Alabama Hills and the Sierra Nevada Mountains
Mobius Arch in California is hardly remarkable as far as natural arches go, but it draws photographers anyways because it offers the opportunity to photograph Mount Whitney, the tallest peak in the lower 48 states, framed by the arch. The jagged peaks of the Sierra Nevada Mountains contrast beautifully against the rounded contours of the 2-meter (6 feet) tall Mobius Arch and the other rocks of the Alabama Hills. Despite what their drastically different appearances might suggest, the rocks that make up the two neighboring formations are the same age - both were the result of geologic uplift 100 million years ago. Different geologic processes have shaped them since.
Sometime after the uplift, the Alabama Hills became a moist, highly vegetated region, meaning the granite was chemically weathered by percolating water. This type of erosion creates the rounded rock.
About 5 million years ago, fault-block uplift (the crust is pulled apart and some large blocks are pushed upwards while others collapse downward) created the Sierra Nevada Mountains. The mountains were shaped initially by the uplift, and more recently by glaciers.
The mountains put the Alabama Hills in a rain shadow that killed the vegetation. Over time, the soil eroded away revealing the weather rocks.
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Photo Credit: Barb Ignatius http://bit.ly/1ydIpZV
References: http://bit.ly/1Fmrj98 http://bit.ly/1CpxbNb