Spread thin in the Arctic

摘要

The northernmost segment of the global mid-ocean-ridge system, the Gakkel ridge, is a bit of an oddity. Provocative data are emerging from an international geophysical and geochemical study of the region. In 1893, Fridtjof Nansen and members of his expedition set out to conduct a remarkable scientific study in the Arctic. Their ship, the Fram, was designed to become encased in pack ice and to move with it, and over a three-year period the Fram's stately motion demonstrated the drift of the polar ocean current. Just over a century later, a fresh chapter in the scientific study of the northern high latitudes opened with a two-ship, international expedition to study the ocean floor beneath the Arctic Ocean. Some results from this study ― AMORE, for Arctic Mid-Ocean Ridge Expedition ― appeared in Nature early this year, and others are described by Michael et al. 2 and Jokat et al. 3 on pages 956 and 962 of this issue. The Arctic Ocean is covered by sea ice, so the studies were carried out on scientifically equipped icebreakers, the US Coast Guard Cutter Healy and the German PFS Polarstern.