First-Day Road Log: Bernalillo to San Ysidro, with Stops at Tierra Amarilla Anticline and Twin Mounds Travertine Springs
— Karl E. Karlstrom, Koning Daniel J., Laura J. Crossey, Cameron C. Reed, Spencer G. Lucas, and Matthew T. Heizler

Day 1 of the field conference travels U.S. Route 550 north- westward from Bernalillo to the Cabezon Road turnoff (on left), 2 miles before San Ysidro. The drive is through the western part of the Rio Grande rift and Santa Fe Group rift fill.

The larger area of the nexus is neotectonically active and hosts the Jemez volcanic field and Valles Caldera. From the turnoff, we drive south to the White Ridge Bike Trails parking area through Jurassic and Cretaceous strata. These rocks are similar to those of the San Juan Basin of the Colorado Plateau, but here they have been affected by both Laramide contraction and Miocene to Recent (Rio Grande rift) extensional faulting.