▁of ▁Jur ass ic ▁dy kes ▁accum ul ates , ▁hence ▁a ▁giant ▁dy ke ▁sw arm ▁can ▁be ▁developed ▁in ▁the ▁region . ▁ ▁Model ▁ 2 : ▁Mant le ▁pl ume ▁hypothesis ▁Scient ists ▁usually ▁relate ▁development ▁of ▁large ▁ igne ous ▁province ▁with ▁active ▁up well ing ▁mag ma ▁pl umes , ▁which ▁are ▁short - l ived , ▁rapid ▁and ▁high ▁volume ▁mag mat ism . ▁The ▁development ▁of ▁the ▁Kar oo ▁triple ▁j unction ▁geometry ▁was ▁believed ▁to ▁be ▁formed ▁by ▁u pl ift ▁of ▁a ▁mant le ▁pl ume ▁right ▁under ne ath ▁the ▁triple ▁j unction ▁itself . ▁▁ ▁St retch ing ▁of ▁l ith os phere ▁is ▁found ▁from ▁ 1 5 0   km ▁to ▁ 5 0   km ▁depth ▁from ▁the ▁Kar oo ▁Lar ge ▁Ig ne ous ▁Province , ▁which ▁fav ours ▁an ▁up well ing ▁pl ume ▁head . ▁ ▁A ▁mant le ▁pl ume ▁is ▁likely ▁to ▁form ▁below ▁extensive ▁contin ental ▁cr ust . ▁ ▁Pic rit es ▁and ▁ne ph el init es ▁ ▁are ▁found ▁in ▁Kar oo ▁mag mat ism . ▁They ▁are ▁known ▁as ▁ igne ous ▁rocks ▁formed ▁from ▁pl ume ▁mel ts . ▁ ▁The ▁mant le ▁pl ume ▁in ▁Kar oo ▁can ▁be ▁induced ▁by ▁dist al ▁plate ▁sub du ction ▁along ▁Pacific ▁margin ▁of ▁southern ▁G ond w ana . ▁ ▁However , ▁the ▁Kar oo ▁triple ▁j unction ▁where ▁the ▁Ok av ango ▁Dy ke ▁Sw arm ▁is ▁located