Sandstone composition is a function of four complex and interrelated variables: provenance (itself a function of source rock, relief, and climate), transportation effects, depositional environment, and diagenesis. Documentation of source rock composition and comparison to derivative sandstone composition not only allow evaluation of sandstone provenance changes through time, they also provide evaluation of the relative importance of the variables controlling sandstone composition. Source rock composition is best determined by Gazzi-Dickinson point counts of the source rocks themselves, thus allowing direct comparisons between source rock and sandstone composition and taking into account source rock texture. This study uses this technique combined with study of sandstone composition to pursue two main objectives: to investigate the relationship between tectonic history and sandstone composition, and to document sandstone compositions of the Pennsylvanian-Permian of north-central New Mexico. Upper Paleozoic strata of north-central New Mexico were derived from Precambrian crystalline rocks and were associated with the Ancestral Rocky Mountain orogeny. They display subtle changes in detrital modes with age that can be correlated with the area’s Ancestral Rocky Mountain tectonic history. Periods of high tectonic activity resulted in deposition of sandstones with compositions closest to those of the Precambrian source rocks, so high tectonic activity allows source rock control to overwhelm other factors such as climate. During periods of low tectonic activity, other factors such as climate or transport/depositional environment were more important.