Santa Cruz Bay Geological Materials

The Santa Cruz Bay is made up of different geological materials, some of which are hundreds of millions of years old. The geological forces, the wearing effect of the waves as well as the advances and retreats of the sea level have modelled this coastline to give it its current appearance, forming shallows and small islands such as Santa Cruz.

Santa Cruz Bay Geological Materials

The geological materials forming the bay are millions of years old

 

The Santa Cruz Bay is made up of different geological materials, some of which are hundreds of millions of years old. The geological forces, the wearing effect of the waves as well as the advances and retreats of the sea level have modelled this coastline to give it its current appearance, forming shallows and small islands such as Santa Cruz.

We can see a small sample of the different geological materials that make up the landscape of the Ría de A Coruña during this short walk around the island.

 

Most of the island, like much of the region, is made of shale, rocks that are more than 476 million years old, formed at high pressure and temperatures from the sediments produced by the erosion of other stones. These rocks are easily eroded so they form a landscape of soft relief.

Among the shale in the western part of the island, there are veins of another grey-white material that is much more erosion resistant. These veins of granite porphyry are popularly known as seixos and on the north coast of Oleiros they reach a huge size and form what is known as the Seixo Branco.

In front of us there is an outcrop of granite, a geological material upon which a large part of the city of A Coruña sits. It is much more difficult to erode and generates more rugged landscapes. It originated over more than 320 million years ago.

However, the deposits that make up the beach and banks of the River Cubos are much newer materials that barely exceed 100 thousand years.

 

There is a site of geological interest near the Naval beach

A curious geological formation is visible on a slope near the Naval beach. Known as Santa Cruz watershed deposits, they are part of the Inventory of Places of Geological Interest in Spain.

It is an accumulation of sediments formed by the debris of pebbles included in a mass of fine clays, the origin of which is about 2 million years. At that time, our climate was very different to the present one, with very little vegetation, in which torrential rains dragged down boulders, forming fan or cone-shaped sediment deposits.


 

Depósitos de Vertente

Depósitos de Vertente

Preto da praia do Naval hai un Lugar de Interese Xeolóxico

Nun noiro nas proximidades da praia do Naval é visible unha curiosa formación xeolóxica. Coñecido como depósitos de vertente en Santa Cruz forma parte do Inventario de Lugares de Interese Xeolóxico de España.

Fotos xeolóxicas da Baía