ORIGINAL ARTICLE

Geomorphological features of the Manengouba Volcano(Cameroon Line): assets for potential geopark development

Ghislain Zangmo Tefogoum & Armand Kagou Dongmo &

David Guimolaire Nkouathio & Pierre Wandji &Merlin Gountié Dedzo

Received: 31 August 2012 /Accepted: 24 March 2014# The European Association for Conservation of the Geological Heritage 2014

Abstract Mount Manengouba is a volcanic complex, agebetween 1.5 and 0 Myr, situated in the Cameroon Line inCameroon, approximately 120 kmNE ofMount Cameroon. Itcomprises some important geomorphological features, ofgeoheritage significance, i.e., geomorphosites, namely, twonested sub-circular calderas, broken cones, crater lakes(Female Lake, Male Lake, and Beme Lake), domes andbasins. The scientific values, aesthetic appeal, and the unique-ness of Mt Manengouba geomorphosites are suitable forgeotourism. However, there are conflicting land-use valuesas its fertile soils favor farming in the downslope areas of thevolcano, and the pyroclastic cones are quarried for pozzolana.While there are field excursions and research programs un-dertaken by Universities to educate the public about itsgeoheritage values, currently, tourism at Mt Manengouba isnot well developed. It is proposed to promote better localenvironmental management of the area, improve roads tofacilitate the accessibility to these geomorphosites, and pro-duce interpretative panels, guide books and postcards to edu-cate tourists on the geological setting and geoheritage valuesof the Mt Manengouba area.

Keywords Geomorphosites . Anthropogenic activities .

Calderas .MountManengouba

Introduction

The Republic of Cameroon is traversed by the CameroonLine, which is an oceano-continental axis composed of vol-canic and plutonic complexes (Fig. 1), oriented N 30°E andstretching from the Gulf of Guinea to Lake Chad (Tchoua1974). There are still periodic volcanic eruptions in this region(Kling et al. 1987; Sigurdsson et al. 1987; Nana 1991; Evanset al. 1993; Tanyileke 1994; Wandji et al. 1994, 2001, 1998;Tchoua et al. 1998, 2001; Njilah et al. 1999; Bardintzeff et al.2001; Ghogomu et al. 2001; Kagou Dongmo et al. 2005;Zangmo Tefogoum et al. 2009, 2011a, 2012a; NechiaWantim et al. 2012). The region is characterized by an equa-torial climate of Guinean type, dominated by about 7 monthsof precipitation (with average of 2,742mm/year) and 5monthsof dry season, with temperatures ranging from 21 °C to 24 °C(Olivry 1986).

Mt Manengouba constitutes a geological heritage dominat-ed by numerous geomorphological features. However, in spiteof its important geoheritage values and the tourist potential inthis region, there have been no systematic studies of thegeoheritage values of the Cameroon Line. Mt Manengoubahas been selected for such a study.

The objective of this work is to identify the values ofgeomorphosites of Mt Manengouba, for (1) its tourist poten-tial, and (2) its environmental management. It is important toraise the level of awareness of the geoheritage values in thisheavily populated area and to implement sustainable manage-ment policies and practices for maintaining the geoheritagevalues of the Manengouba volcano.

In terms of geomorphosites, according to Reynard (2005)and Grandgirard (1997), a geomorphosite is any part of the

G. Zangmo Tefogoum (*)Department of Earth Sciences, Faculty of Sciences,University of Maroua, P.O. Box 46, Maroua, Cameroone-mail: zangmotefogoum@gmail.com

G. Zangmo Tefogoum :A. Kagou Dongmo :D. G. NkouathioDepartment of Earth Sciences, Faculty of Sciences,University of Dschang, P.O. Box 67, Dschang, Cameroon

P. WandjiLaboratory of Geology, High Teacher Training School,University of Yaoundé 1, P.O. Box 47, Yaoundé, Cameroon

M. Gountié DedzoDepartment of Life and Earth Science, High Teacher TrainingCollege, University of Maroua, P.O. Box 55, Maroua, Cameroon

GeoheritageDOI 10.1007/s12371-014-0109-9

Earth’s surface that is important for the knowledge of Earth,climate and life history. Panizza and Piacente (1993, 2003)and Quaranta (1993) define geomorphological sites ofgeoheritage significance as landforms and processes that haveacquired a scenic/aesthetic, scientific, cultural/historical and/or a social/economic value due to geological, geomorpholog-ical, historical and social factors.

Geological context

The evolution of Mt Manengouba is due to successive extru-sion of two volcanoes (Elengoum and Eboga) from 1.55 to0 Myr on an uplifted granite-gneiss basement of 800 m relief,located at about 120 km NE of Mt Cameroon. The MtManengouba complex covers an area of 500 km2 and occursbetween the Tombel and Mbo grabens, located at the South-Eastern external slopes of the Eboga caldera, betweenLatitude 04°49′ and 05°15′ and Longitude 09°42′ and 10°10′(Kagou Dongmo et al. 2005). The maximum height of thevolcano is at 2,411 m. Mt Manengouba is surrounded byplutonic-tectonic related geomorphological units such as the

Ekomane cliffs to the north (1,685 m), Mount Bakossi to thewest (1,678m),Mount Koupé to the south-west (2,064m) andMount Nlonako to the south-east (1,825 m).

