Juana Lopez Member | |
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Stratigraphic range: | |
Type | Member |
Unit of | Mancos Shale (San Juan basin) Carlile Formation (Denver and Raton Basins) Benton Shale (North Park Basin) |
Underlies | Niobrara Formation |
Overlies | Codel Sandstone member of the Carlile |
Thickness | 140 feet (43 m) |
Lithology | |
Primary | Sandstone with abundant carbonate fossil grains |
Other | Gravel, Codel fragments |
Location | |
Coordinates | 35°29′12″N 106°12′04″W / 35.4866°N 106.2010°W |
Country | United States |
Type section | |
Named for | Mesita Juana Lopez Grant, six miles northwest of Los Cerrillos, New Mexico |
Named by | Rankin |
Year defined | 1944 |
Juana Lopez refers to both the uppermost member of the Carlile Shale formation and to the environment that caused it to form. The Juana Lopez Member is calcareous sandstone dated to the Turonian age of the Upper Cretaceous and is exposed in the southern and western Colorado, northern and central New Mexico,[1] and northeastern Utah.[2] The unit has been described as "the most enigmatic" member of the Carlile Shale.[3]