The Upper Cenomanian–Lower Turonian of the Preafrican Trough, Morocco

Lézin, Carine; Andreu, Bernard; Ettachfini, El Mostafa; Wallez, M.-J.; Lebedel, V.; Meister, Christian

doi:10.1016/j.sedgeo.2011.12.003

Cited by 40 publications

(35 citation statements)

References 22 publications

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“…The Akrabou Formation is fully marine, comprising shallowwater carbonates (mostly dolomitized) at the base, and finely-bedded carbonate mudstone at the top. This formation is similar to the CTB sections described elsewhere in the Central High Alas (ETTACHFINI et al, 2005) and the PreAfrican Trough (LÉZIN et al, 2012). The stratigraphic position of the CTB δ 13 C shift, as well as biostratigraphic data (LÉZIN et al, 2012) suggest that the basal shallow-water carbonates of the formation are latest Cenomanian, and the overlying, evenly-bedded mudstone early Turonian in age.…”

Section: Tinghir Sectionsupporting

confidence: 82%

“…This formation is similar to the CTB sections described elsewhere in the Central High Alas (ETTACHFINI et al, 2005) and the PreAfrican Trough (LÉZIN et al, 2012). The stratigraphic position of the CTB δ 13 C shift, as well as biostratigraphic data (LÉZIN et al, 2012) suggest that the basal shallow-water carbonates of the formation are latest Cenomanian, and the overlying, evenly-bedded mudstone early Turonian in age. So, contrarily to what has been found in the western Askoutti and Afansou sections, there is no stratigraphic hiatus indicative of prolonged emergence in the C-T boundary intervall at Tinghir.…”

Section: Tinghir Sectionsupporting

confidence: 82%

“…Cenomanian deposits are only known on the shoulders of the two branches of the rift. In these eastern areas, the map is constructed from the works of CISZAK et al (1999) and HADDOUMI et al (2008HADDOUMI et al ( , 2010 in the Middle Atlas, of ETTACHFINI et al (2005) and LÉZIN et al (2012) on the southern border of the High-Atlas in eastern Morocco, and from BENYOUCEF et al (2014) in the Bechar area (Saharan platform, western Algeria). Stratigraphic data from CAVIN et al (2010) and satellite images are used to delineate the Kem Kem embayment.…”

Section: Palaeogeographic Contextmentioning

confidence: 99%

“…The dolomite beds are overlain by mixed marine The dolomite beds of the Bou Tazoult section are not accurately dated. They could represent the deposits of the latest Cenomanian transgression documented farther east in the PreAfrican Trough (LÉZIN et al, 2012) as well as Turonian carbonates. This latest Cenomanian transgression has been documented over the whole northeastern Saharan craton (GROSHÉNY et al, 2008, just prior to the C-T boundary δ 13 C shift.…”

Section: Bou Tazoult Sectionmentioning

confidence: 99%

“…The present study deals with uppermost Albian to Cenomanian sequences, in which the relationships between marine and continental facies can be clearly deciphered from a sequence stratigraphic point of view. In the latest Cenomanian to lower Turonian a major marine flooding occurred (ETTACHFINI et al, 2005;GROSHÉNY et al, 2008GROSHÉNY et al, , 2013JATI et al, 2010;LÉZIN et al, 2012) all along the northern margin of the Saharan craton, and is responsible for the temporary disappearance of continental deposits in short-term, high-frequency sequences.…”

Section: Introductionmentioning

confidence: 99%

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Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

Essafraoui¹,

Ferry²,

Groshény³

et al. 2015

Carnets Geol.

