An introduction to the last 145 M.a. of Moroccan geology
During the Cretaceous, a carbonate-rich sea continued to wash over Morocco and formed limestones and marls. Seventy million years ago, towards the end of the Cretaceous, the sea gradually receded. Rocked by large earthquakes, the seabed was slowly uplifted. Forty-five million years later, Africa collided with Europe. The Straits of Gibraltar found itself in the centre of a tectonic battlefield. The rock layers of Morocco and Spain were compressed between the continents as if in a clamp. The rocks were uplifted several kilometres and the High and Middle Atlas and the Rif Mountains were born.
After the birth of the Atlas Mountains, the process of weathering and erosion began. Water, wind and temperature fluctuations began to take their effect. The resulting debris formed huge fans. Streams transported the rubble downhill in large quantities. In the mountain valleys of the High Atlas, some of the debris hardened. However, here again, the forces of nature got to work, sculpting elegant structures out of it. This is how the imposing cliffs of the Amesfrane, located in a remote part of the High Atlas, were formed.
The high pressures within the mountains have also created an impressive fracture pattern. Subsequently, nature has carved beautiful forms out of the area’s gravelly sand, including shapes like chimneys, towers and mushrooms. The end product of these destructive forces is quartz sand, trillions of grains of which are now blown about the deserts of Morocco to pile up into huge sand dunes. (www.seven-continents.com/morocco.htm - Adapted from Natural Wonders of the Maghreb by Sebastian Lüning).
In Agadir, located in the foothills of the Anti-Atlas Mountains, the hilltop kasbah (see image below) was destroyed in a 1960 earthquake, but its original old wall remains standing. It is in this small hill north of the city where you can see some very well defined bedding. It is this bedding (the layering of the rocks) that is the focus of this simple EarthCache.
The EarthCache:
Look at the layers of rock in front of you and answer the following questions:
1- What is the dip and strike of these layers (approximately) - Follow the links to find out what is and how to measure dip and strike!
2- How thick, on average, are the strata (layers) of rock?
The observation point is near the access road! Watch out for traffic!
The most exciting way to learn about the Earth and its processes is to get into the outdoors and experience it first-hand. Visiting an Earthcache is a great outdoor activity the whole family can enjoy. An Earthcache is a special place that people can visit to learn about a unique geoscience feature or aspect of our Earth. Earthcaches include a set of educational notes and the details about where to find the location (latitude and longitude). Visitors to Earthcaches can see how our planet has been shaped by geological processes, how we manage the resources and how scientists gather evidence to learn about the Earth. To find out more click HERE.