AZGS scientists contribute to breakthrough examine on Colorado River and Grand Canyon historical past

The Colorado River and the Grand Canyon are icons of the American Southwest. For many years, geologists have labored to uncover the historical past of the river and the formation of the canyon. A paper published today in Science, coauthored by AZGS Research Scientists Brian Gootee, Phil Pearthree, and Kyle House, reveals a key piece of this historical past: a precursor to the formation of the Grand Canyon.

“This study comes on the heels of many years of research on the Lower Colorado River led by Kyle House, Phil Pearthree, Jon Spencer, Ryan Crow, and others,” mentioned Brian Gootee. “They found that the Colorado River arrived suddenly in the area below the mouth of the Grand Canyon by about 5 million years ago, and filled successively lower lake basins before reaching the Gulf of California by 4.6 million years ago. That finding led us to ponder what was happening upstream of the Grand Canyon, prior to the development of the Lower Colorado River.”

Efforts led by Gootee and John Douglass of Paradise Valley Community College over the past 20+ years led to a brand new concentrate on sediments within the Bidahochi Basin, positioned upstream of the Canyon in northeastern Arizona.

The present crew, led by John Douglass, John He of UCLA, and Ryan Crow of the US Geological Survey, succeeded in figuring out the signature of Colorado River sediments within the Bidahochi Basin for the primary time.

Specifically, they analyzed hundreds of zircons, that are tiny mineral grains that persist for thousands and thousands of years in sediment deposits, preserving details about their age and supply space. The zircons within the Bidahochi Basin matched these beforehand recognized downstream because the early model of the Colorado River.

The presence of Colorado River sediments on this area means that the river deposited water and sediment into a big lake east of the trendy Grand Canyon, forming a delta ecosystem earlier than ultimately overflowing and starting to carve the canyon between 6 and 5 million years in the past.

A key part of this wealthy scientific discovering was collaboration between a number of establishments: scientists at UCLA, AZGS, USGS, and three different schools and universities got here collectively for the investigation.

The findings construct off long-standing relationships between many of those scientists, highlighting each the complexity of this geological story and the joy of progressively placing the items of this historical past collectively.

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