An Inventory of Geoheritage Sites in the Draa Valley (Morocco): a Contribution to Promotion of Geotourism and Sustainable Development
le géoparc du jbel bani - tata

An Inventory of Geoheritage Sites in the Draa Valley (Morocco): a Contribution to Promotion of Geotourism and Sustainable Development

By Mohamed Beraaouz1 & John Macadam & Lhoussaine Bouchaou & Moha Ikenne & Richard Ernst & Tarik Tagma & Moussa Masrour

Abstract

 This study describes the geoheritage sites in the Draa valley between Ouarzazate and M’Hamid in south-eastern Morocco. This area is remarkable for its diverse landscapes and very interesting geological, geomorphological, and archeological sites that could be used to explain the history of the earth as well as regional climate changes both to tourists and to the general public. The educational aspects of these sites are highlighted; in order to emphasize their magnificence and their scientific interest, the area includes many sites with the Ordovician Fezouata Biota. Information needs to be provided in various media, as geological and archeological booklets, guidebooks or interpretive panels at the geosites. The approach presented below can serve as a model for sustainable development of geotourism, for preservation of geological and archeological heritage, and also as a contribution toward establishing a geopark in the south-eastern provinces of Morocco.

Introduction

Located in south-eastern Morocco, the Ouarzazate and Zagora provinces belong to the Anti-Atlas Mountains and its sub-Saharan regions (Fig. 1). These provinces are characterizedµ by an arid climate, without any major industry or intensive agriculture. However, the diversity of landscapes including the Anti-Atlas area, Tabanit and Bani mountains, and desert uplands with acacia, mud brick ksours, kasbahs, and green oases make these two provinces an attractive tourist destination. The number of hotels, inns, guest houses, and camp-sites has continued to increase in recent years and reflects the growing attraction of these Saharan regions for tourists. The number of tourists is constantly increasing, mainly coming from European and Asian countries. The absence of vegetation in the two provinces allows the outstanding geology to be well exposed, and this makes the area an ideal destination for geologists from across the world either for thematic studies or for educational field trips, but the excellent exposure also means geological features and structures can be explained to nongeologists—Bgeotourists^ (Beraaouz 2011).

Research carried out by geologists during the last two decades has provided a better understanding of the geological history of the Anti-Atlas and surrounding regions (Walsh et al. 2002; Gasquet et al. 2004; Thomas et al. 2004; Hefferan et al. 2014; and references therein). In the Anti-Atlas, old Paleoproterozoic basement rocks are unconformably overlain by a Neoproterozoic (Cryogenian and Ediacaran; 1000-541million years old) cover series. The basement consists of a siliciclastic series intruded by granitoids that are dated 2050–1760 million years old. The Cryogenian to early Ediacaran rocks of the Bleida and Saghro Groups are respectively attributed to passive margin and oceanic and island-arc formation stages of the Pan-African events. The late Ediacaran series (Ouarzazate Supergroup) is mainly a syn- to post-tectonic, continental volcanic and clastic sequence associated with post-collisional granitoids (Thomas et al. 2004; Toummite et al. 2012). The transgressive series of the Taroudant Group forms the transition to the Paleozoic series. To the south, the Bani and Tabanit jbels form two parallel low mountains composed of quartzites and sandstones. They are cut by grooves (or ravines) called foums. The jbels are separated by feijas, quaternary plains underlain by shales which form a valley bounded by palm-trees along the Draa wadi. In addition to this rich geological heritage, the region contains various geomorphological forms and important areas of archeological and cultural heritage. Unfortunately, this cultural and scientific richness is not sufficiently showcased, as yet, by professionals. Tourism may be the best way to promote this heritage, but both the development of the region for current generations and the preservation of its rich heritage for future generations need to be considered. Reynard (2004) defines geotourism as a set of practices, infrastructure, and products to promote the earth sciences by tourism. It is a type of tourism through which tourists can acquire information and a clear understanding of geological and geomorphological processes in the area concerned (Malaki 2006; Komoo and Kadderi 1997). The term geotourism has also been defined as tourism where the tourist is interested in both the natural and cultural aspects of the planet and is mindful to minimize their own personal impact. In this case, the Bgeo^ of geotourism refers to the whole planet rather than merely the planet’s geology: this definition has been closely associated with National Geographic magazine, and also has been adopted, particularly in the Arouca Declaration (European Geoparks Network 2011), by many geoparks globally as more relevant to the interest they wish to engender in all aspects of their area.

