Our very own 1.7 billion year old mountain range—the Phoenix Mountains.
Shaw Butte isn’t the tallest peak in the range, but it is one of the oldest.
More than 1700 million years ago, this whole place we know as “the Valley of The Sun” was a submarine volcanic environment on the southern edge of the North American continent.
Gradually, the ocean basin filled with volcanic material to such a degree that the deep ocean environment changed to a more shallow marine setting, receiving mud, silt, and sand. This shallow marine environment gave way to near-shore environments that accumulated additional mudstone and sandstone in a shallow, shifting sea or floodplain.
Large volcanic eruptions interspersed volcanic material with the sediments, culminating in the valley floor and Phoenix Mountains we see today.
The major features of the Phoenix Mountains are:
Moon Hill, Lookout Mountain, Shaw Butte, North Mountain, Thunderbird Hills, Shadow Mountain, Stoney Mountain, Dreamy Draw, Piestewa Peak, Quartzite Ridge, Mummy Mountain, and Camelback Mountain.