Complex sentence: His first geological work dealt with the Oslo Rift in kambrosilur, and he was part of the 1909-11 expeditions to Svalbard, 1914-17 he explored Lapland Geology, 1918, he worked at Bear Island.
Split into simpler sentences: His first geological work dealt with the Oslo Rift in the Cambrosilurian period, and he was part of the 1909-11 expeditions to Svalbard. Between 1914-17, he explored the geology of Lapland, and in 1918, he worked at Bear Island.