Geologic Map of Nevada
Image courtesy U.S. Geological Survey
Nevada's territory is almost entirely within the Great Basin, the heart of the Basin and Range province of North America. There's no other place quite like Nevada in all the world. Consider the Himalaya region, where two continents are colliding and creating an area of very thick crust. Nevada is the opposite, a region where a continent is stretching apart and leaving the crust exceptionally thin.
Between the Sierra Nevada, just over the western border in California, and the Wasatch Range in central Utah to the east, the crust has been extended by some 50 percent over the last 40 million years. The crust responds differently at different depths—in the upper crust, the brittle surface rocks break up into long blocks, while in the hotter, softer lower crust there is more plastic deformation, allowing these blocks to tilt. The upward-tilting parts of the blocks become mountain ranges while the downward-tilting parts become basins. The basins fill with sediments, topped with dry lake beds and playas in the rainless climate.
Beneath the thinned crust, the mantle feels lower pressure and responds by melting and expanding. This is why Nevada is a plateau, lifted more than a kilometer high. Volcanism and intrusions of molten rock have covered the state deep in lava and ash, and also injected hot fluids in many places to leave metal ores behind. The unusual tectonic setting and mineral wealth of Nevada, coupled with the spectacular rock exposures in its deserts, make Nevada a hard-rock geologist's paradise.
Northern Nevada has extensive young volcanic deposits that are associated with the Yellowstone hotspot track, which arcs from Washington to the corner of Wyoming. Southwestern Nevada is where the most crustal extension is occurring these days, along with recent volcanism. At this scale the Walker Lane, a wide zone of tectonic activity, is visible paralleling the diagonal border with southern California.
Before all this tectonic activity, Nevada had quite a different geologic history as a crustal convergent zone, similar to South America or Kamchatka today. To the west was an oceanic plate, sweeping eastward and being subducted. Exotic terranes came riding in on this plate and slammed into the continent, slowly building the land of California. In Nevada, large bodies of rock were shoved eastward in great thrust sheets by this activity on several occasions during Paleozoic and Mesozoic time.
This particular geologic map of Nevada is derived from a large national map, so it simplifies lots of detail. Still, it's worth seeing at 800x1200 pixels (730 KB) to get a synoptic view, especially if you're familiar with the colors and symbols of geologic mapping.
For something closer to real detail, I've scanned an enormous 1:1,000,000-scale map of Nevada and mounted it here in three overlapping pieces:
Northern section (3350x1700, 3 MB)
Middle section (3350x1600, 2.7 MB)
Southern section (3350x1900, 2.5 MB)
The explanation (560x1200, 160 KB) is also included separately for convenience.
More Nevada resources on About.com:
About Las Vegas
About Reno/Tahoe
About Las Vegas Travel
Nevada Maps
Nevada Geography, State Symbols & Facts
Nevada National Parks
Nevada State Parks, Winter
Nevada State Parks, Spring
Nevada Campgrounds
Nevada Public Lands
Nevada Scenic Roads
Nevada Resorts
Nevada Skiing
Nevada Archaeology
Back to Geologic Maps of the States