Fig. 1 Map of proposed geosite locations Geotourism, in the restricted sense, will diversify what is offered to tourists and increase the attractiveness of these two provinces, but it is probable that most visitors will be interested in more than the geology.

The development of geotourism products requires a good working relationship between local elected officials, scientists (including geographers and geologists), tourism stakeholders, and professional interpreters (who may, or may not, also be geologists) (Beraaouz 2011). The basic principles of modern interpretation were first set out by Freeman Tilden, working in the USA’s National Park Service (Tilden 1957). In 2015, the IUCN Geoheritage Group stressed that interpretation is not merely the transmission of information, and that communication of geoheritage needs to be in the language of civil society (pers. comm. Roger Crofts, ProGEO Conference 2015, Reykjavik, Iceland), rather than in the special language (Bjargon^) of geoscientists (see also European Geoparks Network 2011 and UNESCO 2016). In the years since Tilden’s seminal work, accepted professional best practice in interpretation has been developed by authors such as Mike Gross, Sam Ham, and John Veverka (Gross et al. 2006; Ham 2013; Veverka 2015) and much Binterpretation^ for geoheritage can be seen to be inappropriate for the supposed target audience of non-geologists. Humor and cartoons have rarely been used in communicating for geoheritage, although there are exceptions (Macadam and Lacković 2010), and while geological books with cartoons for children are often about dinosaurs (and too often with little intended or achieved scientific credibility), some authors have worked on communicating more challenging topics with integrity, e.g., karst (Lacković 2008) and the geology of a whole UNESCO Geopark (Oki Islands Global Geopark Promotion Committee 2014). To achieve scientific integrity of interpretation, with or without cartoons and humor, scientists will need to provide the information in their specialisms for education trails, interpretive panels, booklets, and guidebooks.

This contribution will allow interpreters (who may also be science-trained), elected officials, and tourism stakeholders to develop tours in the region of Ouarzazate and Zagora cities that include visits to geosites and thereby help promote geosciences and public awareness of the importance of the preservation of these sites. Promotion of these geosites will also cause visitors to think more broadly about changes to climate and landscape on our planet. According to Strasser et al. (1995) and De Wever et al. (2006), geosites are portions of the geosphere delimited in space and with a particular geological, geomorphological, or geo-ecological significance. They are important witnesses of Earth history and collectively give an overview of landscape and climate evolution. Panizza and Piacente (2003) defined a geosite as all geological objects having scientific, historical cultural, esthetic, or socio-economic value. Geosites have also been defined in the context of the ProGEO/IUGS Global Geosites Project as of special importance for science (Ischchenko et al. 1998; Ishchenko and Gerasimenko 1999), but on the other hand, some authors are using the term geosite for any geological outcrop (i.e., Bgeological site^ = Bgeosite^): in this paper, we use Bgeosite^ in the sense of the first two definitions though several of the geosites, particularly those with Fezouata Biota, clearly are candidates for Global Geosite status, as evidenced by the success of the RALI (Rise of Ancient Life) Conference in Marrakech in 2015 which attracted participants from over 20 countries.

