Great Unconformity

The Great Unconformity (GU) is one of geology's deepest mysteries. It is a gap of missing time in the geological record between 100 million and 1 billion years long, and it occurs in different rock sections around the world. When and how the GU came to be is still not totally resolved.

The Great Unconformity represents ~1.2 billion years of missing rock record, either due to erosion or non-deposition, thus, appears to have been erased.

Understanding unconformities, how they formed, and where they occur is an important part of learning the geologic history of Earth. That, in turn, helps us understand potential mineral resources, potential geologic hazards, and even potential health effects of certain minerals.

For years, researchers have debated the cause of the massive erosion of rock. Some believe that the phenomenon was the result of ice age glacial activity, while others point to plate tectonics from the assembly and breakup of the ‘Rodinia supercontinent’ (also known as the “Nuna” (or Columbia), and “Ur” supercontinent that existed in early Mesoproterozoic and Neoproterozoic time).

The areas that underwent glaciation were approximately those where the Great Unconformity is located today. When glaciers move, they drag and erode sediment away from the underlying rock. This would explain how a large section of rock was taken away from widespread areas around the same time.

There are theories that have been proposed; it is widely accepted that there was a combination of more than one event which may have caused such an extensive phenomenon. However, there is currently no widely accepted explanation for the Great Unconformity among geoscientists, as for religions, it is an off the table topic, as it challenges all the stories of creation…

Food for thought!