References of "Facies"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailSedimentary development of a continuous Middle Devonian to Mississippian section from the fore-reef fringe of the Brilon Reef Complex (Rheinisches Scheifergebirge, germany)
Pas, Damien ULg; Da Silva, Anne-Christine ULg; Cornet, Pierre et al

in Facies (2013), 59

The Brilon-reef complex is one of the biggest Devonian carbonate buildups (~80 km²) of the Rheinisches Schiefergebirge. The Burgberg section is located in the south-eastern fore-reef area of the Brilon ... [more ▼]

The Brilon-reef complex is one of the biggest Devonian carbonate buildups (~80 km²) of the Rheinisches Schiefergebirge. The Burgberg section is located in the south-eastern fore-reef area of the Brilon reef-complex and exposes a succession of strata (117 m thick) which extend from the Middle Givetian (middle varcus conodont Zone) to the Viséan (bilineatus conodont Zone). Field and microfacies observations led to the definition of nine microfacies which are integrated into a sedimentary model divided into off-reef, intermediate fore-reef and proximal fore-reef sedimentary domains (SD). The off-reef domain (SD1) is the most distal setting observed and is characterized by fine-grained sediments, dominated by pelagic biota and the local occurrence of gravity-flow deposits. The intermediate fore-reef (SD2) is characterized by a mixture of biota and sediments coming from both, deeper-water and shallow-water sources and is influenced by storm and gravity-flow currents. In this domain Renalcis mound-like structures developed locally. Finally, the proximal fore-reef (SD3) corresponds to the most proximal setting which is strongly influenced by gravity-flow currents derived from the Brilon reef-complex. The temporal evolution of microfacies in the fore-reef setting of the Burgberg section show five main palaeoenvironmental trends influenced by the onset, general development, and demise/drowning of the Brilon reef-complex. Fore-reef to off-reef lithologies and their temporal changes are from the base to the top of the section: (U1) - fine-grained sediments with large reef debris, corresponding to the initial development of the reef building upon submarine volcanoclastic deposits during the Middle Givetian (middle varcus Zone) and first export of reef debris in the fore-reef setting; (U2) - high increase of reef-derived material in the fore-reef area, corresponding to a significant progradation of the reef from the Middle Givetian to the Early Frasnian (maximum extension of the Brilon reef-complex to the south, disparilis to the falsiovalis conodont biozones); (U3) - progressive decrease of shallow-water derived material and increase of fine-grained sediments and deep-water biota into the fore-reef setting, corresponding to the stepwise withdrawal of the reef influence; from the Middle to the Late Frasnian (jamieae conodont Zone); (U4) - development of a submarine rise characterized by nodular and cephalopod-bearing limestones extending from the Late Frasnian to the Late Famennian corresponding to the demise and drowning of the Brilon reef-complex as a result of the Late Frasnian Kellwasser events (upper rhenana and triangularis conodont biozones); (U5) - significant deepening of the Burgberg area starting in the Late Famennian, directly followed by an aggrading trend marked by pelagic shales overlying the nodular limestone deposits. [less ▲]

Detailed reference viewed: 52 (12 ULg)
Full Text
Peer Reviewed
See detailDeposition within the vicinity of the Mid-Eifelian High : detailed sedimentological study and magnetic susceptibility of a mixed ramp-related system from the Eifelian Lauch and Nohn formations (Devonian ; Ohlesberg, Eifel, Germany)
Mabille, Cédric ULg; Pas, Damien ULg; Aretz, Markus et al

in Facies (2008), 54

This study focuses on the base of the Eifelian stage and on the abandoned Ohlesberg quarry. The exposed section (92 m thick) is related to the Lauch and Nohn formations. Petrographic study leads to the ... [more ▼]

This study focuses on the base of the Eifelian stage and on the abandoned Ohlesberg quarry. The exposed section (92 m thick) is related to the Lauch and Nohn formations. Petrographic study leads to the defnition of 11 microfacies which are integrated in a palaeogeographical model. It corresponds to a complex ramp setting where carbonate, mixed and siliciclastic deposits coexist. The microfacies evolution is interpreted in terms of bathymetric and lateral variations, showing a general shallowing upward trend and transitions between carbonate-dominated and siliciclastic-dominated sedimentary domains. This interpretation is supported by trends in magnetic susceptibility data. Even if the proximity to emerged areas appears to be the major influence on magnetic susceptibility values, the influence of carbonate productivity and wave agitation is also noted. The Ohlesberg section clearly points to the local and regional complex facies architecture, and advocates to variegated depositional environments along the Mid-Eifelian High. [less ▲]

Detailed reference viewed: 50 (13 ULg)
Full Text
Peer Reviewed
See detailReconstructing atoll-like mounds from the Frasnian of Belgium
Boulvain, Frédéric ULg; Cornet, Pierre ULg; Da Silva, Anne-Christine ULg et al

in Facies (2004), 50(2), 313-326

A succession of Frasnian mounds on the southern border of the Dinant Synclinorium (Belgium) was investigated for their facies architecture, sedimentary dynamics and palaeogeographic evolution. Seven mound ... [more ▼]