The term Bgeopark^ likewise has a range of definitions and has been used to refer to a space as small as an outcrop up to a large geographical area whose management can contribute to sustainable development. Since November 2015, UNESCO has had a formal designation of UNESCO Global Geopark, along with the already well-known designations of World Heritage Site and Biosphere Reserve. UNESCO Global Geoparks Bare single, unified geographical areas where sites and landscapes of international geological significance are managed with a holistic concept of protection, education and sustainable development^ (UNESCO 2016) UNESCO welcomes the inclusion of an area’s natural and cultural heritage in a geopark. Several countries (e.g., China and Germany) have National Geoparks from which a few have become UNESCO Global Geoparks. Many countries (e.g., Japan, Ireland, and Italy) also have national geopark committees which work to identify and develop new geoparks, helping them to function as a Baspiring geopark^ before formal application to UNESCO. But the desire to become a geopark—and the application dossier—has to come from the local community (UNESCO 2016). Even if an area does not become a geopark, the process of auditing of sites (as begun informally in this paper), and planning management and popularization should result in a useful plan for further progress (Macadam 2003; Macadam et al. 2006). In this paper, we use the word Bgeopark^ in the sense of a large geographical area which could develop sustainably through the Baspiring geopark^ stage to then apply to UNESCO i.e., we use the term Bgeopark^ in the same way that UNESCO does.

The provinces of Ouarzazate and Zagora are very rich in exceptional geological and geomorphological sites (geosites) that could be of major interest to tourists and should be included in the tours of travel companies.

The main purposes of this paper are the following:

& to provide an inventory of the main geological and geomorphological geosites in Ouarzazate and Zagora provinces;

& to demonstrate the importance of these exceptional sites for geotourism and to indicate other natural and cultural heritage;

& to briefly explain how these geological, geomorphological, and cultural sites could be promoted to curious visitors to increase their appreciation of the importance of both the cultural and scientific heritage.

Geosites along the Draa Valley is the longest valley in Morocco. It is irrigated by the El Mansour Eddahbi reservoir, which is located a few kilometers from Ouarzazate city and stores water from Ouarzazate and Dades wadis. From the dam, water in Draa wadi travels for nearly 200 kmbetween the towns of Agdz and M’Hamid, in the Anti-Atlas mountains, irrigating a succession of palm oases, fields, and impressive old adobe ksours.

Beyond M’Hamid, Draa wadi is lost in the sand hills of the former Iriki Lake. Along Jbel Bani, the Draa valley is rich in exceptional landscapes and has diverse geological, geomorphological, archeological, and historical sites (Fig. 1).

Stromatolite Geosite of Amane-n’Tourhart the stromatolites of Amane-n’Tourhart outcrop on both sides of the national road P31 connecting Ouarzazate to Zagora cities (Fig. 1). The site is located about 25 km south-east of Ouarzazate at N 30° 47′ 33.0″ and W 06° 43′ 19.7″.

These stromatolite limestones were reported first by Raguinin 1948 (in Choubert and Faure-Muret 1970). They form an outcrop which has proved to be the most spectacular Conophyton site in the Anti-Atlas (Choubert et al. 1952a, 1952b) with an exposure extending over about 0.04km2 (4 ha) and a thickness of 10–20 m.

Stromatolite limestone units are interbedded with andesite, rhyolite, tuff, and conglomerate of Jbel Tinghouy in the east, and andesite, tuff, and sandstone of Jbel Tissouktai in the west.

The sequence belongs to the Ouarzazate Supergroup of the upper Neoproterozoic (Fig. 2a); the three separate limestones Bbenches^ with stromatolites are clearly shown on the lithological log (Fig. 2b) for the Amane-n’Tourhart site.

Stromatolite domes outcrop in limestone deposited in a shallow sedimentary basin, most likely in a lacustrine environment.

They take the form of a lamellar structure that developed from the accumulation of carbonates or sand grains by felting of cyanobacteria. Stromatolite colonies are grouped into sub-circular or sometimes elliptical domes which are 5–60 cm in diameter and up to 1 m in height (Fig. 3a), with well preserved lamellar structure (Fig. 3b). The domes are outlined in shiny black patina and have regularly spaced fractures filled with red ochre. The importance of the site is both in its wonderful visual appearance and for its scientific importance. This site can be related to the role of stromatolites in early life on Earth.

The Formation of Stromatolites Stromatolites are interpreted as organo-sedimentary structures resulting from lithified microbial mats where cyanobacteria are the main contributors; most Proterozoic stromatolites probably accreted by microbial trapping and/or binding (Knoll 2008). Because of morphological similarity, most described Precambrian microfossils have been attributed to cyanobacterial activities (Golubic 1991; Golubic et al. 2000; Knoll 2008).

