bluuebunny/crossref_metadata_2025 huggingface dataset:
Desequilibres entre phases solides et fluides mineraux dans la petrogenese
Authors: Deicha Georges
Published: March 2020

The importance of phenomena conditioned by the disequilibrium between gases, liquids, or magmas, and solid minerals is discussed. Four modes of crystal growth are capable of causing the precipitation of a crystalline species in a supersaturated or supercooled fluid solution. In homogeneous nucleation crystallization occurs at the moment when saturation is reached and only in the presence of preformed crystals of the same species. Germinal nucleation occurs when crystallization develops in conditions of disequilibrium causing the formation of minerals of the same composition but of different structure. Crystals of this mode are twinned. Metastable nucleation involves the formation of a species different in structure from the stable crystal which developed after twinning. In heterogeneous nucleation crystallization of a species has its beginning on the surface of another crystal. This introduces impurities which inhibit nucleation and crystal growth. Secondary intervention of liquid or solid solutions in the rocks also produces phenomena equally effected by disequilibrium.
Contribution a l'etude du Cretace inferieur du massif des Arbailles (Basses-Pyrenees)
Authors: Poignant A.
Published: March 2020

On the basis of the microfacies and correlations of the stratigraphic units of the Arbailles massif with those further to the north (Arancou-Bergouey, Orthez-Sainte Suzanne, France), more precise information is available on the upper Jurassic and lower Cretaceous stratigraphy of the area. Due to the absence of the Perisphinctus bed (Oxfordian) the Callovian-Oxfordian boundary is indefinitely drawn; the Kimmeridgian-Portlandian boundary is likewise imprecise. The Neocomian exists but is undifferentiated. The Aptian can be divided into upper (limestones) and lower (marls) units, a regionally recognizable subdivision. The Cretaceous is transgressive, but more concordant than discordant.
La lindinosite (granite mesocrate a riebeckite) du massif d'Evisa (Corse)
Authors: Quin Jean Pierre
Published: March 2020

The Evisa riebeckite granite massif of western Corsica is an alkaline hololeucocratic granite through which are scattered, with gradational contact, enclaves of a mesocratic riebeckite granite (lindinosite) with rare automorphic crystals of fluorite associated with clusters of riebeckite, and also included in it. The lindinosite is a facies of the Evisa granite.
Stratigraphie et paleogeographie de l'Ordovicien de l'Anti-Atlas (Maroc): un essai de synthese
Authors: Destombes Jacques
Published: March 2020

The Ordovician formations on the south flank of the Anti-Atlas mountains of Morocco extend from the edge of the Guir hamada near Taouz 850 kilometers southwestward to a hamada in the Tarfaya area. The strike, although parallel to that of the axis of the mountains, contrasts with the southeastward strike of tectonic elements of the Sahara shield to the east. The lithology and paleontology of the Ordovician formations indicate an epicontinental sea with a sinking bottom receiving sandy detritus from the shield area. Distribution of facies indicates the presence of two ridges (moles) extending from the northern part of the adjacent sole.
Morphologie des galets des nappes alluviales de l'Adour et de l'Arros entre Vic-en-Bigorre et Aire-sur-l'Adour
Authors: Portier Jean
Published: March 2020

Statistical analysis of the morphology of pebbles in Pleistocene alluvial deposits of the Adour-Arros river region, between Vic-en-Bigorre and Aire-sur-l'Adour, France, permitted formulation of a set of parameters on the basis of which distance of transport and relationships between the different Riss and Wuerm (Pleistocene) sheets are interpreted. The Adour captured the Arros at the end of the Riss.
Note sur le gisement d'uranium dans les sables oligocenes de Saint-Pierre (Cantal)
Authors: Brassens Alain
Published: March 2020

The uranium mineralization of the Saint-Pierre region consists of francevillite- impregnated fluviatile Oligocene sands deposited in a basin forming part of the regional Permo-Carboniferous coal-bearing trough developed in the crystalline basement complex of the Central Massif, France. The mineralization is considered syngenetic, and was probably controlled both by climatic and topographic conditions.
Age de la serie des diabases-porphyrites (roches vertes du flysch calabro-lucanien; Italie meridionale)
Authors: Bousquet Jean Claude
Published: March 2020

Diabases and porphyrites in Lucania are encased in limestone underlain by flysch. Previous datings, based on the flysch, have placed the diabases and porphyrites between the Cretaceous and Eocene. New datings, based on microfauna in the limestone encasement, yield a Jurassic age. A re-examination of the formations of southern Lucania and a comparison of facies to those of the northern Apennines is in order.
Sur certains problemes de structure et d'histoire de la plate-forme de l'Europe orientale
Authors: Bogdanov A. A.
Published: March 2020

The eastern European platform is an irregular shield limited on the east by a line between Polyudov Kamen' and Aktyubinsk Its southern boundary extends from the Caspian sea through the Volga delta toward the source of the Sal river and the Azov sea. The western boundary follows the foot of the Scandinavian Caledonian range in the north but is poorly defined southward. Shatsky's theory of aulacogenes (ancient platforms formed in initial evolutionary stages) is discussed in some detail. Continuous, transverse, and internal aulacogenes are distinguished within the European platform. The area shows the effect of Baikalian, Caledonian, Variscan and Alpine orogenies illustrated by tectonic maps.
Remarques stratigraphiques et structurales sur la region de Palazzo-Adriano, monts Sicani (Sicile)
Authors: Mascle Georges
Published: March 2020