Mt Manengouba is a polygenic volcanic complex charac-terized by adventive fissural volcanic activity giving rise toaround 70 strombolian cones, of which some were initiated byphreato-magmatic explosive events (Kagou Dongmo et al.1998). Numerous lithologic units are distributed in MtManengouba such as basalts, hawaiites, mugearites,benmoreites, trachytes, dolerites and pyroclastic ejecta(scoria) (Figs. 2 and 3). The outcrops of such rocks result inthe development of several geomorphological units and giverise to the uneven topography of Mt Manengouba.

The geomorphological features of Mt Manengouba

In general, Mt Manengouba has a high geodiversity, inparticular a high lithological diversity. The lithologicaldiversity and the tectonics have been the main influencein developing the distinctive geomorphological features ofthis area (Meireles et al. 2002; Pereira et al. 2004a, b). In

Fig. 1 Cameroon Line (CL) inAfrica (1); location of MtManengouba in the CL (2) (fromNkouathio et al. 2008, modified)

Geoheritage

Mt Manengouba, as well as in other volcanoes along theCameroon Line, tectonism has been underlined by erup-tive events and their volcanic products (Tchoua 1972;

Marzoli et al. 2000; Zangmo et al. 2011b; Gountie et al.2011). These events created five major volcanic land-forms, namely, calderas, cones, domes, cliffs, and lava

Fig. 2 Geological map of MtManengouba. 1 alluvium; 2recent adventive strombolianvolcanoes, with cones andbasaltic flows; 3 diatremes-relatedhyaloclastites in the Ebogacaldera and at Djeu-seh; 4mugearite extrusions in the Ebogacaldera; 5 piles of basalt andhawaiite flows of the Ebogamiddle and lower flanks; 6 maficto intermediate lavas and tephrasof the Eboga central edifice; 7intermediate to acidic (trachytes)lavas of the Elengoum volcanoemplaced before the Eboga; 8 oldtrachytic outpourings, mainlyignimbritic; 9 relative substratummade of Mio-pliocene basalticplateau flows; 10 pre-volcanicCenozoic intrusion of syenite; 11Precambrian granito-gneissicshield; F fault; FS fissural system;C caldera scarp (from KagouDongmo et al. 2005)

Fig. 3 Geological cross section of the Mt Manengouba (symbols are same as in Fig. 2)

Geoheritage

plateaux (Wandji 1995; Kagou Dongmo et al. 2010), asexemplified by the volcanic terrain in the Park of FogoIsland, Cape Verde by Costa (2011).

Geomorphosites are only considered as the result of humanvaluation (Reynard and Coratza 2013). To assess thegeoheritage significance of the Mt Manengouba landforms,we undertook a literature review of the criteria to determineintrinsic, scientific, and additional values (ecological, aesthet-ic, economic, and cultural) used by Gray (2004), Pereira et al.

(2006), Pereira et al. (2007), Reynard et al. (2007), Reynard(2008) and Ilies and Josan (2009) to assess any potentialgeomorphosites. The geomorphosites of geoheritage signifi-cance in the Mt Manengouba region include calderas, brokencones, crater (and their lakes), domes, and basins.

Calderas

Mt Manengouba stands as an example of a Hawaiian shield.At its summit, there are two sub-circular nested calderas:Elengoum and Eboga (Fig. 4). The largest is the Elengoumcaldera, some 6 to 7 km in diameter, but its margins are nownot everywhere clear. The floor of Elengoum is occupied bythe smaller Eboga caldera, which is well shaped and is 4 to5 km in diameter. The floor of the Eboga caldera is slightly flatand is at about 1,900 m in relative relief.

Cones

Volcanic cones result from the accumulation of ash, lavas, andbombs, erupted through the vents of a pre-existing scoria cone(Costa 2011). Mt Manengouba has around 70 cones (KagouDongmo et al. 1998). More than three-quarters of these arebroken (Figs. 5 and 6). Broken cones result from lavas thathave erupted downslope of pre-existing normal cones, and arecomposed of volcanic ejecta (bombs, cinders and scoria). Theslope of a cone will slide because of the incoherent nature ofthe volcanic ejecta (Kagou Dongmo 1998).

Crater lakes

The Eboga caldera is characterized by two major craterlakes (Female Lake and Male Lake). Female Lake (Fig. 7)is the larger one, some 22 ha in area and 168 m deep. Thesmaller one is Male Lake (Fig. 8), 2 ha in area and 92 mdeep (Kling 1988).

