The Eocene carbonate platforms of the Ghomaride Domain (Internal Rif Zone, N Morocco): A segment of the westernmost Tethys

The Eocene platforms deposits in the Moroccan Ghomarides have been studied in this paper. These marine carbonate platforms were located in the westernmost Tethys approximately 30°N and 0°–10°W during the Cuisian to Bartonian. This study includes observations from fossiliferous assemblages (such as larger benthic foraminifera and colonial corals), their paleoenvironment as well as rock texture and fabric. Eight microfacies were identified that represent different ramp environments in a ‘distally-steepened carbonate ramp’ type of platform. The studied deposits are organised into a transgressive succession composed of three sedimentary cycles: lower Cuisian, middle Cuisian and middle Lutetian to Bartonian. In the lower cycle, photic inner to middle ramp environments in mesotrophic conditions were prevalent. In the second cycle, photic inner ramp (sea-grass) to mid ramp environments in mesotrophic to oligotrophic conditions were observed. The upper cycle, which is more extensive and variable, represents mesophotic mid ramp to aphotic slope environments and change gradually from oligotrophic to eutrophic conditions. During the Eocene, larger benthic foraminifera were dominant overtaking the zooxanthellate corals in the Tethys regions. Nevertheless, our study and the performed comparison with other Tethyan sectors have revealed that in some areas both coexisted in similar proportions. In some western Tethys regions close to the Atlantic Ocean, coinciding with areas influenced by upwelling currents, larger benthic foraminifera and coral build-ups were replaced by oyster reefs. The Ghomaride Domain represents an intermediate case between fossil assemblages of northern Tethyan margin and eastern sector of the southern margin of the Tethys, with a dominance of larger benthic foraminifera but with a certain presence of corals as well. A good correlation exists between Eocene warm intervals and carbonate platform deposits in these domains. Contrarily, during cooling ones shallowing and gaps in the sedimentation is registered. Two anomalies have been detected in the Ghomaride Domain during Ypresian and Bartonian times indicating particular climatic conditions or local tectonics interferences.Research supported by: Research Project PID2020-114381GB-I00, Spanish Ministry of Science and Innovation; Research Groups and Projects from M. Martín-Martín, Alicante University (CTMA-IGA)

Metodología para un inventario y evaluación de sitios geológicos en Marruecos: propuesta para su aplicación a otras regiones africanas

Officially, there is no exhaustive inventory of Sites of Geological Interest (SGI) in Morocco. Nonetheless, the Geological Service of Morocco started identification of these sites a few years ago, and published 9 volumes on the subject as geological and mining guides of Morocco. This was only limited to identification of SGI without their characterization and assessment, or identification of the threats that could affect them. In the last few years several PhD Thesis and research papers have dealed with this subject. Unfortunately, these initiatives are sporadic and far from establishing a global strategy for geoconservation and valorization of the Moroccan geological heritage. This paper proposes a global methodology for the inventory of geoheritage in Morocco by: i) providing a detailed synthesis of the research work on geoheritage in the world; ii) proposing the ways for assessing the Moroccan geoheritage at different scales (scientific education, geotourism, sustainable development, etc.); and iii) applying them to a wide variety of landscapes in Morocco. The obtained results and conclusions can be further extended to other African regions.No existe un inventario exhaustivo oficial de Sitios de Interés Geológico (SGI) en Marruecos. El Servicio Geológico de Marruecos ha promovido en los últimos años iniciativas para identificar estos sitios y las ha publicado, en 9 volúmenes, en forma de guías geológicas y mineras de Marruecos. Esta iniciativa sólo se limitaba a identificar los SGI sin caracterizarlos, evaluarlos o reconocer las amenazas que pudieran afectarles. En los últimos años varias tesis doctorales y trabajos de investigación han abordado esta cuestión. Desafortunadamente, han sido iniciativas esporádicas que no pueden cumplir el ambicioso reto de establecer una estrategia global de geoconservación y valorización del patrimonio geológico marroquí. En este trabajo se propone una metodología global para inventariar el geopatrimonio marroquí mediante: i) una síntesis detallada de trabajos de investigación llevados a cabo sobre geopatrimonio en el mundo; ii) la propuesta de criterios para evaluar estos resultados a diferentes escalas (educación científica, geoturismo, desarrollo sostenible, etc.); y iii) su aplicación a una gran variedad de paisajes de Marruecos. Los principales resultados y conclusiones obtenidos se pueden aplicar a otras regiones africanas.The present work has been funded by the Research Project reference PID2020-114381GB-I00 (Spanish Ministry of Education and Science), the Research Group reference VIGROV-53 (Alicante University, CTMA-IGA), both coordinated by M. Martín-Martín; and the Research Project “Identification, conservation et valorisation du Patrimoine Géologique de la région Tanger-Tétouan-Al Hoceima pour un développement durable” (Abdelmalek Essaadi University, Morocco) coordinated by R. Hlila