The stratigraphic series in the Palazzo Adriano area comprises formations ranging in age from Permian to Mio-Pliocene. The Permian formation is present as sedimentary klippen in the Triassic flysch deposits. The highest stratigraphic unit, which probably represents the lower part of the evaporite series, is overridden by the Pizzo Mondello structural unit in which are represented all the stratigraphic units except the evaporites. The Monte Rose unit is primarily composed of Triassic rocks and is thrust over the Pizzo Mondello unit and the evaporite series. The last tangential movements responsible for the thrusting probably occurred at the end of the Miocene.
Paragale huerzeleri nov. gen., nov. sp., mustelide nouveau de l'Aquitanien de l'Allier
Authors: Petter Germaine
Published: March 2020

A new genus of the family Mustelidae (carnivores), Paragale huerzeleri n. gen. n. sp., is described from two complete crania, the anterior portion of another cranium, and a mandible from Aquitanian [Miocene] deposits at Montaigu-le-Blin (Allier). The characters which distinguish the new species from Plesiogale angustifrons Pomel are discussed.
Nouvelle anomalie dans la reproduction asexuee du genre Archaeolithothamnium Rothpletz
Authors: Segonzac Genevieve
Published: March 2020

The filling of a sporangium cavity by cells is a new peculiarity which is added to the other aberrations already noted in the asexual reproduction of the genus Archaeolithothamnium. This phenomenon is interpreted as the result of an abnormal secondary development.
Quelques microfacies neogenes nord-aquitains
Authors: Puechmaille Chantal
Published: March 2020

The Aquitanian and Burdigalian deposits outcropping in Villandraut and Saucats have similar microfacies, and the depositional environments of the two series appear to have been relatively uniform as evidenced by the structure of the limestone matrix. Microfacies of the Helvetian deposits exposed at Salles were deposited under different conditions, probably influenced more by coastal currents than the Aquitanian and Burdigalian sediments.
L'erosion littorale du pays de Caux
Authors: Nesteroff Wladimir D. , Melieres Frederic
Published: March 2020

Coastal erosion, gravitational and biologic forces, France
Tectonique du Subbetique dans le nord de la province de Cadix (Espagne meridionale)
Authors: Chauve Pierre
Published: March 2020

Tectonics of the Subbetic zone, structurally and lithologically controlled deformation, overthrust faults, decollement surfaces
La chaine de l'Eg'ere (Hoggar septentrional)
Authors: Duplan Louis
Published: March 2020

Egere mountains, Algeria, geologic survey, rhythmic sequences of lithologic units, catazonal and mesozonal metamorphism, tectonic phases
Diagnose d'une nouvelle espece de Chlamys du Tortonien du bassin de Visan
Authors: Barbillat Roger
Published: March 2020

Miocene, France
L'isthme durancien en Basse-Provence occidentale
Authors: Blanc Jean J. , Gouvernet Claude
Published: March 2020

Valanginian-Albian (Cretaceous) paleogeography, paleorelief, anticlinal ridges, depositional environment, France
Donnees nouvelles sur la geologie de la Thakkhola (Himalaya du Nepal)
Authors: Bordet Pierre , Colchen Michel , Lefort Patrick , Mouterde Rene , Remy Marcel
Published: March 2020

Precambrian-Quaternary formations, east-west folds, northeast-southwest fractures, Precambrian and Paleozoic metamorphism
Les Mammiferes fossiles recoltes a Sansan au cours du XIXe siecle
Authors: Ginsburg L.
Published: March 2020

One of the richest occurrences of fossil Mammalia in Europe was discovered in 1834 in the Helvetian (middle Miocene) deposits of Sansan in southwestern France. Nearly all groups are represented, from Chiroptera to proboscidians. The extraordinary richness of the deposit makes statistical treatment possible. Although many changes occurred in the marshy to lacustrine environment during the time of deposition, as reflected in clays, marls, limestones, and molasse, the amplitude of the changes never was large enough to destroy the balance that prevailed through the Helvetian in the area. Restudy of the fossil materials collected over a long period of time resulted in some nomenclatural changes.
Le volcanisme permo-carbonifere de la region de Nompatelize (Vosges)
Authors: Rocci Georges , Chretien Jean Claude
Published: March 2020

The upper Stephanian acidic volcanic rocks--trachyandesites and rhyolites, which crop out in the Nompatelize area, plunge below subhorizontal Permian sandstones. Near Voivre and Brehimont (France), explosion breccias occur with the homogeneous trachyandesite lavas suggesting that those areas were isolated centers of eruption, or perhaps represent the main eruptive center. The rhyolites are believed to be massive extrusive lavas, mixed in places with pyroclastic elements, and at the time of eruption were sufficiently porous for water and gas to produce significant effects as indicated by the phyllitic and argillaceous alteration products from the feldspars and by the low sodium percentage. The dip observed in the rhyolites probably resulted from extrusions over a short distance on the steep slopes of the Permian terrain. However the side-by-side occurrence of different facies indicates a possible composite extrusive-explosive origin for the lavas. The Nompatelize rhyolites do not represent an outlier of a large-scale ignimbrite nappe but rather seem to have come from two distinct but related centers, La Salle and Brehimont.
Sur trois granites des sondages de Marchenoir, Boissy-sur-Saint-Yon et Courgent de la partie occidentale du bassin de Paris
Authors: Morre Nicole , Planat Chantal
Published: March 2020

