Mapping Geosites as Gateways to the Geotourism Management in Central High-Atlas (Morocco)

In the area of Demnate and High-Tessaout valley the outcrops of Palaeozoic rocks end and the High-Atlas limestone begins. It can be a key region for analysing the deformations and relations Palaeozoic basement rock/Mesozoic sedimentary cover. The major rock formations outcropping in the study area are represented in map of Figure 1 extracted from the geological map of Morocco 1:200 000, sheet of Demnate-Télouet (Roch 1941), and described in e.g. Tricart et al. (1972), Jenny et al. (1981), Biron (1982), Jenny, Couvreur (1988) and Michard et al. (2008).

The Palaeozoic basement, deformed during the Variscan orogeny, emerges from the surrounding Mesozoic sedimentary rock layers. It is constituted from base to top by Green olive shales of Cambrian, green shales and sandstone of Ordovician, flyshs with graptolith of Silurian and conglomerate, shales and sandstone of Late visean.

The Mesozoic geological formations overlying the Palaeozoic basement, are from bottom to top: Conglomerate, sandstone and red clay of Permo-Triassic, basalts of Late Triassic, red clay with gypsum and salts, Limestone, Dolomitic-Limestone Coralline Limestone and Marls, sand-stone and red conglomerate of Lower Jurassic, marls and Limestone of Middle Jurassic, and red sandstone and conglomerate of Late Jurassic.

The Cenozoic covering the Mesozoic formations, is composed of sandstone and conglomerate with pink cement of the Oligocene to Miocene.

Geomorphology of the study area is the result of various factors and morphogenetic processes, namely structural, karstic, periglacial and nival that have shaped the landscape through time. The geomorphological map of the study area is realized from the geological map of Morocco 1:200 000 sheet of Demnate-Télouet and geomorphological maps of Couvreur (1988) (Fig. 2). The geomorphological landforms of the study area are described below.

Fig. 2

Litho-structural landforms: The main landforms of the central High-Atlas are created by alpine tectonics that folded sedimentary sequences, generating large synclines and anticlines with SW-NE direction. The anticline hinges have been eroded due to their high altitude and the thinness of the Upper Jurassic deposits. This led an inverted relief which is made by perched valleys in the Lower Jurassic limestone and sometimes by deep valleys cut into the Paleozoic rocks.

Karstic landforms occupy a significant area in the central High Atlas. The carbonate formations have been subjected to chemical weathering, which created dispersed or grouped karst landforms. Two types are observed; namely, the Quaternary lapies, swallow holes and sinkholes having decametric size, and the kilometer-scale uvalas and poljes that are older.

Periglacial landforms: The evolution of the high Atlas has involved, since the Plio-Villafranchian, periglacial processes responsible for the formation of gelifracts (cryoclastic debris) whose accumulation has led to the formation of scree cones and scree slopes. The latter occurs at the base of steep slopes built of Triassic to Lower Jurassic carbonate rocks. The freeze-thaw activity is responsible of solifluction that is marked by the formation of gradual mass of marls and clays wasting slope.

Nival landforms are formed by rock fragments resulting of physical rock disintegration and veiling the slopes and by reshaped talus deposits.

In the last two decades, several authors have proposed approaches to establish specific geoheritage maps, i.e. Regolini-Bissig (2010) and Comănescu et al. (2013) for interpretative maps, Erhartic (2010) for conserving geoheritage map, Ilieş et al. (2011) for geoheritage map, Coratza et al. (2008) for geo-hiking map, Serrano and Gonzales Trueba (2011) for environmental education and landscape leisure, Fuertes-Gutiérrez and Fernández-Martínez (2012) for geosites maps and Zwoliński (2009) for geodiversity maps. From our perspective, it is the interpretative map that is most relevant for promoting geotourism in the Demnate and High-Tessaout valley, in the fact that it presenting a balanced proportion between scientific and touristic information. It is used to communicate geoscientific themes with non-specialist public to provide the opportunity to understand geomorphological or geological phenomena, formations or evolution. Tourist information is of secondary importance as mentioned by Rodrigue et al. (2011). The map is derived from the appropriate simplifications of the geomorphological map. It combines the most evident geological and geomorphological natural and anthropic features which can be observed and recognized even by non-experts and touristic information as suggested by Erhartič (2011).

