photo #7681973

The Bisti/De-Na-Zin Wilderness is a 45,000-acre wilderness area located in San Juan County, New Mexico that features a variety of rock formations, fossils and petroglyphs. The badlands expose the longest, most complete and most richly fossiliferous sequence of beds spanning the Cretaceous-Paleogene boundary in any single sedimentary basin in the world. The Cretaceous-Paleogene boundary marks the end of the Mesozoic Era and the beginning of the Cenozoic Era, about 66 million years ago, when a massive asteroid impact caused a mass extinction of about 75% of all species on Earth, including the dinosaurs. The badlands were formed by erosion of sedimentary layers that were deposited by ancient rivers,deltas and swamps during the Cretaceous Period, when the area was near the shoreline of the Western Interior Seaway a vast island see that covered much of North America.The psychedelic pattern on the rocks are caused by the different colors and textures of the sandstone, shale, mudstone, coal and silt that make up the badlands.Image credit: Rick Goldwaser