Three cores from the western part of the Paris basin (France) were taken in the equigranular granite of the basement complex. The three phases in the development of this rock are characterized by microclinization of albite and pneumatolysis, possibly occuring contemporaneously. A cataclastic granite was retrieved from the Boissy-sur-Saint-Yon core. The formation of this rock occurred in two phases corresponding to the original paragenesis of quartz, orthoclase, and albite, and subsequent low-temperature paragenesis of quartz and albite. The Courgent core yielded a fine-grained granite containing mica, albite with polysynthetic twinning, perthitic microcline, quartz and accessory minerals. Evidence of secondary silicification is present in the zones of orthogneissic planar texture, where neomineralization has been especially strong. The origins of the three granites, all of which are alkalic, are determined using the method proposed by M. Gorai (1951), and the results are plotted on a triangular diagram. Results of chemical analyses of the rocks are presented in tabular form.
Etude stratigraphique et micropaleontologique d'une serie jurassique de l'le de Minorque, Baleares (Espagne)
Authors: Bourrouilh Robert , Moullade Michel
Published: March 2020

The Jurassic of Minorca is known from a composite section described from outcrops on the Cape of Fornells and on the Atalaya de Fornells peninsula. The Liassic is primarily a microcrystalline dolomite; the middle Jurassic, containing Orbitammina (Dictyoconus) cayeuxi (Lucas), is composed of dolomites containing large dolomite crystals, and always displaying oolitic texture; the upper Jurassic consists of limestone and microcrystalline dolomites. Comparison of the Orbitolinidae genera, Meyendorffina and Coskinolina, does not reveal significant differences between the two, therefore justifying the reduction of Meyendorffina to the rank of subgenus in the genus Coskinolina. Coskinolina (Meyendorffina) bizonorum, n. sp., C. (M.) minoricensis n. sp., and C. (M.) sp. 1 are described and figured. The beds containing Meyendorffina, which lie between the middle and upper Liassic brachiopod marls and the upper Jurassic limestones with Valvulinella sp., are assigned to the Dogger, possibly the upper part, on the basis of 'Dictyoconus' cayeuxi (also figured).
Mesures d'ages absolus sur les series precambriennes et paleozoiques du Senegal oriental
Authors: Bassot Jean Pierre , Bonhomme M. , Roques Maurice , Vachette Michelle
Published: March 2020

Absolute ages using the strontium method were obtained for Precambrian and Paleozoic rocks of the Senegal basin (Africa). These dates compare favorably with the previous work done recently in the area. The Birrimian series is the oldest unit, with an age of 2045 m.y. The Segou-Madinakouta series unconformably overlying the Birrimian is dated, at its base, as 1020 m.y. The date of 645 m.y. obtained for the Niokolo-Koba granite may represent later rejuvenation of an older granite and not the granitization itself. No age was obtained for the Faleme series. The Youkounkoun series is dated as 560 m.y. Metamorphism of the Koulountou series probably occurred at the beginning of the Gothlandian (430 m.y.). The Bakel series was metamorphosed at the end of the Devonian (355 m.y.), and again in the Triassic (206 m.y.).
Etude geologique de la region de Trescore-Balneario (Alpes meridionales, province de Bergame, Italie)
Authors: Piat Bernard
Published: March 2020

The stratigraphic sequence of the Trescore-Balneario region in the southern Alps is entirely marine consisting of thick concordant deposits from the Triassic to the upper Cretaceous. They are discordantly overlain by Pliocene beds. Liassic rocks in the sequence represent a shallow water facies whereas the Dogger, Malm, and Neocomian reflect deposition in deep water. The remainder of the Cretaceous is a flysch sequence derived from a source to the west. The Pliocene represents a transgressive marine sequence of red sandstones and argillites containing fragments of pelecypods and gastropods.
Connaissances nouvelles sur la geologie du socle de la Limagne d'apres les sondages de la Regie autonome des petroles
Authors: Grolier Jacques , Tchimichkian Georges
Published: March 2020

Analysis of cores from ten holes between Moulins and Cournon (central France) indicates that the basement rock is found at widely variable depths and that it is not markedly different petrographically from the basement series of the adjacent crystalline plateaus. The rock is a recrystallized and silicified quartzo-feldspathic mass with feldspar phenocrysts. Correlation of the data obtained from the cores with the surface geology shows that the Treban granite does not extend above the Allier river; the granitic basement possesses light-colored variations and cuts across volcanic dikes. The mineral composition of selected samples from the cores is presented in a table.
Les regressions marines et le probleme du renouvellement des faunes au cours des temps geologiques
Authors: Ginsburg L.
Published: March 2020

One basis for geochronology is the succession of faunal groups. Evolutionary transformations, the extinction of species, and the appearance of new forms is neither a chance occurrence nor one marked by a regular rhythm. The disequilibrium provoked by alternating transgressions and regressions has a profound effect on animal populations. At the end of each marine regression a hecatomb of fauna is left in the neritic zones. A return of the sea in the succeeding transgression provides opportunity for the multiplication and diversification of the surviving forms. Through this process of natural selection evolutionary development is stimulated by alternating marine cycles.
Bryozoaires du 'Sparnacien' des Corbieres et du Plantaurel
Authors: Plaziat Jean Claude , Balavoine Pierre
Published: March 2020

Outcrops of a series attributed to the Sparnacian (lower Eocene) can be followed with rare breaks in continuity from the eastern part of the Corbieres region, SW of Narbonne (southern France), westward into Haute-Garonne. Facies in the Orbieu river valley on the northeast are dominantly littoral, but at Carla de Roquefort in the Plantaurel area, they are dominantly marine. Bryozoa from these strata are poorly known. Species found in the Plantaurel area include many found in the Orbieu valley. Five new species were found, two common to both areas, two in the Orbieu valley only, and one in the Plantaurel area only. Fourteen known species were found. A shallow sea, with easy communication between the two areas is indicated. The lateral distribution suggests major stratigraphic importance for this fauna.
'Traces en rosette' du flysch eocene de Jaca (Aragon). Essai d'interpretation
Authors: Lucas Gabriel , Rech-Frollo Marguerite
Published: March 2020