Fig. 4 The Mt Manengouba summit. 1 Elengoum volcano and its calde-ra; 2 Eboga volcano and its caldera; 3 crater lakes; 4 caldera boundaries; 5adventive phase flows; 6 broken cones

Fig. 5 Two cones located in theSouth-western bottom of theEboga caldera

Geoheritage

Beside both lakes, in a SW–NE direction, lies Lake Child(Fig. 9). This lake is shallow and seasonal, recharged duringthe rainy season (June to October). During the dry season, thelake floor is overgrown with endemic grasses. Unlike FemaleLake and Male Lake, Lake Child is not a closed system, andits outlet is visible on the NW side of Fig. 9.

At the Beme village (NW of Mt Manengouba) there isanother circular crater lake (Fig. 10). This lake is the largestin the region, some 60 ha in area and 14.5 m deep (Kling1988). It is characterized by steepest rims that make theaccessibility difficult.

Dome and basin

Mt Manengouba slopes are characterized by several extrusivedomes (Kagou Dongmo 2006) that have an uneven topogra-phy. The most interesting is the mugearite dome known asMboriko (2,067 m in altitude), situated in the Eboga caldera(Fig. 11). In addition, the highest point (2,268 m) of theElengoum caldera is marked by two close trachytic domesfound at the south-eastern rim. There is also a spectacularbasin called Djeu-Seh (around 300 m2 in area and 70 m deep),located on the eastern external slopes of the Elengoum

caldera. This basin is not a lake, however, although its flooris swampy (Fig. 12).

The influence of anthropogenic activitieson the geology/geomorphology of the region

The terrain, rocks, and soils of Mt Manengouba have led to anumber of anthropogenic activities such as geotourism, farm-ing, animal breeding, civil engineering works, andgeoeducation.

Geotourism

Geotourism focuses on the geological and geomorphologicalheritage of an area (Gavrila et al. 2011). In Mt Manengouba,geotour sites were selected according to five criteria used byPereira et al. (2009) in the Portugal National Park. Thesecriteria are: value, vulnerability, accessibility, visibility, andspatial distribution.

The scientific quality, the aesthetic appeal and the unique-ness of Mt Manengouba geomorphosites such as calderas,crater Lakes, broken cones, domes and basins (ZangmoTefogoum et al. 2012b), constitute a natural resource for

Fig. 6 Ekambeng broken cone;situated on the North-westernflank of Mt Manengouba

Fig. 7 The Female Lake in theEboga caldera

Geoheritage

Fig. 8 The Male Lake in theEboga caldera

Fig. 9 The Lake Child in theEboga caldera. There is the outsetof water accumulation in thebeginning of the rainy season

Fig. 10 The Beme Lake

Geoheritage

geotourism for foreign and local tourists (Figs. 13 and 14). InMtManengouba, the geomorphosites have local, national, andinternational significance. Currently, more than 600 local andforeign tourists visit this area each year. There are severallocations where tourists have a panoramic view of the land-scape. Local tourists/visitors include researchers from the

universities and students from colleges in the Manengoubaneighboring towns and those from other regions of Cameroon.

Tourist activities in Mt Manengouba occur duringDecember to April, and are focused in the Eboga caldera thatoffers interesting features in a cultural setting - Female Lake,for instance, has a swimming station, and plays a leading role

Fig. 11 The Mboriko dome inthe Eboga caldera

Fig. 12 The swampy Djeu-SehBasin

Fig. 13 Tourists (1, 2) in theEboga caldera

Geoheritage

in show-casing its ancient fishing and traditional ritual cus-toms (Fig. 15), and the Eboga caldera is remarkable with itswell-defined rims; the Mboriko dome, and three broken conescovered by endemic grasses.

To facilitate tourism activity in the region and limit theaccess routes of visitors, Kagou Dongmo et al. (1999), haveproposed the following trails (and some proposals have nowbeen updated) in the Mt Manengouba region:

& Tourists with off-road vehicle can pass through Bangemtown andMbat Village (NWofMtManengouba) to accessthe Eboga caldera directly;

& ThroughMbouroukou, after 3 h of walking, tourists arriveon the NE flank of the Eboga caldera; where there is apanoramic view of the whole caldera;

& ThroughMouanguel, after 1.5 h of walking, tourists arriveon the eastern flank of the Elengoum caldera;

& Through Nsoung, after 2.5 h walking on the uneven track,tourists arrive on the southern flank of the Eboga caldera.

Reynard et al. (2003) and Pralong (2006) state that geositesshould possess unique tourist activities and good facilities.The initial attractant is anything that will attract tourists to aplace, notably rocks, crater lakes, volcanoes, domes, etc. Asoutlined above, while the Mt Manengouba geomorphositesare unique, the facilities at Mt Manengouba are not welldeveloped; accommodation, such as inns can be found in thevillage close to the calderas; however, they do not accord withinternational standards (Zangmo Tefogoum et al. 2012b).Moreover, there are only two degraded shelters in the Ebogacaldera, and guide books and interpretative panels to explainthe geology and the scientific history of the geomorphologicalfeatures to visitors are lacking.

