The Eocene Nummulitique (Lutetian to Priabonian) has been studied in the external chains of the French Alps in Haute Savoie and Haute Provence. The Nummulitique unconformably overlies the Mesozoic passive margin succession and represents the onset of sedimentation in the Alpine Foreland Basin which formed due to lithospheric flexure caused by the advance of the Alpine orogeny. The base of the formation is marked by a regional erosional unconformity that developed during subaerial exposure of the Alpine foreland. The Nummulitique may be divided into two informal members: the lower Infranummulitique, a succession of terrigenous carbonates, and the overlying Nummulitic Limestone, a shallow marine carbonate ramp succession. The Infranummulitique is composed of terrigenous carbonates thought to have been derived from the uplifted and eroding foreland which were redeposited in local depocentres due to the topography on the erosion surface. The Infranummulitique can be divided into four facies associations: i) a lenticular conglomerate/nodular marl deposited from ephemeral streams, ii) a sheet conglomerate deposited in a marginal marine fan delta, iii) a Cerithium marl deposited in a brackish water coastal plain/lagoon and iv) a Microcodium wackestone deposited from coastal marine channels. The Nummulitic Limestone is marked by the appearance of the first fully marine foraminifera and a change from terrigenous to autochthonous carbonate sedimentation on a low-energy ramp dominated by larger benthonic foraminifera. The inner-ramp is represented by the deposition of bioclast shoals (packstones and grainstones) dominated by either calcareous red algae, Nummulites or peloids. The middle-ramp is dominated by mud-rich wackestones with a fauna of flat foraminifera, with local winnowed accumulations attributable to storm reworking. The outer ramp and basin are represented by mudstones and marls with a sparse benthos. The Nummulitique shows a marked cyclicity within an overall deepening upwards succession which is interpreted to be the combined effects of tectonic basin subsidence and high-frequency (4th order) eustatic sea-level variations. As the basin developed, the eustatic signature producing the small-scale cyclicity was successively overprinted by accelerating basin subsidence which controlled the stratigraphy of the underfilled foreland basin. Initially, the carbonate productivity is able to keep pace with the relative sea-level changes and the ramp prograded into the basin. The combination of accelerating subsidence rates and nutrient and detrital influx from the approaching orogenic wedge reduced the carbonate productivity and the ramp drowned, leading to pelagic marl deposition. The drowning surface and small-scale cyclicity have been used to correlate between measured sections within each field area, but problems occur in correlating between areas due to the migration of the foreland basin producing a diachronous sedimentary succession, which shows a similar development around the Alps, regardless of the age of the sediments. This diachroneity is evident in the two study areas with similar sediments, cycles and key surfaces developed at different stages of the basin development. The similarity in the successions demonstrates that the early sedimentation in the French Alpine Foreland Basin was controlled primarily by flexural subsidence.

No description available.

The Marion Plateau is a carbonate-platform complex on the passive northeast Australian margin. During ODP Leg 194, a series of eight sites, on two transects, were drilled through Oligocene to Holocene mixed carbonate and siliciclastic sediments that record the depositional history of the Marion Plateau. Major sediment constituents, including benthic foraminifers, were counted from thin sections made from samples taken from three drilling sites: bryozoan-dominated northern highstand platform site 1193 and northern lowstand ramp site 1194, and coralline red algae-dominated southern platform site 1196. Quantitative multivariate analysis of benthic foraminiferal assemblages revealed three paleoenvironmentally relevant groups of taxa. The first group, dominated by Amphistegina and Lepidocyclina, was found at all three sites and is interpreted to be representative of euphotic open-shelf deposition in less than 50 m water depth. The second group was dominated by Cycloclypeus, Operculina and planktonic foraminifers. This group was found at all three sites, but was more common from sites on the northern platform and is interpreted to represent deposition in deep, oligophotic water, in greater than 50 m water depth. The third group, consisting of soritids, alveolinids, Austrotrillina and Flosculinella, was found only in sediments from the southern platform and is interpreted to represent deposition in a restricted, shallow-marine environment, in less than 20 m water depth, consistent with a sea-grass meadow. These three groups of taxa record changing paleoenvironments on the Marion Plateau, and reveal the depositional histories of the Marion Plateau's carbonate platforms.

