▁his ▁wife , ▁Math ilde ▁Mad sen . ▁▁ ▁Ar ound ▁ 1 9 0 3 ▁he ▁did ▁his ▁oblig atory ▁military ▁service ▁at ▁Gard ermo en , ▁just ▁north ▁of ▁Os lo , ▁and ▁here ▁met ▁Captain ▁G unn ar ▁Is achsen ▁who ▁greatly ▁influenced ▁him , ▁and ▁first ▁inspired ▁his ▁interest ▁in ▁polar ▁regions . ▁In ▁ 1 9 0 9 , ▁Is achsen ▁invited ▁Hol ted ahl ▁to ▁join ▁him ▁in ▁expl or ations ▁of ▁Sp its ber gen ▁as ▁official ▁ge ologist ▁of ▁the ▁group . ▁ ▁He ▁studied ▁Ge ology ▁at ▁the ▁University ▁of ▁Os lo , ▁gradu ating ▁in ▁ 1 9 0 9 ▁and ▁receiving ▁a ▁doctor ate ▁in ▁ 1 9 1 3 . ▁St ay ing ▁in ▁the ▁university ▁as ▁staff ▁he ▁received ▁his ▁professor ship ▁in ▁ 1 9 2 0 . ▁▁ ▁Hol ted ahl ▁was ▁among ▁the ▁last ▁of ▁a ▁generation ▁of ▁ge olog ists ▁that ▁master ed ▁the ▁subject ▁in ▁all ▁its ▁bread th . ▁He ▁delivered ▁a ▁significant ▁contribution , ▁not ▁only ▁in ▁Norway ▁but ▁also ▁for ▁large ▁areas ▁of ▁the ▁Ar ctic ▁and ▁Ant ar ctic . ▁His ▁first ▁ge ological ▁work ▁de alt ▁with ▁the ▁Os lo ▁R ift ▁in ▁the ▁Camb ros il ur ian ▁period , ▁and ▁he ▁was ▁part ▁of ▁the ▁ 1 9 0 9 - 1 1 ▁exped itions ▁to ▁S val b ard . ▁Between ▁ 1 9 1 4 - 1 7 , ▁he ▁expl ored ▁the ▁ge ology ▁of