A forest that met its demise 22 million years ago due to a volcanic eruption has been rediscovered

Researchers have made a remarkable discovery by uncovering a 22-million-year-old mangrove forest that was engulfed by a massive volcanic eruption. This ancient forest, once teeming with towering trees and lush green vegetation on an island in the Panama Canal, met its demise due to natural disasters.

The revelation was made by scientists from the Smithsonian Tropical Research Institute, who stumbled upon the fossilized remnants of trees on Barro Colorado Island. They didn’t find just a few pieces; they unearthed a total of 112 remarkably preserved fossilized wood fragments.

Analysis of these fossils pointed to a cataclysmic volcanic eruption triggering a lahar—a destructive torrent of water, mud, ash, and rocks. A lahar resembles fast-flowing wet concrete, covering everything in its path in a matter of moments. Unlike other natural processes, a lahar doesn’t allow plants and animals to decompose, instantly freezing the landscape in time. Furthermore, the silica-rich waters in a lahar penetrate deep into organic matter, preserving tissues and creating well-preserved fossils.

The researchers believe that this ancient mangrove forest dates back to the early Miocene Epoch, approximately 23 million years ago. It was during this time that the land masses of South America and the Caribbean plate collided, giving rise to the Panamanian landscape, including Barro Colorado Island. Along the island’s edges, a towering mangrove forest flourished, with trees reaching heights of up to 130 feet.

Sediment samples indicate that this forest thrived in the brackish zone where salty and fresh waters mixed—a perfect habitat for mangroves. However, the ideal conditions extended beyond brackish waters. During the Miocene, atmospheric carbon dioxide concentrations were significantly higher than today, exceeding 500 parts per million (ppm), compared to the current 419 ppm. As trees utilize carbon dioxide for growth, it’s believed that the ancient mangroves could attain greater heights than their modern counterparts.

While this discovery sheds light on the past mangrove forest, the research is still in its early stages, with the findings set to be published in the March 2024 issue of the Palaeogeography, Palaeoclimatology, Palaeoecology journal.