In the analyzed area, 27 geosites have been documented and have geoscientific significance, and only few of them are well preserved. These sites have formed the basis of geoheritage elements inventory. The information of these geosites are taken from work field and literature (Couvreur 1988, Jenny, Couvreur 1988, Mombarron, Mombarron 2015) (Table 1). They come from five different morphogenetic agents that reflect the geodiversity of this mountain area, including sixteen geomorphological geosites or geomorphosites, four sedimentological geosites, three paleontological geosites, one igneous and volcanic geosites, and three stratigraphic and structural geosites. Further, six of all geosites belong to M’goun Geopark. All these sites are summarized in Table 1. From an educational point of view, these geosites are valuable examples of the evolution of central High-Atlas. They have been selected by taking into account some fundamental features such as geological relevance, good quality of the exposure and easy access, based on their scientific value, representativeness, high aesthetic value, rarity and potential for both education and tourism.

The geotouristic map produced in this study indicate three geotouristic itineraries connecting the most 27 spectacular geosites and high mountain landscapes of Demnate and High-Tessaout valley in Moroccan central High-Atlas (Fig. 4). This geoheritage and geosites represents the background of the three proposed geotourism itineraries as mentioned by Rodrigues et al. (2011). Therefore, tourist information is added to facilitate the visit of the most remarkable geosites and contains information about tourist offices, access, accommodation facilities, leisure areas, belvedere points, viewpoints. Finally, cultural sites such as the main historical and cultural monuments are added to increase the attractiveness of the visited regions as revealed in his broad definition of geotourism (Rodrigues et al. 2011). This is justified because the analyzed area is famous and much-visited thanks to its beauty and cultural legacy that includes traditional water mills, fortified home (Kasbah) and old collectives granaries that were built by the indigenous Berber tribes.

Fig. 4

The proposed geotouristic itineraries connect a succession of impressive outcrops distributed between the western part and the centre of central High-Atlas whose age ranges from Precambrian (PII) to Holocene. Furthermore, it offers the opportunity to visit some of the most interesting and best exposed geosites. Each itinerary has been conceived in such a way as to illustrate the geological and geomorphological evolution of this mountain. The geotouristic itineraries and trails proposed are approximately 160 km in length and can be completed in 3 days, one day each. These geotouristic routes can be reached out by car, bike, mule or geo-hiking.

1^st Geotouristic itinerary: From Demnate city to Megdaz village, there is an option that combines traveling by car or biking. Taking this route tourists can pass, in one day, the most stunning geosites of central High-Atlas. The starting point is located in Demnate city centre. This itinerary includes the important historical monuments such as the Kasbah and the town walls with its gateway. Furthermore, the area entails Bougrarte potters, as well as the palace of the sons of King Ismail.

This stop is dedicated to the natural bridge of Imi-n-Ifri (Fig. 5), which is the most remarkable geosite of the area. It is located 6 km northeast of the centre of Demnate at about 1000 m a.s.l. Tourists do not have to veer far off the paved road leading to Iouaridene to see the natural bridge. The Tissilt River drains the waters of the large Tisgui syncline located to the southeast of the site. This river has sliced for thousands of years the thick rock bar of gray limestones and dolomite of the Imi-n-Ifri formation of Lower Jurassic (Sinemurian-Pliensbachian). Much later, during the Pliocene, the freshwater springs emerged from the aquifer through both its banks. The spring water charged with dissolved carbonates that may be precipitated as open-air deposit, had gradually built masses of traver-tine deposits forming a natural rock bridge over a gorge (Monbaron, Monbaron 2015). Under this natural bridge, following a path through the travertines, we can admire the concretions and stalactites taking various forms, while we can also admire against the light from the gorge that looked like a map of Africa. This geo-monument is very fragile; the most prominent danger is due to the heavy traffic which transits on the bridge.