Farming and animal breeding

The fertile soils and grasslands of Mt Manengouba attractedmulti-cultural people (Mbo, Bakossi Bamileke, Bamenda, andBororo,) who settled there to undertake agricultural activitiessuch as farming, raising sheep and cattle, and hunting (Ferreraet al. 2001, 2003; Alves et al. 2004).

& Farming: The Mt Manengouba volcano is overlain by theandosoil developed on basic volcanic rocks (mainlybasalts and pyroclastic ejecta that have resulted in traceelement rich fertile soils; Kagou Dongmo et al. 1999). As

Fig. 14 The excursion ofsecondary school students in theEboga caldera

Fig. 15 Swimming and fishing area in the Female Lake

Geoheritage

such, farming is well developed on the downslope areasof Mt Manengouba. A large variety of crops are grown,including coffee, cacao, plantains, bananas, melons,tubers (manioc, yam, tarot), maize, potatoes, beans,fruits (avocado, sugar cane, pineapple), and extracting

pigments (Fig. 16). All these products are marketed innearby villages.

& Animal breeding: The vegetation in the Mt Manengoubaregion is characterized by forests and meadow.Meadows are comprised of endemic grasses (Fig. 17)

Fig. 16 Variety of crops grown in Mt Manengouba. 1 Plantains and bananas; 2 pineapples; 3 sugar canes; 4 tarots; 5 maniocs; 6 gingers; 7 yams; 8potatoes; 9 avocadoes; 10 palm oil; 11 cocoa; 12 coffee; 13 dry manioc for many purposes and 14 mangoes

Geoheritage

that can support livestock at the summit of the volcano -hence, cattle and sheep farming is practiced in thecalderas (Fig. 18).

Civil Engineering Works

Mt Manengouba is composed of several rocks types (KagouDongmo et al. 2005; Zangmo Tefogoum, 2007; ZangmoTefogoum et al. 2011a). The most widespread is pyroclasticejecta that formed the numerous cones scattered in the volca-no. These pyroclastic ejecta are mainly pozzolanas. Along theCameroon Line, pozzolana has the property to react with thelime to form cement (Wandji and Tchoua 1988). Accordingly,they are used in the manufacture of cement in the MtManengouba region. Exploitation of pozzolana for civil engi-neering works led to the opening of several quarries by localcouncils and populations on the flanks of Mt Manengouba(Fig. 19). Moreover, the loose state of pozzolana also rendersthem useful in manufacturing of bond-stones and concretes,and in the surfacing of roads and terraces (Fig. 20). Blocks of

rocks are used for the building house foundations, walls andstabilizing road embankments. While quarrying is the mainthreat to theMtManengouba geomorphosites, the largest threatto the geoheritage atMtManengouba is probably the ignoranceof the potential impacts of human actions (Gray 2008).

Geoeducation

Mt Manengouba geomorphosites are important assets forresearch and scientific purposes due to its geological history,petrographic variability, structure and geographic wealth.Many field studies are carried out by secondary schools anduniversities and other research institutions. Young scientistsfromMasters and PhD candidatures are increasingly focusingtheir research in this region (Fig. 21). Moreover, there arenumerous water streams and four thermo-mineral watersprings that can function as sites for education in magma-related hydrology (or geothermal hydrology). The thermo-mineral water springs are found in Baré, Ngol, Nsoung, andBangem (Tchoua 1974, Kagou Dongmo et al. 1999). Thermo-mineral water springs (Figs. 22 and 23) are evidence of the

Fig. 17 The Northern rim of the Eboga caldera that highlights a primary school enclosed by a natural marvelous lawn

Fig. 18 Animal breedinghighlighted by a sheep flock (1)and cattle herd (2)

Geoheritage

post-volcanic manifestations in Mt Manengouba. In addition,more than three abandoned quarries represent anthropogeniclandscapes that play a scientific and educational role ingeotourism (Gavrila et al. 2011). Thus, as quarries exposingrock systems, they are helpful in the training of scholars, as

out-door classrooms in volcanic processes along theCameroon Volcanic Line.

Conclusions and Discussion

MtManengouba is one of the most scenic volcano complexesalong the Cameroon Volcanic Line. It constitutes a

Fig. 19 Quarrying in MtManengouba surroundingvillages: 1 Njombé, 2 Njom, 3Ndom, and 4 Ekoh

Fig. 20 Surfacing of road with the pozzolana in the Njom Village Fig. 21 Students fields work in Mt Manengouba

Geoheritage

geomorphological heritage of a volcano extruded between 1.5and 0 Myr. It has some important vegetation and naturalresources that foster numerous economical activities. To thatend, there are several active populations (Mbo, Bakossi,Bamileke, Bamenda, and Bororo), and peoples from theneighboring regions are still migrating and settling there.“Green space” conflicts have given rise to tribal conflicts thathave led to the settlement and animal farming on the summitand agricultural farms on the downslope areas of the volcano.