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No. of bitstreams: 1 Dissertacao_KatyMarilym.pdf: 15479101 bytes, checksum: aedfdc050a05128d76fa06e8cfa26c4c (MD5) Previous issue date: 2018-03-28 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work was carried out aiming at the interpretation and inference of the paleoenvironments of a carbonate succession belonging to the Itaituba Formation (Pensilvaniano of the Amazon Basin), which appears on the banks of the Tapajós River, SW of the state of Pará, petrographic studies focused at the characterization and identification of sedimentary microfacies were performed from the analysis of 50 thin sections. The petrographic analysis was developed according to the standard methodology for studies of this nature, essentially involving the classification of carbonate rocks and the characterization and individualization of microfacies. As a result of these analyzes, five lithotypes (mudstones, wackestones, packstones, grainstones and boundstones) and nine microfacies were identified: Mudstone with evaporites (Me), Wackstone with terrígenos (Wt), Wackstone with autigenic quartz and phytoclasts (Wqf), Wackstone (Wbc), Packstone with brachiopods (Pb), Grainstone with brachiopods (Gb), Grainstone with fusulinids (Gf), Grainstone with binders (Ga) and Boundstone with intraclasts (Bi). From these microfacies, four biofacies were distinguished (Biofacies 01, Biofacies 02, Biofacies 03 and Biofacies 04), based on the trends and paleocology of the bioclasts, and five associations of non-skeletal grains (Association 01, Association 02, Association 03, Association 04 and Association 05), based on the sedimentological significance of these grains. From this, five types of microfacies, representative of five distinct depositional systems were interpreted: MFT-01) semi-restricted coastal sabhka, MFT-02) tidal plain, MFT-03) lagoon, MFT-04) tidal channels and MFT -05) bioclastic bars. These types of microfacies indicate a depositional carbonaceous platform model in ramp, with the development of a shallow marine depositional system, dominated by carbonate sedimentation, influenced by tide, under the dominant regime of semiarid climatic and temperature of the water mass varying from temperate to hot. / Este trabalho foi realizado visando à interpretação e a inferência dos paleoambientes de uma sucessão carbonática pertencente à Formação Itaituba (Pensilvaniano da Bacia do Amazonas), que aflora às margens do Rio Tapajós, SW do estado do Pará, estudos petrográficos voltados à caracterização e identificação de microfáceis sedimentares foram realizados a partir da análise de 50 seções delgadas. A análise petrográfica foi desenvolvida de acordo com a metodologia padrão para estudos desta natureza, envolvendo, essencialmente, a classificação das rochas carbonáticas e a caracterização e a individualização de microfácies. Como resultado destas análises foram identificados cinco litótipos (mudstones, wackestones, packstones, graisntones e boundstones) e nove microfácies: Mudstone com evaporitos (Me), Wackstone com terrígenos (Wt), Wackstone com quartzo autigênico e fitoclastos (Wqf), Wackstone com braquiópodes e crinóides (Wbc), Packstone com braquiópodes (Pb), Grainstone com braquiópodes (Gb), Grainstone com fusulinídeos (Gf), Grainstone com aglutinantes (Ga) e Boundstone com intraclastos (Bi). Destas microfácies, foram distinguidas quatro biofácies (Biofácies 01, Biofácies 02, Biofácies 03 e Biofácies 04), baseadas nos trends e paleocologia dos bioclastos, e cinco associações de grãos não-esqueletais (Associação 01, Associação 02, Associação 03, Associação 04 e Associação 05), fundamentadas no significado sedimentológico destes grãos. A partir disto, foram interpretados cinco tipos de microfácies, representativos de cinco sistemas deposicionais distintos: MFT-01) sabhka costeira semi-restrita, MFT-02) planície de maré, MFT-03) laguna, MFT-04) canais de maré e MFT-05) barras bioclásticas. Estes tipos de microfácies compõem o modelo deposicional de plataforma carbonática em rampa, com o desenvolvimento de um sistema deposicional marinho raso, dominado por sedimentação carbonática, influenciado por maré, sob regime climático dominante de clima semiárido e temperatura da massa d’água variando de temperada a quente.

