Subsidencia y levantamiento durante el Plio-Cuaternario en los sectores de Oued Laou y Tirinesse (Zona Interna Rifeña, Marruecos)

The Oued Laou area and the Tirinesse basin are filled with early Pliocene (Zanclean) marine sediments very slightly deformed but currently outcropping at different altitudes. In Tirinesse area Zanclean sediments reach high altitudes (+600 m), whereas coeval sediments appear near the coastal level in Oued Laou area and even more than 100 m under the sea level in a borehole near the coast. The difference of altitudes is explained by two successive processes. First there was an important regional subsidence permitting sedimentation. Moreover, in the Tirinesse basin, due to the combined movement of the two SW-NE conjugated normal faults, an additional tectonic subsidence took place. Later, a regional and not homogenous uplift, progressively more important to the west, occurred in the Rifian Internal Zone, then surpassing the effects of the subsidence. Differential vertical displacements also existed in a N-S directionEl valle de Oued Laou y la cuenca de Tirinesse están rellenos de sedimentos marinos del Plioceno (Zancliense) débilmente deformados aunque afloran a diferentes altitudes. En Tirinesse, el Zancliense alcanza gran altura (+600 m), mientras que sedimentos equivalentes se encuentran al nivel del mar en Oued Laou e incluso a más de 100 m bajo este nivel en un sondeo cerca de la costa. Las diferentes alturas se explican por dos procesos sucesivos. Primero se produjo una importante subsidencia regional que facilitó la sedimentación. En la cuenca de Tirinesse, la subsidencia fue más acentuada por el efecto de fallas normales SW-NE. Después, en la Zona Interna Rifeña hubo un levantamiento regional, tanto más importante cuanto más al oeste, que en conjunto sobrepasó el efecto de la subsidencia.También hubo movimientos verticales diferenciales en la dirección N-

The Paleogene successions in the upper Ghomaride unit in Talembote (Internal Rif, Morocco)

43ª Sesión Científica. Móstoles, Noviembre de 2007The lower Paleogene stratigraphic successions of the Talembote upper Ghomaride Unit represent an interval of age going from the (middle?) Ilerdian to the early Bartonian, showing a transgressive sequence interrupted by intermittent sedimentary gaps, which are indicated by surfaces of discontinuity. These sediments correspond essentially to carbonatic facies with benthic foraminifers deposited in a shallow platform that was maintained probably until the late Lutetian. The abrupt rupture of this platform allowed, during the early Bartonian, sedimentation of pelagic to hemipelagic facies in a bathyal sedimentary environment. Later, the sudden interruption of the sedimentation in the early Bartonian, indicated by a paleosoil, may be better explained by tectonic reason than eustatism taking into account many actual geodynamic reconstructions.Esta nota se ha hecho en el marco de la beca concedida a uno de los autores (R.H) por la Agencia Española de Cooperación Internacional (AECI) y del proyecto CGL 2005-00404/BTE.Peer reviewe

La cuenca de Tirinesse de edad Plioceno inferior (SO de Oued Laou, Rif, Marruecos): propuesta de un modelo de formación

The Tirinesse basin, filled mainly by lower Pliocene marine sediments, is a small tectonic graben bounded by two NE-SW normal faults, with the eastern one surpassing 500 m in throw. These faults proved to belong to a much longer system of faults that transversally cut the entire Rifian Internal Zone. The subsidence of this basin was controlled by a jointed scissor movement of the two faults, which rotation axis coincided with the basin itself. This explains the important thickness of its sedimentary infilling, mainly occurred during the ZancleanLa cuenca de Tirinesse, rellena por sedimentos marinos del Plioceno inferior, es una pequeña fosa tectónica limitada por dos fallas normales de dirección NE-SO, de las que la oriental tiene un salto vertical que supera los 500 m. Estas fallas forman parte de un sistema de fallas mucho más largo que corta transversalmente la Zona Interna Rifeña. La subsidencia de la cuenca fue controlada por el movimiento conjugado en tijera de ambas fallas, cuyo eje de giro coincide con la posición de la cuenca. Esto explica la importancia de su relleno sedimentario ocurrido fundamentalmente durante el Zancliens

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

The Eocene platform deposits in the Moroccan Ghomarides have been studied. These marine carbonate platforms were located in the westernmost Tethys approximately 30°N and 0°–10°W during the Cuisian to Bartonian. The study includes observations from fossiliferous assemblages (such as larger benthic foraminifera and colonial corals), their palaeoenvironment 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 mid 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 changes 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 the 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 are registered. Two anomalies have been detected in the Ghomaride Domain during Ypresian and Bartonian times indicating particular climatic conditions or local tectonic interferences

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)

Integrating remote sensing, GIS and in-situ data for structural mapping over a part of the NW Rif belt, Morocco