The geomorphological features of Mt Manengouba ofgeoheritage significance, or geomorphosites (Fig. 24),

comprise two nested sub-circular calderas, three permanentlakes, basin, domes and broken cones, and natural lawns. Theuniqueness of such geomorphological features and thermo-mineral water springs nationally and some extent internation-ally gives Mt Manengouba its national and international im-portance. The main threats to Mt Manengouba natural assetsare the opening of quarries on pyroclastic broken cones, andoverpasturing. The main barriers to tourism are poor roads andthe lack of shelters and facilities at tourist sites. Thegeomorphosites of the summit of Mt Manengouba (calderas,lakes, cones, and domes) are the main tourist attractions. Inview of this, it is a necessity in Mt Manengouba to:

– Investigate regrouping the animal farmers in a singlecamp and create stock farms in order to avoid the currentovergrazing;

– Create a balance between quarrying and promotion ofgeotourism;

– Improve and maintain the main tracks and roads to facil-itate the accessibility to geomorphosites;

– Create new tracks in Mt Manengouba;– Train volunteers for conducting guided tours;– Provide interpretative panels and adequate scientific doc-

umentations about the geoheritage values of sites of geo-logical interest;

– Foster cost-effective activities and infrastructure (handi-crafts, shops, inns or hotel) to enhance the local economy;

– Build a tourist center for the exhibition of rock samples,and sale of geological maps, tourist sites map, postcards,and souvenirs.

Although most geomorphosites are well exposed andwould attract tourism which can progressively influence their

Fig. 22 The reddish thermo-mineral water spring in the Ndibse village.There is a colorless fresh water stream that is quite close to the hot spring

Fig. 23 The thermo-mineralwater spring in the Baré village

Geoheritage

protection, there is no current specific legal protection ofgeomorphosites in Mt Manengouba. However, as notedabove, geomorphosites constitute the center of interest fornumerous research activities led by students from collegesand universities. These studies could play an effective role inthe raising the consciousness of the local, national and inter-national community about the geomorphological heritage ofMt Manengouba with the view to securing its protection.Thus, through the African and Arabian Geoparks Networkwhich promotes geoparks in Africa and Arab World, we hopeto create our first geopark in the region of Mt Manengoubathat will be well managed and preserved as the LesvosPetrified Forest Geopark is in Greece (Zouros 2010).

Acknowledgments The authors are grateful to the Head of Departmentof Earth Sciences of the University of Dschang for their permission toundertake this work, to Kagou Dongmo for his technical assistance, to theInternational Association of Geomorphologists and the University ofLausanne for having supported their attendance to the Intensive Courseon Alpine Geomorphosites in Lausanne-Hérens valley (Switzerland) and,to Professor José Brilha for providing us with documents to improve thequality of this paper. The authors also thank the Bororo, Mbat, andBangem people for their hospitality during our field surveys. Moreover,they acknowledge the text editor of Geoheritage journal and reviewersand thank them for their thoughtful suggestions and comments.

References

Alves MIC, Monteiro A, Ferreira N, Dias G, Brilha J, Pereira DI (2004)Landscape as a support for biodiversity: The Arribas do Dourocase study. In: PARKES MA (ed) Natural and cultural land-scapes—the geological foundation. Royal Irish Academy, Dublin,pp 65–68

Bardintzeff JM, Déruelle B,Wandji P, Ngounouno I, Lissom J, NkouathioD, Fosso J (2001) Les éruptions 1999–2000 du mont Cameroun etles risques associés. GSAf 12: Geo-environnemental catastrophes inAfrica. J Geosci Soc Cameroon 1(1A):29–30

Costa FL (2011) Volcanic geomorphosites assessment of the last eruption,on April toMay 1995, Within the Natural Park of Fogo Island, CapeVerde. Geo J Tour Geosites 8(2):167–177

Evans WC, Kling GW, Tuttle ML, Tanyileke G, White DL (1993) Gasbuild up in lakes Nyos, Cameroon: the recharge process and itsconsequences. Geochemistry 8:207–221

Ferreira N., Pereira D.I., Alves M.I.C., Castro P., Brilha J. & Dias G.,2001 Aspectos geomorfologicos da regiao de Ribacoa: contributopara o conhecimento do patrimonio geologic do Parque Natural doDouro Internacional. Livro de resumos do Congresso Internacionalsobre Patrimonio Geologico e Mineiro, Beja, Portugal, 185-186

Ferreira N., Brilha J., Dias G., Castro P., Alves M.I.C. & Pereira D.,2003. – Patrimonio geologico do Parque Natural do DouroInternacional (NE de Portugal): caracterizacao de locais deinteresse geologico. Ciencias da Terra, volume especial 5,CD-ROM, I40-I42

