Complex sentence: In 1929 and 1930 the icebreaker Sedov carried groups of scientists to Franz Josef Land and also to Severnaya Zemlya, the last major piece of unsurveyed territory in the Soviet Arctic; the archipelago was completely mapped under Georgy Alekseyevich Ushakov between 1930 and 1932.
Split into simpler sentences: In 1929 and 1930 the icebreaker "Sedov" carried groups of scientists to Franz Josef Land and also to Severnaya Zemlya, the last major piece of unsurveyed territory in the Soviet Arctic. This archipelago was completely mapped under Georgy Alekseyevich Ushakov between 1930 and 1932.