# Grand Canyon Missing 1.2 Billion Years

> Scientists explain why Earth's Grand Canyon lacks 1.2 billion years of geological history.
- Title: Grand Canyon Missing 1.2 Billion Years · Gizmodo | Shortify
- Summary: Scientists explain why Earth's Grand Canyon lacks 1.2 billion years of geological history. Earth's Grand Canyon shows a 1.2 billion year gap in rock layers…
- Keywords: grand canyon, great unconformity, mantle convection, cambrian era, earth history, geological layers, unconformity, Gizmodo
- Source: Gizmodo — https://gizmodo.com/the-grand-canyon-is-missing-1-2-billion-years-of-earth-history-scientists-figured-out-why-2000834872
- Read time: 1 min
- Topics: grand canyon, great unconformity, mantle convection, cambrian era, earth history, geological layers, unconformity, science
## Earth's Geological Book
Earth's geological history is like a book with missing sections covering hundreds of millions to billions of years.
## Great Unconformity Discovery
Geologist John Wesley Powell first identified the Great Unconformity at the Grand Canyon in sedimentary rocks from the Cambrian sitting above older igneous and metamorphic rocks.
## Mantle Convection Model
Researchers modeled mantle convection over hundreds of millions of years to explain the Great Unconformity at the Grand Canyon.
## 1.2 Billion Years Missing
The Great Unconformity represents roughly 1.2 billion years of missing rock record at the Grand Canyon.
## Earth's Uplift and Sinking
Continents gradually rose due to mantle convection before sinking into the ocean during the Phanerozoic, creating the missing rock layers.
## Cambrian Era Connection
The cutoff at 540 million years marks the start of the Cambrian era when life on Earth experienced unprecedented growth.
## What This Means
The Great Unconformity shows how Earth's geological history has gaps that may help explain the Cambrian explosion.
## Key takeaway

Earth's Grand Canyon shows a 1.2 billion year gap in rock layers due to mantle convection causing continents to sink into the ocean.