Tony Grove Geology, 10 July, 2022
After introductions and a quick overview of the destination, 13 hikers departed the Smith's parking lot around 8 a.m. After a 28-mile drive, the group arrived at the Tony Grove backcountry parking lot. The hikers gathered for a group photo before heading towards the Naomi Peak trail. Abundant wildflowers in the meadows along the way provided several photo opportunities as the group made its way northward, past the Tony Grove paid lot before stopping near the stair-step formation of Swan Peak Quartzite at mile 1.3. Dave P gave a brief summary of the area geology before the group continued up the Naomi peak trail. At mile 1.6, the group left the well-worn trail and turned southward into the backcountry area on the plateau above the west side of Tony Grove Lake.
Seven caves and 3 prominent sinks were on the group's agenda for the day and the first cave, GMZ, was located not far from the Naomi Peak trail. The group then continued southward to the second cave, Double-Sink, to find lingering snow in both of the cave's sinks. The next caves on the group's list were Snowcone and Main Drain. Both caves required a steep climb up from the plateau with Snow Cone being about 200 feet above the meadows and Main Drain being about another 100 feet vertical from there. Knowing the steep climb, a few hikers decided to take a break in a cool, shady area while the others ventured to Snow Cone. Fewer still made the additional climb to Main Drain - Utah's deepest cave at 1227 feet and its 4th longest cave at 2.02 miles. The amount of snow still covering the cave entrance and hillside of Snow Cone cave was much more than the group saw on its visit last year. Leaving Snow Cone, the group traveled about 0.75 miles before stopping for lunch on the rim of a prominent sink.
After lunch the group continued southward, past another prominent sink, and on to Teacup cave and Thundershower cave at the 4.6 mile mark. One final push onward brought the group to the final, and more visited, cave of the day - Polygamy cave. From Polygamy Cave, the group scrambled up rocks to an area above the cave before discussing the best way to cross the ridge to the southwest of the cave in order to reach Coldwater Spring. Trip leaders had scouted a few routes the prior weekend but one hiker found a better-worn trail which allowed the group to make its way to the ridge with a minimum of effort.
From the ridge, the group split in two, with some venturing south-west towards the 3rd sink on the agenda; while the remainder of the group headed towards Coldwater Spring to wait for the first group. Upon regrouping at mile 5.8, the hikers made their way back to the Tony Grove Backcountry parking lot, and departed for home.
Thanks to David for the narrative, video and photos, and Dave P, Ralph and Dave W for photos.