Eastern Paris Research Articles

Alluviation in the Meurthe and Moselle valleys (Eastern Paris Basin, France): Lithological contribution to the study of the Moselle capture and Pleistocene climatic fluctuations

Geomorphological and lithostratigraphic analysis allow the definition of a record of eleven alluvial stepped units in the Meurthe valley downstream from the Vosges Massif. The deposits are mainly composed of sands derived from Permo-Triassic strata. A similar system of stepped terraces is identified in the Moselle valley near Toul, where the deposits are coarser and contain more crystalline sediments than those of the Meurthe. A distinction is made in these units between the levels deposited before the capture of the Upper Moselle river by the Paleo-Meurthe, which follow the former course towards the Meuse valley, and the post-capture levels, which follow the modern valley Downstream from the present Moselle-Meurthe confluence, the higher deposits (above 25 m relative height) are similar to the Meurthe sediments (Permo-Tnassic origin), as opposed to the youngest deposits (0 to 25 m relative height) which contain crystalline sediments from the Upper Moselle basin. This contrast allows the Moselle capture to be positioned between formations F4 and F3 of the alluvial system downstream from the present confluence. The correlation between these sections of valley underlines the parallelism of the terraces and the weakness of the syn-capture altitudinal gradient between the Upper-Moselle and the Paleo-Meurthe rivers. In certain parts of the valleys, a contrast is shown between sandy hthofacies from the Permo-Tnassic cover and coarse hthofacies with crystalline elements. The deposition of the sandy series is attributed to full-glacial episodes, while that of the coarse series is correlated with periods of retreat of the Vosgian glaciers, especially during lateglacial episodes. The consensus of absolute dates of the capture (250-300 000 years B P) allows the incision rate for the Meurthe and the Moselle valleys to be estimated at 0 1 1 mm/y-1 since the capture. This rate is comparable with the rate already obtained for the Moselle valley in Germany.

ABSTRACT: Correlation of Upper Jurassic Carbonate and Reef Facies Across the Burgundy and Ardennes Platforms, Eastern Paris Basin, France

ABSTRACT: Correlation of Upper Jurassic Carbonate and Reef Facies Across the Burgundy and Ardennes Platforms, Eastern Paris Basin, France

ABSTRACT: Local, Regional, and Global Controls on the Distribution of Upper Jurassic Reefs in the Eastern Gulf Coast, U.S.A. and Eastern Paris Basin, France

ABSTRACT: Local, Regional, and Global Controls on the Distribution of Upper Jurassic Reefs in the Eastern Gulf Coast, U.S.A. and Eastern Paris Basin, France

A Cernaysian mammal from the Upnor Formation (Late Palaeocene, Herne Bay, UK) and its implications for correlation

An isolated upper deciduous (milk) premolar identified as the primitive ungulate Arctocyonides arenae Russell is recorded from the local base of the Upnor Formation at Herne Bay, Kent, England. The species was previously known only from marginal marine to fluvial deposits of the eastern Paris Basin at Cernay, Berru and Montchenot, where exact correlation with the standard marine succession is controversial. Nevertheless, the mammal fauna from these sites is discrete and referred to the Cernaysian European Land Mammal Age. The Upnor Formation contains calcareous nannoplankton indicative of the lower part of zone NP9, thus accurately calibrating the Cernaysian (and the equivalent Mammalian Reference Level MP6) to the marine standard biozonation. The tooth represents the first unequivocally Palaeocene mammal from Britain.

Contrôle géodynamique de la sédimentation argileuse du Callovien-Oxfordien moyen dans l'Est du bassin de Paris: influence eustatique et volcanique

The Middle Callovian to Middle Oxfordian clay deposits drilled in the eastern Paris Basin (borehole HTM 102, ANDRA) show a strong mineralogical change occurring in the lowermost Oxfordian (Scarburgense subzone, Mariae zone). Such a change probably results from the initial development of connections between the young Atlantic Ocean and the Paris Basin. A bentonitic layer identified close to the boundary between Lower and Middle Oxfordian and also recognized in the subalpine Basin (South-East of France) at the same age, reflects a volcanic activity probably resulting from an extensional regime located in the North Sea.