This study adopts an integrated approach using the geographic information system (GIS) and remote sensing techniques for structural mapping in inaccessible zone of the internal segment of North-Western Rif belt, Morocco. The Principal Component Analysis (PCA), Optimal Index Factor (OIF), band ratios and directional filtering are applied to Landsat 8 OLI (Operational Land Imager) image for mapping lithology and geological structures. Tectonic lineaments are extracted using the remote sensing and GIS approach and verified by in-situ data. Lithology and detailed structural features in the study area as well as the main sets of fractures trending NW–SE and E–W are identified and highlighted. The results obtained in this research demonstrate that the integration of remote sensing imagery and GIS techniques is a reliable and low-cost approach to fracture extraction and structural mapping, particularly in remote and inaccessible regions of the African plate and other analogue zones around the world

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

Revista de la Sociedad Geológica de España 23 (1-2) THE MALALYINE PLIOCENE SUCCESSION (NE RIF, MOROCCO): SEQUENCE STRATIGRAPHY AND REGIONAL CORRELATION

Abstract: Malalyine area (Northern Morocco, about 10 km NNE of Tetouan), located in the Rifian Internal Zone, hosts a sedimentary basin filled since the early Pliocene. The sedimentary filling of this basin comprises three members. Member 1: inner platform basal marls dated as early Zanclean. They are rich in thinshelled pectinids (Amussium, mainly) and characterized by Ophiomorpha burrows; Member 2: a lagoonal silty sand and conglomerate alternation containing conspicuous Thalassinoides burrows and shows welldelineated Fe-encrusted surfaces on the conglomerate beds; Member 3: fan-delta red conglomerates experiencing a pronounced thickening and upward-coarsening trend. Member 1 corresponds to the regressive stage of a late highstand regime, while the erosional surface at its top delineates the subsequent sequence boundary. Member 2 marks the onset of a new sequence, with the lime-free basal interval and the overlying Fe-surfaces representing the transgressive interval and the condensed section respectively. Member 3 marks the subsequent highstand with the well-expressed downlap surfaces pointing to a regressive regime accompanied by a prograding fan-delta. The whole Malalyine succession proved to be correlatable with a Spanish early Pliocene counterpart known in the Malaga area where it is similarly made up of marine marls (Pl-2) and above discordantly fan-delta conglomerates (Pl-3). Based on its early Pliocene age, these deposits would correlate with the Pliocene I of the eastern Betic basins. Key words: Early Pliocene, Sequence stratigraphy, Trace fossils, N Morocco. Resumen: El área de Malalyine (Norte de Marruecos, a unos 10 km al NNE de Tetuán), localizada en la Zona Interna rifeña, corresponde a una cuenca sedimentaria que se rellenó a partir del Plioceno inferior. Su relleno sedimentario comprende tres miembros. Miembro 1: margas basales de plataforma interna datadas del Zancliense inferior. Estas margas son ricas en pectínidos de concha fina (principalmente Amussium) y muestran túneles de Ophiomorpha; Miembro 2: alternancia de arenas limosas y conglomerados depositados en un lagoon, conteniendo bioturbaciones de Thalassinoides y superficies de incrustaciones de Fe bien delineadas sobre las capas de conglomerado; Miembro 3: conglomerados rojos de abanico deltaico ordenados según una pronunciada tendencia estrato y granocreciente. El Miembro 1 corresponde a la etapa regresiva de un régimen de nivel alto tardío, mientras que la superficie de erosión en su techo caracteriza el subsecuente límite de secuencia. El Miembro 2 marca el comienzo de una nueva secuencia, con un intervalo basal sin carbonatos que representa el intervalo transgresivo y, por encima, una secuencia condensada con superficies ferruginosas. El Miembro 3 representa el subsiguiente estadio de nivel alto con claras superficies de biselamiento basal (downlap) apuntando a un régimen regresivo acompañado de una progradación de abanicos deltaicos. La sucesión completa de Malalyine podría correlacionarse con el Plioceno inferior español que aflora en la cuenca de Málaga, el cual también está compuesto por margas marinas (Pl-2) sobre las que se disponen discordantemente conglomerados de abanicos deltaicos (Pl-3). Por su edad (Plioceno inferior), estos depósitos se correlacionarían con el Plioceno I de las cuencas béticas orientales

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)

Characterization of the Lago Mare sedimentation (latest Messinian) and the transgression of the beginning of the Pliocene in the Malaga basin (Betic Cordillera)

A stratigraphic unit deposited close to the Messinian-Pliocene boundary is newly discovered in the Malaga basin. This unit mainly consist of alluvial and lagoonal deposits. Paleontological and paleomagnetic data from these deposits and from the overlying sediments indicate that the former were formed in the latest Miocene, thus can be correlated with the so-called Lago Mare deposits. The latest Messinian and lower Pliocene deposits are separated by an erosive surface (latest-Messinian discontinuity) that is related to a relative sea-level fall previous to the earliest Pliocene general floodin