Joshua Tree NP

Joshua Tree NP is named after the endemic Joshua trees (Yucca brevifolia) although they are not trees, but rather, belong to the genus Yucca. The parks oldest rocks, Pinto Gneiss, are 1.7 billion years old and are exposed in the parks mountains. Much later, tectonic forces pushed volcanic materials toward the surface as granites. Erosion eventually exposed the harder rocks and reduced the softer rocks to debris, filling the canyons and basins. Moved by water and gravity, alluvial fans and bajadas (overlapping alluvials) formed. Flash floods rounded the boulders and left piles known as inselbergs. Photo © copyright by Robert Faucher.

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