Abstract: Stratigraphic Architecture of Upper Jurassic (Oxfordian) Reefs in the Northeastern Gulf Coast, U.S. and the Eastern Paris Basin, France 

ABSTRACT The Late Jurassic was a major period of reef expansion. Many Jurassic reefs are potential hydrocarbon reservoirs, but their stratigraphic distribution has been difficult to predict. Examination of the stratigraphic architecture of Oxfordian reefs in the northeast U.S. Gulf Coast and the eastern Paris Basin, France affords a comparison of mixed coral-algal sponge reefs versus microbial-dominated reefs. The Smackover Formation in the northeastern Gulf Coast contains microbial-dominated reefs. The Smackover represents deposition during a major transgression and reefs occur within late transgressive system tract (TST) deposits. Reefs of mixed coral, algae, and sponges characterize the Oxfordian of the eastern Paris Basin. In the Ardennes-Lorraine, reefs appear after the maximum flooding event of a stratigraphic sequence and are maintained through the highstand systems tract (HST) deposition and into the overlying stratigraphic sequence. In Burgundy, reefs occur in association with the maximum flooding event of the upper stratigraphic sequence. Dominated by platy microsolenids, reef growth begins in the TST. This interval is traditionally called the lower reef complex. More diverse reef growth (the upper reef complex) continues above the maximum flooding event through the early HST. Reef growth ceases by deposition of the late HST with the introduction of grainstones and other high-energy lithologies. All reefs in this examination, regardless of biota, are associated with maximum flooding events. The sequence stratigraphy of the Oxfordian reefs in France and the Gulf Coast provides a framework for studying Jurassic reefs of both mixed and microbial-dominated assemblages.

New remains of the giant bird Gastornis from the Upper Paleocene of the eastern Paris Basin and the relationships between Gastornis and Diatryma

New remains of the giant bird Gastornis from the Upper Paleocene of the eastern Paris Basin and the relationships between Gastornis and Diatryma

95/03279 Preventive maintenance keeps mine operating through severe Alaskan winters

The Callovian–Oxfordian claystones located at 500 m depth in the eastern Paris Basin are currently being investigated by ANDRA (the French National Radioactive Waste Management Agency) for long-term geological nuclear waste disposal. For this purpose, a recent 2000 m deep well was drilled close to the ANDRA underground research laboratory. This borehole penetrated the Mesozoic sedimentary series for a detailed study of the sediments located beneath the target formation. It also provides the opportunity to study the vertical evolution of the sedimentary organic matter and its thermal maturity in this part of the Basin, where the thickness of sedimentary eroded cover is poorly constrained. To extend this study at the scale of the eastern Paris Basin, 5 more wells and numerous outcrops were sampled. Sedimentary organic matter characterization was performed on kerogen (Rock-Eval pyrolysis, organic petrography and mean huminite and vitrinite reflectance measurements) and on the extractible organic fraction (Gas Chromatography–Mass Spectrometry). Results show that inputs of organic matter during the Mesozoic were essentially of terrigenous origin, except during the Toarcian where marine contributions are predominant. The major macerals present are huminite (ulminite), vitrinite (collotelinite) and inertinite (inertodetrinite and fusinite). Vitrinite shows a regular increase of reflectance with depth in the 2000 m depth well. Correlations between Tmax, vitrinite reflectance, and biomarker data define the thermal maturity of the Mesozoic sediments: maturity is reached at 1300–1500 m present day depth in the 2000 m well, in the Upper Triassic. At the regional scale, the organic matter maturity of each sedimentary formation decreases towards the eastern part of the basin, probably in relation to a decrease of the Jurassic and/or Cretaceous cover thickness, which is now eroded. All results indicate the lack of hydrocarbon generation in the Mesozoic series in this part of the basin.

Cadomian terranes, wrench faulting and thrusting in the central Europe Variscides: geophysical and geological evidence

