Surprise Canyon Formation | |
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Stratigraphic range: Late Mississippian (Serpukhovian) [1] | |
Type | Formation |
Underlies | Watahomigi Formation, basal member of Supai Group |
Overlies | Redwall Limestone |
Thickness | 0–122 m (0–400 ft) |
Lithology | |
Primary | sandstone, conglomerate, limestone, siltstone |
Location | |
Region | southwest Colorado Plateau, Arizona-(northern) |
Country | United States-(Southwestern United States) |
Extent | Grand Canyon |
Type section | |
Named for | Surprise Canyon, Grand Canyon National Park |
Named by | George H. Billingsley and Stanley S. Beus[2] |
The Surprise Canyon Formation is a geologic formation that consists of clastic and calcareous sedimentary rocks that fill paleovalleys and paleokarst of Late Mississippian (Serpukhovian) age in Grand Canyon. These strata outcrop as isolated, lens-shaped exposures of rocks that fill erosional valleys and locally karsted topography and caves developed in the top of the Redwall Limestone. The Surprise Canyon Formation and associated unconformities represent a significant period of geologic time between the deposition of the Redwall Limestone and the overlying Supai Group.[1][2][3]