Complex sentence: Sierra de Algairén runs north of Sierra de Vicort with a long tectonic basin between them, the Grio River Valley, a tributary of the Jalón, having its source in Sierra de Vicort.
Split into simpler sentences: Sierra de Algairén runs north of Sierra de Vicort with a long tectonic basin between them. The Grio River, a tributary of the Jalón has its source in Sierra de Vicort.