Complex sentence: Later he trawled the mountain wilds with his wife in areas like Jotunheimen, Rondane and Dovrefjell, and professionally, as Quartenary geologist he mapped the major mountain regions in Norway during the 1950's and 60's.
Split into simpler sentences: Later he trawled the mountain wilds with his wife in areas like Jotunheimen, Rondane and Dovrefjell, and professionally. As Quartenary geologist he mapped the major mountain regions in Norway during the 1950's and 60's.