The Colorado River was making its way across the north of Arizona for millions of years, but what really prevented people in their paths is the Tonto group rocks in the Grand Canyon walls themselves.

From the edge, you can track bars of stacked colors such as huge strip symbols, each shocking witness of the oceans, deserts and rivers that have long disappeared.

It is hidden near the base of that stack on the Tonto Cambrian-Age collection, a group of rocks that are famous for its evidence of the explosion of new forms of life that has reshaped the earth more than half a billion years ago.

These rocks sit at the center of the lead in a new study that reconsiderate the idea of ​​the textbook on how the oldest sedimentary classes appear in the valley.

The work brings the most obvious time tables, faster pace, and a large mix of environments that geologists first imagine in the mid -twentieth century. It also shows the amount of the familiar scene that can still teach us about how our planet works.

Grand Canyon

In 1945, Grand Canyon Geology Edwin Maki He suggested that a fixed sea level has turned into a flat coastal line in North America into a shallow sea.

He photographed the beach sands in a deeper clay in the water, then the seafood deposits, all in a long wiping process, most of them without interruption.

New measurements across more than 50 sites from the valley reveal a different story. Instead of great progress, the coastal line has risen at least five times separate, leaving the sandstone, oil rock, and limestone in narrow, rear and accumulated sequences in just a few million.

“The Grand Canyon group carries a treasure of sedimentary layers and rods that chronicle the Cambrian explosion about 500 million years ago, when the first animals with solid shells spread quickly and sea levels rise to continents with emerging marine life,” said Carol Deller, a professor of spreading quickly and high sea levels. Utah State University.

The mapping of her team shows that some sand bodies were placed by rivers or winds, while the limestone that has been marked long ago as the deep water may be in the tidal and light apartments.

A new model for the Tonto Group

“Our new model to deposit Tonto group is more accurate, and it shows a mixture of marine and non -maritime settings,” said Karl Carlstersum. New Mexico University.

This exact view comes from the pair of rocks with the fossil-privileged formation, symbols that resemble Armadillo for early animal life.

Each pulse of the coastal line coincides with distinguished triple societies, which turns the layers into a biological orthodontic as well as geological.

“The results we have reached are a reminder that science is practical,” he added, adding Denver Museum The world of excavation James Hagadorn.

By matching rock beams throughout the valley, the researchers rebuilt a series of variable rivers, lakes, and shallow storms and seas-barely the monotonous bathtub that is imagined 80 years ago.

Thirties and evolutionary rhythms

To capture the pace of change, the geogram scientist Mark Schmits and his colleagues from sandstone to insulate the microscopic zircon crystals.

“Our new U-PB dating methods improve the fine ages of each layer in the caliphate and the transformations between the triple triglycerides,” said Schmits. “We find that different triple types radiate, then extinct in a very fast pace, a million years.”

This speed challenges the old views that the Cambrian developed slowly; Instead, it seems that life was turned out, temporarily stopped, then ran again at the rhythm with the rise of the seas and the fall.

“The sedimentary rocks are difficult so far,” said Laurie Krossey. “But the deposition of the deposits and fossils that were installed inside them must be smaller than the era of the smallest grain, so, with many dates, we can be arches for sediments.”

By combining these brackets with fossil charges, the team collected a timetable that displays the entire animal transformations that are revealed in less than 800,000 years – a geological flash.

Why do you care about the Tonto group?

To summarize everything, holds layers of 500 meters (1640 feet) of the Tonto group unusual evidence about the old climate of the Earth.

They reveal a time when sea levels have risen, and tropical storms – likely to be more intense than today’s hurricanes – all over the world without ground plants.

During this era free of extreme heat, the oceans were immersed in vast areas of continents, and putting the sediments like those in the Tonto collection.

These warm shallow marine environments have helped stir a dramatic explosion in the diversity of animals throughout the planet.

This perspective is frequented by the crawl of modern seas and storms. The updated Grand Canyon reminds us that the coasts can turn into rapid jumps, rather than smooth climbing, and reshape habitats in a short time.

It also highlights how new tools-high-resolution dating, the cross sectors of the computer, and the old fossil fishing-can breathe a new life in the rocks that have been studied for generations.

The colored gangs in Canyon may still look like the lines. However, below the surface, the story of rapid change, biological innovation, pressure and observation that is uncomfortable between the earth and the sea-which scientists have now begun to read completely.

The full study was published in the magazine GSA today.

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