Question

Describe examples of how different methods of dating events and rocks were used to reconstruct the geologic history of the Grand Canyon; and illustrate why the canyon does not represent all of geologic time.

Answer 1

Grand Canyon which is a series of different layered rock formations is one of most interesting geologic feature that has taken millions of years for its formation.One of the different dating method used to trace the age of Grand Canyon is Principle of stratiagraphy. This method was helpful as the canyons have different sedimentary layers which was helpful in estimating the relative age of the rocks.Also,the presence of fossils in the rock layers gives important clues about the geologic time scale and hints back to the Cambrian period.

The radiometric dating technique was used to date the oldest rocks as the walls of the canyons had radioactive elements such as thorium and uranium which allowed to find the numeric age of the canyon dating back to not less than 90 million year old.

The canyons do not represent all the geologic time scale because of the presence of Unconformities in the rocks which represent gap in the geologic time period.