USING ISOLATED STRUCTURAL OUTCROPS TO SYNTHESIZE A LARGE REGIONAL STRUCTURE

In southern Utah, the extensional, Tertiary age Hurricane Fault marks the abrupt transition between the Colorado Plateau and the Basin and Range provinces. This is particularly true in the Ash Creek segment between the towns of Cedar City and Toquerville, Utah where the southwest trending Hurricane Fault is expressed as an abrupt escarpment with as much as 4000 feet of vertical relief. South of Touquerville, in the Anderson Junction segment, the Hurricane fault assumes a more southerly trend and is characterized by an escarpment with less relief (900 feet). Sevier age (mid-Cretaceous) compressional structures are also concentrated along the Colorado Plateau - Basin and Range transition. In the Anderson Junction segment, Sevier structures are characterized by simple open anticlines and synclines, often containing west verging flank thrusts (snake head structures). In the Ash Creek segment, compressional features transition into into a rollover thrust complex that is completely inverted.

At Southern Utah University (SUU), field camp students spend two weeks mapping Sevier age structures in the Anderson Junction and Ash Creek segments if the Hurricane Fault. These range from a breached anticline and associated thrust in the St. George, Utah area, to closed and overturned antiforms in and near the Kolob section of Zion National Park. Each map constitutes a transect across different parts of a regional antiformal structure. Students are then asked to use field observations and their different maps to interpret and draw the regional structure. This series of exercises allow students to practice making a regional synthesis. The basics of this exercise were developed by the faculty of the University of Missouri-Rolla Summer Field Camp and were modified and incorporated into the SUU Summer Field Camp.