Fig. 5

This stop is linked to one of the most famous geosites within central High Atlas and the Geopark M’goun. The dinosaur footprints and tracks of Iouaridene geosite are located 10 km NE of the city of Demnate; the site is indicated by an information panel. They represent traces of the dinosaurs that inhabited these areas during the period from the Lower Jurassic to the Lower Cretaceous between 180 Ma and 80 Ma. This site shows more than a dozen of footprints and two tracks of agile Theropods (Fig. 6A) as well as heavy Sauropods (Fig. 6B). The dinosaur footprints and tracks of Aït Iouaridene constitute scientific heritage of worldwide importance. They are printed on tilted layers of siltstones of the Iouaridene Formation (165 Ma). This siltstone showed desiccation cracks and sedimentary structures of bidirectional ripple marks. All above paleontological and sedimentological features are characteristics of the shallow lagoon depositional environment with hot and humid climate (Monbaron, Monbaron 2015).

Fig. 6

In this stop, a normal fault of direction N70 called the Atlas direction appears clearly (Fig. 7A). It affects stratified limestones of Jbel Rat Rock Formation. These limestone layers also present a distinctive tepee sedimentary structures (Fig. 7B) consisting of a fold that resembles an inverted depressed V in cross section. These sedimentary structures are the result of sedimentation in a basin with evaporates such as gypsum and salt.

Fig. 7

This stop is located 19 km from the natural bridge, at the bottom of the river canyon within the Til Mountain. The canyon is the result of constant erosion of the limestone of the Lower and Middle Jurassic by the Asif-n-Ghasf River. The Asif-n-Ghasf River flows into the canyon from the southeast to the northwest between 1 640 m and 1 498 m a.s.l., over a length of about 3 km. The water pressure of the river cut deep into the syncline of Til generating a steep slope of approximately 350 m high. Scree covers these slopes; the rock fragments came from the overlying limestone cliffs. The Til Mountain is that of a perched syncline folded during the Alpine orogeny. The syncline shows northeast-southwest axial direction. It consists of the Lower Jurassic limestone resting on red siltstones, sandstone, and basalt of the Late Triassic age (Couvreur 1988).

In this stop, the route leaves the Triassic sedimentary cover and passes above the Palaeozoic basement having a total area of 400 km². The Paleozoic basement correspond to the imbricate thrust sheets developed under the influence of the Variscan orogeny. The Lower Jurassic carbonates overlay the Triassic sandstones, siltstone, and basalt. The horizontally parallel strata of sedimentary Triassic rock overlay the Paleozoic thrust sheets by angular unconformity which are gaps in the geologic record that may indicate episodes of crustal deformation especially during central High-Atlas orogeny. The Til Mountain is a perched syncline of the Lower Jurassic limestone that overlays the Triassic rocks and Palaeozoic bedrock and has some stunning cliff. This stop represents a key area for the study of the relations between the Mesozoic sedimentary cover and the Palaeozoic basement and the High-Atlas orogeny (Monbaron, Monbaron 2015).

2^nd Geotouristic itinerary: The second itinerary is a one-day trip. It serves as a link between Megdaz village and the waterfall of Megdaz. This itinerary may just be one of the best geo-hiking trails in this area, traveling by mule is an option.

The proposed itinerary has been established due to a desire to present the peculiarities of this area. This stop is one hour’s walk along the trail and leads to a type of sedimentary structure of cross-stratification in Triassic sandstones (Fig. 8A), which consists of sets of laminae that are inclined to the main horizontal bedding planes. These sedimentary structures are not common because they require the current to be equal in both directions, which rarely happens in nature. The time represented by each cross-stratified layer is likely to be many years (Nichols 2009). On the same sandstone rocks of the Triassic age, there is a rock engraving in the shape of a semicircle. This rock engraving is explained by the nomadic shepherds as a copy of the original rock encountered in this region. On this stop, tourist will also see a limestone rock block of Lower Jurassic detached from the above carbonates, on which ten footprints and one track of the paws derived from unknown wild mammal animals are present (Fig. 8B).

