Structural evolution of the southern and northern Central High Atlas in paleogene and Mio-Pliocene times

Fraissinet, Cyril; Zouine, M.; Morel, Jean-Luc; Poisson, A.; Andrieux, Jean; Faure-Muret, Anne

doi:10.1007/bfb0011597

Cited by 55 publications

(69 citation statements)

References 7 publications

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“…Most authors (e.g. Fraissinet et al, 1988) propose four tectonic phases. Some authors suggest that the inversion is an all-Tertiary event, but others (Froitzheim et al, 1988;Beauchamp et al, 1999;see our Fig.…”

Section: Geophysicsmentioning

confidence: 99%

The Canary Islands origin: a unifying model

Anguita

Hernán

2000

Journal of Volcanology and Geothermal Research

197

128

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A new model, partially based on the three most widely cited previous hypotheses, is proposed to explain the genesis of the Canary Islands. From the hotspot hypothesis it retains the notion that the islands originated from a thermal anomaly in the mantle. From the propagating fracture hypothesis it takes the critical role of regional fractures in the onset of magmatism. The uplifted block hypothesis contributes with the notion that the islands are in their present freeboard attitude due to the action of tectonic forces.The main drawbacks of the three preceding hypotheses are solved within this unifying approach: the thermal anomaly is an upper mantle residue from an old plume, and therefore it does not carry (or does it in a highly diluted form) the typical geophysical and geochernical plume signatures; the fractures are well developed on the continental and oceanic crust, but not in the extremely thick sedimentary pile between the Canary Islands and Africa; and the Canary Islands uplift took place through transpressive shears, and not by means of purely reverse faults. This unifying model, which integrates the thermal and tectonic histories of the lithosphere and the sublithospheric mantle, is considered to be a valid approach to a number of volcanic areas where, as has been highlighted in recent years, pure hotspot or pure fracture models are found wanting to explain oceanic or (less frequently) continental volcanic lines.

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Section: Geophysicsmentioning

confidence: 99%

The Canary Islands origin: a unifying model

Anguita

Hernán

2000

Journal of Volcanology and Geothermal Research

197

128

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“…By the end of the Cretaceous, inversion and dextral shear of the Mesozoic rifts and formation of the Atlas system occurred in response to convergence of the African and European plates (Morabet et al 1998). Resulting tectonic structures consist of thrust faults, strike-slip faults, and block uplifts (e.g., Schaer and Rodgers 1987;du Dresnay 1988;Fraissinet et al 1988;Jacobshagen et al 1988a, b;Medina 1988;Jacobshagen 1992;Giese and Jacobshagen 1992). The Paleogene-Neogene marine clastics and continental deposits, occurring above a regional unconformity, formed from syndeformational erosion of the existing mountain belt (MiocenePliocene molass deposits).…”

Section: Atlas Systemmentioning

confidence: 98%

Geologic and Metallogenic Framework of North Africa

Bouabdellah

Slack

2016

Mineral Deposits of North Africa

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North Africa is noteworthy for having a great diversity of geology and mineral resources. Geologically, the region contains numerous terranes that contain rocks ranging in age from Archean to Quaternary, including diverse igneous, sedimentary, and metamorphic lithologies. Major geological features were built during the main phases of Proterozoic and subsequent Phanerozoic orogenies, the break-up of the supercontinents Rodinia, Gondwana, and Pangea, and during the opening and closing of major ocean basins such as the Iapatus, Atlantic, Pacific, and Tethys. Three major tectono-stratigraphic domains are recognized (1) the Precambrian province that includes the African-Nubian Shield (ANS) to the east and the West African Craton (WAC) to the west, and the intervening Tuareg Shield and "Saharan Metacraton"; (2) the Variscan (Paleozoic) fold belt; and (3) the Atlas-Alpine (Mesozoic-Cenozoic) system. Mineral deposits of North Africa formed in a variety of geologic settings at different time periods from Archean to Quaternary. Mineral commodities including gold, silver, cobalt, nickel, chromium, arsenic, copper, lead, zinc, iron, and many other elements. Major deposit types present in the region are (1) orthomagmatic Cr-Ni-platinum group elements (PGE); (2) rare-metal granites and related rare-element pegmatites; (3) volcanic-hosted massive sulphide (VHMS); (4) sedimentaryexhalative (SEDEX); (5) orogenic and intrusion-related gold; (6) iron oxide-copper-gold (IOCG); (7) banded iron formation (BIF); (8) Mississippi Valley-type (MVT) lead-zinc; (9) sediment-hosted stratiform copper;Electronic supplementary material The online version of this chapter

