Palaeoecology of non marine algae and stromatolites: Permian of France and adjacent countries

Freytet, Pierre; Toutin-Morin, Nadège; Broutin, Jean; Debriette, P.; Durand, Marc; Wartiti, M. El; Gand, Georges; Kerp, Hans; Orszag, Fabienne; Paquette, Yves; Ronchi, Ausonio; Sarfati, Janine

doi:10.1016/s0753-3969(99)80010-x

Cited by 14 publications

(11 citation statements)

References 19 publications

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“…5). Based on the rich, fossiliferous content (algae, permineralized plants, amphibians, shark teeth and scales), Freytet et al (1999Freytet et al ( , 2002 assigned the succession to the uppermost Gzhelianlower Asselian, whereas Pittau et al (2008) assigned it to the Asselian. The base of the succession unconformably covers the Variscan basement with 5-15 m of lens-shaped polygenic breccias and clast-to matrix-supported conglomerates and breccias (locally fanglomerates) made up of Variscan basement pebbles and a lesser amount of quartz pebbles.…”

Section: C1 Stratigraphymentioning

confidence: 99%

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The carbonates of the post-Variscan basins of Sardinia: the evolution from Carboniferous–Permian humid-persistent to Permian arid-ephemeral lakes in a morphotectonic framework

Costamagna¹

2019

Geol. Mag.

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Late to post-Variscan sedimentary basins of Sardinia were influenced during Pennsylvanian to Permian times by two main tectono-sedimentary cycles: a Pennsylvanian to Cisuralian cycle represented mainly by dark limnic deposits, overlain by a Guadalupian to a possibly Lopingian cycle, mostly characterized by red-bed deposits. Lacustrine waterbodies developed in some sedimentary basins that were filled with siliciclastic to frequently early silicified carbonate deposits, depending on the climate and environmental conditions, landscape morphology and tectonic regime. The limnic successions of the lower tectono-sedimentary cycle were deposited in permanent, tens of metres deep lakes in deep, narrow tectonic strike-slip basins under a temperate to warm-humid climate. They started as lakes with terrigenous sedimentary input and developed minor carbonate deposits mainly at the end of their story. Conversely, the red-bed successions of the upper cycle were deposited in ephemeral, shallow playa lakes related to wider basins in an extensive alluvial plain under a hot and arid climate. Here, the siliciclastic sediments are intercalated with thin carbonate beds that are typical of a high evaporation rate. The evolution of the lake type could be related not only to a major climatic shift, but also to the changing morphotectonic conditions of the Variscan chain influencing the local microclimate. Comparisons with coeval successions in the Provence Basin, the Massif Central Aumance basin (France) and the Saar–Nahe Basin (Germany) show both similarities and differences between the basins.

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Section: C1 Stratigraphymentioning

confidence: 99%

“…LG Costamagna dolomitic mudstones with scarce and poorly preserved ostracods and gastropods, nodular peloidal wackestones and grainstones with circumgranular cracks, algae (Freytet et al 1999(Freytet et al , 2002 and microbial mats (Fig. 17a, b); these latter locally alternate with blackish organic matter.…”

mentioning

confidence: 99%

The carbonates of the post-Variscan basins of Sardinia: the evolution from Carboniferous–Permian humid-persistent to Permian arid-ephemeral lakes in a morphotectonic framework

Costamagna¹

2019

Geol. Mag.

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“…Domal laminae indicate irregularities in the substrate and their recumbent margins indicate that the micro-organisms acted as biostabilizers of the substrate (Hofmann, 1975;Arp et al, 2005;Taher & Abdel-Motelib, 2014). Type 1 and type 2 tubules are identified as filamentous algae (Riding, 1991a) and the micrite accumulations (ma) correspond to coccoid cyanobacteria (Hofmann, 1975;Freytet & Verrecchia, 1998;Freytet et al, 1999). Circular structures with a micrite nucleus and external halos are interpreted as spherulites (Freytet & Verrecchia, 2002).…”

Section: Cerro Puntudo Formationmentioning

confidence: 99%

Comparison of lacustrine successions and their palaeohydrological implications in two sub‐basins of the Triassic Cuyana rift, Argentina

