TY - RPRT TI - Intrusion of horizontal dikes: tectonic significance of Middle Proterozoic diabase sheets widespread in the upper crust of the southwestern United States AU - K. A. Howard PY - 2012 DO - 10.1029/91jb00112 UR - https://pubs.usgs.gov/publication/70016410 ID - 70016410 ER -