Fossil fruits discovered buried under ancient Indian lava flows | NSF

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Fossil fruits found buried under ancient Indian lava flows

Remains of plant material stuck between layers of volcanic rock

The fruit of Euphorbiotheca deccanensis was probably fossilized about 66 million years ago.

March 24, 2022

Just before the final scenes of the Cretaceous period, India was a rogue subcontinent on a collision course with Asia. Before the two landmasses merged, however, India hovered over a “hot spot” in the Earth’s crust, triggering one of the largest volcanic eruptions in the planet’s history, which likely contributed to the extinction. dinosaurs.

In a recent study in the International Journal of Plant Science, scientists supported by the National Science Foundation of the United States who excavate the fossilized remains of plant material stuck between layers of volcanic rock describe a new plant species. The work is based on the presence of distinctive fruit capsules which have probably exploded to disperse their seeds. The fossils may be the oldest fruit discovered to date from the euphorbia family, or Euphorbiaceae, a group of plants with more than 7,000 species, including poinsettia, castor bean, rubber trees and crotons.

The fossilized fruits were discovered near the village of Mohgaon Kalan in central India, where remnants of volcanic rock lie just below the surface in an intricate mosaic.

“You can walk around these hills and find pieces of chert that have broken through the topsoil,” said lead author Steven Manchester, a paleobotanist at the Florida Museum of Natural History. “Some of the best pickups are where farmers have plowed the fields and moved the pieces to the side.”

Although there is some uncertainty as to the timing, the volcanic eruptions are thought to have lasted for up to 1 million years, occurring in prolonged pulses that covered the surrounding landscape with thick layers of lava up to 1 mile deep. Today, the basalt rocks left behind by eruptions, known as the Deccan Traps, cover an area larger than the state of California.

Sandwiched between basalt, paleontologists have found shales, chert, limestone and clays piled up in a giant layer cake of alternating bands, most of which are rich in fossilized remains of plants and animals. These fossils provide insight into what appear to have been relatively quiet periods of stability between massive lava flows.

The newly described species were likely shrubs or small trees that grew near hot springs created by the interaction of groundwater with naturally heated rock below the surface, similar to present-day environments in Yellowstone National Park.

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