Chlorofluorocarbons or CFCs are a chemical compound containing carbon, chlorine, and fluorine. Throughout the 20th century, CFCs were mass produced for their popularity in refrigeration and spray cans. In the 1970s, evidence began to show the harmful effects of CFCs on Earth.
Originally created as Great Sand Dunes National Monument on March 17, 1932, Great Sand Dunes National Park and Preserve was established by an act of the United States Congress on September 13, 2004.
Importance of Coastal Sand Dunes Patterns and Processes Blowouts Parabolic Dunes Transgressive Dunefields. Introduction. Sand dunes are formed at the interface between the sea and land. They are formed from sand which is eroded and ground rock, derived from terrestrial (e.g., glacial or river) and oceanic sources (e.g., coral reefs).