Question: Helmer Julius Hanssen, was a Norwegian sailor, pilot and polar explorer, he participated in three of the polar expeditions led by Roald Engelbregt Gravning Amundsen, was a Norwegian explorer of polar regions, he was the leader of the Antarctic expedition of 1910–12, which was the first to reach the South Pole, on which date?
Sentence (from "Mullins Valley"): US Antarctic Program (USAP) research has dated the subsurface ice in Mullins Valley at 4 million years old making it among the oldest ice on earth.
Relevant evidence: No