The palaeoenvironment from which early tetrapods emerged is crucial to comprehend in order to understand the mechanisms that drove and allowed the terrestrialization of vertebrates; one of the most important evolutionary ‘events’ in the history of animals. Nevertheless, much of the terrestrialization is shrouded in obscurity, inter alia, due to scarcity of early tetrapods in the fossil record. Each new discovery of anything linked to vertebrate terrestrialization is therefore of great importance. Here, I present new detailed analyses of the palaeoenvironmental conditions at the time of formation of the earliest (early Middle Devonian) tetrapod trackways found in the Zachełmie Quarry in the Holy Cross Mountains of southern Poland. The trackways are found in three horizons in a clay-rich dolomitic succession represented by the Lower Complex of the Wojciechowice Formation. This Lower Complex is composed of short shallowing upward sequences that often terminate with desiccation cracks and/or paleosols. Vertically fluctuating δ18O values in the complex suggest multiple episodes of closed hydrological systems. A model of ephemeral to perennial lakes in a terrestrial setting is therefore proposed. Such environment is in concordance with evidence of scarce bioturbation and a flourish of microbial communities that, in contrast to a normal marine setting, most likely represent an ecologically stressed ecosystem. Furthermore: non-marine rare earth element (REE) signals, desiccation events, fossils of green algae (charophytes), paleosol development, low energy cyclic deposits and general lack of marine taxa in the body and trace fossil records in this complex firmly establishes the interpretation of palustrine carbonates formed in a lacustrine-like setting. However, in the lower part of the complex, some highly fractioned marine fossils occur. These are suggested to have been transported during wash-up events which temporally places the setting in marine proximity. Seasons of monsoonal rainfall resulted in erosion and influx of detrital grains which is evidenced by fine planar lamination (of seasonal cyclicity) in most of the sediments and occasional occurrence of blackened clasts (and rain-drop imprints). Thus, none of the pre-existing palaeoenvironmental hypotheses of tetrapod emergence are in full concordance with the data from the Zachełmie Quarry. Instead, a new palaeoenvironment is proposed for the earliest tetrapods: schizohaline ephermal to perennial lakes with periodic desiccation. This infers that already in the early Middle Devonian, tetrapods had conquered the terrestrial realm and were perhaps already capable of terrestrial locomotion over quite substantial distances. / Däggdjur, reptiler, fåglar och amfibier utgör tillsammans en besläktad djurgrupp som kallas för tetrapoder (fyrfotingar). Deras gemensamma förfader härstammade från de lobfenade fiskarna men skiljde sig från dem genom att inneha utvecklade ben med tår istället för de ”köttiga” fenor som de lobfeniga fiskarna karaktäriseras av. Denna evolutionära nyhet tillät, tillsammans med en rad andra egenskaper (lungor, skydd för uttorkning av dermis etc.), att vertebrater helt och hållet kunde koloni-sera land. I och med att vår egen existens är en direkt följd av denna evolutionära händelse är detta ett hett forskningsämne inom evolutionsbiologin. Ändå är mycket fortfarande höljt i dunkel beträffande hur koloniseringen av land gick till och vad det var som drev denna utveckling eftersom övergången skedde under en, i geologisk mått, snabb tidsrymd. Dock har de sista årtiondena resulterat i flertalet nya fossilfynd av primitiva tetrapoder. Ett fynd som är speciellt spektakulärt eftersom det är den hittills äldsta efterlämningen av tetrapoder, är fotspår som uppenbart är gjorda av ett djur som hade ben och tår istället för fenor. Detta förvånade hela det vetenskapliga samfundet eftersom det innebar att vi (tetrapoderna) utvecklades tidigare än vad som var dittills trott och att vertebrat-koloniseringen av land förmodligen skedde flertalet miljoner år tidigare. Vad som också skiljer ett spårfossil från andra fossil är att de är spår av djuren från när och där de levde till skillnad från bara deras skelettdelar som oftast transporterats från där de dog och bara preserveras i speciella miljöer. Detta har jag utnyttjat i detta arbete för att försöka avgöra i vilken miljö de är avsatta i. Jag har analyserat de sedimentära bergarterna i stenbrottet i södra Polen med skärningen som innehåller de lagren i vilka fotspåren finns. Analyser av sällsynta jordartsmetaller från de tre lager där fotspår är tydliga, antyder en speciell avsättningsmiljö som inte liknar en typisk havsmiljö. I den undre delen av lagerföljden där de spårbärande lagren påträffats finns återkristalliserade saltkristaller, torkningssprickor och fossila jordar som