The geological story of southern Spain
Chapter 1
the formation of Pangaea
Around 237 my the planet's continental plates had all essentially joined together to form one 'supercontinent' called Pangaea (also spelled 'Pangea' - from the Greek, meaning "all lands"). Two oceans encircled Pangaea - the Panthalassic and the Tethys.
Pangea had achieved this state via a succession of collisions between smaller continental pieces during the preceding 150 million years, eventually resulting in the stitching together or welding of the various component parts into one entity. The 'final weld' occurred between two continental masses called Laurasia and Gondwana, and in Europe was known as the Variscan or Hercynian orogeny. The types of rock that made up Pangea were very varied, basically being composed of the wide variety of rocks that had previously made up the Crust of the individual continents now forming Pangea. Similarly, the ages of the rocks were wide and varied, although most recently of Palaeozoic age. (The Palaeozoic is the name for the Era that spans 252 to 541 million years ago). Once Pangea had formed, Spain found itself in the interior of the supercontinent, in an arid environment, and in the ensuing Triassic times, non-marine sediments were deposited - for example sands and muds deposited in arid river plains and lakes. However, with the restless Asthenosphere churning below, Pangea did not last that long as a single entity. About 200 million years ago, 'just' 40 million years (3 'days') after it was pieced together, it began to break up again. As it began to split apart, a new ocean was destined to emerge, running North-South along the centre of Pangea (the Atlantic); the Panthalassic would become the Pacific Ocean; and the remnants of the Tethys Ocean would eventually become the Mediterranean Sea. Next: Chapter 2 - the break-up of Pangaea and closure of the Tethys Ocean |