Sixty five per cent of the Paleozoic basement of western and central Europe is hidden by a sedimen- tary cover and/or sea. This work aims to remove that blanket to detect new structures which could used to build a more comprehensive model of the Variscan or- ogeny. It is based on the interpretation of various forms of data: (a) published gravity maps corrected for the ef- fects of the crust-mantle boundary topography and light sedimentary basins; (b) aeromagnetic maps; (c) measurements of densities; and (d) induced and rema- nent magnetizations on rocks from Paleozoic outcrops of the upper Rhenish area. From the northern B ohem- ian Massif to the eastern Paris Basin, the Saxothurin- gian is characterized by a 500 km long belt of gravity highs, the most important being the Kraichgau high. Most of the corresponding heavy bodies are buried un- der a post-early Visdan cover. They are interpreted as relics of Late Proterozoic terranes overlain by an Early to Middle Paleozoic sequence, equivalent to the Bo- hemian t errane in the Bohemian Massif. The most probable continuation of these dense Bohemian ter- ranes toward the west is the Southern Channel-North- ern Brittany Cadomian terrane. The gravity lows are correlated with Variscan granites and pre- and early Variscan metagranites. Gravity and magnetic maps demonstrate large-scale displacement in Devonian-Early Carboniferous times along the parallel and equidistant, NW-SE striking, Vistula, Elbe, Bavarian, Bray and South Armorican dextral wrench faults. In the Vosges-Schwarzwald and Central Massif the faults continue with the east-west striking Lalaye-Lubine-Ba den-Baden and Marche faults and with south vergent thrusts. The Bavarian faults shift the Kraichgau terrane by 150 km relative to the Bohemian terrane, whereas the offset of the North- ern Brittany Cadomian relative to the Northern Vosges-Kraichgau terranes is estimated at 400km along the Bray fault. Sinistral wrench faults are the NE-SW striking Sillon Houiller, Rheingraben, Rodl, Vitis and Diendorf faults. The southern Vosges- Schwarzwald Devonian-Dinanti an basin is interpreted as a pull-apart basin at the south-easterly extremity of the Bray fault. The Bohemian and Kraichgau body form allochthonous terranes which were thrust over the Saxothuringian crust. Thrusting to the north-west was accompanied by back-thrusting and led to the forma- tion of pop-up structures. Contemporaneous dextral and sinistral wrench faulting resulted in transpressive strain during collision. The zonal structure of the Varis- cides in the sense of Kossmat (1927) is relevant only to the Rhenohercynian Foreland Belt. Kossmat (1927) al- ready spoke of a Moldanubian Region because it dis- plays no real zonal structure. The Saxothuringian Zone was formed by terrane accretion. Their apparent zonal structure is not a pre-collisional feature, but only the result of accretion and collision.

Subsurface High Resolution Stratigraphy in the Jurassic of the Eastern Paris Basin: ABSTRACT

Subsurface High Resolution Stratigraphy in the Jurassic of the Eastern Paris Basin: ABSTRACT

Geochemistry and origin of formation brines from the Paris Basin, France: 1. Brines associated with Triassic salts

Small amounts of brines associated with Triassic (Keuper) layered halite from the eastern Paris Basin have been collected during salt mining operations. Critical consideration of the possible reactions and interactions involving Br − indicates that Cl − Br − ratio values are conservative except in two cases: (1) precipitation or dissolution of solid chlorides; and (2) convective or diffusive mixing of saline solutions. Calculations suggest that halite recrystallization could be a source of aqueous Br −, but this process is probably not significant under natural conditions as Triassic salt has retained a Br − content higher than calculated for equilibrium conditions. Bromide-chloride data for the brines associated with Triassic salts are presented on a log-log diagram of Cl − Br − vs. Cl −, including the evolution of present-day marine solutions and literature values for the chloride salts between halite and tachyhydrite ((CaCl 2, 2MgCl 2)·12H 2O) deposition. This diagram allows discernment of primary or secondary origins of brines. Chemical variations of major and trace elements during the evaporative concentration of seawater are estimated from selected literature and from additional measurements of salt ponds on the Mediterranean shore. Low values of the Cl − Br − ratios in brines from Triassic salt can be reconciled with high Na + contents if the sampled solutions are mixtures of a secondary brine (halite dissolution) and a highly evolved primary brine. Mass-balance considerations indicate that the primary brine component was more concentrated than the stage of bischofite (MgCl 2·6H 2O) deposition. Contents of Br −, Cl −, Na + and K + can be accounted for by a conservative behaviour of these ions, possibly slightly affected by some precipitation of NaCl induced by the mixing of the two types of solutions. The secondary brine component would have contributed all Na + and K + through halite and sylvite (KCl) dissolution. Several hypotheses are discussed for the origin of the high contents in Li +: diagenesis, halite dissolution, global or local enrichment of Triassic seawater, and contribution from the primary brine. The high Li + concentration is attributed to the highly concentrated brine component. Rubidium would also behave conservatively after all K + has been removed by sylvite and carnallite ((KCl,MgCl 2)·6H 2O) precipitation. Boron, Ca 2+, Sr 2+, Mg 2+ and SO 2− 4 are not conservative. Mass-balance calculations indicate that the high content in Ca 2+ and in Sr 2+ imposes a diagenetic origin. The values of the 87 Sr 86 Sr isotope ratio are clearly higher than the Keuper marine values of the literature, which could be explained by a major contribution of reworked Permian evaporites with high 87Sr content. Such hypothesis would be in agreement with the low heavy-isotope content of aqueous SO 2− 4. Dolomitization, either by the primary brine or by the mixing of primary and secondary brines, would have implied Ca-sulphate precipitation, in agreement with the observed additional depletion in heavy isotopes of aqueous SO 2− 4, relative to anhydrite deposits from Triassic layers of the Paris Basin. Stable isotope contents ( 2H and 18O) of the brines can be accounted for by mixings of a secondary brine of continental origin with a primary brine enriched in 18O by evaporation. In conclusion, emphasis is put on the conservation of Li +, the near-conservative behaviour of the elements Cl −, Br −, Na +, K + and Rb +, whereas diagenetic reactions control B 3+, Mg 2+, Ca 2+, Sr 2+ and SO 2− 4.

