Facies and climate/environmental changes recorded on a carbonate ramp: A sedimentological and geochemical approach on Middle Jurassic carbonates (Paris Basin, France)

The Jurassic was punctuated by several episodes of abrupt environmental changes associated with climatic instabilities, severe biotic crisis, and perturbations of the global carbon cycle. Over the last decades, the Toarcian Oceanic Anoxic Event (Early Jurassic, ~183 Ma) and the early Bajocian Event (Middle Jurassic, ~170&#8211;168 Ma) have attracted much attention because they represent such episodes of global and severe environmental change. Bracketed in between the Toarcian and the Bajocian, the Aalenian stage (Middle Jurassic, ~174-170 Ma) has received less attention, although there is some evidence from Tethyan and Boreal records that it was a time of environmental changes marked by marine biotic turnovers. The lack of knowledge about the Aalenian palaeoenvironments leaves a gap in our understanding of the wider context of the Toarcian and Bajocian events and hence of environmental feedback mechanisms surrounding Mesozoic carbon cycle perturbations. In this study, we provide a high-resolution, biostratigraphically well-defined carbon isotope records (&#948;13Corg&#160;and &#948;13Ccarb) combined to Rock-Eval data for the upper Toarcian&#8211;lower Bajocian interval from two expanded marl/limestone alternation successions from France (French Subalpine Basin) and Chile (Andean Basin). The comparison with available records from the Tethyan and Boreal domains highlights that medium-term &#948;13C fluctuations are reproducible across different palaeoceanographic settings from both hemispheres and between different carbon substrates. The new high-resolution dataset highlights the complexity of the Aalenian &#948;13C record, including previously identified &#948;13C shifts and hitherto undescribed fluctuations. This study provides one of the most expanded high-resolution chemostratigraphic reference records for the entire Aalenian stage, and shows compelling evidence from both hemispheres that it was a time marked by recurrent perturbations to the global carbon cycle and environmental changes.&#160;

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Sur les divisions du Dogger dans la vallee de la Creuse (Indre); correlation avec le sud-est du Bassin parisien

BSGF - Earth Sciences Bulletin ◽

10.2113/gssgfbull.s7-iii.6.588 ◽

1961 ◽

Vol S7-III (6) ◽

pp. 588-598 ◽

Cited By ~ 1

Author(s):

J. C. Fischer

Keyword(s):

Middle Jurassic ◽

River Valley ◽

Paris Basin ◽

Southwestern Part ◽

Southeastern Part ◽

The North ◽

Starting Point ◽

Working Out ◽

Valley Area

Abstract Stratigraphy of the Dogger (middle Jurassic) in the southwestern part of the Paris basin, at the north border of the Central Massif is very poorly known because facies are monotonous and outcrops and fossils are scarce. A starting point for working out the stratigraphy is provided by the Creuse river valley, from Argenton-sur-Creuse northwestward to St. Gaultier. Stratigraphic correlations with the southeastern part of the Paris basin were made from 21 good outcrops in the Creuse valley area despite the lack of characteristic ammonites. Dogger formations total more than 100 m thickness, chiefly marine neritic limestones, with intercalated marl in the upper portion. Several meters of lagoonal marl and lignite above the base of the Dogger are transitional from lower to middle Bathonian (upper Dogger). Brachiopods and corals, including reef types, are the chief means of correlation.

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Characterization and origin of permeability–porosity heterogeneity in shallow-marine carbonates: From core scale to 3D reservoir dimension (Middle Jurassic, Paris Basin, France)

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2014.07.004 ◽

2014 ◽

Vol 57 ◽

pp. 631-651 ◽

Cited By ~ 32

Author(s):

Benjamin Brigaud ◽

Benoît Vincent ◽

Christophe Durlet ◽

Jean-François Deconinck ◽

Emmanuel Jobard ◽

...

Keyword(s):

Middle Jurassic ◽

Paris Basin ◽

Shallow Marine ◽

Marine Carbonates ◽

Porosity Heterogeneity

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Magnetostratigraphy of Mesozoic Shallow-Water Carbonates: Preliminary Results from the Middle Jurassic of the Paris Basin

AAPG Bulletin ◽

10.1306/20b23ab1-170d-11d7-8645000102c1865d ◽

1991 ◽

Vol 75 ◽

Author(s):

AISSAOUI, DJAFAR M., and JOSEPH L.