Tectono-Sedimentary Cenozoic Evolution of the El Habt and Ouezzane Tectonic Units (External Rif, Morocco)

An interdisciplinary study based on lithostratigraphic, biostratigraphic, petrographic and mineralogical analyses has been performed in order to establish the Cenozoic tectono-sedimentary evolution of the El Habt and Ouezzane Tectonic Units (External Intrarif Subzone, External Rif, Morocco). The reconstructed record allowed identification of the depositional architecture and related sedimentary processes of the considered units. The Cenozoic successions were biochronologically defined allowing, at the same time, identification of unconformities and associated stratigraphic gaps. The presence of five unconformities allowed for the definition of the main stratigraphic units arranged in a regressive trend: (1) lower Paleocene interval (Danian p.p.) assigned to a deep basin; (2) Eocene interval (lower Ypresian-lower Bartonian p.p.) from a deep basin to an external carbonate-siliceous platform; (3) lower Rupelian-upper Chattian p.p. interval deposited on unstable slope with turbidite channels passing upward to an external siliciclastic platform; (4) Burdigalian p.p. interval from a slope; (5) Langhian-Serravallian p.p. interval from slope to external platform realms. The petrography of the arenites and calcarenites allowed for the identification of the supplies derived from erosion of a recycled orogen (transitional and quartzose subtypes). The clay-mineralogy analysis indicates an unroofing (first erosion of Cretaceous terrains followed by upper Jurassic rocks) always accomplished by erosion of Cenozoic terrains. Several tectofacies checked in some stratigraphic intervals seem to indicate the beginning of deformation of the basement generating gentle folds and first activation of blind thrusts, mainly during the Paleogene. A preorogenic tectonic framework is considered as responseto the generalized tectonic inversion (from extension to compression) as frequently registered in the central-western peri-Mediterranean areas. The large volumes of reworked terrigeneous supply during the latest Oligocene-Miocene p.p. indicates the beginningsof the synorogenic sedimentation (foredeep stage of the basins) controlled by active tectonics.Research Project CGL2016-75679-P (Spanish Ministry of Education and Science); Research Groups, Projects of the Generalitat Valenciana, Alicante University (CTMA-IGA); Grants from the University of Urbino Carlo Bo (M. Tramontana)

Miocene evolution of the External Rif Zone (Morocco): comparison with similar and lateral southern Mediterranean Tethyan margins