In the Amane-n’Tourhart geosite, the cyanobacteria have developed as follows: initially, some precipitation of calcareous concretions occurred at irregularities (bumps) in the muddy sediment, caused by a cyanobacteria species (this forms the lower limestone Bbench^). Subsequently, the intense growth of this cyanobacteria species, or invasions by other species, leads to growth of encrusting forms and lamellar tubes because of their biological activity during the day and inactivity during the night. Indeed, after sunset, the cyanobacteria bend over, and suspended sediment, particularly fine-grained sands and silts, settle on these cyanobacteria forming crusts, which then alternate to produce laminations. Regular growth builds both small and large domes. Lake shores receive mud that can disrupt the development of crusts and so cyanobacteria typically flourish in the middle of lakes where waters are sufficiently non-turbid. The role of stromatolites in the appearance of life on earth is very important: cyanobacteria display significant morphological and metabolic versatility (Stal 1991), two attributes that confer on them a great adaptive capacity that positions them as key precursors of early ecosystems.

Whether cyanobacteria were also present in the Archean (>2500 million years ago) is still subject to discussion, but their geobiological impact on Earth history has been crucial.

At some point in the Precambrian, oxygen released by cyanobacterial activity changed from being poisonous to becoming vital and thus changed forever the course of geobiological evolution on Earth (Chacón et al. 2011).

Unlike any other biological group, cyanobacteria triggered major evolutionary events that shaped the biosphere that we see today: cyanobacteria were the first organisms to employ oxygenic photosynthesis, being responsible for the transition of the Earth’s atmosphere from anoxic to oxic (Ehrlich 1981).

The interpretation and promotion of this stromatolite geosite are important for two main reasons: first, because it can be easily integrated into sustainable geotourism development, since it is located near the road between Ouarzazate and Zagora; and second, because the history of the primitive micro-organisms tells an important story about the history of life on Earth.

Promotion of Stromatolite Geosite of Amane-n’Tourhart this site has exceptional exposures of stromatolites in 3-D, as well as such features as ripple-marks. In some views (e.g., Fig.3a), the morphology of these Precambrian stromatolites can be seen to be similar to modern day stromatolites in Shark Bay, Western Australia (which are well-known to viewers of popular science TV programs). It is proposed that possibly two interactive panels be used to develop understanding of the life and death of stromatolites and their role in the geological record.

Fig. 2 a generalized stratigraphic column for the Anti- Atlas Pan-African orogen. PII and PIII are the classic Stratigraphic symbols used on Anti-Atlas geological maps. Modified from Gasquet et al. (2008). B Lithological log for the Amanen’Tourhart Geosite Ordovician Trilobites of Zagora Area In the Zagora area (Fig. 4), the lowest levels of the Ordovician consist of 1500 m of interbedded pelitic and ferruginous sediments of the Outer Feijas Group (Tremadocian to early Darriwilian Stages) (Destombes 2004; Lefebvre et al. 2015).

These form plains called feijas and are overlained by the micaceousvfine-grained sandstones which form 600 m cliffs at Bani Jbel. The sandstones are assigned to the First Bani Group (Early Darriwilian to middle Sandbian) and border the Draa wadi for more than 100 km. The shales of the Ktaoua Group (middle Sandbian and Katian) underlie the depression with the palm oases in the Tagounite area. The Hirnantian Stage is represented by the periglacial sandstones of the Second Bani Group. This series corresponds to the last Ordovician sedimentary cycle (Destombes 2004; Lefebvre et al. 2015; Martin et al. 2015).

Ordovician fossil sites are numerous in the Zagora area (Fig. 1). Below, we mention some verywell-known fossil sites in the Draa Valley.

Exceptional Biota of Lower Ordovician Since 1999/2000, a dozen sites of exceptional preservation have been discovered in the Ordovician of the Moroccan Anti-Atlas (Van Roy 2006; Lefebvre et al. 2016). Half of these sites were discovered in Lower Ordovician units (approximately 478 million years old) in the region of Zagora (central Anti-Atlas); others are located in Upper Ordovician units to the west of Tafilalt and around Erfoud in eastern Anti-Atlas (Van Roy 2006; Lefebvre et al. 2010).

