Lake Bonneville: Ancient Glacial Lake and Its Coastlines

Explore Lake Bonneville, a vast Pleistocene lake in Utah. Discover its ancient coastlines (Bonneville and Provo), its peak depth, and its dramatic outflow via Red Rock Pass, shaping the landscape.

The Bonneville Coastline and its Outflow

Lake Bonneville was a huge Pleistocene lake that covered much of western Utah, extending into the edges of adjacent Nevada and Idaho, throughout the elevation of the last Glacial epoch. It reached its maximum degree and depth about 17.5 KYBP (thousand years prior to present). The lake eroded what’s now called the Bonneville Coastline at this level, around 5100 feet over present sea level. At its acme the lake then overruned over Red Rock Pass, now in Idaho, to make sure that a huge flooding put down the Serpent River drain and eventually into the Pacific via the Columbia River. As the outflowing water eroded a channel, the level of Lake Bonneville went down, overall dropping concerning 410 ft to around 4750 feet over mean sea level, where the downcutting network finally experienced immune bedrock. This supported the lake level, and a well-defined coastline, the Provo Coastline, was eroded around this elevation. A river seems to have actually streamed out this network right into the Snake for about a thousand years, acting as the outflow for Lake Bonneville. Eventually, however, as the climate dried out the level of Lake Bonneville dropped listed below the outlet degree.

Navigating to Window Rock

After 1.5 miles the primary roadway makes a superficial right; remain on Pilot Road and go 8.7 miles, to a junction with a county road at 40.98164 N, 114.17799 W. Follow this roadway 3.2 miles pretty much straight southern to where it flexes left (east), around 40.93603 N, 114.16616 W. Adhere to the road around eastern. It intersects another road around 40.93165 N, 114.1393 W; maintain right and follow this road up the ridge in advance for concerning an additional mile. When the roadway covers out concerning 40.9223 N, 114.12326 W, you will certainly see a primitive roadway on the right leading off to Home window Rock in the distance.

Provo Coastline and Erosion Scale

Lake Bonneville was a huge Pleistocene lake that covered a lot of western Utah, extending into the edges of surrounding Nevada and Idaho, throughout the height of the last Ice Age. The lake eroded what’s currently called the Bonneville Coastline at this degree, around 5100 feet over existing sea level. As the outflowing water wore down a channel, the level of Lake Bonneville dropped, in general dropping regarding 410 feet to around 4750 feet above mean sea level, where the downcutting network finally encountered immune bedrock. As may be anticipated, a lake loads of miles throughout and hundreds of feet deep could erode shoreline features at a scale more regular of a sea than a lake, and that’s what occurred below.

As might be expected, a lake lots of miles across and hundreds of feet deep might deteriorate coastline features at a range much more regular of a sea than a lake, and that’s what took place below. Window Rock is at an elevation of about 4839 feet, so it has to have been worn down prior to the lake degree went down to the Provo Shoreline.