03. Crystal Cave, Iceland
This cave in the glacier ice formed as a result of glacial mill, or floss. This phenomenon occurs when rain and melt water from the glacier surface is formed in the streams, and flows into a glacier through its cracks. Waterfall makes a hole in the ice, and collected water flows to lower heights, forming long ice caves with access, formed at the edge of the glacier.
Fine-grained and wind-borne sediments give dingy color once frozen streams of melt water, while the top of the cave has a dark blue color. Due to the fast movement of the glacier on bumpy terrain is about 1 meter per day, this ice cave cracked at the end, forming a deep vertical slit. This allows non-directional sunlight get into the cave from both sides, providing an ice tunnel steady.
The cave can be accessed from the coast, at 7 meter hole. The tunnel is gradually narrowed, and finally its height is no more than 1.2 meters. Ice caves in general are unstable and could collapse at any moment. They are safe to visit only in the winter when cold temperatures severely frozen ice. The cave is constantly heard a cracking sound. They heard not because the cave is about to come crashing down, but because the cave moves with the glacier itself. Each time the glacier moved a millimeter – heard loud noises.