No. 25: Jan-Feb 1983
High in the Bolivian Andes are some shallow, saltwater lakes. From some of these white-shored lakes rise bizarre "islands" of fresh-water ice, neatly layered horizontally, and up to 20 feet higher than the saltwater surface. The ice crystals comprising these islands are vertical, proving that they grew in water and are not pieces of glaciers. Clearly, they did not form from the present saltwater lakes, but they might be relics of the Ice Ages, when the lakes were deeper and fresher. But whence the nicely layered structure? Some scientists have thought that volcanic springs might be the sources of fresh water, but some ice islands occur in lakes where there are no volcanic springs nearby. At the moment, every-one seems stumped by these strange creations of Nature.
(Anonymous; "Who Made the Andes Islands of Ice?" New Scientist, 96:272, 1982.)
Comment. Could the ice islands be related to the Arctic pingoes -- those debris-covered ice hills?