▁that ▁reached ▁am ph ib ol ite ▁grade ▁on ▁the ▁sequence ▁of ▁met am orph ic ▁fa cies . ▁Close ▁to ▁Mak kov ik , ▁bre cc ia ▁from ▁the ▁Mes oz o ic , ▁cut ▁by ▁l am pro phy re - car bon at ite ▁d ikes ▁marks ▁the ▁opening ▁of ▁the ▁Lab r ador ▁Sea . ▁ ▁The ▁region ▁experienced ▁repeat ▁gla ci ations ▁during ▁the ▁Ple ist oc ene . ▁Gla ci om ar ine ▁sil ts ▁and ▁mud ▁records ▁the ▁mel ting ▁of ▁the ▁gla ci ers ▁on ▁the ▁Lab r ador ▁Sh elf , ▁with ▁significant ▁de position ▁around ▁ 2 0 , 0 0 0 ▁years ▁ago . ▁Analysis ▁suggests ▁most ▁of ▁these ▁sed iments ▁origin ated ▁on ▁land ▁in ▁Lab r ador , ▁although ▁large ▁amounts ▁of ▁lim estone ▁( which ▁is ▁completely ▁absent ▁in ▁the ▁Lab r ador ) ▁indicate ▁a ▁second ▁source ▁to ▁the ▁north , ▁likely ▁Pale oz o ic ▁lim estone ▁on ▁the ▁Hudson ▁Stra it ▁and ▁Ung ava ▁Bay . ▁ ▁Natural ▁resource ▁ge ology ▁of ▁Lab r ador ▁Mass ive ▁iron ▁depos its ▁are ▁found ▁in ▁the ▁Lab r ador ▁Tr ough ▁along ▁with ▁co pper , ▁u ran ium ▁and ▁mol y b den um . ▁Iron ▁forms ▁in ▁ch ert ▁from ▁the ▁Ung ava ▁Bay ▁to ▁the ▁Gren ville ▁Front , ▁over ▁a ▁span ▁of ▁ 7 0 0 ▁miles , ▁while ▁co pper ▁and ▁nick el ▁min er als ▁such ▁as ▁py rite , ▁p yr