3648 x 2736 px | 30,9 x 23,2 cm | 12,2 x 9,1 inches | 300dpi
Data acquisizione:
11 agosto 2011
Ubicazione:
Munising, Michigan, USA
Altre informazioni:
Pictured Rocks National Lakeshore is a U.S. National Lakeshore on the shore of Lake Superior in the Upper Peninsula of Michigan, United States. It extends for 42 miles (67 km) along the shore and covers 73, 236 acres (114 sq mi; 296 km2). The park offers spectacular scenery of the hilly shoreline between Munising, Michigan and Grand Marais, Michigan, with various rock formations like natural archways, waterfalls, and sand dunes. Pictured Rocks derives its name from the 15 miles (24 km) of colorful sandstone cliffs northeast of Munising. The cliffs are up to 200 feet (60 m) above lake level. They have been naturally sculptured into shallow caves, arches, formations that resemble castle turrets, and human profiles, among others. Near Munising visitors also can view Grand Island, most of which is included in the Grand Island National Recreation Area and is preserved separately. The U.S. Congress made Pictured Rocks the first officially-designated National Lakeshore in the United States in 1966. It is governed by the National Park Service (NPS), had 22 year-round NPS employees as of May 2006, and received 476, 888 visitors in 2005. The colors in the cliffs are created by the large amounts of minerals in the rock. The cliffs are composed of the Munising Formation of 500 millon year old Cambrian period sandstone. The Munising Formation sits atop a Precambrian sandstone of the Jacobsville Formation. The mottled red Jacobsville Formation is the oldest rock in the park. On top of the Munising Formation is the younger Au Train Formation from the Ordovician period. The Au Train Formation is a hard sandstone and acts as a 'cap' over the other layers. Streaks on the face of the cliffs comes from the groundwater leaching out of the rock. With it comes iron (reds), manganese (black-white), limonite (yellow-brown), copper (pinks-green) and other minerals. As the water evaporates, these minerals leave streaks of color.