At the base of a bed of flysch sandstone of Eocene age in the Jaca area of the Aragon river valley (Spain), occur rosette type markings about fifty centimeters in diameter consisting of shallow grooves radiating from a central cone-shaped impression. They are believed to be marks left by large pelecypods.
Esquisse stratigraphique du Jurassique superieur et du Cretace inferieur du chainon du Mail-Arrouy (Basses-Pyrenees)
Authors: Poignant A.
Published: March 2020

A relatively complete section of upper Jurassic and lower Cretaceous strata occurs on the north flank of the Mail-Arrouy mountain in the Basses-Pyrenees. Apparently only basal lower Cretaceous is lacking or perhaps incompletely represented. Study of the microfacies in these formations facilitates correlation with other outcrops in southern and western Aquitaine.
Ultramicroscopie petrographique; le rutile du quartz des granites
Authors: Deicha Georges
Published: March 2020

Rutile needles of macroscopic, microscopic, and submicroscopic sizes occur in the quartz of acidic igneous rocks. Although it is not known whether they are present as the result of mechanical inclusion, crystallization simultaneous with that of the quartz, oriented exsolution, or replacement they are an important means of tectonic and geochemical study. A grain of granitic quartz torn by erosion from its crystalline petrographic context retains its submicroscopic inclusions throughout the course of its sedimentary peregrinations no matter how small the detrital fragments may become.
Vers une logique mathematique des series sedimentaires
Authors: Allegre Claude
Published: March 2020

A statistical method based upon the measure of a sedimentary stratigraphic unit is proposed to supplement present stratigraphic methods of study, and lead to quantitative stratigraphy.
Les relations petrogenetiques entre les eclogites et les amphibolites dans le massif cristallophyllien du mont Snieznik
Authors: Smulikowski Kazimierz
Published: March 2020

Two different lithologic series of metamorphic rocks, granulite-eclogite and amphibolite-eclogite, in adjoining areas of the Snieznik massif of the Sudetes mountains on the Czech-Polish frontier, underwent different equilibrium conditions yet both had the paragenetic conditions for development of eclogite. Differences in the chemical composition of the original rocks and in the properties of intergranular solutions during metamorphism, rather than differences in temperature and pressure resulting from differences in depth of burial, determined the rock types resulting from metamorphism.
Pistes d'oiseaux et remaniements synsedimentaires dans le Lutetien du detroit de Carcassonne (Aude)
Authors: Plaziat Jean Claude
Published: March 2020

The Lutetian (middle Eocene) formations deposited in the Carcassonne straits in southern France comprise a thick sequence of marine limestones and sandy marls overlain by a similar thickness of continental molasse in which numerous bird tracks occur.
Comportement de la sillimanite et de l'andalousite dans quelques roches pyreneennes
Authors: Macaudiere Jean
Published: March 2020

The high valley of Louron is occupied by a complex of granitic and metamorphic rocks of which the Lys-Caillaouas granite is best known. The stability domains and modalities of transformations of silicates during metamorphism, particularly andalusite and sillimanite, are discussed.
Note preliminaire sur le Bathonien inferieur du Bugey (Jura meridional)
Authors: Mangold Charles , Enay R. , Dominjon Pierre
Published: March 2020

The recent discovery of lower Bathonian (upper middle Jurassic) ammonites at several places in the Bugey region of the southern Jura mountains of eastern France resolves the problem of the relationship of the Bajocian to the Bathonian in this key region. Fauna of upper Bajocian (lower middle Jurassic) and middle and upper Bathonian had long been known but lower Bathonian was unknown. One bed is particularly rich in a varied fauna of ammonites, pelecypods, gastropods, and echinoderms in a remarkable state of preservation. The faunal association shows the coexistence of the forms of the Zigzag beds of England and the Wuerttembergicus beds of Germany, thus confirming the homology of these two horizons. The geographic distribution of type genera of the lower Bathonian in western Europe permits the identification of two faunal domains overlapping in Lorraine and the northern Jura mountains as well as the Bugey region. The genus Zigzagiceras extends from southern England through Switzerland, the Jura mountains, and the Basses-Alpes to Sicily, and also has been found in Portugal. The western limit of the species Parkinsonia (Oraniceras) wuerttembergica occurs in Germany, Lorraine, the Jura mountains, and Sicily. It appears that the genera Morphoceras and Ebrayiceras may have an even greater distribution.
Stratigraphie du Silurien du Tassili N'Ajjer
Authors: Dubois Paul , Mazelet Pierre
Published: March 2020

A new lithostratigraphic nomenclature is established for the Silurian of the Tassili N'Ajjer and the mole anticlines of Essaoui Mellene in southeastern Algeria from a new series of sections examined from Tihemboka westward to Oued Amassine. The unit termed the graptolite clay formation is a homogeneous unit of plastic clays ranging from 350 to 450 meters in thickness, with thin lenticular beds of ripple-marked fine-grained sandstone. The sandstones in the upper part of the formation thicken eastward, and in the eastern half of the region the fine-grained sand gives way to coarser grained sand and grit. In the eastern third of the region, the Gara Marhet sandstone is an important member. The overlying heterogeneous Atafatafa formation comprising multiple facies of lenticular silty clays, siltstones, shaly sandstones, ferruginous oolitic sandstones, massive sandstones, and quartzites thins from a thickness of 150 meters on the west, to 80 meters on the east. Ripple marks, markings of organic origin, and tigillites are numerous.
Etat actuel de nos connaissances sur la geologie de la Guyane francaise
Authors: Choubert Boris
Published: March 2020