Fig. 24 Geomorphologicalfeatures of Mt Manengouba ofgeoheritage significance. 1Caldera boundaries; 2 cones; 3quarries; 4 domes; 5 lakes; 6basin; 7 thermo-mineral watersprings; 8 settlements; 9 asphaltedroads; 10 off-road vehicle tracks;11 pedestrian tracks

Geoheritage

Gavrilă IG, Man T, Surdeanu V (2011) Geomorphological heritage assess-ment using GIS analysis for geotourism development in MăcinMountains, Dobrogea, Romania. Geo J Tour Geosites 8(2):198–205

Ghogomu TR, Tangumonkem ET, Tiethop AC, Linonge ON (2001)Landslides in the Bamboutos region, Western Cameroon. GSAf12: Geo-environnemental catastrophes in Africa. J Geosci SocCameroon 1(1A):54–55

Gountie DM, Nono A, Njonfang E, Kamgang P, Zangmo TG, KagouDA, Nkouathio DG (2011) Le volcanisme ignimbritique des montsBambouto et Bamenda (Ligne du Cameroun, Afrique Centrale):signification dans la genèse des caldeiras, vol 33. Bull InstitutScientifique, Rabat, pp 1–15

Grandgirard V., 1997. Géomorphologie, protection de la nature et gestiondu paysage. – Thèse de doctorat, Institut de Géographie, Universitéde Fribourg

Gray M (2004) Geodiversity: valuing and conserving abiotic nature.Wiley, Chichester

GrayM (2008) Geodiversity: a new paradigm for valuing and conservinggeoheritage. Geosci Can 35:51–59

Ilies DC, Josan N (2009) Geosites-geomorphosites and relief. Geo J TourGeosites 3(1):78–85

Kagou DA (2006) Le mont Manengouba: Evolution volcanologique,caractères magmatologiques et risques naturels; comparaison avecles monts Bambouto et Bamenda (Ligne du Cameroun). Th Doctd’Etat Univ Yaoundé 1:230p

Kagou Dongmo, A., 1998. Etude volcanologique, pétrographique etgéochimique d’un stratovolcan polygénique de la Ligne duCameroun : Le mont Manengouba (Provinces du Littoral et duSud-Ouest Cameroun. Th. Doct. 3ème cycle. Univ. Yaoundé 1, 197p. + 1 carte HT

Kagou DA, Wandji P, Tchoua FM, Nkouathio DG, Vicat JP (1998)Volcanologie, pétrographie et géochimie d'un volcan polygénique :le stratovolcan Manengouba (secteur sud continental de la ligne duCameroun). Ann Fac Sci Université Yaoundé I série Sci nat et Vie34(2):169–183

Kagou DA, Wandji P, Nkouathio DG, Tchoua FM, Tchouankoue JP,Vicat JP (1999) Etude d’un environnement volcanique à aléasmultiformes et en plein essor démographique : les régions du montManengouba (Cameroun). In: Vicat JP, Bilong P (eds) Géologie etenvironnement au Cameroun. Coll. Geocam 2 Press. UniversitéYaoundé, Cameroun, pp 61–70

Kagou DA, Wandji P, Pouclet A, Nkouathio DG, Tchoua FM (2005) Lemont Manengouba (Ligne du Cameroun), Un volcan bénéfique,mais potentiellement dangereux, typologie des aléas et évaluationdes risques naturels associés. Afr Geosci Rev 12(2):97–109

Kagou DA, Nkouathio DG, Pouclet A, Bardintzeff JM, Wandji P, NonoA, Guillou H (2010) The discovery of Late Quaternary basalt onMount Bambouto: implications for recent widespread volcanic ac-tivity in the southern Cameroon Line. J Afr Earth Sci 57:87–108

Kling GW (1988) Comparative transparency, depth of mixing and stabil-ity of stratification in lakes of Cameroon, West Africa. LimnolOceanogr 33(1):24–40

KlingGW,ClarkMA, ComptionHR, Devine JD, HumphreyAM,KoenigsbergEJ, Lockwood JP, Tuttle ML, Wagner GN (1987) The 1986 LakeNyos disaster in Cameroon, West Africa. Science 236:169–175

Marzoli A, Piccirillo EM, Renne PR, Bellieni G, Lacumin M, Nyobe JB,Tongwa AT (2000) The Cameroon volcanic Line revisited:Petrogenesis of continental basaltic magma from lithospheric andasthenospheric mantle source. J Petrol 41(1):87–109

Meireles C, Pereira DI, AlvesMIC, Pereira P (2002) Interesse patrimonialdos aspectos geologicos e geomorfologicos da regiao de Aveleda-Bacal (Parque Natural deMontesinho, NE Portugal). Comunicacoesdo Instituto Geologico e Mineiro, Lisboa, pp 225–238