Indeed, the Upper Fezouata Formation (Lower Ordovician) in the Zagora area has revealed an exceptionally preserved biota, not only preserving more than just the hard shells of marine animals but also offering critical insights into the history of life. Such biotas are relatively common in rocks of Cambrian age, but our knowledge of life during the period that follows, the Ordovician, is almost entirely based on the evidence of shells alone (Van Roy et al. 2010). This situation has improved dramatically with the discovery of the Fezouata Biota in south-eastern Morocco, the first early Ordovician exceptionally well-preserved fossil assemblage from a normal, open marine setting. These Ordovician animals show considerable diversity and contain a large number of forms typical of older Cambrian Burgess Shale-type deposits as well as more modern-looking creatures.

The sites have yielded a benthic fauna that was extraordinarily rich and diverse, living on a muddy seabed, before being suddenly buried by an influx of sediment. The soft parts of the bodies have been preserved in the form of pyrite (iron sulfide); the alteration to iron oxide has given to the fossils a beautiful yellow, orange, or brown color (Fig. 5a, b).

These discoveries in Morocco indicate that the characteristics of the Cambrian fauna continued to have a considerable impact on the biodiversity and ecology of marine communities more than 20 million years later, into the Ordovician. In addition, the presence of a number of advanced animals, like horseshoe crabs, in the Fezouata Biota indicates that these groups had radiated into more diverse species much earlier than was previously thought, before the beginning of the Ordovician. Some indication of the richness of the fauna is shown by the black-and-white reconstruction (Fig. 6) of a dead anomalocaridid lying in an eocrinoid meadow (Lefebvre et al. 2016). The artist, pseudonymously known as Madmeg, was guided by 16 scientists for scientific integrity.

The authors provide a key and a comment that the assemblage of scavengers may seem unrealistically diverse but Bsome sites in the Fezouata Shale have yielded multiple specimens from a couple of dozen different taxa from an excavation area less than the size of an average billboard^. Over 160 genera, half of them soft-bodied, have been reported (Van Roy ET al.2015).

Fig. 3 Outcrop of stromatolite cupolas (fossil cyanobacteria about a half a meter in diameter). a View of site. b Close-up view Promotion and Protection of This Geosite The Zagora geosite includes a fauna characterized by its very small size (millimeter to centimeter scale, Fig. 5b) which makes it very vulnerable and easily destroyed. Another risk threatening this heritage is that all these sites contain other fossils, such as trilobites and echinoderms, have a monetary value to fossil dealers. Unfortunately, this leads to the destruction of the tiny and exceptional biota (which is of no interest for merchants) during extraction of the larger fossils (Fig. 7).

Two protective measures must be taken immediately: & the closing of the richest zone in this biota and the prohibition of all human activity that threatens the destruction of the site (particularly the extraction of fossils), and the continuous presence of a guard, as is being done by the Ministry of Culture for the Ait Wazik rock art site in the Tazzarine area, & Improving public awareness of the importance and major scientific interest of the exceptional fauna of these sites.

The Upper and Lower Fezouata Formations These formations (Tremadocian-Floian) located between Jebel Bou Zeroual and the base of Jebel Tibasksoutine to the south-east are mainly composed of pelitic and fine sandstone units totalling 550–600 m (Destombes 2004). These contain some well-known species of trilobites such as Neseuretus sp.

(Vidal 1996) and Asaphellus fezouataensis (Vidal 1996, 1998) (Fig. 8a, b). Examples of partial soft-body preservation of Fig. 3 Outcrop of stromatolite cupolas (fossil cyanobacteria about a half a meter in diameter). a View of site. b Close-up view Fig. 4 Simplified geological map of the Zagora area (modified from„ Destombes 2004; area originally interpreted by Destombes extended using satellite images by second author) trilobites have also been reported (Gutiérrez-Marco et al. 2017).