Alpine1/Federal corehole--Subsurface stratigraphy of the eastern White Mountains, Apache County, Arizona
James C. Witcher, W. Richard Hahman, and Chandler A. Swanberg
The Alpine 1/Federal corehole provides the first observations of Permian, Upper Cretaceous, and lower Tertiary rocks in the eastern White Mountains of Arizona. Due to erosion beneath a pre-Late Cretaceous unconformity, no Triassic to Lower Cretaceous rocks exist. Only 74 ft of Permian San Andres Formation is preserved. The Permian Glorieta Sandstone, 203 ft thick, is intruded by basaltic rocks that also truncate the top of the underlying Corduroy Member of the Supai Formation. An additional basaltic intrusion separates the Corduroy Member, 515 ft thick, from the underlying Fort Apache Limestone, 48 ft thick. Only 49 ft of Big A Butte Member was cored before encountering another basaltic intrusion. Permian carbonate units represent restricted marine and coastal sabkha environments and hydrocarbon shows indicate source potential. Carbonaceous Upper Cretaceous Dakota (?) sandstone, 116 ft thick, is preserved beneath a Laramide unconformity. Homoclinal downwarping, less than one degree of dip to the south and with possible faults, has formed a basin with at least 1600 ft of structural relief on the Laramide erosional surface. An unnamed early (?) Laramide unit, 107 ft thick, unconformably rests on reddened Cretaceous sandstone and underlies the basal conglomerate of the Eocene Eagar Formation, 1087 ft thick. Volcaniclastic rocks of the Eocene to Oligocene Spears Group, 2032 ft thick, conformably overlie the Eagar Formation. The only distinct volcanic flow that was cored is a 20-ft-thick Datil (?) Group rhyolite ash-flow tuff. Composite thickness of the Tertiary sediments in the corehole is 3226 ft. Basaltic intrusions in Paleozoic rocks may range in age from mid-Tertiary to Quaternary and could represent several magmatic events.
- Witcher, James C.; Hahman, W. Richard; Swanberg, Chandler A., 1994, Alpine1/Federal corehole--Subsurface stratigraphy of the eastern White Mountains, Apache County, Arizona, in: Mogollon Slope, west-central New Mexico, Chamberlin, Richard M.; Kues, Barry S.; Cather, Steven M.; Barker, James B.; McIntosh, William C., New Mexico Geological Society, Guidebook, 45th Field Conference, pp. 233-240.