Morocco is a popular tourist destination. Most people travel to the white beaches of Agadir to sunbathe and relax, to watch the magicians on Djemaa el-Fna square in Marrakech, or to go shopping in the UNESCO-protected Osouk of Fes. However, Morocco has much more to offer. Some of the most attractive specimens found at international fossil fairs originate from this country. Morocco is home to exceptionally well-preserved trilobites and attractive Orthoceras assemblages from the Palaeozoic. The beds containing these fossils are systematically mined in the Anti-Atlas. Other fossils, such as goniatites and ammonites, complement the diverse palaeontological national treasure.
These fossils are part of an exciting geological past. This article aims to guide you through the highlights of Morocco’s geological history, exploring the stories behind the country’s natural wonders and its multi-million-year-old inhabitants. Concealed in its spectacular mountain chains are some fascinating snapshots from the past. Our trip will commence at the very beginning of this history and will take us gradually forward through time. We will visit various sites on a route starting in the Precambrian of the Anti-Atlas, in the southern part of the country, and then moving northwards to the Triassic and later periods of the High and Middle Atlas. Where necessary, the journey will involve some hopping about, to enable stratigraphic continuity.
Much of Morocco is covered by mountains. These are exposed scars that are testimony to the awesome power of continental collisions. The Anti-Atlas, soaring as high as 2,500m, dominates the south-east of the country. The High Atlas Mountains rise above central Morocco and are the Alps of the Maghreb. This mountain chain is 700km long and reaches heights of over 4,000m. It remains a formidable barrier and you can count the number of passes through it on the fingers of one hand. North of the High Atlas is its somewhat smaller twin, the Central Atlas and in the far north of the county, the Rif Mountains watch over the straits leading into the Mediterranean Sea.
Precambrian rock melt from the deep
Morocco’s oldest rocks date from the earliest era of the Earth’s geological history: the Precambrian. Granites from this time can be found around the town of Tafraoute, located one kilometre above sea level in the western Anti-Atlas. Nature and her tools – wind, temperature fluctuations and water – have etched the rocks into bizarre forms. Steep, barren mountain slopes surround an ancient granite dome, and the pink granite is shaped into astonishing rock needles, spheres, towers and sugar loaves. The piled stones look as if they could fall down at any moment. The Chapeau de Napoléon (Napoleon’s hat), two kilometres south of Tafraoute, is the masterpiece of this open-air museum. ‘As hard as granite’ – the old saying, seems not to apply here. Granite consists of grains of minerals, between which are tiny cavities that make the rock porous to air and water. The grains are made up mainly of the minerals feldspar, quartz and mica. The water that penetrates the rocks attacks those minerals that are more easily dissolved – feldspar and mica – and causes the granular decay of the granite. However, just as important for the formation of the rock sculptures of Tafraoute is their regular fracture pattern. Cooling and pressure relief in the mountains formed the fractures and joints in the granite. The stone was split into blocks and the corners were slowly rounded off by nature. Chemical weathering penetrated the rock and, layer-by-layer, the outer surface of the granite was eroded away, almost like the peeling of an onion. That’s exactly how geologists refer to it: ‘onion skin weathering’. The shape of the blocks and the stone statues follows the prevailing pattern of the fracture system. The vertical joints, lying close to one another, give rise to the formation of needle rocks, whereas square blocks tend to become spheroidal forms.