Chile: A prehistoric reptile graveyard is captured by NASA satellites, after Tyndall Glacier receded

A group of scientists, backed by images from NASA’s Landsat 5 and Landsat 8 satellites, have shown how the retreat of Tyndall Glacier (Chile) has exposed the remains of prehistoric reptiles.

These are fossils of ichthyosaurs, marine reptiles or “lizardfish” that swam the oceans 250 to 90 million years ago, coexisting with dinosaurs and pterosaurs.

According to a NASA statement, paleontologists have found 76 ichthyosaurs in bedrock adjacent to Tyndall Glacier in the Southern Patagonian Ice Field.

Some of the fossils were discovered during an expedition to the site in April 2022, when scientists sought to extract the remains of Fiona, a 4-metre-long female with multiple embryos and dated between 129 and 139 million years old .

Judith Pardo-Perez, from the University of Magallanes, discovered the Fiona fossil in 2009.

With the movement of the glacier, more and more fossils were discovered.

Images captured by NASA of the area where the prehistoric reptile fossils are found

Two satellite images are being used by South American scientists to reflect how the edge of the glacier exposes remains over time.

The first corresponds to January 14, 1986; the second, on January 17, 2022.

These images were captured by the Thematic Mapper on board the Landsat 5 and 8 satellites, and by the Operational Earth Imager (OLI). With the added color, the differences are better observed.

DeanLomax, University of Manchester paleontologist, points out in the statement: “I’m sure many specimens were under the glacier in the 1986 image.” Includes a well-preserved complete skull, previously discovered by Lomax.

Here is the explanation of the images captured by NASA, always following the line of the note:

  1. The exposed bedrock corresponds to an area where, in a typical year, the melting of snow and ice has exceeded the accumulation of new snow.
  2. A detailed view of this ablation zone along the east side of the glacier is visible in the natural color image above, captured by the Landsat 8 satellite on April 7, 2022, on one of the few clear days of the recent month-long expedition.
  3. Previous ice edge locations are visible on the lines, including its last maximum extension around 1700 during the Little Ice Age, and its position of retreat from 1986.
  4. Over the past decades, parts of the glacier’s edge have retreated up to 2 kilometers.

Pardo-Pérez explains that the ichthyosaurs could have been trapped “by the turbidity current and thrown into the abyss, drowned, disoriented and buried almost instantly.”

By remaining in an anoxic environment (areas of marine, fresh, or underground water in which dissolved oxygen is depleted), bacterial decomposition was avoided, keeping their skeletons articulated.

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