The Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado

Dinosaurs, pollen and spores, and the age of the Ojo Alamo Sandstone, San Juan Basin, New Mexico
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Published:January 01, 1987
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CiteCitation
James E. Fassett, Spencer G. Lucas, F. Michael O’Neill, 1987. "Dinosaurs, pollen and spores, and the age of the Ojo Alamo Sandstone, San Juan Basin, New Mexico", The Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado, James E. Fassett, J. Keith Rigby, Jr.
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The Ojo Alamo Sandstone of the San Juan Basin of New Mexico is composed of interbedded conglomeratic sandstone, sandstone, siltstone, and mudstone. Conglomerates are found in the western part of the basin; siliceous pebbles diminish in size both southward and eastward across the basin, becoming rare to nonexistent in the eastern part. There is great variation in the internal stratigraphy of the Ojo Alamo: Individual sandstone or mudstone beds thicken, thin, and pinch out laterally. The thickness of the Ojo Alamo varies from 6 m (20 ft) to more than 122 m (400 ft). The formation varies in composition from...
- biostratigraphy
- Cenozoic
- Chordata
- clastic rocks
- Colorado Plateau
- conglomerate
- Cretaceous
- dinosaurs
- lower Paleocene
- McKinley County New Mexico
- megaspores
- Mesozoic
- microfossils
- miospores
- mudstone
- New Mexico
- Ojo Alamo Sandstone
- Paleocene
- Paleogene
- palynomorphs
- Reptilia
- Rio Arriba County New Mexico
- San Juan Basin
- San Juan County New Mexico
- Sandoval County New Mexico
- sandstone
- sedimentary rocks
- siltstone
- stratigraphic boundary
- stratigraphy
- Tertiary
- Tetrapoda
- United States
- Upper Cretaceous
- Vertebrata