Original sentence: After returning from Trinidad, he worked on Norway's Svalbard and Arctic Ocean surveys.As a "hobby", he mapped limestone caves in Nordland county and published a number of papers on their formation.Dr Gunnar Horn (-1946) was a Norwegian petroleum geologist and Arctic explorer.Dr Horn died in 1946 while in charge of building radio stations and beacons in Svalbard.Dr Horn studied mining at the Norwegian Institute of Technology and petroleum geology at London's Royal School of Mines, and took a PhD in coal petrography at the Berlin Technical University.He is most renown as the leader of the Bratvaag Expedition that found the long-lost remains of the Swedish explorer S.He worked in 1920-23 as a petroleum geologist in Trinidad and Venezuela.In addition to his purely scientific work, Dr Horn also had important practical and administrative duties in the Arctic islands.In the autumn of 1925, Dr Horn travelled with Johan Braastad to Kaidak Bay on the eastern shores of the Caspian Sea to investigate local oil resources
Edited sentence: After returning from Trinidad, he worked on Norway's Svalbard and Arctic Ocean Surveys.Gunnar Hansen Horn (1894 – 1946) was a Norwegian petroleum geologist and Arctic explorer.He also studied karst topography.He is most renown as the leader of the Bratvaag Expedition that found the long-lost remains of S.He then studied petroleum geology at London's Royal School of Mines, and took a PhD in coal petrography at the Berlin Technical University.He worked from 1920 to 1923 as a petroleum geologist in Trinidad and Venezuela.Horn died in 1946 while in charge of building radio stations and beacons in Svalbard.Horn studied mining at the Norwegian Institute of Technology, graduating in 1916.In addition to his purely scientific work, Horn also had important practical and administrative duties in the Arctic islands.In the autumn of 1925, Horn travelled with Johan Braastad to the eastern shores of the Caspian Sea to investigate local oil resources.Other expeditions went to East Greenland and Franz Josef Land