There are four notable mountain ranges in the Tuscon area as well as hundreds of peaks in south eastern Arizona, many of which have remain unnamed. To the north of Tuscon the foothills of the Catalina Mountains can be found that begins where the city ends, rapidly rising to well over a vertical mile to over 9,000 feet. Separated by a few high passes are the forested slopes of the Rincons, and the peaks of the Santa Ritas rise south of the town. Literaly minutes away from downtown the jagged, barren crags of the Tucson mountains can be found to the west of the Tucson Vallley.
Considered a minor mountain range, it includes Wasson Peak, the highest, point in the Tuscon Mountains at 4,687 feet. The area where the Tuscon Mountains are located was once the top of a large volcano that formed about 70 million years ago where the Santa Catalina Mountains are located today. When the volcano collapsed in on itself it formed a caldera, or cicular basin. Then, about 30 million years ago, the top of the volcano slid down 20 miles to the west to form a valley between the Catalina and Tucson Mountains. The upper part of the caldera that was higher than the valley on the west side formed the Tucson Mountains and the other part of the caldera that was higher than the valley on the north side became the Rincon and Santa Catalina Mountains.
The valley was caused by detachment faults that dropped the area where the Tucson Mountains are situated today more than 10,000 feet. The valley has since filled in with about 5,000 feet of sediment. Much of the Tucson mountain area is composed of rhyolite, the extrusive igneous rock created when the volcano erupted. Thousands of cactus plants thrive on the slopes of the Tucson Mountains.
The rock layers in the Tucson Mountains record ancient landscapes that are much different from the southern Arizona we see today. It included a large, shallow, oyster-rich freshwater lake that was located south west of today’s Wasson Peak. Dinosaurs roamed the area for around a million years before the land was raised and the area where the Tucson Mountain are today experienced repeated catastrophic volcano eruptions.
Although not impressively high, this hot rugged mountain range nevertheless represents the character of Tucson and is a highly popular mountainous area that attracts many nature enthusiasts including hikers and climbers.