The Cenomanian–Turonian boundary event on the Moroccan Atlantic margin (Agadir basin): Stable isotope and sequence stratigraphy

Jati, Mohamed; Groshény, Danièle; Ferry, Serge; Masrour, Moussa; Aoutem, Mohamed; Içame, Nourrisaid; Gauthier-Lafaye, F.; Desmares, Delphine

doi:10.1016/j.palaeo.2010.07.002

Cited by 30 publications

(22 citation statements)

References 35 publications

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“…The position of the Cenomanian-Turonian boundary (CTB) δ 13 C positive shift (Fig. 3) in this section (JATI et al, 2010), allows the stage boundary to be located precisely which, in worldwide reference sections (see for instance GROSHÉNY et al, 2013, Fig. 5), is always within the upper part of the isotope anomaly, in this section within the uppermost part of sequence Ce7.…”

Section: Biostratigraphymentioning

confidence: 69%

“…It is also based on regional correlations (see later section). Sequence Ce7 is probably restricted to the Taghazoute area (JATI et al, 2010), as the CTB δ 13 C shift is not found in eastern sections (Tahanoute to Afansou), as a result of a stratigraphic hiatus.…”

Section: Medium-frequency Sequencesmentioning

confidence: 96%

“…Additional observations have been made in the nearby open country, especially to examine the lateral evolution of some facies, e.g., oyster beds that are a prominent feature in this distal depositional environment in the Cenomanian. The Cenomanian-Turonian transition has already been studied in detail in this section (JATI et al, 2010). The lithostratigraphic scheme is from AMBROGGI (1963).…”

Section: Taghazoute Sectionmentioning

confidence: 99%

“…3.C) occurs as an additional facies, intercalated between the oyster beds and the overlying grey marlstone. According to JATI et al (2010), two unusual surfaces occur near the top of the formation, a karst surface (labelled ks, Fig. 3) and a ravinement surface covered by a polygenic microconglomerate (labelled cgt, Fig.…”

Section: Lithology and Depositional Faciesmentioning

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: Biostratigraphymentioning

confidence: 69%

Section: Medium-frequency Sequencesmentioning

confidence: 96%

Section: Taghazoute Sectionmentioning

confidence: 99%

Section: Lithology and Depositional Faciesmentioning

confidence: 99%