The Piñon Hills plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
Piñon Hills’s center stands about 4,180 ft above sea level. Within three miles the land runs from 3,590 ft to 6,060 ft, a difference of 2,470 ft: mountain country. The highest named summit within 15 miles is Mount San Antonio, about 10,040 ft, 10 miles south.
Under the town center the state geologic map shows Quaternary alluvium and marine deposits (coarse-detrital), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 3×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 12 mi of the line.
Mica-schist. Age: Late Cretaceous to Eocene, 34 to 100 million years old. About 5 mi of the line.
Granodiorite. Age: Permian to Tertiary, 2.6 to 260 million years old. About 3 mi of the line.
Gneiss. Age: Paleoproterozoic to Miocene, 5.3 to 2,500 million years old. About 2 mi of the line.
Sandstone, conglomerate. Age: Miocene to Pleistocene, less than 23 million years old. About 1 mi of the line.
Schist, gneiss. Age: Paleoproterozoic to Cretaceous, 66 to 2,500 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit along the line are not listed.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.