Are you seeing double? Zion and @yosemitenps have a lot in common with both having a distinct U-shaped canyon. However, these canyons formed in different ways. Zion - Zion’s canyon formed by the Virgin River cutting through the soft sandstone forming the towering cliffs. However, usually a river cut canyon forms a deep V-shaped canyon instead of a U-shaped canyon. The reason Zion has this flat bottom is because around 5000 years ago, there was a large landslide that blocked the flow of the Virgin River in the canyon. This rockslide created a lake in the area that is now the scenic drive known as Sentinel Lake. Sentinel lake then filled up with sediment creating the flat bottom the canyon has now. You can still see the remains of the rockslide when riding the shuttle between Canyon Junction and the Court of the Patriarchs. Yosemite - Yosemite Valley was initially a deep V-shaped canyon cut by the Merced River. For millions of years, the river cut through the landscape as the Sierra Nevada Mountain range tilted westward. Beginning around three million years ago, a series of glaciers filled Yosemite Valley. These glaciers scoured the valley walls, steepening them and deepening the canyon. Later glaciations deposited sediment in the valley, filling it to a depth of nearly 2,000 feet. The last glacier retreated about 15,000 years ago, leaving behind a flat floor of sand and gravel that is the valley floor today. #EarthScience #ZionRocks