On Sunday 12 October 2025 We delve into Earth Sciences by looking for «clues» in the rocks that provide us with information about the regional geological history of the «Sierra de Aracena y Picos de Aroche» area.
We began by identifying the calcosilicated rocks found at the Espadaña Puerta del Castillo, before moving on to explore the marbles that crown the hill. It is the endokarst processes within these rocks that, over millennia, have led to the formation of the Gruta de las Maravillas. But before delving into its relatively recent formation, we learnt to read the language of the rocks in order to understand the geological processes that took place in the region.
We learnt about the geological significance of carbonate rocks and the type of sea in which they were formed; we understood why they have been metamorphosed and observed their deformation structures (folds, boudins, etc.) to learn how these reveal what happened in the Sierra 320 million years ago. On a more local level, we discovered how the Gruta de las Maravillas was formed and the geochemical processes involved in the genesis of one of Spain’s most beautiful caves
Georoutes allow us to delve into the history of a living, ever-changing and dynamic planet. Taking the time to understand the Earth’s dynamics not only allows us to explore our planet’s past, but also provides clues about the present and the future. And from a personal perspective, it enables us to develop a broader and more mindful understanding of the place we call home.
Under the motto ‘WE LOOK AFTER WHAT WE KNOW’, we aim to foster an appreciation, respect and conservation of our geological heritage through outreach, interpretative and environmental education activities.
An experience I would highly recommend. The walk up the hill to Aracena Castle was absolutely marvellous, both for the surroundings and for the way its geological formation was explained. They manage to achieve something that is by no means easy: making highly scientific content accessible, explained with simplicity, clarity and great passion.
The explanations are engaging, well-structured and perfectly suited to all audiences, from those with no prior knowledge to those who are simply curious about geology. Ideal for families, as even the youngest children enjoy themselves and learn without realising it.
You can really tell how knowledgeable the guide is and, above all, how well they convey that knowledge in a friendly and accessible way. You come away from the tour with a better understanding of the landscape around you and seeing it in a whole new light. Without a doubt, it’s an educational, entertaining and very well-organised activity. We’ll definitely be back.Bilal Paladini San Martín, geography teacher at IES San Blas
I went on a guided geological tour led by Helena at Aracena Castle and it was spectacular. Helena proved to have more than enough knowledge of geology. She’d also prepared the tour thoroughly, explaining the relevant details for each feature, using diagrams and a variety of other educational materials. And she did it all with great clarity, confidence and humour. For me, it was a real eye-opener. I’d definitely recommend it.
Rafael Flores, Biologist
If you’d like to find out more about the geological history of the region:
READ THE ARTICLE WRITTEN BY DR HELENA CHACÓN: Geological History
JOIN OUR UPCOMING GEORUTAS: Events
BOOK A GEORUTA BY APPOINTMENT: On demand