et al. 2015

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Continental carbonates are rich in palaeoclimatic, palaeoenvironmental and palaeontological information. While carbonate accumulation mechanisms have been described for many types of continental environments, especially in extensional basins, there are still uncertainties that existing facies models fail to address. The Triassic Cerro de las Cabras and Cerro Puntudo formations are alluvial-fluvial-lacustrine sequences that represent a part of the sedimentary infill of two sub-basins of the Cuyana Basin during the early stages of the Triassic rift in west-central Argentina. Previous work has provided absolute dates, confirming that these deposits are coeval (Anisian) allowing a comparative study of carbonate sedimentation in an extensional tectonic context. The description and origin of freshwater carbonate deposits and their surrounding siliciclastic sediments in specific areas of the Cuyana rift, gives insight into the major factors that control carbonate precipitation in all rift basins, including the characterization of the palaeohydrology and the importance of provenance. The Cerro de las Cabras Formation represents an ephemeral, playa-lake depositional system with subaerial exposure and pedogenesis. Its aggradational succession corresponds to the evaporative facies association lake type, diagnostic of underfilled lake basins where persistently closed surface hydrology can lead to thick evaporites. However, this formation lacks thick evaporites and has microbialitic limestones, pointing to an open groundwater supply. The Cerro Puntudo Formation represents an alkaline playa-lake system fed by groundwater and ephemeral surface-water input. The unit is an aggradational-minor progradational succession, pointing to a fluctuating profundal facies association, suggesting a balanced-filled lake type. These two synchronous, lacustrine depositional systems were influenced by tectonics and climate. Provenance and hydrology are key controls in carbonate accumulation in continental rift basins that must be included in future facies models for continental carbonates. Comparison with other rift basins suggests that application of lake-type characterizations coupled with palaeohydrology and provenance patterns will aid in developing new sedimentation models for freshwater limestones in extensional settings.

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“…The succession evolves upward to floodplain heterolithic facies (sandstone, siltstone, and shale) associated with carbonates. Such deposits are also commonly observed in other continental basins of this age in Europe, Freytet et al 1999). Carbonate deposits of this unit, the subject of this research, are represented by two typical facies: (i) oncoidal limestone (reported from many parts of the basin (Table 1) and (ii) aligned to coalescent carbonate nodules in sandstone beds.…”

mentioning

confidence: 67%

Oncoids and groundwater calcrete in a continental siliciclastic succession in a fault-controlled basin (Early Permian, Northern Italy)

Berra

Felletti

Tessarollo

2019

Facies

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Lower Permian continental deposits of the fault-controlled Orobic Basin (Central Southern Alps; Northern Italy) include alluvial fan facies interfingering with muddy basin-floor deposits, consisting of three facies associations: heterolithic finegrained siliciclastic facies, laminated sandstone facies, and oncoidal limestone facies. Besides oncoidal and microbial limestones, carbonates occur as nodules in sandy tabular beds within the laminated sandstone facies association. Microfacies analyses distinguish several types of oncoidal carbonate (consisting of an alternation of microbial carbonate and fibrous calcite) and carbonate nodules. Each type of carbonate has been characterized in terms of δ 18 O and δ 13 C. The two types of carbonate in the oncoids record a stable δ 18 O and a slightly varying δ 13 C, whereas the isotope composition of the calcite in nodules is completely different. Carbonate nodules in sandy beds of the laminated sandstone facies association have a diagenetic origin as indicated by cross-cutting relationships between nodules and lamination; the nodules are interpreted as groundwater calcrete, formed in the subsurface at the top of the unconfined water table. The exclusive sedimentation of oncoidal carbonate facies within siliciclastic deposits indicates that when oncoids were formed in ephemeral shallow ponds, siliciclastic input was minimal. The sedimentological and geochemical characteristics of the studied succession and the stable isotopic composition of the oncoids (the absence of covariance between δ 18 O and δ 13 C excludes deposition in evaporating basins) indicate persistent stable conditions for sufficient time to permit growth of centimeter-sized oncoids. Oncoids are interpreted to have formed in spring-fed ponds and outflow channels, with flowing, clean water, at the toe of major alluvial fans. Episodes of rapid delivery of sand and silt-sized sediments by flash floods, with an oscillating water table, caused the observed facies alternation. The precipitation of calcareous cements close to the water table surface produced nodules in sandy layers. Carbonate precipitation within laminated sandstone reduced porosity and permeability, causing a strong compartmentalization in the well-bedded continental succession.

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Palaeoecology of non marine algae and stromatolites: Permian of France and adjacent countries

Cited by 14 publications

References 19 publications

The carbonates of the post-Variscan basins of Sardinia: the evolution from Carboniferous–Permian humid-persistent to Permian arid-ephemeral lakes in a morphotectonic framework

The carbonates of the post-Variscan basins of Sardinia: the evolution from Carboniferous–Permian humid-persistent to Permian arid-ephemeral lakes in a morphotectonic framework

Comparison of lacustrine successions and their palaeohydrological implications in two sub‐basins of the Triassic Cuyana rift, Argentina

Oncoids and groundwater calcrete in a continental siliciclastic succession in a fault-controlled basin (Early Permian, Northern Italy)

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