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After 110 million years, what’s a few more seconds? The tour is 0% loaded.

Meet Borealopelta

The Making of a Most Extraordinary Fossil

An Ancient Planet

110-112 million years ago

North America was a very different place, with a large seaway that penetrated the continent’s northern interior. The nodosaur, named Borealopelta markmitchelli, likely lived along its warm, vegetation-rich shoreline, feeding on plants such as ferns and cycads.

Greenland

Nodosaur

site

EUROPE

CANADA

UNited

States

Relative location

of present-day

shoreline

AFRICA

SOUTH AMERICA

Greenland

EUROPE

Nodosaur

site

CANADA

NORTH

AMERICA

UNited

States

AFRICA

Relative location

of present-day

shoreline

SOUTH AMERICA


One unlucky day the nodosaur ended up dead in a river, possibly swept in by a flood. The belly-up carcass wended its way downriver—kept afloat by gases that bacteria belched into its body cavity—and eventually washed out into the seaway, scientists surmise.


Burial at Sea

110-112 million years ago

Winds blew the carcass eastward, and after several days afloat, the bloated carcass burst. The body sank back-first into the waters below, which were at least 160 feet deep.


As the body landed on the ocean floor, it kicked up soupy mud that engulfed it in several inches of sediment. A stony sarcophagus rapidly cemented around the carcass, and minerals infiltrated Borealopelta’s skin and armor.


Turned to Stone

LATE PLEISTOCENE

Additional layers of sediment piled atop the nodosaur, hardening into stone. As the ice ages of the Pleistocene epoch (11,700–2.58 million years ago) waxed and waned, glaciers that covered the site retreated, depositing more debris. In time, vegetation stabilized the overlying soil.


Chance Encounter

MARCH 21, 2011

Oil-sands miners working in Alberta, Canada for energy company Suncor unknowingly dug through the nodosaur’s back half before noticing the fossil. A keen-eyed worker then spotted unusual patterns in the rock: Borealopelta’s armor plates.


If the nodosaur had drifted another few hundred feet on that ancient sea, it would have fossilized beyond Suncor’s property line, keeping it entombed. Instead miners stumbled upon the oldest Albertan dinosaur ever found, frozen in stone as if it had gazed upon Medusa.

Take a 3-D tour
of the nodosaur fossil
Manuel Canales, Brian T. Jacobs, Matthew W. Chwastyk, Daisy Chung, NG Staff. Art: Davide Bonadonna. Text: Michael Greshko. Photo: Robert Clark, Research: Patricia Healy


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