Supplemental road log 1: From Sante Fe to Sante Fe ski area via Hyde Park road
— Rodney V. Metcalf and Christopher G. Daniel

This road log describes the geology along NM-475, which runs for 15 mi from the city of Santa Fe to the parking lot of the Santa Fe ski area. The Borrego fault, a major N-striking high-angle fault running the length of the Santa Fe Range (see Metcalf, this volume), divides the geology of NM-475 into two parts. The lower 7.2 mi, below Hyde State Park, lies west of the Borrego fault. Rocks along this section consist mainly of Proterozoic supracrustal rocks, felsic gneiss and amphibolite, intruded by granite and granitic pegmatite. In addition, this section contains the only outcrops of Paleozoic rocks within the Santa Fe Range. Hyde State Park lies within the trace of the Borrego fault. Above Hyde State Park, the road passes to the east of the Borrego fault into the metasupracrustal and plutonic rocks that form the batholithic assemblages of the central and northern Santa Fe Range. This road log focuses on the Proterozoic plutonic rocks of the central Santa Fe Range with six formal stops along the upper 6.3 mi of the road.

Bedrock geology along NM-475 east of the Borrego fault is composed exclusively of Proterozoic crystalline basement. The rocks of the central Santa Fe Range can be divided into four major groups. These are, in order of decreasing relative age, (1) a suite of upper amphibolite facies migmatitic supracrustal rocks composed of biotite gneiss, felsic gneiss and amphibolite; (2) a suite of foliated, megacrystic felsic granitoid rocks (granites); (3) a suite of relatively undeformed mafic granitoid rocks (diorite and tonalites); and (4) small bodies and dikes of alkali granite and granitic pegmatite. Metcalf (1990; this volume) provides discussion of the geology of the central Santa Fe Range, east of the Borrego fault. Metcalf (1990) focused primarily on the migmatites and Metcalf (this volume) focuses primarily on the plutonic rocks.