The Miocene evolution of the External Rif Zone (NW Africa Plate) was determined through the multidisciplinary analysis of fourteen successions. The updated stratigraphic framework shows how Miocene sediments rest on the Cretaceous–Paleogene terrains through unconformity surfaces, whereas it rests with sedimentary continuity in two sectors. After recognition of lithofacies and three unconformities located near the Oligocene–Aquitanian, Aquitanian–Burdigalian and Serravallian–Tortonian boundaries, the Miocene sedimentary record was divided into three stratigraphic intervals representing deep to shallow marine deposits as Aquitanian–Burdigalian, Langhian and Upper Serravallian–Missinian. The two oldest unconformites are restricted to the central sector, while the upper one is generalized and probably related to the nappe tectonics registered in all sectors of the External Rif. Data from analysis of tectofacies, petrology, mineralogy, meaning and implications of unconformities, and subsidence indicate that: (i) mass flow deposits (turbidites, slumps, olistostromes) are common in all successions but more frequent during the Lower Miocene; (ii) petrology of the detrital components of the arenites indicates recycled orogen-derived sediments, with quartz coming from erosion of metamorphic rocks of the Atlas orogen and/or the African craton; (iii) mineralogy of mudstones suggests a complex erosional evolution of local emerged areas derived from a mixture of contributions coming from the erosion of Upper Jurassic to Paleogene suites, and especially from kaolinite-rich Albian–Cenomanian to Paleogene successions with absence of a clear unroofing. The conjunction of all these clues reinforce the idea of a synsedimentary tectonics affecting the margin/basin system during the Miocene. A thickness analysis of the studied sedimentary successions allows proposing the evolution of the orogenic front and main depozones (foredeep, bulges, wedge-top and intramontane sub-basins) integrated in a complex foreland system migrating from north to south with the Atlas-Mesetas area acting as foreland during MIocene. The orogenic front moved from the Internal Intrarif to Mesorif and later to Internal Prerif. The main wedge-top basin also migrated from the Internal Intrarif to External Intrarif. The foredeep migrated from the Mesorif to the Internal Prerif, while the main forebulge was located in the External Prerif and a asecondary bulge developed in the External Intrarif. Intramontane basins developed behind the orogenic front in relative extensional conditions moving from the Internal Extrarif to External Intrarif. The reconstructed Miocene evolution was inserted into a 2D paleogeographic-geodynamic evolutionary model using Gplates software, and then compared to those reported in other external margins of the western Tethys (Betic Chain, Tunisian Tell, Sicilian Maghrebids and Apennines), revealing important similarities and local differences.Research supported by PID2020-114381GB-I00 Research Project (Spanish Ministry of Education and Science), EU HORIZON project CiROCCO under Grant Agreement No 101086497, Research Groups and projects of the Generalitat Valenciana from Alicante University (CTMA-IGA), and Research Group RNM-188 of the Junta de Andalucía from EEZA–CSIC

Detrital signatures of the Ghomaride Culm cycle (Rif Cordillera, N Morocco): New constraints for the northern Gondwana plate tectonics

The Carboniferous detrital suites of the Ghomaride Subdomain (Rif Cordillera, N Morocco) has been undertaken in order to obtain paleogeographic and paleotectonic constraints. Microconglomerate and sandstone samples from eight sections belonging to four sectors were petrographically studied. This northern Gondwana domain was part of the Paleo-Mesomediterranean Plate, located between the Iberian-French Plates and the African Paleo-Atlas-Saharian Domain, which outlines a gap of knowledge since these domains are now part of the Alpine peri-Mediterranean chains. Part of this data-lacking is related to the sandstone detrital modes that have never studied in this area, allowing to obtain information about provenance derived from growing orogens, as well as orogenic processes, and tectonic, climatic and/or erosional events. The study has revealed that the sandstones are litharenites to feldsphatic litharenites, evolving upward to lithic arkoses, and has evidenced a quartzolithic petrofacies with a transitional recycled orogen provenance. The metamorphiclastic detritus displays a low to middle-upper metamorphic rank upwardly referred to a subducted terrane. Serpentinite-like detritus indicates a metamorphosed oceanic crust being dismantled. A supply from the Rheic Ocean seems improbable since it was very far and beyond the Iberian Plate. Therefore, closer oceanic sutures should be proposed, probably separating the Paleo-Mesomediterranean Plate from the Iberian-French Plate and from the Paleo-Atlas-Saharian Domain. The sin-sedimentary volcanic activity (felsic to mafic) reinforces the idea of subductions. A correlation with other Culm successions of the western Paleotethys has allowed the performing of a paleogeographic-paleotectonic model during the Paleotethysian tectonic phase, in which the studied sandstones were deposited in a foredeep connected northward with limestone platforms and with a crystalline emerged domain (hinterland-orogenic front: Iberia-French Plate and part of the Paleo-Mesomediterranean Plate) and transitioning southward to an oceanic branch of the western Paleotethys, and finally with the Paleo-Atlas-Saharian band acting as passive margin in the foreland.Research Project PID2020-114381GB-I00 to M. Martín-Martín, Spanish Ministry of Education and Science; Research Groups and Projects of the Generalitat Valenciana, Alicante University (CTMA-IGA) are acknowledged. Support from Ministero Italiano dell'Università e della Ricerca Scientifica (MUR), and the MUR-PRIN 2022 (P2022WNCEC_002, H53D23011410001) to S. Criniti, is also acknowledged

