Granada Basin facts for kids
The Granada Basin, also known as the Granada Depression, is a special valley in Andalusia, Spain. It's like a big bowl surrounded by mountains. The Genil River flows through this valley after it leaves the Sierra Nevada mountains.
The valley is bordered by different mountain ranges and areas. To the north, it meets Los Montes. To the northwest, you'll find the Sierra de Loja. The Sierra Gorda is to the southwest, and the Sierra de la Almijara is in the south. The famous Sierra Nevada mountains are to the east. This basin is part of a chain of valleys called the Surco Intrabético.
There are two main ways to enter or leave this enclosed valley. One is a natural pass between the Sierra Nevada and the Sierra de la Almijara. This area is known as the Lecrin Valley. The other way is through a deep gorge carved by the Genil River. This gorge is called the Infiernos de Loja. The Granada Basin stretches about 65 kilometers (40 miles) from east to west. It is widest in its eastern part and becomes much narrower near the Infiernos de Loja gorge.
How the Granada Basin Formed
The Granada Basin has been a closed-off valley since the Miocene era. This is a very long time ago, possibly as far back as 20 million years ago. It got its current shape by the end of the Miocene period. At that time, it was like a giant, enclosed bowl that collected water and materials from all the mountains around it.
Sedimentation and Erosion
The most active period of filling this basin was during the Villafranchian age. This was the first part of the Pleistocene epoch, which began about 2.5 million years ago. During this time, the climate changed. It became very dry, which meant less plant cover on the ground. This led to a lot of erosion in the surrounding mountains.
Huge amounts of rock and dirt fell into the basin from the mountains. For example, large piles of material formed near La Zubia. The famous Alhambra in Granada also sits on a similar type of rock formation.
Deepening and Drainage
After the basin filled up, it began to sink deeper. This happened because the weight of all the new material pushed down on the older layers of earth. At the same time, the mountains around the basin started to grow taller.
The basin, which was once like an inland lake, began to drain its water. The Genil River and its smaller streams started to flow out through the Infiernos de Loja gorge. As the river flowed, it carved out its path. After a major climate crisis in the Quaternary period, river terraces formed. These are like steps along the riverbanks, showing old levels of the river.
The deepening of the basin near the Sierra Nevada mountains created a flooded area. This area was between the towns of Santa Fe and Granada. Also, a mass of gypsum clay pushed up from underground near the town of Láchar. This made the area from Láchar to Granada more prone to flooding. It also split the original Granada Basin into two parts: the main Granada Depression and the Pasillo or Depression of Loja.
See also
In Spanish: Depresión de Granada para niños