Keyword(s):

Shallow Water ◽

Middle Jurassic ◽

Paris Basin ◽

Preliminary Results

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Residence time of Chalk groundwaters in the Paris Basin and the North German Basin: a geochemical approach

Applied Geochemistry ◽

10.1016/s0883-2927(97)00110-8 ◽

1998 ◽

Vol 13 (5) ◽

pp. 593-606 ◽

Cited By ~ 54

Author(s):

W. Kloppmann ◽

L. Dever ◽

W.M. Edmunds

Keyword(s):

Residence Time ◽

North German Basin ◽

Paris Basin ◽

The North ◽

Geochemical Approach ◽

German Basin

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Organic Matter in the Early Toarcian Shales, Paris Basin, France: a Response to Environmental Changes

Revue de l Institut Français du Pétrole ◽

10.2516/ogst:1991027 ◽

1991 ◽

Vol 46 (5) ◽

pp. 543-562 ◽

Cited By ~ 26

Author(s):

D. J. Hollander ◽

G. Bessereau ◽

S. Belin ◽

A. Y. Huc ◽

J. P. Houzay

Keyword(s):

Organic Matter ◽

Environmental Changes ◽

Paris Basin

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The Middle Jurassic coal-forming plants of the Ulug-Khem Basin (Republic оf Tyva, Russia)

Palaeobotany ◽

10.31111/palaeobotany/2020.11.48 ◽

2020 ◽

Vol 11 ◽

pp. 48-73

Author(s):

E. V. Bugdaeva ◽

S. A. Ondar ◽

V. S. Markevich ◽

D. A. Bushnev

Keyword(s):

Plant Communities ◽

Middle Jurassic ◽

Environmental Changes ◽

Ordos Basin ◽

Reproductive Organs ◽

Late Mesozoic ◽

Northern Regions ◽

Electron Microscopes ◽

Main Components ◽

Scanning Electron Microscopes

Dispersed cuticles of plants from coals of the Middle Jurassic Ulugkhem Formation (locality 229 near Mount Begreda, Ulug-Khem Basin, Republic of Tyva) were studied. As a result of the study of mesofossils using light and scanning electron microscopes, it was found that the coals are composed mainly of the remains of ginkgophytes. They are represented by the leaves of Pseudotorellia cf. angustifolia Doludenko, the female reproductive organs of this plant Umaltolepis sp., as well as the leaves of Eretmophyllum neimengguensis Li, Sun, Wang, Dilcher, Tan, Li, Na. The conifers played subordinate role. The palynospectrum of the coal seam is dominated by the spores of ferns; bisaccate and monosulcate pollen are next in importance. Thus, ginkgophytes and ferns predominated in the Middle Jurassic swamp communities in the Ulugh-Khem Basin. For the first time, the coal-forming role of the genus Eretmophyllum was revealed. The Middle Jurassic flora of Tyva is similar to the floras of the Kansk-Achinsk and Irkutsk basins of Eastern Siberia, Angren Basin of Uzbekistan, and the Ordos Basin of Inner Mongolia, China by predominance of Pseudotorellia. The vegetation was clearly differentiated into the lowland and the slope one. In the latter the leptostrobaleans, ginkgoaleans, and conifers were represented. Pseudotorellia is one of the main components of swamp plant communities in the more northern regions: in the Ulug-Khem and Irkutsk basins, and in the Aban and Pereyaslovka coal fields of the Kansk-Achinsk Basin. This genus disappears in the Nazarovo coal field of the Kansk-Achinsk Basin, being replaced by the leptostrobaleans. Here the compositions of swamp and slope communities practically do not differ. The Late Mesozoic swamp plant communities were characterized by conservatism, as well as by extreme sensitivity to environmental changes, which apparently developed because of their existence in the same conditions of high humidity. Degradation of the swamps led to the disappearance of swamp plant communities.

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