A summary of the geology of northern French Guiana includes brief discussions of the stratigraphy, tectonics, dolerite dikes, Quaternary deposits and mineral resources. Precambrian rocks, which constitute a major part of the area, are represented by a discordant series ranging between 4000 and 1800 m.y. in age, which have been metamorphosed by successive granitization and intrusions of basic rocks. Two tectonic depressions, oriented in an ESE-WNW direction, occupy part of the area, one in the north extending halfway into Surinam, the other in the central region. Dolerite dikes up to 70 km long strike NNW-SSE. Transgressions and regressions in the Quaternary resulted in the deposition of three series of sediments on fossiliferous Eocene beds. Gold deposits, the basic resource of the country, seem to be related to the Caribbean granitization. A table correlates the stratigraphy of French Guiana, Guyana, and Surinam.
Formations eruptive antejurassiques en Eubee moyenne (Grece)
Authors: Guernet Claude
Published: March 2020

In addition to the well-known upper Jurassic or lower Cretaceous lava flow in the central part of Euboea island, Greece, an older flow occurs between a Permian formation with neritic fossils and an upper Triassic algal limestone. A Ladenian-Carnian (Triassic) age is tentatively assigned to the flow. Between this and the Jurassic flow, spilites and related rocks overlie shales interbedded with crinoidal and fusulinid limestones and overlain by algal limestones. Outcrops at Tharounia expose the flows and the intermediate beds.
Stratigraphie du Paleogene du bassin de Paris en relation avec les bassins avoisinants
Authors: Blondeau A. , Cavelier Claude , Feugueur Leon , Pomerol Charles
Published: March 2020

New data on the lower Tertiary of the Paris basin places the Vigny limestone in the Montian (Paleocene). The Thanetian-Sparnacian (lower-upper Paleocene) boundary is well-marked. The Ypresian (lower Eocene) in the basin includes the basal lagoonal Sparnacian and the Cuisian at the top. The upper section of the Lutetian includes the Biarritzian. The Ledian (upper Eocene) and probably the Wemmelian in Belgium, and the upper Bracklesham beds in Hampshire (England) should be correlated with the upper Lutetian. The Bartonian substage is extended to include the Auversian, Marinesian, and Ludian which are equivalent to the upper Eocene. The Eocene-Oligocene boundary is situated at the base of the Romainville green shale. The supragypsiferous marls, the lower Tongrian and the Bembridge beds are assigned to the upper Eocene. The Sannoisian is referred to the Stampian in the Paris basin, which corresponds to the upper Tongrian and Rupelian in Belgium and to the Hamstead beds in England. Charts correlating the stages in the Paris basin with the neighboring countries of Belgium and England are given for each stage.
Rotundomys, nouveau genre de Cricetidae (Mammalia, Rodentia) de la faune neogene de Montredon (Herault)
Authors: Mein Pierre
Published: March 2020

On the basis of molars found in white marls between the villages of Bize, Argeliers, and Montouliers, a new Miocene rodent genus, Rotundomys, is erected. Cricetodon montisrotundi Schaub (1944) is rediagnosed and designated as the type species.
Les cordilleres dans les mers cretacees et paleogenes des Carpathes du nord
Authors: Ksiazkiewicz Marian
Published: March 2020

The flysch deposits of the northern Carpathian Alps (southern Poland) contain abundant exotic blocks and pebbles whose dimensions exclude the possibility of their being transported over a long distance. This suggests the presence of cordilleras from which the material was detached. The localization of these features can be shown approximately as a function of the stratigraphic and geographic distribution of the exotic material. The cordilleras have crystalline basements overlain by Paleozoic and Jurassic sedimentary rocks; while in the submerged troughs between the cordilleras, flysch or pelagic formations were accumulated in the Cretaceous and lower Tertiary. Adjoining the cordilleras, in certain periods, littoral sediments were deposited. The erosion of the cordilleras progressed gradually, wearing away the sedimentary cover and exposing the basement complex. The distribution of the exotic material in the stratigraphic series indicates that the cordilleras were mobile, alternately emerging and submerging. This is particularly distinct in the external klippen of the Inwald zone, suggesting that one of the Carpathian cordilleras was better preserved.
Contribution par l'etude des mineraux lourds et argileux a l'interpretation stratigraphique du Quaternaire des Landes meridionales
Authors: Alvinerie J. , Latouche Claude , Thibault Claude
Published: March 2020

Stratigraphic, paleoclimatic, pedological, and archaeological study of cuts in the area of the confluence of the Adour and Midouze rivers defines several Quaternary formations. Analysis of the clay shows a mineralogical break between the lower kaolin-rich beds and the overlying beds rich in illite and interbedded chlorite-vermiculite. This break is described from the Chalosse alluvials and at the base of the Landes eolian sands. Although the suites of heavy minerals are generally homogeneous in these cuts, two zones can be recognized: one by well preserved metamorphic minerals; the other by more resistant minerals that withstood alteration.
Les grandes epoques de fracture et de bombement du Sahara central
Authors: Karpoff Roman
Published: March 2020

