Dean M. Chriss
Megabreccia Mosaic, Landscape Photograph by Dean M. Chriss

Megabreccia Mosaic

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This large mosaic rock forms part of a canyon wall. In geology formations like this are called megabreccia. There are several types of megabreccia that are formed in different ways giving each a different appearance. In this case the darker fragments were formed by stretching of older Cambrian era (541-485 million years ago) rocks due to folding that occurred during the middle to late Mesosoic era (250 to 65 million years ago). Gaps that developed between the fragments were filled with the lighter colored rock, called travertine. Travertine is a form of calcium carbonate leached from adjacent layers of limestone and dolomite.