It’s in the dunes of Ica, on the southern coast of Peru. It is one of the most important deposits in the world. The enormous quantity and good state of preservation are surprising. The large cemetery of fossilized marine animals is an important place of study.
These are thousands of prehistoric cetacean fossils. It is known as the Pisco Formation. A study was published in PLOS ONE. It allows to understand the keys of its genesis and its preservation.
Dead animals were quickly buried in the marine substrate. They were thus protected from degradation factors. Low levels of dissolved oxygen on the seabed played a role. Other factors added to this. For example, the early onset of mineralization processes. And the rapid sinking of the carcasses in a thick substrate.
A “self-burial” mechanism was also key. Researchers made a discovery. It happens when a heavy weight sinks to a seabed with constant ocean currents. The sediments under the corpse move rapidly. This makes it easier for the body to sink. And it quickly covers it with new sediment. This creates a protected environment in which it decomposes. It then fossilizes without the action of erosion or scavengers.
Geologist Claudio Di Celma of the University of Camerino explains. “Now there is a desert along the coast of Peru. But in the past there was a large marine basin, the Pisco Basin. It had a great abundance of nutrients and a rich biodiversity.” Paleontologist Elisa Malinverno is from the Bicocca University in Milan. She adds: “The inhabitants of this ancient bay have been preserved for millions of years. And now they are exposed around Ica thanks to tectonic movement. Also, because of erosion in today’s desert environment”.
The great cemetery of marine animals houses hundreds of fossils. There are marine and coastal animals. Sharks, whales, dolphins, penguins, seabirds, crocodiles and more. Elisa Malinverno says the absence of vegetation helps. “It makes it much easier to discover the findings”. All this makes this corner of the Peruvian coast a mecca for researchers of prehistoric marine life.