Former Fans
Look closely at the rock exposed in the canyon walls. Notice that the layers are composed of sediment that ranges in size from boulders to fine-grained sand and silt. Does it remind you of the debris at the canyon's mouth? Estimated to be about 5 million years old, these rocks tell of a former alluvial fan. Burial and cementation transformed the loose material into a solid conglomerate. Subsequent uplift and erosion have exposed these deposits.What was the source for the material that composes these older alluvial fans? These layers of conglomerate become thinner farther to the east, suggesting they eroded from mountains to the west. Within this conglomerate is the story of a former landscape that predated Golden Canyon and the dramatic basin of Death Valley.
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| GLOSSARY | > abrasion, alluvial fan, canyon, conglomerate, erosion, flash flood, landscape, rock, sand, sediments, silt, , , |
Layers of alluvial material from previous fans