Cambrian-Precambrian Unconformity near Colorado Springs, Colorado.


This photo shows the Cambrian Sawatch Sandstone overlying the Precambrian Pikes Peak Granite. Like the unconformity near the bottom of the Grand Canyon or in the Tetons or near Ogden, Utah, this one consists of Cambrian sandstone overlying Precambrian igneous or metamorphic rock. Its difference is that here, the sandstone was deposited slightly later in the Cambrian than in the other places mentioned. It is younger because the shoreline was moving eastward as the ocean transgressed. By the same reasoning, we can guess that the Cambrian sandstone above the unconformity in Wisconsin is even younger. It is.

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