Geologic Overview

The origins of Kings Peak go back about 750 million years to late Precambrian time, when life on Earth consisted solely of very simple organisms such as cyanobacteria (blue-green algae). Utah occupied a place on the edge of a former continent called Laurentia, which at that time was beginning to separate from what would eventually become Antarctica and Australia along a continental rift zone. As Laurentia slowly moved away from the other continents, an arm of the rift opened and extended inland, forming a long, narrow basin. Over time, sand, gravel, silt, and clay were deposited in the rift basin in a variety of coastal environments including deltas, tidal flats, lagoons, and shallow marine waters, as well as in alluvial fans and the channels and floodplains of streams flowing from the continental interior. The resulting sequence of sedimentary rocks (shale, sandstone, siltstone, orthoquartzite, and conglomerate), over 20,000 feet thick, is known as the Uinta Mountain Group and contains cyanobacteria that were preserved to become Utah’s oldest fossils (see Survey Notes, v. 37, no. 2, p. 6–7).

Left – Schematic diagram of rifting along the margin of the former continent of Laurentia in late Precambrian time. Arrows indicate crustal extension. The narrow arm of the rift across northern Utah filled with sediments that would become the sedimentary rock of the Uinta Mountain Group, eventually forming the east-west-trending core of the Uinta Mountains. Right – Present-day physiography of the Uinta Mountains and location of Kings Peak.

Hikers negotiate loose talus on interbedded sandstone, siltstone, and shale of the Uinta Mountain Group at the head of the Henrys Fork basin; view looking north. Like all the major valleys throughout the Uintas, the Henrys Fork basin contained ice during Pleistocene glacial episodes, the most recent being around 24,000 to 12,000 years ago.

Fast-forward to about 70 million years ago, near the end of the Mesozoic Era (the “Age of Dinosaurs”). What had been the rifted margin of Laurentia has undergone geologic and tectonic changes and evolved into the continental margin of western North America. And instead of being extended and pulled apart, the crust is now being squeezed and compressed in a mountain-building event called the Laramide orogeny. During Laramide time (about 70 to 34 million years ago), numerous upwarps and adjacent basins formed throughout the Rocky Mountain region, including what would become known as the Uinta Mountains, the Green River Basin to the north, and the Uinta Basin to the south. Uplift of the Uinta Mountains occurred partly by broad folding and partly by movement along reverse faults that extend the entire length of the range along both the north and south flanks. So, the sediments that accumulated 750 million years ago in a rift basin near sea level now lie as sedimentary rocks 13,000 feet above sea level, forming a mountain range whose unusual eastwest orientation reflects the configuration of the ancient rift basin.

Much more recently, glacial erosion sculpted the present topography of the Uinta Mountains during Pleistocene glacial episodes, the most recent having reached its maximum extent about 20,000 years ago. Cirque glaciers joined to form confined valley glaciers, which generally did not cover the crest of the range or major drainage divides. The results are deep, glacially scoured valleys separated by sharp ridges (arêtes) and broad, unglaciated alpine plateaus (collectively known as “biscuit-board topography” for the resemblance to dough left on a cutting board after the biscuits have been cut). The main and south summits of Kings Peak form the highest points on a short arête that extends south from the main crest of the Uinta Mountains.

Oblique aerial view looking east at Kings Peak and the upper Henrys Fork basin, showing the characteristic biscuitboard topography of the Uinta Mountains. Peaks, ridges, and alpine plateaus preserve bedrock that remains after glaciers eroded the valleys. Google Earth image © 2015 Google Inc. Map data: Google, USDA Farm Service Agency

Story Behind the Name

Kings Peak is named after Clarence King, leader of the Fortieth Parallel Survey (1867–72) and first director of the U.S. Geological Survey (1879–81). Photo source: U.S. Geological Survey, public domain.

Utah’s highest point was called Tei’an-Ku-ai (meaning “a small peak” or “peak with a small tip”) by the Eastern Shoshone who formerly occupied the area. Later, the mountain was named for Clarence King, an American geologist, mountaineer, and author who, along with Ferdinand Hayden, John Wesley Powell, and George Wheeler, led one of the “Great Surveys” that explored the American West after the Civil War. King’s survey was focused along the 40th Parallel and extended from Wyoming to eastern California, including northern Utah. The four western surveys led to creation of the U.S. Geological Survey as a federal science agency, and King served as the agency’s first director from 1879 to 1881. King was succeeded by John Wesley Powell, famous for his explorations of the Colorado River through the Grand Canyon. Mount Powell (13,159 feet), a few miles west of Kings Peak, honors this intrepid explorer and scientist, and Gilbert Peak (13,442 feet), a few miles northeast of Kings Peak, bears the name of G.K. Gilbert, a key geologist on the Wheeler and Powell Surveys who went on to conduct groundbreaking research on Utah’s Henry Mountains and prehistoric Lake Bonneville.