(A) Road cut in Burro Mountains, southwestern New Mexico, outcrop of ∼5-m-thick sheet cutting local fabric in ca. 1.65 Ga metamorphic rocks at a low angle. (B) Photograph of sill (at river level) in the Salt River Canyon, central Arizona. (C) Hand sample of diabase 09Sr-6b from Salt River Canyon, sample is 10 cm wide. (D) Photomicrograph of sample 03BM-88, diabase from Burro Mountains, crossed polars, width of image 2 mm. (E) Scan of thin section of sample 09HU-14, diabase from Hualapai Mountains, central Arizona. See Table 1 for locations.