New structural data on the Tertiary of the External Tanger Unit (Intrarif, Morocco)

A tectonic study has been carried out in the Cenozoic of the External Tanger Unit. This parauthocthonous unit, characterized by open SW-vergent folds, overrides by mean of a thrusting the Intrarif Loukkos Unit and it is located at the footwall of different external tectonic units of the Maghrebian Flysch Basin Domain. The tectonic pile is unconformably covered by Upper Miocene-Lower Pliocene postorogenic deposits. The External Tanger Unit experienced a cenozoic polyphasic tectonic deformation generating ENEWSW, NE-SW, NNE-SSW and NW-SE oriented fracture systems

Nuevos datos estructurales sobre el Cenozoico de la Unidad Tánger Externa (Intrarif, Marruecos)

A tectonic study has been carried out in the Cenozoic of the External Tanger Unit. This parauthocthonous unit, characterized by open SW-vergent folds, overrides by mean of a thrusting the Intrarif Loukkos Unit and it is located at the footwall of different external tectonic units of the Maghrebian Flysch Basin Domain. The tectonic pile is unconformably covered by Upper Miocene-Lower Pliocene postorogenic deposits. The External Tanger Unit experienced a cenozoic polyphasic tectonic deformation generating ENEWSW, NE-SW, NNE-SSW and NW-SE oriented fracture systemsSe ha realizado un estudio estructural en el Cenozoico de la Unidad Tánger Externa. Esta unidad parautóctona, caracterizada por pliegues suaves de vergencia SO, cabalga a la Unidad Loukkos del Intrarif y es cabalgada por diferentes unidades tectónicas del Dominio de la Cuenca de los Flyschs Magrébides. La pila tectónica es recubierta discordantemente por depósitos postorogénicos del Mioceno Superior-Plioceno Inferior. La Unidad Tánger Externa experimentó una deformación tectónica polifásica terciaria generando sistemas de fracturas de orientación ENE-OSO, NE-SO, NNE-SSO y NO-S

Nuevos datos estructurales sobre el Cenozoico de la Unidad Tánger Externa (Intrarif, Marruecos)

A tectonic study has been carried out in the Cenozoic of the External Tanger Unit. This parauthocthonous unit, characterized by open SW-vergent folds, overrides by mean of a thrusting the Intrarif Loukkos Unit and it is located at the footwall of different external tectonic units of the Maghrebian Flysch Basin Domain. The tectonic pile is unconformably covered by Upper Miocene-Lower Pliocene postorogenic deposits. The External Tanger Unit experienced a cenozoic polyphasic tectonic deformation generating ENEWSW, NE-SW, NNE-SSW and NW-SE oriented fracture systems.Se ha realizado un estudio estructural en el Cenozoico de la Unidad Tánger Externa. Esta unidad parautóctona, caracterizada por pliegues suaves de vergencia SO, cabalga a la Unidad Loukkos del Intrarif y es cabalgada por diferentes unidades tectónicas del Dominio de la Cuenca de los Flyschs Magrébides. La pila tectónica es recubierta discordantemente por depósitos postorogénicos del Mioceno Superior-Plioceno Inferior. La Unidad Tánger Externa experimentó una deformación tectónica polifásica terciaria generando sistemas de fracturas de orientación ENE-OSO, NE-SO, NNE-SSO y NO-SE.Research supported by: Spanish Ministry of Education and Science Research Project CGL2016-75679-P; Research Groups and Projects of the Generalitat Valenciana, Alicante University (CTMA-IGA); M. Tramontana Grants from University of Urbino “Carlo Bo”

Un enfoque cuantitativo para la evaluación de geositios del Parque Nacional de Talassemtane (NO de Marruecos)

