Geologic map of the Fort Morgan 7.5' quadrangle, Morgan County, Colorado

Abstract

[Calibrated radiocarbon ages are expressed as “cal ka B.P.,” which stands for calibrated thousand years before present (0 yr B.P. = 1950 A.D.). Uncertainties are given at the 95 percent (2σ) confidence level. Calibrated ages are reported as the midpoint of the calibrated range. In cases where calibration produced more than one age range with a probability of 5 percent or more, ages are based on the mean of the ranges weighted by their probabilities and are presented without uncertainties. Soil-horizon designations and other descriptive soil terminology used in this report follow criteria outlined in Soil Survey Division Staff (1993), Birkeland (1999), and Schoeneberger and others (2012). Most colors are field dry colors and based on Munsell soil color charts (Munsell Color, 1975). The term “consistence” is the resistance to crushing of soil or surficial material in the hand, as described by Soil Survey Division Staff (1993). Textures are field estimates. In descriptions of clast lithology, the term “granite” refers to phaneritic igneous or meta-igneous rock types that are felsic to intermediate in composition. Geochronology sites are named by letters in their field numbers (tables 1–3, sheet 2), and correspond to letters shown in red on figure 1]