End of the mystery: scientific research solves how the Costa Verde was formed

It is one of the spaces that most identifies Lima. The Green Coast It has aroused the curiosity of ancient cultures, tourists, photographers, writers, but above all the researchers of the Sedimentary Geology Research Group (Geosed PUCP) who have given an answer to the question about its formation.

The team led by dr. Willem Viveen presented the evidence in an article in the international scientific journal Earth Surface Processes and Landforms, published by Wiley. This is a paper in collaboration with Dr. Jorge Sanjurjo, the mag. Rodrigo Uribe, and the Geological Engineering student Gustavo Bravo.

What is proposed is to define not only the antiquity but also the formation of this rocky chain that looks like a wall facing the sea. According to a report from the Andina agency, attempts were made to define the training on two occasions: in 1907 and in 2000.

For Viveen, these are contradictory results, with a great variety of ages in the same place.

Thus, one of the results suggests that the base of the Costa Verde would be 121 thousand years old, while its top would reach 6,000 years. This estimate was achieved by using the luminescence dating technique.

“I consider that this technique has worked very well because the ages we have achieved are very consistent with each other and with what the literature on geological formations of Peruvian rivers says,” says the teacher in an Andina report.

For this result, samples of 5,000 stones were taken, from the base to the top, and their diameter was measured. This allowed us to determine that the grain size varied cyclically – from larger to smaller and vice versa – depending on how the flow of the ancient Rímac River changed.

In total, up to 13 cycles of grain size change have been identified. On the one hand, it was due to the action of the Rímac River and also to the rains coming from the Atlantic Ocean. The last stage of the Ice Age is also taken into account, since the sea level dropped to 130 meters from the current level, and made the river advance and later carry the land that formed the Costa Verde.

But the research also showed the need for specialized laboratories. The luminescence technique is used in the United States and European countries, so samples were transported to the laboratory of the University of La Coruña, Spain.