INDICATORS OF EARLY PLEISTOCENE GLACIATION IN SOUTHWESTERN UTAH AND ADJACENT STATES

Landforms and sedimentary textures of surficial deposits on and adjacent to the Markagunt Plateau near Cedar City, Utah, indicate that the landscape was primarily formed by early Pleistocene glaciation. Widespread glacial landforms include U shaped valleys; lateral, terminal, and medial moraines; terraced and dissected ground moraines; polished and striated bedrock outcrops; cirques, hanging valleys, kettle lakes, outwash plains, and reversed dendritic topography.

Unconsolidated sediments include poorly sorted boulder tills, gap graded muddy gravels, erratic boulders, and lake bed clays. Thick tills in lateral and terminal moraines were intruded and overlapped by basalts about 1.2 Ma BP, and some U shaped valleys were partially filled by younger basalts about 0.5 to 0.8 Ma BP.

Similar features have now been mapped in Arizona, Nevada, and California, suggesting that early Pleistocene glaciation occurred at elevations as low as 3,300 feet (1,000 meters) in much of the southwestern United States.