indikerar korta respektive långvariga perioder av uttorkning. Andra fossil som i en normal marin miljö borde bevaras i en dolomitisk kalksten lyser med sin frånvaro och istället påfinns massiv koloni-sering av cyanobakterier. Detta brukar ske i speciella miljöer som avviker från vanlig marin komposi-tion, så som äldre sötvattensmiljöer eller laguner med hög salthalt, som därmed är ”svårbebodd” för djur som annars livnär sig på de fotosyntiserande bakterierna. Implikationen av mitt arbete är att tetrapoderna redan i tidig mellan Devon (ca 390 miljoner år sedan) inte bara hade utvecklat ben utan också att de kunde använda dem över landsträckor för att ta sig till, och mellan, kontinentala vatten. Detta är ännu en viktig pusselbit i pusslet som ämnar rekonstruera tetrapodernas (och vår egen) uppkomst.

This master thesis comprises results of sedimentologic, microfacies and physical stratigraphic research of the Suchomasty Limestone at Zlatý kůň Hill near Koněprusy (Prague Basin, Lower Devonian - Dalejan). Six instructive sections have been selected for detailed study. Physical stratigraphic records (MS and GRS) have been used for correlation of two lithologically different sections (Section I - to the East of the Herget Quarry and Section IV - near the entrance to the Koněprusy Caves). This comparison showed that both sections correspond to the same stratigraphic level, and thus can be included in one sedimentary system. This assumption is also supported by preliminary results of studies on stratigraphic distribution of conodonts. Stratigraphic variations in MS and GRS may also be used for reconstructions of sedimentary environment and its evolution (e.g., changes in sea level). However, all measured parameters show only low oscillations and reflect probably only local conditions. Five microfacies types corresponding to three facies belts have been identified in the studied sections. The lower part of the Suchomasty Lm. is dominated by fine-grained limestones (MF 1 - tentaculite wackestone/packstone) in the NW part of the area (Section IV - near the entrance to the Koněprusy Caves). They deposited in a...

The Lower Triassic Sinbad Limestone Member of the Moenkopi Formation has produced minor amounts of oil in the Grassy Trail Creek field near Green River, Utah and is present below much of central Utah including the recently discovered Covenant field. Superb outcrops of this thin (15 m), mixed carbonate-silicilastic unit in the San Rafael Swell permit detailed analysis of its vertical and lateral reservoir heterogeneity. Vertically, the Sinbad Limestone comprises three facies associations: (A) a basal storm-dominated, well-circulated skeletal-oolitic-peloidal limestone association, (B) a storm-dominated, poorly-circulated hummocky cross-stratified siliciclastic/peloidal association, and (C) a capping peritidal cross-bedded oolitic dolograinstone association. Eleven microfacies are present in 14 measured sections within the Sinbad Limestone. Lateral variation is most pronounced in the upper part of the basal limestone where storm-deposited beds pinch out over a lateral distance of one kilometer. Otherwise, individual beds and microfacies display a large degree of lateral homogeneity and regional persistence. Diagenesis is strongly controlled by microfacies. Diagenetic elements include marine fibrous calcite cements, micritized grains, compaction, dissolution and neomorphism of aragonite grains, meteoric cements, pressure dissolution, and dolomitization. The paragenetic sequence progresses from marine to meteoric to burial. Marine and meteoric cements occlude much of the depositional porosity. Hydrocarbon-lined interparticle and separate vug (largely molds) pores (1-5%) characterize the skeletal-oolitic limestones with permeability ranging from 0-100 md. Low permeability/porosity characterizes the middle silicilastic unit. The best reservoir qualities (permeability 400 md) occur in portions of the dolomitized oolitic grainstones that form the upper 2 to 3 m of the Sinbad Limestone. Fracture analysis of the studied area indicates a strong NW-SE trend. Fracture spacing is associated with lithology. Fracturing of limestone possibly displays a higher dependence upon bed thickness and microfacies type. The degree of dolomitization controls and increases fracture spacing while siltstones display more closely spaced fractures. The basal limestone unit is an oil storage unit, medial siltstones are flow baffles/barriers, and the dolostone caprock is an oil flow unit. If good connectivity through fractures can be obtained between the dolostone and limestone units, the Sinbad Limestone has potential to serve as a reservoir. This study will not only aid in future Sinbad exploration, but will serve as a model for parasequence-scale intervals in thicker mixed carbonate-siliciclastic successions.

