A recent study looked at the possibility that a land bridge existed between South America and the Greater Antilles more than 30 million years ago. This bridge, or rather this island, which has now disappeared, would have allowed the migration of animal species.
A land bridge in the West Indies
Let us first mention the first observation: certain mammals of the Greater Antilles have South American ancestors. From this phenomenon arises a hypothesis: the GAARLandia. It is a land bridge that existed between 33 and 35 million years ago. However, geological data that could explain this is lacking as the area in question is currently at least one kilometer deep. In addition, no one had yet clearly identified the geodynamic mechanisms testifying to the emergence of this bridge and then its return underwater. Nevertheless, the Greater Antilles contain fossil rodents very similar to those found in the past in the Lesser Antilles. This, therefore, suggested a possible exchange between these two areas, which needed proof.
In a study published in Plos One on October 20, 2020, a transdisciplinary team led by the Institute of Evolutionary Sciences in Montpellier looked at the junction between the Greater Antilles and the northern Lesser Antilles. This research concerns both the sea and the land and brings together different specialties. These include plate tectonics, geophysics, and marine geology, geochronology, biostratigraphy, and geodynamics.
“Our study highlights how regional geodynamic evolution may have resulted in paleogeographic changes that are still reflected in current biology,” the publication read.
A valid hypothesis
According to the results, the researchers suggested a crustal shortening of the northern Antilles. This led to its thickening, uplifting, and emergence. However, this emergence seems compatible with the GAARLandia hypothesis. Scientists evoke an island called GrANoLA (Greater Antilles – Lesser Antilles of the North) comparable in size to that of the current Greater Antilles. However, this island had to exist and allow communication between the Greater and Lesser Antilles.
Thus, this event could explain an important change in the tectonic plates. There is talk of immobilization of the Caribbean plate and a change in direction of the North American plate (from South to East). However, despite this breakthrough, researchers have yet to prove the connection with South America. They are continuing their research in order to provide an answer to this question.