Nana R., 1991. Contribution à l'étude volcanique et pétrographique deslacs de la région de Wum (Province du Nord-Ouest, Cameroun).Thèse Doctorat 3ème cycle, Université Yaoundé I, Cameroun, 155 p

Nechia Wantim M., Kervyn M., Ernst G., Suh C.E., Jacobs P., MarmolM.A., 2012; Assessing lava flow hazard at Mount CamerounVolcano, West-Central Africa with a parabolistic maximum slopemodel. The 24th Colloquium of African Geology, Addis Ababa,p.163

Njilah KR, Ghogomu R, Lamilen BD, Mandeng CG, Belinga SE (1999)Naturals catastrophes in Cameroon. In: Vicat JP, Bilong P (eds)Géologie et environnement au Cameroun. Coll. Geocam 2, Press.Univ Yaoundé, Cameroun, pp 71–81

Nkouathio DG, Kagou Dongmo A, Bardintzeff JM, Wandji P, Bellon H,Pouclet A (2008) Evolution of volcanism in graben and horststructures along the Cenozoic Cameroon Line (Africa).Implications Tectonic Evol Mantle Source Compos 94:287–303

Olivry JC (1986) Fleuves et Rivières du Cameroun. MESRES-ORSTOM-ISBN2-7099-0844-2, 733 p

Panizza M, Piacente S (1993) Geomorphological assets evaluation. ZGeomorph Suppl Bd 87:13–18

Panizza M, Piacente S (2003) Geomorfologia culturale. Pitagora Editrice,Bologna, 350 pp

Pereira DI, Meireles C, Alves MIC, Pereira P, Brilha J, DIAS G (2004a)The geological heritage on the Montesinho Natural Park (NEPortugal) – an interpretation strategy for an areawith high geologicalcomplexity. In: PARKES MA (ed) Natural and cultural land-scapes—The Geological Foundation. Royal Irish Academy,Dublin, pp 253–256

Pereira P., Pereira D.I., Alves M.I.C. & Meireles C., 2004b. PatrimonioGeomorfologico e medidas para a sua valorizacao no Parque Naturalde Montesinho (NE Portugal). In: MATA-PERELLO J. (Ed.): Actasdel Congreso Internacional sobre Patrimonio Geologico y Minero(Defensa del Patrimonio y Desarrollo Regional). Sociedad Espanolapara la Defensa del Patrimonio Geologico y Minero, Madrid, 133-140

Pereira, D.I., Pereira P., Caetano Alves M.I.C & J Brilha J., 2006.Inventariação temática do património geomorfológico português. –In: Publicações da Associação Portuguesa de Geomorfólogos 3:155-160

Pereira P, Pereira D, Caetano Alves MI (2007) Geomorphosite assess-ment in Montesinho Natural Park (Portugal). Geogr Helv 62:159–168

Pereira P., Pereira D.I., Caetano Alves M.I., 2009. The geomorphologicalheritage approach in protected areas: Geoconservation vs.Geotourism in Portuguese natural parks Mem. Descr. Carta Geol.d’It. pp 135-144

Pralong J-P., 2006. Géotourisme et utilisation de sites naturels d’intérêtpour les sciences de la Terre. Les régions de Crans-Montana-Sierre(Valais, Alpes suisses) et Chamonix-Mont-Blanc (Haute-Savoie,Alpes françaises). Travaux et Recherches n° 32, Lausanne, Institutde Géographie, 224 pp

Quaranta G., 1993. Geomorphological assets : conceptual aspect andapplication in the area of Crodo da Lago (Cortina d’Ampezzo,Dolomites). In Panizza M., Soldati M., Barani D. (Eds) :European Intensive Course on Applied Geomorphology.Proceedings, Modena – Cortina d’Ampezzo, 24 June – 3 July1992, 49–60

Reynard, E., 2005. Geomorphosites et paysages. – In: Géomorphologie:relief, processus, environnement 3:181-188

Reynard E (2008) Scientific research and tourist promotion of geomor-phological heritage. Geogr Fis Dinam Quat 31:225–230

Reynard E, Coratza P (2013) Scientific research on geomorphosites. Areview of the activities of IAG working groupnon geomorphositesover last twelve years. Geogr Fis Dinam Quat 36:10

Reynard E., Holzmann C. & Guex D., 2003. Géomorphologie ettourisme: quelles relations?. In: E. Reynard, C. Holzmann, D.Guex & N. Summermatter (Eds.), «Géomorphologie et tourisme».Travaux et Recherches n° 24, Lausanne, Institut de Géographie, 1-10

Geoheritage

Reynard E, Fontana G, Kozlik L, Scapozza C (2007) A method forassessing the scientific and additional values of geomorphosites.Geogr Helv 62:148–158

Sigurdsson H, Devine JD, Tchoua FM, Presser TS, Pringle MKW, EvansWC (1987) Origin of lethal gas burst from lakeMonoun, Cameroon.J Volcanol Geotherm Res 31:1–16

