Archuleta Mesa (Archuleta County, Colorado - near the New Mexico/Colorado border) has exposures of a diorite sill approximately 10.5 square miles in size. This sill intruded the Tertiary Animas Formation. The harder igneous rock of the sill resisted erosion to form the mesa.
Archuleta Mesa panorama by Chris Carroll - Colorado Geological Survey geologist
The Tertiary Animas Formation was deposited above the Tertiary Ojo Alamo Sandstone. The Colorado Geological Survey recently completing mapping the coal beds of the Fruitland Formation. This study mapped the extent of the Ojo Alamo Sandstone in Colorado, providing insight into the extent of the large sill on the surface of Archuleta Mesa.
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Please enjoy this fully interactive 3D Google Earth viewer to explore the alien terrain of Archuleta Mesa (Click on the X to remove the place marker).
11/1/2012 3:51 PM