A study of the Precambrian massifs of the central Sahara confirms movements of great magnitude in the basement rocks which affected the overlying strata. There were successive readjustments along the faults and reactivation of the folds. The major period of dislocation and deformation of the sediments was the Mesozoic and not the Hercynian. Because of its wide extent this period is called the 'Ramadian movements.' It ended after the lower Eocene and at the time of the Tertiary movements (Timetrinian phase or episode).
Decouverte du genre Amphipora et autres stromatopores dans les formations devoniennes d'Afghanistan central
Authors: Brice D.
Published: March 2020

The genus Amphipora and other stromatopores of the genera Clathrodictyon, Stromatopora, and Stromatoporella occur in Devonian marine limestones at Zard Sang mountain, central Afghanistan. Associated fossils include numerous brachiopods and corals of upper Devonian, probably Frasnian, age. The best specimens, unfortunately, came from loose rocks among which both Frasnian and Famennian elements are present, hence the stratigraphic horizon cannot be assigned precisely.
La cause de l'orientation des mineraux dans les roches metamorphiques
Authors: Goguel Jean
Published: March 2020

The orientation of minerals in metamorphic rocks is postulated as resulting from selective pressure solution, not from rotation, during deformation. The calculations upon which the hypothesis is based are given. If the pressure-solution hypothesis is correct, statistical studies of the distribution of crystal orientations can indicate not only the direction of principal stress but also the relative pressures in different directions.
Sur quelques ammonites du Valanginien de l'Oued Guelta' (Tunisie)
Authors: Memmi Lucia
Published: March 2020

An upper Jurassic and lower Cretaceous sequence in the Guelta wadi basin, northeastern Tunisia, includes a richly fossiliferous marl containing abundant ammonites of the middle Valanginian (lower Cretaceous) Kilianella roubaudiana zone. Berriasellidae occur in great variety; Lytoceratidae and Belemnitidae are represented by only a few individuals. Several ammonites are systematically described.
La presence de Gazellospira torticornis Aymard (ruminant) dans le gisement villafranchien de Saint-Vallier (Drome); essai de repartition geographique et stratigraphique
Authors: Heintz Emile
Published: March 2020

A study of the third lower molar and the second and third upper molars of Gazellospira torticornis found in the Villafranchian (Quaternary) deposit of Saint-Vallier (Drome, France) is presented. Comparison with specimens from Spain indicates a size decrease. Spain and France were two distinct climatic provinces during the Villafranchian, with similar faunas differing from each other only in the frequency of species.
Sur le rapport des gneiss de Bormes et des micaschistes du cap Negre a l'ile du Levant (Var)
Authors: Tanazacq Francois
Published: March 2020

On Levant island (Var, France), south of the Maures massif, anticlinal crests and folds of the Negre Cape mica schist plunge into and under the Bormes gneiss and are clearly visible along the coast. Both the schist and the gneiss have behaved as distinct stratigraphic units, with no evidence of overturning. The Bormes gneiss therefore apparently overlies the Negre Cape mica schist. The feldspars in the entire series are principally detrital.
Ages isotopiques K/A de roches prelevees dans les possessions francaises du Pacifique
Authors: Krummenacher Daniel , Noetzlin Jacques
Published: March 2020

The authors present some forty age determinations made by the K/Ar method on the volcanic rocks of Tahiti and the archipelagoes of French Polynesia by means of a Philips omegatron. The results obtained may be divided grossly into three groups: sub-Recent ages (from 0 to 3 m.y.); Mio-Pliocene ages (about 10 to 15 m.y.) and an age of about 150 m.y., given by a granular inclusion in a nephelinic gabbro-diorite from the center of the island of Tahiti. The last age is particularly interesting because no fossiliferous formations older than Cretaceous are known in the Pacific. These rocks may thus be older and may date at least from the Jurassic. They accordingly pose the problem of the existence, beneath the present volcanoes, of a much older crystalline basement.
Etat actuel des connaissances sur le volcan Niragongo (Republique democratique du Congo)
Authors: Tazieff Haroun
Published: March 2020

The Niragongo volcano of the Congo region is located in the western Great Rift Valley in east Africa. The cone is formed of feldspathoidal lavas containing augite and accessory minerals, and the crater contains terraces representing ancient lava levels. Studies were conducted on the chemical composition and petrography of the rocks, on the chemistry of the gases and sublimates, and on the temperature of the lavas. The magnetic and gravimetric values for the volcano and the area were measured and energy discharge was estimated. The study confirmed the importance of the gaseous phase in volcanic phenomena.
Reflexions sur les types de consolidation des produits du magmatisme crustal superficiel
Authors: Panto Gabor
Published: March 2020

The plutonic and volcanic domains of magmatism are generally regarded as independent; the distinction of typically volcanic igneous formations from all those that were consolidated in the interior of the crust rests generally on purely petrographic criteria. Nevertheless, these criteria alone do not allow precise definition of the depth of formation. Differentiation of volcanic, intravolcanic, and subvolcanic formations can only be based on genetic study of the igneous phenomena within their geologic environment.
L'accident de Gigondas (Vaucluse)
Authors: Demarcq G. , Truc G.
Published: March 2020

In the Gigondas area (Vaucluse, French Alps of Provence), Cretaceous and Burdigalian (Miocene) rocks related to the Suzette massif are thrust northwestward over Tortonian (Miocene) rocks of the Comtat Venaissin basin. This decollement is cut by three fault systems, one oriented north-northeast, one trending east-northeast, and one trending northwest. The pre-Oligocene pyrenean-provencal phase of the alpine orogeny, and the erosion which followed, controlled the future outlines of the decollement. The second, post-Miocene, alpine phase formed the decollement and faults.
Les olistholites du Riou d'Entraix et leur signification paleostructurale
Authors: Artru Philippe
Published: March 2020

