mascon
n.— «The scientists used gravity fluctuations measured by NASA’s GRACE satellites to peer beneath Antarctica’s icy surface, and found a 200-mile-wide plug of mantle material—a mass concentration, or “mascon” in geological parlance—that had risen up into the Earth’s crust.» —“Big Bang In Antarctica—Killer Crater Found Under Ice” Newswise June 1, 2006. (source: Double-Tongued Dictionary)