University of Arkansas at Little Rock

Earth Sciences professor Jamey Jones published an original research article in the April 2010 issue of Lithosphere (v. 2, p. 119-135). The article is titled “Characteristics and implications of ca. 1.4 Ga deformation across a Proterozoic mid-crustal section, Wet Mountains, Colorado, USA.” It was co-authored by research colleagues at Colorado College and The University of Texas at Austin.

Approximately 1.4 billion years ago, a major thermal event affected most of southern North America and involved the generation and emplacement of large volumes of granite throughout a vast region of the continent. The tectonic setting of this event has long been debated, with the main issue being the seeming incompatibility of widespread evidence for deformation and the particular geochemical characteristics of the granites. Jones et al. present a study focused on numerous 1.4-billion-year-old granites exposed across a tilted section of the middle crust in the Wet Mountains of southern Colorado. They document widespread and long-lived deformation in outcrops that represent some of the deepest levels of exposure in the Rocky Mountains. Their results lead to a better understanding of the interactions between magmatism and deformation in an actively deforming region and confirm the dynamic nature of the crust into which 1.4-billion year-old-granites intruded. Furthermore, they revisit the debate about the tectonic setting of these granites and suggest some new alternatives that may ultimately help to resolve the issue.