While in Payson for the gem show, I was able to get a hike this morning (hoping for another Monday morning!) since the show doesn’t start until 10 am!! While out I was totally enjoying the landscape and geology. I’ve always been intrigued by the geology of the Rim Country area.

View to the west of Payson, I believe these are the Mazatzal Mountains, from Lousey Saddle Trail photo © Suzanne Morrison September 2025

Payson, Arizona is situated on the southern edge of the Colorado Plateau, and its geology reflects, what I think, is a fascinating mix of ancient rock formations and some wicked cool dynamic geologic processes. One of the most prominent features in the area is the Mogollon (Pronounced like a local: Mug -e - own) Rim, a dramatic escarpment that forms the boundary between the Colorado Plateau and the Basin and Range, which includes the lower desert regions to the south. Payson is in the Transition Zone between the two. The Rim is composed largely of Paleozoic sedimentary rocks, including limestone, sandstone, and shale, which were deposited in shallow seas over 250 million years ago. This is where many of the fossils available in the area to collect come from. Over time, tectonic uplift and erosion exposed these layers, creating the stunning cliffs and mesas seen today.

Beneath the sedimentary layers of the Rim lies an even older foundation of Precambrian granite and schist, some of which dates back more than 1.6 billion years. These metamorphic and igneous rocks form the bedrock of the region and are visible in places where erosion has worn away the younger layers. The Mazatzal (the gem show is taking place in Mazatzal Casino stop by and say hi on the last day! We’re there 10-) Mountains, just south of Payson, contain some of these ancient rocks and are remnants of significant geologic uplift during the Mazatzal Orogeny, a mountain-building event that shaped much of central Arizona.

Payson’s geological diversity also includes more recent volcanic activity, particularly from the Mogollon-Datil volcanic field to the east. Basaltic lava flows and volcanic ash deposits, dating back roughly 15 to 20 million years, overlay some of the older formations in spots. These volcanic materials contribute to the area's complex soils and support a variety of ecosystems, from pine forests on the Rim to desert scrub in the lower elevations. Overall, Payson’s geology tells a rich story of ancient oceans, mountain-building events, and volcanic activity that has sculpted the landscape into the rugged beauty visible today.

Payson, AZ geology

Payson, AZ Gem Show: Sept 19th-21st, 2025