The Talassemtane National Park (TNP), registered in the tentative list of Morocco for a future nomination as World Heritage by the UNESCO, is characterized by its great biodiversity and integration in the Intercontinental Biosphere Reserve of the Mediterranean (UNESCO). Although authorities are very concerned about valorization and protection of biodiversity (flora and fauna), the interest in geological heritage is still much lower. Therefore, this paper intends to expose and provide value to the best sites of geologic interest (Geosites) recognizable in the area. We propose 34 Geosites as the most suitable to be considered representatives of the geological diversity of the National Park, displaying a great variety of geological typologies such as: structural geoloy, stratigraphy, sedimentology and paleontological sites, geomaterials and petrography, landforms and hydrogeology-hydraulic features. In order to classify and rank the Geosites while avoiding subjectivity, a numerical methodology based on two modules has been applied. The two modules consist of the Scientific Value (SV) and Additional Value (AV) each one being composed, in turn, by an important number of criteria. In addition, the Degradation Risk (DR) of the Geosites has also been valorized on the basis of several criteria. Some actions, following the criteria of the Global Geoparks Network by UNESCO, have been proposed for better conservation of the Geosites, as well as to contribute to education and to promote tourism. These actions would also stimulate economic activity and sustainable development in the area by attracting increasing numbers of visitors.El Parque Nacional de Talassemtane (TNP), recogido en la lista tentativa de Marruecos para su nominación como Patrimonio de la Humanidad por la UNESCO, se caracteriza por su gran biodiversidad y está integrado en la Reserva de la Biosfera Intercontinental del Mediterráneo. Aunque las autoridades están muy interesadas en la puesta en valor y protección de la biodiversidad (flora y fauna), su interés en el patrimonio geológico es mucho menor. Así, este trabajo trata de dar a conocer y poner en valor los excelentes lugares de interés geológico (Geositios) reconocibles en el área. Se proponen 34 Geositios que deberían ser considerados parte del patrimonio geológico y que despliegan una gran variedad de tipologías geológicas como geología estructural, estratigrafía, sedimentología, paleontología, geomateriales, petrología, geomorfología e hidrogeología-hidráulica. Para clasificar y ordenar los Geositios, evitando la subjetividad, se ha empleado una metodología numérica basada en dos módulos. Dichos módulos consisten en el Valor Científico (SV) y el Valor Adicional (AV) estando cada uno compuesto, a su vez, por un importante número de criterios. Además, el Riesgo de Degradación (DR) de los Geositios se ha valorado sobre la base de diversos criterios. Para una mejor conservación de los Geositios, pero también para contribuir a la educación y promoción del turismo, se han propuesto algunas acciones siguiendo los criterios de la Red Global de Geoparques de la UNESCO. Esas acciones podrían estimular también la actividad económica y el desarrollo sostenido de la región atrayendo un número creciente de visitantes.Research Project CGL2016-75679-P (Spanish Ministry of Education and Science), Research Groups of the Alicante University (CTMA-IGA)

The Geological Heritage of the Talassemtane National Park and the Ghomara coast Natural Area (NW of Morocco)

The Talassemtane National Park and the Ghomara Coast (TNP-GC) natural area, registered in the list of the exceptional patrimony of Morocco by the UNESCO, are characterized by their great biodiversity integrated in the Intercontinental Biosphere Reserve of the Mediterranean. Although authorities are very interested in valorization and protection of biodiversity (flora and fauna), the interest in geological heritage is still much lower. So, this paper tries to expose and give value to the very best sites of geologic interest (Geosites and Geodiversity sites) recognizable in the area. Forty-one sites are proposed as suitable to be considered as geological heritage. Twenty-nine of which are organized in three accessible georoutes (Oued Laou Valley and Ghomara Coast, Talambote-Akchour, and Chaouen-Ametrasse, respectively), and 12 others are located on trails and forest tracks inside or near the TNP. The 41 selected sites display a great variety of geological typologies as structural geology, stratigraphy-sedimentology, paleontology, geomaterials, petrology, geomorphology, and hydrogeology-hydraulic. In order to classify and rank (avoiding subjectivity) the sites and georoutes, a numerical methodology based on recent literature is applied. The scientific value (SV), potential educational value (PEV), and potential touristic value (PTV) are quantified (using several criteria in each case), making easy for possible users to select the most suitable route according to their goals. The degradation risk (DR) is also measured giving political and technical managers of the region important keys for an adequate geoconservation action plan. Finally, some actions following the criteria of the Global Geoparks Network by the UNESCO are proposed for the better conservation of the sites but also to contribute to education and promote tourism. These actions would also stimulate economic activity and sustainable development in the area by attracting increasing numbers of visitors.Research supported by: Research Project CGL2016-75679-P, Spanish Ministry of Education and Science; Research Groups and Projects of the Generalitat Valenciana, Alicante University (CTMA-IGA)