Several suggestions, ranging from light conditions to the presence of metallic compounds, have been offered to explain why some icebergs appear green. A. Ice cores were used to determine that green icebergs were formed from the compaction of metallic compounds, including copper and iron. B. All ice shelves can produce green icebergs, but the Amery Ice Shelf is especially well suited to do so. C. Green icebergs form when a twolayer block of ice breaks away from a glacier and capsizes, exposing the bottom sea ice to view. D. Ice cores and samples revealed that both ice shelves and green icebergs contain a layer of bubbly glacial ice and a layer of bubble-free sea ice. E. Green icebergs are white until they come into contact with seawater containing platelets and soluble organic green pigments. F. In a green iceberg, the sea ice contains large concentrations of organic matter from the seawater.