A succession of Frasnian mounds on the southern border of the Dinant Synclinorium (Belgium) was investigated for their facies architecture, sedimentary dynamics and palaeogeographic evolution. Seven mound facies were defined from the Arche (A) and Lion (L) members, each characterized by a specific range of textures and association of organisms (A2/L2: red or pink limestone with stromatactis, corals and crinoids; A3/L3: grey, pink or green limestone with stromatactis, corals and stromatoporoids; A4/L4: grey limestone with corals, peloids and dasycladaceens; A5/L5: grey microbial limestone; A6/L6: grey limestone with dendroid stromatoporoids, A7/L7: grey laminated limestone with fenestrae; and A8/L8: grey bioturbated limestone). Laterally equivalent sediments include substantial reworked material from the buildups and background sedimentation. Textures and fossils suggest that A2/L2 and A3/L3 facies developed close to storm wave base, in a subphotic environment. Facies A4/L4, occurring near fair weather wave base in the euphotic zone, includes lenses of A5/L5 with stromatolitic coatings and thrombolithes. A6/L6 corresponds to a slightly restricted environment and shows a progressive transition to fenestral limestone of A7/L7. This facies was deposited in a moderately restricted intertidal area. A8/L8 developed in a quiet lagoonal subtidal environment. The mounds started with A2/L2 or A3/L3 in which microbial lenses and algal facies A4/L4 became progressively more abundant upwards. Following 20 in of laterally undifferentiated facies, more restricted facies occur in the central part of the buildups. This geometry suggests the initiation of restricted sedimentation, sheltered by bindstone or floatstone facies. The facies interpretation shows that after construction of the lower part of the mounds during a transgression and a sea-level highstand, a lowstand forced reef growth to the margin of the buildups, initiating the development of atoll-like crowns during the subsequent transgressive stage. The persistence of restricted facies results from the balance between sea-level rise and reef growth. [less ▲]

Detailed reference viewed: 59 (11 ULg)
Full Text
Peer Reviewed
See detailSedimentology, magnetic susceptibility and isotopes of a middle frasnian carbonate platform: Tailfer section, Belgium
Da Silva, Anne-Christine ULg; Boulvain, Frédéric ULg

in Facies (2002), 46

The Tailfer section (Belgium, northern border of the Dinant Synclinorium) exposes Middle Frasnian shallow-water limestones. This paper proposes a sedimentological analysis based on classical petrology ... [more ▼]

The Tailfer section (Belgium, northern border of the Dinant Synclinorium) exposes Middle Frasnian shallow-water limestones. This paper proposes a sedimentological analysis based on classical petrology, which leads to the identification of 19 fourth order sequences, forming three third order system tracts. This sedimentological analyses is complemented by carbon isotopic and magnetic susceptibility (MS) data (based on the relation between MS and lithogenic input). Each system tracts is characterised by a particular evolution of the isotope and MS curve: Biostromal Unit: the biostromes are built by lamellar and branching stromatoporoids and massive metazoans. MS values are weak, in relation with the important distance from landmasses and lesser amounts of lithogenic contribution. The carbon isotope values are close to Frasnian seawater values. Lagoonal Unit: it corresponds to a lagoonal facies succession, from inter- to supratidal zones, rich in Amphipora, paleosiphonocladales, Umbella, and pellets, alternating with paleosoils. MS values are high, related to landmass proximity and high lithogenic input. The carbon isotopic curve shows strongly negative values, close to -7 parts per thousand, resulting probably from a continental influence. Lagoonal and biostromal Unit: it consists of a lagoonal succession with some biostromal interruptions. MS values are lower than in the lagoonal unit and the isotopic values are higher (close to 0 parts per thousand), related to an increase in distality. [less ▲]

Detailed reference viewed: 93 (17 ULg)
Full Text
Peer Reviewed
See detailIron microbial communities in Belgian Frasnian carbonate mounds
Boulvain, Frédéric ULg; De Ridder, C.; Mamet, B. et al

in Facies (2001), 44

The Belgian Frasnian carbonate mounds occur in three stratigraphic levels in an overall backstepping succession. Petit-Mont and Arche Members form the famous red and grey “marble” exploited for ornamental ... [more ▼]

The Belgian Frasnian carbonate mounds occur in three stratigraphic levels in an overall backstepping succession. Petit-Mont and Arche Members form the famous red and grey “marble” exploited for ornamental stone since Roman times. The evolution and distribution of the facies in the mounds is thought to be associated with ecologic evolution and relative sea-level fluctuations. Iron oxides exist in five forms in the Frasnian mounds; four are undoubtedly endobiotic organized structures: (1) microstromatolites and associated forms (blisters, veils...), possibly organized in “endostromatolites”; (2) hematitic coccoids and (3) non dichotomic filaments. The filaments resemble iron bacteria of the Sphaerotilus- Leptothrix "group"; (4) networks of dichotomic filaments ascribable to fungi; (5) a red ferruginous pigment dispersed in the calcareous matrix whose distribution is related to the mound facies type. The endobiotic forms developed during the edification of the mounds, before cementation by fibrous calcite. The microbial precipitation of iron took place as long as the developing mounds were bathed by water impoverished in oxygen. [less ▲]

Detailed reference viewed: 22 (4 ULg)