mapsontheweb:Geology of Black Hills, South Dakota.The Black Hills are the easternmost block of the L
mapsontheweb:Geology of Black Hills, South Dakota.The Black Hills are the easternmost block of the Laramide Orogeny - a time of an odd faulting style in the U.S. Deeply-rooted igneous basement rocks were faulted upwards, bending the sedimentary curtain on top into monoclines. Mt. Rushmore is made out of granite faulted up by that orogeny. -- source link
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