Protracted magmatism and magnetization around the McClure Mountain alkaline igneous complex

• DOI: 10.1130/l1062.1
• Publication Date: 2019-06-27T17:16:12Z
• Authors: Anthony F. Pivarunas; Joseph G. Meert
• Keywords: Dike

Abstract The McClure Mountain–Iron Mountain igneous complex is an alkalic intrusive center in the northern Wet Mountains of southern Colorado. It was emplaced early Cambrian time into gneissic/granitic 1.75–1.45 Ga Proterozoic host rocks. Numerous dikes are associated with complex, primarily along western side. Although main nepheline-syenite body well dated, ages surrounding poorly known. Crosscutting relationships and defined K-Ar dates suggest that younger than intrusion. Paleomagnetic samples were collected from complex. Geochronologic also two sampled for their paleomagnetism. We obtained U-Pb zircon 526 ± 8 Ma a lamprophyric extracomplex dike 483 2 trachytic dike. These either multistage or protracted intrusion around ca. 524 Our paleomagnetic data consistent previously published results. Dikes exhibit southeast shallow directions, variable declinations. Results several baked contact tests indicate magnetizations secondary. A steeply inclined magnetization pervasive acquired over interval late Laramide to present day.