GeoSights: Palisade State Park in Sanpete County, Utah
by Peter J. Nielsen
Visiting Palisade State Park provides a grand view of ancient landscapes and geologic processes that formed the hills and valleys that encompass the park. The park is at the junction of the linear and narrow mountains of the Basin and Range Province and the flat lying, layer-cake geology of the Colorado Plateau.
Palisade Lake
Daniel Funk and family helped settle Sanpete County in 1857. A surveyor by trade, he became familiar with the valleys and mountains in Sanpete County, and observed a small cove at the mouth of Sixmile Canyon could be dammed and filled to make a lake. Funk, with the help of Brigham Young—second president of the Church of Jesus Christ of Latter-day Saints—acquired the land from the local San Pitch band of the Ute Indian Tribe that wintered in the valley. They built an earthen dam in the small drainage, dug a nearly three-fourths-mile-long canal to the stream channel in Sixmile Canyon, and began to divert water to fill the lake in the 1870s.
Funk Lake became a well-known recreational site for residents in central Utah. It was renamed to Palisade Lake by the second owner, who came from the Hudson River Palisades area in New York. The lake and facilities have had many owners, with attendance waxing and waning over the years until it became a state park in 1962. A nine-hole golf course was added in the 1970s and expanded to 18 holes in the 1980s. The state park is a great place to camp, fish, boat (non-motorized only), hike, bike, and just relax. The park makes a great hub for several hundred miles of designated OHV (off-highway vehicle) trails accessed by Sixmile Canyon to Skyline Drive to the east.
The Palisade
Paleogeographic map showing the ancient landscape during the time that Lake Flagstaff covered the Funk Valley Formation rocks at the park, approximately 61 to 58 million years ago. Blue star is location of Palisade State Park (modified from Reading and others, 1998, UGS Public Information Series 54).
When driving into the state park or while playing golf on the spectacular course, you cannot help but notice on the east side of the park a prominent wall of rocks, called a “palisade.” The nearly vertical beds that form the palisade are part of the Funk Valley Formation, which locally has three different sections that help form the small cove that holds the park. The hill west of the park and golf course is made up of the lower unit and consists of interbedded layers of resistant sandstone and more erodible shale. The middle section is an easily weathered, muddy sandstone that readily erodes, making a “strike valley” or a valley that forms between two resistant, inclined rock layers. Resistant sandstone beds form the eastern cliff or palisade. The Funk Valley rocks were deposited between 97 and 76 million years ago by rivers flowing from the west that deposited sand and mud into a nearby eastern seaway. The Funk Valley Formation is mostly unfossiliferous, but the ancient landscape would have been filled with vegetation and dinosaurs that are not preserved.
The light-yellow, horizontal rock layers that cap the Funk Valley rocks on the eastern palisade are named the Flagstaff Limestone. These rocks were deposited in a freshwater lake called Lake Flagstaff that covered most of central and northeastern Utah about 61 to 58 million years ago. Freshwater fossils are found in these limestone beds.
The Unconformity
Relationship between tilted Funk Valley Formation layers and horizontal Flagstaff Limestone beds. The contact is an onlapping angular unconformity with a 22-million-year time gap.
Make your camp at the lake and head up to the golf course. Take a minute before hitting your best drive of the day at the hole 4 tee and look east at the large display of rocks on the palisade. Several geologic events are recorded in that wall of rocks. The nearly vertical rock layers of the Funk Valley Formation were folded and tilted by the Sevier orogeny, a mountain building event that impacted the rocks in this area about 60 million years ago. The contact between the vertical Funk Valley rocks and the mostly horizontal Flagstaff Limestone beds represents approximately 22 million years of erosion that formed an ancient landscape in this area. This contact is called an “angular unconformity.” Angular because the rocks above and below the contact are at different angles, and unconformable because a time gap exists between deposition of the two rock formations. If you look at the horizontal beds from north to south, you can see that they “onlap” or intercept the ancient topography at different heights. This onlap records progressively higher lake levels and deposition of the Flagstaff Limestone until the lake covered the ancient topography.
The last thing of note are three offset and down-dropped blocks of Funk Valley Formation and Flagstaff Limestone. These blocks were moved by high-angle normal faults (faults that dip greater than 45 degrees) within the last 10 to 20 million years, well after the ancient lake was gone, during Basin and Range extension that has been slowly stretching the crust in an east-west direction. The results of this crustal extension and associated faulting are the repeated valley and mountain landforms which begin with the Sanpete Valley and San Pitch Mountains immediately west of the state park and continue west to the Sierra Nevada mountain range.
Thus, over the course of nearly 100 million years, deposition, tilting, and erosion of the Funk Valley Formation followed by Lake Flagstaff, Basin and Range extension, and differential erosion of a strike valley, all coalesced to write the geologic story of Palisade State Park.
How to Get There
Palisade State Park GPS Coordinates: 39.2092° N, 111.6667° W
From the north
Travel north or south on I-15 to Nephi, Utah. Take Exit 225 east onto Highway 132 and proceed 30 miles to the intersection with Highway 89. Turn south (right) and travel 17 miles to Palisade Road, turn east (left) and go 2 miles to the state park.
From the south
Travel east or west on I-70 to Salina. Take Exit 56 north onto Highway 89 and proceed approximately 24 miles to Palisade Road, turn east (right) and go 2 miles to the state park.