Tanyiléké G.Z., (1994.) Geochemestry of the CO2 rich and Lakes andsoda springs along the Cameroun Volcanic Line, Cameroun. Ph-D,Okoyama Univ., 155 p

Tchoua FM (1972) Sur la formation des calderas des monts Bambouto(Cameroun). C R Acad Sci Paris 799–801

Tchoua M.F., 1974. Contribution à l’étude géologique et pétrographiquede quelques volcans de la "Ligne du Cameroun" (MontsManengouba et Bambouto), Thèse Doct. Etat, Univ. Clermont-Ferrand. 337p. + Biblio +75 figures

Tchoua F.M., Tchouankoue J.P, Kagou Dongmo A., Nkouathio D.G.,Kuepouo G. & Tetsogang S., 1998. Contribution to the reduction ofgeology-related natural risks in west Cameroon highlands (centralAfrica). International IDNDR-conference on early warning systemsfor reduction of Natural Disaster, Postdam, sept 7-11, Abstr. p.79

Tchoua FM, Wandji P, Nana R, Kamgang P, Tietchou I (2001) Leséruptions historiques du mont Cameroun et leur impact sur Bueaet sa région. GSAf 12: Geo-environnemental catastrophes in Africa.J Geosci Soc Cameroon 1(1A):127–128

Wandji P., 1995. Le volcanisme récent de la plaine du Noun (Ouest-Cameroun). Volcanologie, Pétrologie, géochimie etpouzzolanicité.ThèseDoctorat ès-Sciences, Université Yaoundé 1, Cameroun, 295p

Wandji P, Tchoua FM (1988) Le coefficient de Feret: Application à ladétermination des propriétés pouzzolaniques des projectionsvolcaniques de Foumbot (Ouest-Cameroun). Ann Fac Sc Chim2(1-2):201–216

Wandji P.,Ménard J.J. & Tchoua F.M., 1994. L'activité hydromagmatiquerécente dans la plaine du Noun (Ouest-Cameroun) et les aléasvolcaniques associés. Comptes Rendus Académie Sciences, Paris319, sér. II, 417-422

Wandji P, Ménard JJ, Tchoua FM, Nkouathio DG, Kagou DA (1998)Découverte du cratère-puits de Ngouondam : une source desémissions de gaz létaux du lac Monoun (plaine du Noun, Ouest

Cameroun). Ann Fac Sci Univ Yaoundé I série Sci nat et Vie 34(2):144–149

Wandji P, Bardintzeff J-M, Tchoua FM, Déruelle B, Nkouathio DG,Kagou DA, Itiga Z, Wotchoko P, Chakam Tagheu PJ (2001) Lemont Cameroun (ligne duCameroun): un laboratoire naturel d’étudedes risques et des bienfaits du volcanisme. GSAf 12: Geo-environnemental catastrophes in Africa. J Geosci Soc Cameroon1(1A):134–135

Zangmo Tefogoum G., 2007. Les caldeiras du mont Manengouba et desmonts Bambouto: études comparatives et évaluation qualitative etquantitative des risques naturels associés. Master’s Thesis, Univ.Dschang, 125p

Zangmo Tefogoum G, Kagou Dongmo A, Nkouathio DG, Wandji P(2011a) Hazards zonation and assessment of the associated risks inthe Mount Manengouba Calderas (Cameroon Volcanic Line). IAGRegional Conference, Addis Ababa, p 146

Zangmo Tefogoum G., Kagou Dongmo A., Nkouathio D.G., GountieDedzo M., Wandji P., 2011b. The Mount Manengouba (CameroonVolcanic Line): a relevant trump for anthropogenic activities. The 1st

international Conference of African and Arabian geoparks p. 174-176

Zangmo Tefogoum G., Kagou Dongmo A., Nkouathio D.G., Wandji P.,Gountie Dedzo M., 2012b. The geodiversity of the MountManengouba Calderas (Cameroon Volcanic Line): values, threatsand geoconservation. The 6th Conference of the African Associationof Women in Geosciences, p. 138

Zangmo Tefogoum G., Kagou Dongmo A., Nkouathio D.G., Wandji P.,Gountie Dedzo M., Kamgang P., Nono A., 2012a. Multi-hazardstudy and assessment of associated risks in the Lefo caldera ofBamenda volcano (Cameroon Volcanic Line). The 24th

Colloquium of African Geology, Addis Ababa, p.166-167Zangmo TG, Kagou DA, Nkouathio DG, Wandji P (2009) Typology of

natural hazards and assessment of associated risks in the mountsBambouto caldera (Cameroon Line, West-Cameroon). Acta GeolSin 5:1008–1016

Zouros N.C., 2010. Lesvos Petrified Forest Geopark, Greece:Geoconservation, Geotourism, and Local Development Geopark,The George Wright Forum, Nb 27, Vol. 10

Geoheritage