Les formations, de plate-forme carbonatée, d'âge Kimémridgien à Berriasien affleurent, de part et d 'autre du synclinal molassique de Seyssel emprunté par la vallée du Rhône, dans les anticlinaux du Gros Foug, à l'Est et du Grand Colombier, à l'Ouest. Dans ces deux structures des coupes détaillées permettent de séparer les différentes formations et d'analyser les variations latérales de faciès. Les études lithostratigraphiques et pétrographiques associées amènent à distinguer, de bas en haut : - la formation des couches à Céphalopodes (Kimméridgien inférieur) et la formation des calcaires de Tabalcon (base du Kimméridgien supérieur) . Ces formations sont faites de calcaires mudstones micritiques alternant avec des lits de marnes vers la base et correspondent à des dépôts subtidaux face à la mer ouverte ; - la formation des "calcaires construits de la Haute-Chaine" (Kimméridgien supérieur) faite de calcaires boundstones biohermaux coralliens, se développe à l'Est. Il s ' agit d'une véritable barrière récifale séparant la plate-forme de la mer ouverte. En position interne, à l'Ouest donc, cette formation passe à la formation des "calcaires en plaquettes", Elle s 'est déposée dans un lagon intertidal calme , à ambiance réductrice et dans la région même de la mine d'Orbagnoux , la sédimentation est celle des calcaires véritables lemnitiques bitumineux ; - la formation des calcaires de Landaize (sommet du Kimméridgien supérieur). Il s ' agit de calcaires à texture sablo-graveleux de mer agitée surmergeant surtout le bordure externe de la plate- forme recouvrant à l'Est et au Sud la barrière récifale; - la formation des Tidalites de Vouglans (Portlandien) recouvre progressivement la paléogéographie contrastée précédente avec le dépôt des calcaires à grains fins souvent dolomitisés, de faciès supra-tidaux à intratidaux marqués par des structures sédimentaires d'émersion et également par la présence de petits cailloux noirs de composition organo-minérales témoin de quelques événements anoxyques. - Les Assises pürbeckiennes (Berriasien inférieur) correspondent à des dépôts plus calmes à fossiles laguno-lacustres par passées (Characées) de moins forte énergie mais également à cailloux noirs, structures sédimentaires d'émersion et paléosols. Il s ' agit probablement d 'un milieu de plate-forme interne de type lagunaire liée à des épisodes temporaires de régressions marquées. - L ' étude des microfacies montre que la diagenèse des roches est précoce liée à la zone de vadose et à la zone phréatique et que la compaction est faible, liée à une modeste surcharge sédimentaire. Enfin, l'étude de la matière organique effectuée selon les techniques classiques optiques ( lumière réfléchie , lumière fluorescente) et géochimiques ( dosage du carbone organique , analyse Rock-Eval, extraction chloroformique et chromatographique ) montre que seuls les calcair es en plaquettes bitumineux de la mine d ' Orbagnoux sont des roches-mères excellentes. Cette matière organique de type l, ayant une origine algaire à bactérienne est immature. On observe néanmoins la présence d' hydrocarbures en grande quantité dont une proportion non négligeable d 'hydrocarbures satures et aromatiques issus de composés organiques ayant donc subi une maturation thermique non négligeable . Le problème de leur origine est discuté .