Comparison of I/S Transformation and Maturity of Organic Matter at Elevated Temperatures

AbstractComparing the state of reaction advancement of I/S (illite content of illite/smectite mixed layer minerals) and organic matter (vitrinite reflectance) in instances of high temperature gradients allows one to observe the evolution of geologic materials under extreme conditions. In a geothermally heated sedimentary series (Salton Sea area, California), both clays and organics have reacted to completion in the temperature gradient range of 200°-400oC/km during heating episodes of 104 years. We observed an instance of rapid heating, through magmatic intrusion into the Meso-Paleozoic eastern Paris Basin sedimentary series in late Permian time, which induced changes in the organic material, but where clays are apparently unaffected.

Upper Carboniferous source rocks north and south of the Variscan Front (NW and Central Europe)

Some topical aspects of Upper Carboniferous source rocks within the three main tectonic settings in NW and Central Europe are described. These are likely to offer an effective tool for reduction of risk in future exploration. In the foreland, the main geological factors responsible for the nitrogen content of gas accumulations and for the isotopic composition of methane are outlined. It will probably be possible to predict the molecular and isotopic composition of gas accumulations in the future. In addition, the application of the dynamics of diffusion processes to the loss of gas accumulations over geological time offers the possibility of predicting hydrocarbon fill in some areas of the basin. In the Variscan fold belt, the model of thin-skin tectonics suggests that the lowermost, parautochthonous low rank thrust sheets are more likely to be source rocks than are allochthonous, high rank thrust sheets. Additionally young subsidence is required in order to meet the conditions of gas dynamics. The possible source rock potential of the Permo-Carboniferous fills of the intramontane grabens south of the Variscan front are reported here for the first time. Some promising discoveries below the Swiss and German Molasse basin as well as in the eastern Paris Basin mean that the intramontane grabens are now an interesting exploration'objective.

‘Le caprice du prince’ — The problem of the Bastille Opéra

July 1982 saw the launching of a project to build a vast new popular opera house at the Place de la Bastille in eastern Paris. It is one of the Grand Projets, a 15.3 billion francs (about 15 million pounds) urban renewal scheme which includes expanding and renovating the Louvre, two new museums (the Musée d'Orsay and Musée de la Villette), an international communication centre at La Défense, relocating the French Ministry of Finance, an Arab Institute, and at least eleven urban regional projects (see Fig. 1). The defeat of the Socialists at the March 1986 election, to be replaced by a period of cohabitation, has jeopardized the future of the Grands Projets. This article is not a comprehensive appraisal of the Bastille Opéra scheme but has two limited aims. Firstly to discuss how the last government intended to create the new Opéra as the supreme symbol of the Socialist era. This involves an examination of the project's reception by the press and by those responsible for implementing the scheme. Secondly, to suggest that the former government's declared wish to democratize opera may not have been the most important concern and to ask whether opera can ever really become a ‘popular’ art form. The conclusion is that far from being revolutionary, Mitterrand's objectives are not so dissimilar to those of his predecessors. The latest in a series of grand architectural gestures, the Opéra was initiated primarily to commemorate a period of government and, more specifically, an individual ruler.

Late Cenomanian and Turonian ammonites from Ardennes, Aube and Yonne, eastern Paris Basin (France)

Late Cenomanian and Turonian ammonites from Ardennes, Aube and Yonne, eastern Paris Basin (France)

Comparison of three series of organic matter of continental origin

Three series of sediments containing land plant-derived organic matter were studied. They include wells from Mahakam delta, Indonesia (Miocene), Douala basin, Cameroon (Upper Cretaceous) and eastern Paris basin, France (Paleozoic). All of the kerogens and coals isolated from these series can be related to type III in a Van Krevelen diagram, however they obviously differ in terms of chemical structure as reflected by their pyrolysis-GC patterns, and by their bitumen composition. These observations indicate the variations in the nature of land plant-derived sedimentary organic matter and thus differences in quantity and composition of the hydrocarbons which are are released upon maturation. Based on hydrocarbons potential of the insoluble organic matter and on pyrolysis-GC, there is no reason to disregard coals and to favor shales as potential source rocks in these two deltaic sequences. Moreover we assume that the bitumen depletion in coal samples is a reflection of loss by migration which is favored in coals when compared to shales. The GC patterns of the residual saturates, compared to the pyrolysis-GC patterns of the related insoluble coals suggest that migration of hydrocarbons proceeds in these coals without any significant alteration of their distribution, at least in the C 15+ range.