Fig. 8

This stop is proposed to see the most important geodidactic angular unconformity in central High-Atlas (Fig. 9). This major angular unconformity of Megdaz is between the rocks of Palaeozoic and Precambrian age. The Palaeozoic inlier is a thick series of schists and quartzites of the Cambro-Ordovician of Aït Tamlil formation which is separated by angular unconformity from rhyolite of the Precambrian (PIII) and quartzites and schists of Precambrian (PII) (Jenny, Couvreur 1988).

Fig. 9

The last stop of this trail concerns the most remarkable canyon (Fig. 10A) and waterfall (Fig. 10B) in the area. The canyon of Megdaz has a length of about a dozen kilometres and a depth of approximately 100 m in some places. The most important feature of this geosite is the genetic type of rock in which the canyon has developed. In many cases in central High-Atlas and the world, deep narrow canyons are developed in carbonates, limestone and dolomites. In this case, these are metamorphic rocks, namely schists, psammite and quartzites. The canyon is originated through a combination of tectonic features and long periods of fluvial erosion. This is because the direction of this canyon follows a fault zone. The waterfall of Asfdar is developed in the hidden canyons of Megdaz. It is the result of a vertical slope break of a height more than 15 m in the watercourse of Megdaz River. Huge bare cliffs border the waterfall have been carved in the Palaeozoic basement rocks (Couvreur 1988).

Fig. 10

3^rd Geotouristic itinerary: From Aït Ali-n-Attou in the east to High-Tessaout canyons in the west, passing through Ichebaken and Amezri, the most beautiful villages of the High-Tessaout valley are present. This itinerary is running along the bed of the Tessaout River, mostly between two vertiginous cliffs of several hundred meters high. The river shaped its canyon in the Lower Jurassic limestone.

This village is located at Azilal and Ouarzazate provinces border. It was chosen as a stop because it contains remarkable landforms: alluvial fans and scree cones at the foot of outstanding cliffs, Fairy chimneys or earth pyramide, water spring forming waterfall.

The water spring of Tlat-n-Tazart is karstic water spring. Its water comes from the base of carbonates of the Lower and Middle Jurassic (Couvreur 1988). It forms a spectacular water-fall about 30 m high on the Tignousti Mountain slop in the right side of Tessaout River.

Fig. 11

In this village, there are three remarkable geoheritage elements. One is scree slope on the left bank built of rock fragments derived from fault breccias, because the High-Tessaout valley above Amezri follow a fault zone related to alpine tectonic (Fig. 11D) (Couvreur 1988). Further, there are two alluvial on this right bank. Furthermore, in this village the valley meanders around the high cliffs in limestone rocks of the Lower Jurassic which overhang its two banks, generating a remarkable canyon with vertical cliffs whose height exceeds than 100 m, and contrast abruptly with the smooth slopes which one will meet a little further upstream (Couvreur 1988).

The inaccessible canyons of High-Tessaout valley (Fig. 11E) are carved by the Tessaout River which flows along the axial zone of the perched syncline between the M’goun mountain in the south and Tarkeddid and Tignousti mountains in the north. Then it flows westward for a few km between 2 950 and 2 800 m a.s.l., in the opposite direction of the rise of the synclinal limb of Ighil Mgoun and Tarkeddid. The fluvial erosion on this synclinal limb generates one of the most notable canyons of the central High Atlas – High-Tessaout canyons. This latter has been carved in the carbonates of Aït Bou Oulli and Jbel Rat rock formations of Lower Jurassic age. Its depth is more than 500 m, and with a length of about dozen kilometres (Couvreur 1988).