The aim of this study is to investigate the Upper Visean substages, delineate the Visean - Serpukhovian boundary with calcareous foraminifera and interpret the foraminiferal evolution and sequence stratigraphical framework by using sedimentary cyclicity across the boundary section. For this purpose a 59,61 m thick stratigraphic section consisting of mainly limestone and partly sandstone and shale is measured in the Aziziye Gedigi and Oru&ccedil / oglu Formations in the Pinarbasi Region of Eastern Taurides. A detailed micropaleontological study has revealed presence of important foraminiferal groups namely, parathuramminids, earlandiids, endothyroids, archaediscids, biseriamminids, fusulinids, loeblichids, tournayellids and paleotextularids and 145 species and three biozones. The biozones are, in ascending order, Eostaffella ikensis &ndash / Vissarionovella tujmasensis Zone (Mikhailovsky / Late Visean), Endothyranopsis cf. sphaerica &ndash / Biseriella parva Zone (Venevsky / Late Visean) and Eostaffella pseudostruvei &ndash / Archaediscids @ tenuis stage Zone (Taurssk / Early Serpukhovian). A detailed microfacies analysis was carried out in order to understand the depositional history and sedimentary cyclicity and construct the sequence stratigraphic framework of the studied area. Three main depositional environments consisting of open marine, shoal or bank and tidal flat environments were interpreted based on the analysis of 12 major microfacies and 11 sub-microfacies types. Based on the vertical association of microfacies twenty-six cycles, two sequence boundaries and three sequences were recognized in the studied section and these two sequence boundaries, which correspond to the Mikhailovsky and Venevsky horizons, are the records of the global sea level changes during the Late Paleozoic Ice Age. Within this context Visean &ndash / Serpukhovian boundary falls in the transgressive system tract of the third sequence. The duration of cycles are calculated as 117 ky and interpreted as orbitally induced glacioeustatic cycles.

The Garzan Formation is a deepening upward marine carbonate including successions ranging from subtidal to open marine facies deposited in the Maastrichtian. The Garzan Formation is composed of five microfacies types / Miliolid Wackestone (subtidal), Orbitoid Miliolid Wackestone, Rudist Wackestone (backshoal to shoal), Rotalid Miliolid Wackestone (shoal to foreshoal) and Pelagic Foraminiferal Mudstone (foreshoal to open marine). These five microfacies are stacked in different combinations consisting of five types of depositional cycles. The type A and D cycles the building blocks of transgressive systems tract (retrogradational), whereas type B and C cycles are deposited during highstand systems tract (aggradational). The type E cycle is progradational and also corresponds to the highstand systems tract deposits. The maximum flooding surface is usually located within the type D cycle towards the top of the formation. vi Generally, the base of the Garzan Formation deposition starts with highstand systems tract deposits (type E and C cycles) and overlain by transgressive systems tract deposits (type A cycle) in between there is a type 2 sequence boundary. Then deposition continues with highstand systems tract deposits (alternation of type B and C cycles) which are aggradational in character. The top of the Formation is characterized by transgressive systems tract deposits (type D cycle) which usually includes the maximum flooding surface. The second type 2 sequence boundary is located below the type D cycle. There are four of the stacking patterns observed in the Garzan Formation. The GR values change from relatively high to low API in type D and A cycles, whereas a relative shift from low to high API is observed in type E cycle. The GR in the type B and C cycles does not display any relative change. There is no net movement in the SONIC readings in type A, B, C and E cycles / however there is a relative shifting from low velocity to high velocity in type D cycle. In Garzan deposition opposing the general patterns, a decrease in GR readings indicates a decrease in energy and relatively deepening. In carbonate depositional systems predicting the depositional environment from the logs should only be accomplished with microfacies control, otherwise the interpretation will be erroneous.