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“…Petit et al, 1985;Fraissinet et al, 1988;Zouine, 1993;Chellaï & Perriaux, 1996;Morel et al, 2000;Aït Hssaine, 2000). With respect to the data collected from continental (Allard et al, 1958;Ambroggi, 1963;Cahuzac, 1989), and marine (Mridekh et al, 2000;Samaka, 2001;Mridekh, 2002) areas, analysis of the northeastern segment of the studied profile leads to subdivide the geological history of the fault zone into three major stages, two of which are major events.…”

Section: Chronology Of Deformationmentioning

confidence: 99%

“…In the Moroccan High Atlas, the southernmost Alpine chain of the western Mediterranean, the major uplift phase was recorded in Late MiocenePliocene times, as can be inferred from the thick conglomerate formations deposited at the chain borders, which contain clasts derived from the uplifted relief (Duffaud, 1981, Petit et al, 1985, Medina, 1986, 1994, Fraissinet et al, 1988, Zouine, 1993, Chellaï & Perriaux, 1996, Aït Hssaine, 2000. In the western High Atlas ( fig.…”

Section: Introductionmentioning

confidence: 99%

Structure of the Kasbah fold zone (Agadir bay, Morocco). Implications on the chronology of the recent tectonics of the western High Atlas and on the seismic hazard of the Agadir area

Mridekh¹,

Medina²,

Mhammdi³

et al. 2009

Estud. geol.

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Detailed re-interpretation of the north-eastern segment of a profile realized across the Agadir bay along a NE-SW trend and crosscutting the main structures, together with analysis of available isochron maps, allowed us to retrace the geological history of the offshore western High Atlas. Two tectonostratigraphic sequences were distinguished: Unit II, which displays a simple structure, laying unconformably on Unit I, with a more complex structure dominated by a reverse fault (F1) striking E-W with a dip to the north. Correlation to boreholes Souss-1 and AGM-1 allowed us to assign Unit I to the Triassic – Palaeogene and Unit II to the Miocene – Present. The NE fault block shows a ramp-flat fault plane (F2) with an overlying SW-vergent fold that can be interpreted as a fault-bend fold. Three main stages were distinguished: (1) during the Cretaceous, F1 could have been a syndepositional normal fault with the NE block moving downwards; (2) towards the beginning of the Tertiary, the displacement of plane F2 induced the development of a fault-bend fold and erosion of the forelimb and hinge of the fold; displacement along F2 was transferred to fault F1; (3) afterwards, during the Miocene, reverse motion of F1 deformed and tilted the plane F2 and accentuated the folded structure. This evolution is typical for a frontal basin above a fault-related fold. Evaluation of the thickness and bed depth differences shows that the largest growth rate was recorded in Late Miocene times. Seismic activity recorded in the Agadir bay appears to be clearly related to this fault zone, as inferred from focal mechanisms. Seismic moment evaluation suggests that earthquakes of magnitude Mw≥6 are likely to occur, but could not be much larger because of the fault segmentation geometry of the High Atlas Front.<br><br>A partir de una detallada reinterpretación del segmento nororiental de un perfil que corta las principales estructuras de la bahía de Agadir a lo largo de una directriz NE-SW, y un análisis de los mapas de isocronas disponibles, se ha podido establecer la historia geológica de la costa del Alto Atlas occidental. En primer lugar, se han distinguido dos secuencias tectonoestratigráficas: la Unidad II, que muestra una estructura simple, y la Unidad I, de estructura más compleja dominada por una falla inversa (F1) de dirección E-W vergente al norte, sobre la que se dispone la Unidad II de forma discordante. La correlación con los sondeos Souss-1 y AGM-1 ha permitido asignar la Unidad I al Triásico-Paleógeno y la Unidad II al Mioceno-Presente. El bloque NE de la falla muestra un plano de falla de tipo rampa-rellano (F2) con un pliegue superpuesto vergente al SW que puede ser interpretado como un pliegue de flexión de falla. Respecto a su evolución temporal, se han distinguido tres estadios: 1) Durante el Cretácico, F1 pudo haber sido una falla normal sindeposicional, con el bloque NE desplazándose hacia abajo; 2) Al comienzo del Terciario, el desplazamiento del plano F2 indujo el desarrollo de un pliegue de flexión de falla y...

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Structural evolution of the southern and northern Central High Atlas in paleogene and Mio-Pliocene times

Cited by 55 publications

References 7 publications

The Canary Islands origin: a unifying model

The Canary Islands origin: a unifying model

Geologic and Metallogenic Framework of North Africa

Structure of the Kasbah fold zone (Agadir bay, Morocco). Implications on the chronology of the recent tectonics of the western High Atlas and on the seismic hazard of the Agadir area

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