La formation bahloul en tunisie centro-septentrionale: variations latérales, nouvelle datation et nouvelle interprétation en terme de stratigraphie séquentielle

Maamouri, Abdelkrim; Zaghbib-Turki, Dalila; Matmati, Mohammed; Chikhaoui, M.; Salaj, Joseph

doi:10.1016/0899-5362(94)90052-3

Cited by 35 publications

(23 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The present study describes filament accumulations within the Cenomanian-Turonian black shales constituting the Bahloul Formation [Burollet, 1956]. The Bahloul Formation and the Cenomanian-Turonian transition have been widely studied Maamouri et al, 1994;Robaszynski et al, 1994;Accarie et al, 2000;Zagrarni, 1999;Abdallah et al, 2000;Hanini et al, 2004;Caron et al, 2006;Zagrarni et al, 2008], and provide the frame for the environmental interpretation of this "filament event". The purpose of this paper is to determine the origin of filaments and to reconstitute their deposition environment at local and global scales.…”

Section: Introductionmentioning

confidence: 99%

“…Mass accumulations of thin bivalve shells ("filaments") occur in several distinct limestone and marly intervals throughout the Mesozoic Tethyan realm [e.g., Robaszynski et al, 1994;Maamouri et al, 1994;Molina et al, 1997;Accarie et al, 2000;Abdallah et al, 2000;Wan et al, 2003;Ettachfini and Andreu, 2004;Caron et al, 2006;Zagrarni et al, 2008;Navarro et al, 2009]. Jurassic filaments are thought to represent protoconchs or juvenile shells of posidoniid bivalves (Bositra, Posidonia), while Triassic occurrences are attributed to halobiid bivalves [Lapparent, 1923;Colom, 1955;Flügel, 2004].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The filament event near the Cenomanian-Turonian boundary in Tunisia: filament origin and environmental signification

Negra

Zagrarni

Hanini

et al. 2011

Bulletin De La Société Géologique De France

View full text Add to dashboard Cite

Abstract. -Near the Cenomanian-Turonian boundary, the filament event corresponds to the massive occurrence of thin elongate shells, probably bivalves which constitute, in the Bahloul Formation, about 40% of allochems. This biosedimentary event was described in several areas, such as in Tunisia, Algeria, Morocco, North America, Oman and Tibet. In Tunisia, filaments are well represented within well laminated black shales constituting the Bahloul Formation, late Cenomanian -early Turonian in age. These black shales were deposited under anoxic conditions developed in an outer ramp environment. Filaments are particularly abundant in the upper part of the Bahloul Formation, which is topped by a condensation level exhibiting encrusted ammonites associated with frequent burrows, and phosphatic and glauconitic grains. In terms of depositional environments, the filament concentrations announce an evolution towards "normal"-marine conditions, which followed the anoxic conditions favouring black-shale formation. This trend coincided with a deepening that led to maximum flooding at the condensation surface. The petrographic study of samples taken along a N-S transect shows a clear evolution of filament structures from distal to proximal ramp. Limestones deposited in the outer ramp environment mainly contain well preserved "pelagic" bivalve shells showing a thin-shelled structure composed of elongated filaments. Laterally, toward the proximal ramp, the bivalve shells are progressively disintegrated, the filaments being arranged parallel to bedding. In an even more proximal setting, filaments appear finer, highly fragmented and arranged without preferential orientation. The Cenomanian-Turonian "pelagic" bivalves thus probably lived in an outer ramp environment and their thin shells disintegrated progressively into filaments. This happened during high energy conditions generated by storms.The filament event, which is associated to other bio-events expressed by the extinction and the first occurrence of some pelagic species, could be used to establish local to global correlations.When the ammonite Watinoceras, the main early Turonian marker, is rare or absent, the filament-rich facies could indicate the proximity of the Cenomanian-Turonian boundary.At a global scale, the filament event illustrates a sea-level rise in relation with eustatic and climatic changes. The maximum flooding of this transgressive event was identified in several localities and dated about 93 Ma. The very high sea-level conditions are favourable to accumulation and preservation of organic-rich facies such as black shales, which illustrate the anoxic event OAE2.The abundance of filaments near the Cenomanian-Turonian boundary is an indicator of high organic productivity following a climatic change to warmer conditions. The latter have clearly influenced oceanic water-masses circulation, water column stratification and nutrient partitioning. L'événement "à filaments" à la limite Cénomanien -Turonien en Tunisie : origine et milieux de genèse des filamentsMots-c...

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The filament event near the Cenomanian-Turonian boundary in Tunisia: filament origin and environmental signification

Negra

Zagrarni

Hanini

et al. 2011

Bulletin De La Société Géologique De France

View full text Add to dashboard Cite

show abstract

“…Studies on Cenomanian -Turonian boundary interval show that deposition of radiolarian, organic-rich sediment and large positive carbon isotopic excursion are coeval with extreme fertility conditions and correspond to a large-scale proxy that indicate a hypersiliceous period (Premoli Silva et al, 1999;Racki & Cordey, 2000) The Bonarelli equivalent in Tunisia is commonly known by the Bahloul Formation (Burollet, 1956). In the Bargou area, the Bahloul Formation shows organic-rich intervals interbedding cherty and radiolarian limestone layers (Layeb andBelayouni 1999, Soua andTribovillard, 2007) Although the C/T boundary interval outcropping in the Tunisian realm was extensively studied by planktic foraminifera and ammonite biostratigraphy (Maamouri et al, 1994;Nederbragt and Fiorentino, 1999;Abdallah et al, 2000;Amédro et al, 2005), radiolaria assemblages have provided a useful tool for age calibration and subdivision of C/T organicrich beds in this study. Two black shale levels were identified in Oued Kharroub section: 1.…”

Section: Discussionmentioning

confidence: 99%

Radiolarian Age Constraints of Mid-Cretaceous Black Shales in Northern Tunisia

Fadhel¹,

Soua²,

Zouaghi³

et al. 2012

Earth Sciences

View full text Add to dashboard Cite

“…It is represented by a surface of condensation, rich in grains of glauconite and phosphorite. Towards the south, in the adjacent platform (Gafsa basin), as well as in the Oued Bahloul location (Maamouri et al, 1994), this surface is recorded by abundant lowermost Turonian ammonites (e.g. Fagesia sp.…”

Section: Transgressive Systems Tract (Tst)mentioning

confidence: 99%

The Organic-Rich and Siliceous Bahloul Formation: Environmental Evolution Using Facies Analysis and Sr/Ca & Mn Chemostratigraphy, Bargou Area, Tunisia

Soua¹,

Jemia²,

Zaghbib-Turki³

et al. 2011

Earth and Environmental Sciences

View full text Add to dashboard Cite

La formation bahloul en tunisie centro-septentrionale: variations latérales, nouvelle datation et nouvelle interprétation en terme de stratigraphie séquentielle

Cited by 35 publications

References 11 publications

The filament event near the Cenomanian-Turonian boundary in Tunisia: filament origin and environmental signification

The filament event near the Cenomanian-Turonian boundary in Tunisia: filament origin and environmental signification

Radiolarian Age Constraints of Mid-Cretaceous Black Shales in Northern Tunisia

The Organic-Rich and Siliceous Bahloul Formation: Environmental Evolution Using Facies Analysis and Sr/Ca & Mn Chemostratigraphy, Bargou Area, Tunisia

Contact Info

Product

Resources

About