Environmental Geology in Spain - Geology Explains Coral Remains on a Hilltop

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by Katrin Kleemann

Photo credit: Katrin Kleemann

This is the hill we closely examined

Imagine a warm ocean and atolls. Where are we? We are not in the South Seas, but in South Eastern Spain—circa five million years ago. On a geological field trip to the Cabo de Gata-Níjar Natural Park in the Almería province we encountered coral and shell remains on the top of a hill, at about 115 meters above sea level in Los Malenos, roughly five kilometers away from the coastline today.

The different sediment layers at the hilltop.

Closeup: In one sediment layer we found these shells and other maritime remains

Five million years ago the corals lived under water. So, how did the coral remains get to the hilltop? Two possible hypotheses are: 1) the sea level was significantly higher 5 million years ago and thus explains the deposition of maritime elements, or 2) the land on which the hill is situated today was uplifted. The second hypothesis turns out to be correct: The African and the Eurasian Plates are colliding, the result is that in the South East of Spain processes of uplifting and folding occur in the coastal areas since the Pliocene (five million years ago). The deposit of corals shows that the climate must have been warmer in this region than it is today.