This 18 mile auto tour takes you through the unique transition zone between the Mojave and Colorado deserts. 16 markers found along the route highlight some of the fascinating geology that makes up Joshua Tree National Park. This drive takes around 2 hours to complete if you are doing the entire loop, or 1 1/2 hours if you're stopping at Squaw Tank. Two-wheel drive vehicles can easily travel as far as Squaw Tank (at marker #9) but should proceed with caution afterwards. The one-way stretch of road following Squaw Tank enters Pleasant Valley and becomes rougher with patches of deep, loose sand. High clearance is required and four-wheel drive vehicles are recommended. Do not drive Geology Tour Road during or following periods of rain.
Stop to pick up a free interpretive brochure just after you turn off of Park Boulevard. They are located in a metal stand on the southern corner of the parking lot, or you can print it off beforehand.
Joshua Tree National Park is comprised of very old mountains that have undergone periods of uplift and erosion. Most of the geologic history of these mountains has been lost over long stretches of weathering. The two rock bodies that remain, 1.7 billion-year-old Pinto gneiss and 85 million-year-old White Tank monzogranite, form the backbone of what you see today. Each marker discusses a specific part of the geologic process that has shaped the park. The markers themselves can be easy to miss (not all are located in pull outs) so keep your eyes peeled!
Remember to bring extra water, drive slowly, and don't pull too far off the road (the sands gets deep fast!).