The upper Bajocian (middle Jurassic) heterogeneous polygene breccias of the Riou d'Entraix (southeast France) are interpreted as olistostromes formed by gravity sliding along a paleoscarp. The scarp was to the east, in the area presently covered by overthrusts, and separated a euxinic deep basin from a well-oxygenated shallow shelf. Similar deposits in the Barcelonette window and the semi-window at Embrun are probably of the same origin.
Sur l'extension de certains invertebres marins
Authors: Sarkar Satya S.
Published: March 2020

The three large groups considered are the ammonites, trilobites, and graptolites. Curves constructed express variations in the number of genera during the course of time. Most of the paper deals with the Ammonoidea, especially the Indian forms. An attempt to explain the extinction at the end of the Cretaceous involves both environmental changes (shallower seas, sandier deposits) and a phenomenon of overspecialization.
Problemes relatifs a la determination des especes chez les Moorellininae (Thecideidae, brachiopodes)
Authors: Pajaud Daniel
Published: March 2020

The subfamily Moorellininae is revised and Rioultina matisconensis n. gen. n. sp. is described. More than half the Jurassic thecideid species belong to the genera Moorellina Elliott and Rioultina n. gen. Some of the species defined in the 19th century were based on erroneous ideas of specific differentiation, and biometric studies of these species are frequently impossible, which inhibits their clarification. At present it would be as inadvisable to group these former species as it would be to subdivide them or to maintain them provisionally.
Sur la sedimentation et la tectonique du Miocene de la Provence occidentale
Authors: Dubois Paul
Published: March 2020

Two Miocene stratigraphic series are distinguished in western Provence: a marginal series with reduced thicknesses, and a series of subsident type with great thicknesses, denoting synorogenic development of sedimentation in the Miocene of Provence. A description of the effects of the tectonics at the end of the Miocene shows the importance of terminal Miocene folds, asymmetric and slightly overthrust to the south. Their direction of thrust is opposite to the major structures of the region, formed by the Pyrenean-Provencal orogeny.
Especes nouvelles d'inocerames dans le Taurus lycien (Turquie)
Authors: Lefevre Roger , Sornay Jacques
Published: March 2020

An occurrence of inoceramids enclosed within a complex of rudistid limestones of middle Senonian age (upper Cretaceous) in the Lycian Taurus (Antalya province, Turkey) is described. A description of a new species is given: Inoceramus antalyaensis and two associated varieties in this locality.
Les goniatites des argiles viseennes du Mouydir (Sahara central)
Authors: Conrad Jacqueline
Published: March 2020

The discovery of Dimorphoceras gilbertsoni and Beyrichoceras casteltonense in the Dinantian [lower Carboniferous] argillaceous series of Mouydir [Algeria] permits reassignment of these deposits to the upper Visean [upper lower Carboniferous].
Presence d'Eocene transgressif en Thessalie; incidences sur la paleogeographie regionale
Authors: Bizon Germaine , Bizon Jean Jacques , Lalechos Nicolas , Savoyat Edmond
Published: March 2020

Flysch stratigraphy, lower Lutetian tectonism, Greece
Le niveau a Billingsella cf. lingulaeformis Nikitin du Cambrien de la Sierra de la Demanda (Logrono, Espagne)
Authors: Colchen Michel , Havlicek Vladimir
Published: March 2020

Upper Cambrian brachiopods, middle-upper Cambrian boundary, lithologic descriptions, systematic description
L'ilerdien des Corbieres septentrionales (Aude); objections; sa postion stratigraphique exacte
Authors: Massieux Michele
Published: March 2020

Cuisian-Lutetian (Eocene) rather than pre-Cuisian (Paleocene), France
Quelques mineraux authigenes de minerai de fer de l'Ordovicien inferieur de Bretagne
Authors: Chauvel Jean Jacques
Published: March 2020

Zircon, tourmaline, rutile, ilmenite, mineralization in magnetite-bearing sedimentary rocks, France
Sur la structure du massif du Tribulaun (region de Brenner, Tyrol, Autriche)
Authors: Geyssant Jacques
Published: March 2020

Imbricate structures, phase-two folding (near-horizontal axial planes) with axial-plane schistosity and greenschist-facies metamorphism phase-two refolding (near-vertical axial planes), Jurassic lithostratigraphic units
Borelis melo (Fichtel et Moll) dans le Miocene de la partie orientale des cordilleres Betiques (Espagne)
Authors: Azema Jacques , Fernex Francois , Hottinger Lucas , Magne Jean , Paquet Jacques
Published: March 2020

Foraminiferal-ostracod faunas, species lists, discussion of B. melo (by Hottinger), Puerto Lumbreras-Lorca area, Sierra de Espuna, and northern Fortuna basin
Le copeau jurassique de djebel Tafaroui et l'unite senonienne a 'microbreches' des monts de Tessala (Algerie)
Authors: Fenet Bertrand
Published: March 2020

Jurassic block in Albian-Cenomanian (Cretaceous) nappe partially overlain by Senonian microbreccia, lower Miocene autochthonous? substratum, three-stage emplacement of Jurassic block, upper Jurassic deformation, Triassic diapirism, upper Cretaceous decollement, Miocene imbricate structures
Relations tectoniques entre l'Afar et la mer Rouge
Authors: Tazieff Haroun
Published: March 2020

