GEOLOGY

Detailed explanation-1: -The rocks representing the geologic record in between are missing. Geologists call this phenomenon the Great Unconformity. Although unconformities, or gaps in the rock record, are common, the Great Unconformity earns its title. It represents a gap of hundreds of millions to over a billion years.

Detailed explanation-2: -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.

Detailed explanation-3: -An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area.

Detailed explanation-4: -The Great Unconformity. It is fitting that the Grand Canyon should contain some of the best exposures of The Great Unconformity–the gap in the rock record between Cambrian times ( 550 m.y. ago) and the pre-Cambrian (anything earlier).