Bivalves ptériomorphes du Sénonien dans le Bassin Parisien et le sud-ouest de la France

The geographical distribution of some Senonian pteriomorph bivalves from the eastern Paris Basin ià indicated. The faunas are compared with those of the stratotypical regions of the Coniacian, Santonian and Campanian stages in the Charente. The geographical isolation of the Charente region is clearly shown by the presence of several endemic species in different groups. On the other hand, though limited, the faunas from the «stratotypical» Senonian undoubtedly have northern affinities and belong to the White Chalk Sea.

Geochimie et teneurs isotopiques des systèmes saisonniers de dissolution de la calcite dans un sol sur craie

In a soil developed on the Cretaceous chalk of the Eastern Paris basin, calcite dissolution begins at the surface. The soil water is rapidly saturated in calcite. Calcite dissolution follows two different pathways according to seasonal pedoclimatic conditions. During winter: the soil is only partly saturated in water and the CO 2 partial pressure is low (Ca 10 −3 atm.). As a consequence total inorganic dissolved carbon (TIDC) is a hundred times the carbon content of the gaseous phase. Equilibrium is usually observed between the two phases. It is a closed system. The measured carbon 14 activity (87,5%) and 13C content ( δ tidc 13C = −12,2%0 ) of the drainage water are very close to theoretical values calculated for an ideal mixing system between gaseous and mineral phases (respectively characterized by the following isotopic values: δ G 13C = −21,5%0 ; A G 14C = 118% ; δ M 13C = +2,9%0 ; A M 14C = 28% ). During spring and summer: the soil moisture decreases, the input of biogenic CO 2 induces an increase of the soil CO 2 partial pressure (Ca from 3.10 −3 atm to 7.10 −3 atm). The carbon content of the gaseous phase is higher by an order of magnitude compared to winter conditions. Therefore the aqueous phase is undersaturated in CO 2 with respect to the latter. This disequilibrium occurs as a result of unbalanced rates of CO 2 dissolution and CO 2 effusion toward atmosphère. It is an open system. The carbon isotopic ratio of the aqueous phase is regulated by that of the gaseous phase, as demonstrated by the agreement between measured and calculated isotopic compositions (respectively δ L mes = from −9,4%0 to −11,5%0, δ l calc = from −9,8%0 to −13,9%0 A L mes = 119%, A L calc = from 119% to 125%). The solutions originating from both systems (open and closed) move downwards without significant mixing together. It has also been observed that no significant variation of the TIDC isotopic composition occurs during precipitation of secondary calcite.

Continental sedimentation, soil genesis and marine transgression in the basal beds of the Cretaceous in the east of the Paris Basin

ABSTRACTIn the eastern Paris Basin, on the boundary of two French ‘départements’, Marne and Meuse, the Cretaceous deposits begin with Wealden facies assigned to the Valanginian. This is overlain by marine Hauterivian and Lower Barremian.Several techniques have been used for studying these deposits: light‐microscope, scanning electron microscope, grain‐size analysis, chemical and mineralogical analysis.Environmental interpretations of the various facies are based on sedimentological, geochemical and pedological criteria (fossil soils are present). Clay minerals are dominantly illite and kaolinite. In the soil horizons kaolinite is dominant. A mixed‐layer illite‐smectite appears at the base of the transgression. Under marine influence a more stable illite dominant suite is formed.The Wealden sediments appear to have been deposited in a very mature flood‐plain. Part of the sequence was subjected to weathering in situ by soil processes under a warm climate with repeated wetting and drying. Paraconformably above, the marine Hauterivian is the product of a shallow sea that tended to form lagoons. A true marine environment was established in the Lower Barremian, when mixing homogenized the sediments.

Une grande faille NE-NW du sud du Bassin parisien

Abstract Describes the western extension (Aube basin) of the major fault of the eastern Paris basin. The fault can now be recognized for a length of 135 km; it is convex toward the south, reflecting Variscan and Armorican trends connected by a slightly curved line. The Chalvraines fault, discovered a century ago by Royer and Barotte but omitted from later maps, branches southeastward from the major fracture 1.5 km east of Rimaucourt. In a supplementary note, by J. Laffaille, it is noted that the major fault is clearly expressed on a gravimetric map of the region by a band of steeper gravity gradient.