Normal faults, horst-graben structure, tectonic trends paralleling the Egyptian coast of the Red Sea
Precisions paleontologiques et indices climatiques relatifs aux couches pleistocenes de la depression de Brasov (Roumanie)
Authors: Alimen Henriette , Radulesco Costin , Samson Pierre
Published: March 2020

Mammalian fauna, stratigraphic revisions, two or three pre-Guenz cold periods, paleosols, cryergic processes
Étude préliminaire de la surface de Vingrau dans les Corbières méridionales
Authors: Cornet Cécile
Published: March 2020

Sommaire

La surface de Vingrau, qui s'étale, à 300 m d'altitude moyenne à l'E et au S du bassin pliocène de Tuchan, est assez riche en placages de sables argileux (généralement rutilants, parfois jaunâtres) associés à des nodules de limonite. On y trouve également beaucoup de quartz, ainsi que des dépôts de galets et de blocs cristallopylliens, bien roulés, atteignant près de 1 m de grand axe.

L'arasion de la surface s'est effectuée après la phase pyrénéenne paroxysmale et avant le creusement, au Pontien terminal, des canyons sous-marins qui bordent la côte actuelle. Il y a de fortes présomptions pour que le cycle d'aplanissement remonte au Pontien (en tous les cas au Miocène). Quant à l'épandage alluvial des plateaux, il avait sa source au Sud ou Canigou) et il est à rapporter soit à cette même époque, soit au Pliocène.
Tectonique des extrémités de la chaîne des Babors (Algérie)
Authors: Caire André , Coutelle Alain , Obert Daniel
Published: March 2020

Sommaire

Dans les Babors extrême-orientaux et extrême-occidentaux, le style tectonique n'est pas, comme on l'admettait souvent, de plis extrusifs associés à des intrusions triasiques, ni de chevauchements locaux et limités. Le trait majeur de la structure consiste en recouvrements dont l'ampleur atteint plusieurs dizaines de kilomètres.

Les Babors orientaux peuvent être divisés horizontalement, en trois zones E-W, et verticalement en : 1) un parautochtone (autochtone relatif par rapport à l'allochtone franc, allochtone vers le Sud par rapport à la patrie de la lame B 1) qui déborde sur le Tell nordsétifien 2) un allochtone franc, décollé sur le Trias, composé de Mésozoïque et de Miocène, et qui se développe sur une distance méridienne d'au moins 25 km. Cet ensemble est recouvert par du matériel ultra-baborien : lame de type B 2 (unité épitellienne) et flyschs (unités de Guerrouch, numidienne, etc.).

Les Babors d'Akbou montrent : 1) un soubassement (Trias à Cénomano-Turonien) déplacé vers le Sud, avec plissement, schistosité et écaillage du Jurassique, les écailles les plus tardives étant poussées vers l'Est ou le Sud-Est; 2) une nappe sénono-éocène de type 132, venant de la zone de la Basse-Soummam ; 3) un couronnement allochtone de flyschs (surtout Numidien).

Le soubassement des Babors d'Akbou est l'équivalent latéral, par rapport aux nappes plasliques surincombantes, de l'allochtone franc et du parautochtone des Babors orientaux. Tous les grands recouvrements vers le Sud datent du Miocène I. Les unités 1 et 2 des Babors orientaux et des lfabors d'Akbou sont caractérisées par un Sénonien conglomératique, et font partie de la zone intermédiaire. Elles n'ont rien d'autochtone. Cependant, nous continuerons à qualifier l'unité 1 de parauchtone, car c'est la portion dn Tell algérien qui semble le moims déplacée.
Automated Surface Measurements of Drilling Fluid Properties: Field Application in the Permian Basin
Authors: Gul Sercan , van Oort Eric , Mullin Chris , Ladendorf Douglas
Published: March 2020

Accurate and frequent mud checking is essential for optimum drilling operations. Careful measurement and maintenance of drilling fluid properties (density and rheology) maintain the primary well control barrier and optimize fluid hydraulics and hole-cleaning ability. However, a full mud report while drilling is provided only once or twice a day. Moreover, the measurements are mostly performed using traditional equipment. Test interpretation is subjective and might be biased and difficult to verify independently.

In this paper, we present an automated mud skid unit (MSU), which performs continual drilling fluid sampling and measurements at variable temperatures. The unit provides the non-Newtonian rheological constants characterizing a yield-power law fluid as well as the real-time friction factor and critical Reynolds number using a pipe-viscometer measurement approach. Other important fluid properties such as pressurized density, oil/water ratio, and temperature are provided using high-quality in-line sensors. The unit is controlled by a programmable logic controller coupled with a Linux operating system for data analysis. The system sends real-time data to WITSML data servers and provides detailed mud reports to engineers working either on-site or remotely.

The MSU was deployed in the Permian Basin by an independent operator for automated mud monitoring during unconventional shale drilling operations. Rheology, density, and phase content measurements were compared with conventional mud reports provided by the on-site mud engineer. High accuracy (error < 5%) was observed in mud rheology tests. The pressurized mud-density measurements provided by the MSU proved to be more accurate than nonpressurized mud balance measurements, which were affected by mud aeration. Moreover, the MSU provided mud check data 25 times more frequent than those generated by the mud engineer at temperatures of 50 and 65.5°C. Drilling-fluid-related issues, such as chemical overtreatment as well as sudden changes in mud density, rheology, and oil/water ratio, were reported immediately to the drilling crew. This paper provides details about the measurement technology as well as the results from the field deployment of the MSU.