Geoparque Unesco

The Mesozoic Era

After the Hercynian mountain range was eroded, PANGEA was under tensile forces causing its fragmentation at the end of the Triassic period. The fragments rifted away forming the modern oceans.

The Atlantic formation affected the Iberian Plate at its northern border, now the modern Cantabric Sea and the Pyrenees, since its crust was stretched turning it into the sedimentary Pyrenean Basin. .

This area was repeatedly submerged by the sea and huge amounts of sediments were stored, alternating continental with transition and marine sedimentary environments.

The Earth, 120 million years ago.

The Alpine geological cycle starts with the detritic and evaporitic sedimentation of the Triassic Era on continents and shores. Sedimentary rocks at the end of the Triassic (clays, salts, gypsum) played an important role as "lubricants" in fault and thrust propagation in eastern Sobrarbe. Salt was commercialized in the areas surrounding Sin and Salinas de Trillo.

Mesozoic Rocks:

Although we seldom find Jurasic rocks the lower Cretacious are missing in Sobrarbe, we know this region was submerged by the sea for most of the Mesozoic Era. While this sea basin became wider, huge amounts of limestone was formed, abundant in the Upper Cretaceous. At the end of the Cretaceous period, as a consequence of the Atlantic Ocean formation, the Iberian Plate was moved until closing the connection between the Atlantic and the future Mediterranean Sea.

The Mesozoic - Cenozoic limit is clearly distinguishable on the Loma de Sestrales. View from Bestué.

Around 85 million years ago, during the Santonian (Upper Cretaceous), the compressing stage started and pulled the sedimentary basin, giving rise to the Pyrenees. Until the Lower Miocene, the main phase of this compressing stage was active.

We find some remarkable events during the Mesozoic Era: the domination of the large dinosaurs and the appearance of mammals, plants with flowers and primates. The end of this period is marked by one of the greatest mass extinctions in Earth's History. 60% of the crude oil known today was formed then.

Avda. Ordesa 79. 22340 Boltaña. Huesca. 974 518 025.