A team of paleontologists led by Southern Methodist University has discovered more than 260 dinosaur footprints from the Early Cretaceous period in Brazil and Cameroon, marking a place where land dinosaurs were last able to travel freely between South America and Africa millions of years before the two regions split apart.
Theropod dinosaur footprints discovered in the Souza Basin in northeastern Brazil. Image credit: Ismar de Souza Carvalho/SMU.
Africa and South America began to separate about 140 million years ago, causing fissures in the Earth's crust called rifts to form along pre-existing weaknesses.
As the crustal plates beneath South America and Africa moved apart, magma from the Earth's mantle rose to the surface, forming new oceanic crust as the continents moved away from each other.
And eventually the South Atlantic Ocean filled the gap between these two continents.
Evidence of some of these major events was evident between the two sites, where paleontologists from Southern Methodist University discovered footprints of three-toed theropod, sauropod and ornithischian dinosaurs dating back 120 million years. Louis Jacobs and his colleagues.
“We determined that, in terms of age, the prints are similar,” Dr Jacobs said.
“From a geological and plate tectonic point of view, they are similar. In terms of shape, they are almost identical.”
Theropod dinosaur footprints discovered in the Kum Basin in northern Cameroon. Image by Ismar de Souza Carvalho/SMU.
The researchers found the footprints in the Borborema region of northeastern Brazil and the Kum Basin in northern Cameroon, more than 6,000 kilometers (3,700 miles) apart.
“Dinosaurs left their mark on a single supercontinent called Gondwana, which separated from Pangaea 120 million years ago,” Dr Jacobs said.
“One of the newest and narrowest geological connections between Africa and South America was an elbow in northeastern Brazil that borders the present-day coast of Cameroon along the Gulf of Guinea.”
“Because the two continents were contiguous along that narrow stretch, animals on either side of the connection could potentially migrate across it.”
“Before the continental connection between Africa and South America was severed, rivers flowed and lakes formed in their drainage basins,” he said.
“The plants provided food for herbivores, supporting the food chain. Muddy deposits left in rivers and lakes contain dinosaur footprints, including those of carnivores, providing evidence that these river valleys may have provided special migration routes for life to cross the continents 120 million years ago.”
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This article is based on a press release provided by Southern Methodist University.
Source: www.sci.news
