when did the grand canyon became a national monument
Grand Canyon National Park Despite Roosevelt's enthusiasm and strong interest in preserving land for public use, the Grand Canyon was not immediately designated as a national park. The first bill to establish Grand Canyon National Park was introduced in 1882 by then-Senator Benjamin Harrison, which would have established Grand Canyon as the second national park in the United States after Yellowstone. Harrison unsuccessfully reintroduced his bill in 1883 and 1886; after his election to the presidency, he established the Grand Canyon Forest Reserve in 1893. Theodore Roosevelt created the Grand Canyon Game Preserve by proclamation on 28 November 1906,[8] and the Grand Canyon National Monument in 1908.[9] Further Senate bills to establish the site as a national park were introduced and defeated in 1910 and 1911, before the Grand Canyon National Park Act was finally signed by President Woodrow Wilson in 1919. The National Park Service, established in 1916, assumed administration of the park.
Geology of the Grand Canyon area At about 2.5 and 1.8 billion years ago in Precambrian time, sand, mud, silt, and ash were laid down in a marine basin adjacent to an orogenic belt.[1] From 1.8 to 1.6 billion years ago at least two island arcs collided with the proto-North American continent.[2] This process of plate tectonics compressed and grafted the marine sediments in the basin onto the mainland and uplifted them out of the sea. Later, these rocks were buried 12 miles (19 km) under the surface and pressure-cooked into metamorphic rock.[3] The resulting Granite Gorge Metamorphic Suite, which is part of the Vishnu Basement Rocks, consists of the metasedimentary Vishnu Schist and the metavolcanic Brahma and Rama Schists that were formed 1.75 billion to 1.73 billion years ago.[4] This is the resistant rock now exposed at the bottom of the canyon in the Inner Gorge.