ▁mant le . ▁ ▁References ▁ ▁Category : Rad i ometric ▁d ating ▁Category : R hen ium ▁Category : O sm ium <0x0A> </s> ▁Mark ▁Hun ting ton ▁H igg ins ▁( J une ▁ 2 6 , ▁ 1 9 4 0 ▁– ▁July ▁ 2 5 , ▁ 1 9 6 0 ) ▁was ▁an ▁American ▁student ▁employed ▁in ▁Lamb ar ene , ▁Gab on , ▁West ▁Africa ▁by ▁Albert ▁Schwe itzer ▁from ▁May ▁ 1 9 5 9 ▁to ▁June ▁ 1 9 6 0 . ▁ ▁Early ▁and ▁personal ▁life ▁Mark ▁Hun ting ton ▁H igg ins ▁was ▁born ▁to ▁Carter ▁Chap in ▁H