Natural wonders of the Maghreb in Morocco

Sebastian Lüning (UK) 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. Fig. 1. Location map of geological sites mentioned in this article. 1) granites near Tafraoute, 2) algal mats near Ouarzazate, 3) Ordovician glaciation, 4) Silurian graptolithic shales, 5) Orthoceras limestones, 6) Devonian mud mounds and Merzouga sand dunes, 7) Triassic Argana river sands, 8) Cascades d’Ouzoud, 9) Friouato karst shaft, 10) Dades Gorge, 11) blowholes near Agadir and Cretaceous oysters, 13) Amesfrane cliff. 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 … Read More

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Essential collectibles #4: Orthoceras nautiloids

Dr Neale Monks (UK) Orthocone nautiloids, loosely referred to as Orthoceras in the trade, are another type of fossil exported from Morocco in large numbers, like the Diacalymene trilobites discussed earlier in this series. Both their common and scientific names refer to the long, narrow, conical shape of their shell, the Greek prefix ‘ortho’ meaning ‘straight’, and contrasting them with most other nautiloids (not to mention ammonites) which have coiled shells instead. Orthocones were a very common type of cephalopod during the Palaeozoic, some types reaching enormous sizes, well over six metres long, making them among the largest animals in the seas at the time. The ones sold to fossil collectors are generally smaller than those giants, anything up to 30 cm being typical, and because they’re usually sectioned and polished before sale, it’s easy to see some of their key anatomical features. For a start, there’s the chambered external shell. Partly the shell was there to provide protection from predators, but the shell was also important for providing neutral buoyancy. As it grew the orthocone nautiloid would add additional chambers, allowing gases to diffuse out of its bloodstream and so replace the water in the chamber. The basic idea was not dissimilar to how a submarine works in terms of being able to hold its position in midwater without sinking or rising, but unlike a submarine nautiloids aren’t able to rapidly change the amount of gas and water in the chambers, so they couldn’t use their shells to quickly … Read More

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Monster nautiluses of the Palaeozoic

Neale Monks (UK) The handful of nautilus species found in seas today are small, retiring animals that scavenge about at night, foraging for carrion and crustacean moults. However, nautiluses were not always so insignificant and, during the first half of the Palaeozoic Era especially, nautiluses were major predators, occupying the same niches in Ordovician and Silurian seas as sharks do today. The first nautiluses Compared to their cousins, the ammonites, the Palaeozoic nautiluses are relatively unfamiliar animals. That is a shame, because they are truly remarkable, in all likelihood being the first really big predators to evolve on Earth. But, to understand how they reached the top so quickly, we need to look back at their ancestors, the floating ‘snails’ of the Cambrian. Nautiluses are the most primitive of all the cephalopods, the group of molluscs that also includes squids, octopuses, cuttlefishes, ammonites and belemnites. Nautiluses appeared during the Late Cambrian, about 500Ma, but what their ancestors might have been remains uncertain. The traditional explanation is that the first nautiluses, such as Plectronoceras exile, were derived from monoplacophorans. These are snail-like molluscs today, limited to a few species only found in relatively deep water, but in the past they were quite diverse. Although they look a lot like a limpet, their internal anatomy is distinctive, with unusual features such as serial repetition of the gills, kidneys and reproductive organs along the body. At least some monoplacophorans had chambered shells. The Late Cambrian animal, Knightoconus antarcticus was one such species, but, … Read More

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