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Seven sections, covering the upper Albian to lowermost Turonian, have been correlated from full-marine to continental-dominated deposits across a passive margin, along a transect 425 km long, from the present-day Atlantic coast to the "Pre-African Trough" between the Anti-Atlas and the HighAtlas. The thickness of the Cenomanian succession changes from around 500 metres in the fully marine sections to 250 metres in mostly continental facies in the western High-Atlas, about 150 km updip, to a few tens of metres in the Bou Tazoult area. The strata thicken again eastwards into the Pre-African Trough where they can be traced without major facies changes to the Kem Kem embayment and to the Bechar area in Algeria. Over all this eastern area, continental facies are overlain by the fully-marine shallow-water deposits of the Cenomanian-Turonian boundary interval. A first major conclusion is that fluvial aggradation in high-frequency transgressive-regressive sequences is coeval with the seaward-shift of the shoreline, in accordance with the genetic sequence stratigraphic model of GALLOWAY (1989). Both the flatness of the depositional profile and the corresponding very low energy of the marine environment during the transgressions account for the blanket of red continental clays on top of marine facies in updip depositional sequences, which is then preserved under the marine transgressive surface of the next sequence. Carnets Geol. 15 (12)A second major conclusion is that the high-frequency transgressive-regressive (T-R) sequences do not look like classical parasequences bounded by transgression surfaces. They usually exhibit a surface created by a sea-level fall within the regressive half-cycle. This is interpreted in the following way: regressions did not operate through a regular seaward-shift of the shoreline, but through stepped sealevel falls. The very low slope of the depositional ramp is thought to have enhanced the sequence stratigraphic record of such stepped regressions. Short-term, high-frequency sequences are organized into medium-frequency T-R sequences (seven in the Cenomanian) which show an overall aggrading and slowly retrograding pattern along the whole transect.Comparisons with other basins show that medium-frequency sequences do not fit the third-order depositional sequences described elsewhere, casting doubts about a eustatic mechanism for their deposition. Tazoult), sur environ 250 km. La série s'épaissit à nouveau vers l'est dans le sillon pré-africain où elle peut être suivie sans changements notables vers le golfe des Kem-Kem et le secteur de Béchar en Algérie. Sur toute la partie orientale de la transversale, les faciès continentaux ou mixtes sont recouverts par les dolomies marines du passage Cénomanien-Turonien. Une première conclusion majeure est que, dans les séquences transgression-régression (T-R) à haute fréquence, l'aggradation fluviatile accompagne sans hiatus le déplacement de la ligne de rivage au cours du demi-cycle régressif, en accord avec le modèle génétique de GALLOWAY (...

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Section: Tinghir Sectionsupporting

confidence: 82%

Section: Tinghir Sectionsupporting

confidence: 82%

Section: Palaeogeographic Contextmentioning

confidence: 99%

Section: Bou Tazoult Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

Essafraoui¹,

Ferry²,

Groshény³

et al. 2015

Carnets Geol.

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The first skeletal record of the enigmatic Cretaceous sawfish genus Ptychotrygon (Chondrichthyes, Batoidea) from the Turonian of Morocco

Villalobos-Segura

Underwood

Ward

2019

Papers in Palaeontology

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A new fossil batoid (ray) Ptychotrygon rostrispatula sp. nov. is described from five exceptionally well‐preserved, three‐dimensional skeletal remains from the Turonian (Late Cretaceous) of Morocco. These specimens represent the first known skeletal remains for the genus Ptychotrygon and allow an almost complete description of the genus, providing a new insight into its phylogenetic relations and validating its taxonomic status as a member of the Sclerorhynchoidei. Mechanical preparation of the fossil remains revealed a relatively large batoid species (estimated total length above 1 m). Overall the morphology resembles that of sclerorhynchoids, with a robust hypertrophied rostrum that lacks enlarged rostral denticles with enlarged paddle‐like pectoral proximal elements (propterygium, mesopterygium and metapterygium). Never before seen details of the branchial skeleton are presented (large second hypobranchial without anterior process, which was probably fused to the basibranchial and no evidence of articulation with other branchial element). To assess the phylogenetic relations of these specimens within the sclerorhynchoids a parsimonious analysis using TNT and PAUP was performed. These analyses included Asflapristis cristadentis and Ptychotrygon rostrispatula sp. nov., which were used as representatives of Ptychotrygonidae, and also includes six other genera of sclerorhynchoids with relatively good skeletal remains. Both analyses recovered two monophyletic groups within sclerorhynchoids: the first contains Ischyrhiza, Onchopristis and Schizorhiza, and a second that includes Micropristis, Sclerorhynchus, Libanopristis and Ptychotrygonidae.

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The Upper Cenomanian–Lower Turonian Anoxic Event in the Carbonate Platform of the Pre-African Trough, Morocco

et al. 2014

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The Upper Cenomanian–Lower Turonian of the Preafrican Trough, Morocco

Cited by 40 publications

References 22 publications

Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

The first skeletal record of the enigmatic Cretaceous sawfish genus Ptychotrygon (Chondrichthyes, Batoidea) from the Turonian of Morocco

The Upper Cenomanian–Lower Turonian Anoxic Event in the Carbonate Platform of the Pre-African Trough, Morocco

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