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Hssaida T.,Hassan II University | Chahidi S.,Hassan II University | Benzaggagh M.,Moulay Ismai University | Riding J.B.,British Geological Survey | Oumalch F.,Office National des Hydrocarbures et des Mines ONHYM
Annales de Paleontologie | Year: 2014

A biostratigraphic study of dinoflagellate cysts of the Upper Jurassic series from the eastern External RifChain, has been achieved for the first time on four outcrop sections : the DM section (Douar Marticha),the TB section (the Tarhchenna "Sof"), the KSD section (the Kef Mallou "Sof") and the Y section (DouarLamriene) among which three sections (TB, KSD and Y) are well-dated by ammonites and calpionellidsfauna. The DM and TB sections are complementary in terms of stratigraphy and correspond respectivelyto the upper part of the "Ferrysch" Formation, a thick shaly-silty and sandy sequence assigned to theCallovian-Oxfordian stages and to the El Gouzat limestones Formation (Kimmeridgian - Lower Tithonian age) and to the Tarhchenna marly limestones Formation (Upper Tithonian age) from the EL Gouzat area(Mesorif). The KSD and Y sections are also complementary and correspond to the Kimmeridgian-LowerTithonian Msila limestones Formation and to the overlying marly limestones Massif Formation of UpperTithonian age, outcropping in the Msila region (Internal Prerif). These four sections have shown manydinocysts rich levels, which had allowed characterizing the Middle? and Upper Oxfordian substages inthe DM section. In the other sections, the dinoflagellate cyst assemblages are nearly similar to those ofthe Kimmeridgian-Tithonian of many sections from the Boreal, Sub-boreal and North tethyan realms,particularily from England, Russia and South-East France basin. The results of the present work confirmonce again, the important value of dinoflagellate cysts, for age dating of ammonites-lacking Mesozoicsedimentary sequences and for biostratigraphic correlations. © 2014 Elsevier Masson SAS. All rights reserved. Source


Bodin S.,University of Manchester | Bodin S.,Ruhr University Bochum | Frohlich S.,University of Manchester | Frohlich S.,Statoil | And 3 more authors.
Journal of Petroleum Geology | Year: 2011

The early Toarcian is characterized by the occurrence of widespread black shale deposits, recorded extensively across Europe and interpreted to be related to an Oceanic Anoxic Event. In order to investigate the source-rock potential of lower Toarcian deposits in Morocco, detailed sedimentary logging accompanied by outcrop spectral gamma-ray measurements were carried out on four sections representative of different palaeo-depositional settings in the Central High Atlas. Authigenic uranium enrichment is used as a proxy for oxygen-depleted depositional conditions, and may thus indicate potential organic-rich lithologies. Of the four measured sections, only one (the Amellago section, which represents the deepest marine setting) shows relative authigenic uranium enrichment. Complementary TOC analyses (with maximum values of 3.24%) over this interval confirm an associated enrichment trend in organic matter. The organic matter recovered from the outcrop samples is however highly oxidised, and thus the absolute value is not regarded as being a true record of the rocks' organic content. It is concluded from this study that early Toarcian potential source rocks were deposited within restricted sub-basins in the Central High Atlas. It is therefore possible that organic-rich deposits of Toarcian age are present in similar palaeogeographic settings in other areas of Morocco. This increases the exploration potential of Moroccan basins in which Jurassic deposits are potential source rocks. © 2011 The Authors. Journal of Petroleum Geology © 2011 Scientific Press Ltd. Source


Bodin S.,University of Manchester | Mattioli E.,University Claude Bernard Lyon 1 | Frohlich S.,University of Manchester | Marshall J.D.,University of Liverpool | And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010

The Early Toarcian is marked by a global perturbation of the carbon cycle and major marine biological changes. These coincide with a general decrease in calcium carbonate production and an increase in organic carbon burial, and culminate in the so-called Toarcian Oceanic Anoxic Event. It is believed that the environmental crisis was triggered by the activity of the Karoo-Ferrar large igneous province. In order to further document the Early Toarcian palaeoenvironmental perturbations, carbon isotope, total organic matter, calcareous nannofossils and phosphorus content of the Amellago section in the High Atlas rift basin of Morocco were investigated. This section is extremely expanded compared to the well-studied European sections. Its position along the northern margin of the Gondwana continent is of critical importance because it enables an assessment of changes of river nutrient input into the western Tethyan realm. The carbon isotope curve shows two negative excursions of equal thickness and amplitude, at the Pliensbachian-Toarcian boundary and at the transition from the Polymorphum to the Levisoni Zone. This confirms the supra-regional nature of these shifts and highlights the possible condensation of the first "boundary" shift in European sections. Phosphorus content is used to trace palaeo-nutrient changes and shows that the two negative carbon isotope shifts are associated with increased nutrient levels, confirming that these episodes are related to enhanced continental weathering, probably due to elevated greenhouse gases in the atmosphere. In the High Atlas Basin, the increase in nutrient levels at the Pliensbachian-Toarcian boundary is moreover likely to be the main factor responsible for the coeval demise of the Saharan carbonate platform. A middle Toarcian event, centered on the boundary between the Bifrons and Gradata Zones, characterized by a positive carbon isotope excursion and nutrient level rise, is documented in the Amellago section. © 2010 Elsevier B.V. Source


Elbatal Y.,Hassan II University | Aadjour M.,Hassan II University | Saber N.,Hassan II University | Elabibi R.,Office National des Hydrocarbures et des Mines ONHYM | Nahim M.,Office National des Hydrocarbures et des Mines ONHYM
Physical and Chemical News | Year: 2012

The Upper Cretaceous of Boujdour-Tarfaya Basin contains an interesting petroleum source rock potential. Geochemical analysis based mainly on the Rock-Eval pyrolysis was performed to determine the oil origin and its degree of maturation, in order to evaluate the hydrocarbon potential in the basin. The results show a Cenomanian-Turonian high-quality petroleum source rock with a TOC content mostly around 12%. The organic matter is of type II which develops in the area between Tarfaya and Boujdour. The stratigraphic analysis of the exploration wells in the basin allowed to better characterize the source rock capable of generating hydrocarbons. In fact, the maturation of the Cenomanian-Turonian source rock up to 430 ° C, increasing from north to south and from east to west, allowing it to be early mature to mature in the basin of Boujdour. Source

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