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This paper discusses the sedimentary evolution of an area with Neogene fluvial and lacustrine deposits in the northwestern part of the Iberian Range, and its relation to the effects of Alpine compressional tectonics affecting a major, formerly extensional fault. Stratigraphic analyses allow characterizing three tectosedimentary units. Units 1 and 2 are dominated by clastics lithofacies, and are separated by an unconformity and the correlative conformity. Unit 3 is formed of tufa and micritic limestones and represents a sharp lithological change throughout the area. Total thickness is 120 m. These units are involved in two NNW-SSE Alpine trending, kilometric-scale structures: 1) the Nigüella fault, that put into contact Triassic rocks, in the footwall, with Cenozoic rocks, in the hanging-wall, and 2) the Nigüella syncline, subparallel to this fault, with strata dips between 19° up to 70°. In units 1 and 2, four facies associations represent deposition in proximal to middle alluvial fans, from local reliefs, and a braided fluvial system with limited floodplain, running southward; both environments record minor fluvial and lacustrine carbonate deposition. Three other facies associations represent dominant carbonate deposition, either palustrine-fluvial-lacustrine or lacustrine settings. In the three units, oncoid and phytoclast rudstones formed in shallow, low-sinuosity channels and pools with extensive tufaceous palustrine areas, where hydrophilous plants throve. In contrast, micritic limestones with ostracods and marls correspond to offshore dominant carbonate lacustrine deposition in still and permanent lakes. Thus the overall sedimentary system evolved from dominant alluvial-fluvial to dominant lacustrine carbonate environments through time. These facts, along with calcrete development in Units 1 and 2, indicate increasing precipitation and probably the passage to a hydrologically-closed lake basin through time. The Nigüella fault played as a normal fault at the early Jurassic and during the Cenozoic compression it promoted the formation of a hanging-wall syncline basin through buttressing of the NE block against the fault. This scenario conditioned the distribution and extent of the Miocene lithofacies through space and time, and the location of depocentres. Decreasing tectonic activity through the studied interval favoured fluvial incision, capture of the Mesozoic aquifer, and then outflow of ground water rich in Ca2+ and HCO-3, thus favouring widespread carbonate deposition, and finally the expansion of the lake area. En este artículo se discute la evolución sedimentaria del relleno neógeno de un área situada en la parte Noroeste de la Cordillera Ibérica que presenta depósitos fluviales y lacustres, y su relación con la tectónica alpina compresiva que afectó a una falla anteriormente extensional. Los análisis estratigráficos permiten caracterizar tres unidades tectosedimentarias, con un espesor total de 120m. Las Unidades 1 y 2 están formadas dominantemente por litofacies clásticas, y están separadas por una discordancia y su correlativa conformidad. La Unidad 3 está formada por calizas tobáceas y micríticas, y representa un salto litológico brusco con la Unidad 2 en toda su extensión. Estas unidades están involucradas en dos estructuras de escala kilométrica con dirección alpina NNW-SSE: 1) la Falla de Nigüella, que pone en contacto materiales triásicos con cenozoicos en los bloques levantado y hundido, respectivamente, y 2) el Sinclinal de Nigüella, subparalelo a la falla anterior, con buzamiento de estratos entre 19º y 70º. En las unidades 1 y 2, cuatro asociaciones de facies sedimentarias representan el depósito en áreas proximales y medias de abanicos aluviales, procedentes de relieves locales, y un sistema fluvial braided con reducida llanura de inundación, procedente del Norte. Ambos ambientes registran sedimentación carbonática fluvial y lacustre. Otras tres asociaciones de facies representan el depósito dominante de carbonatos, tanto en entornos palustre-fluvial-lacustres como en lacustres. En las tres unidades, los rudstones de oncoides y fitoclastos se formaron en canales de aguas someras, con baja sinuosidad y en zonas encharcadas, con extensas zonas palustres tobáceas, con desarrollo de plantas hidrófilas. Por el contrario, las calizas micríticas con ostrácodos y las margas corresponden al depósito de calcita en zonas lacustres de aguas tranquilas y permanentes. Por tanto, el sistema sedimentario evolucionó desde un ambiente aluvial-fluvial dominante hasta un ambiente lacustre. Este hecho, junto con el desarrollo de calcretas en las unidades 1 y 2, indica condiciones más húmedas y posiblemente el paso a un lago cerrado hidrológicamente. La falla de Nigüella funcionó a principios del Jurásico como una falla normal, y durante la compresión del Cenozoico provocó la formación de una cuenca sinclinal mediante buttressing del bloque NE contra la falla. Este contexto condicionó la distribución y extensión de litofacies miocenas a lo largo del espacio y del tiempo y la localización de depocentros. La disminución de la actividad tectónica a lo largo del intervalo estudiado favoreció la incisión fluvial, la captura del acuífero mesozoico y la salida del agua subterránea rica en Ca2+ y HCO-3, dando lugar al depósito generalizado de carbonato cálcico y, finalmente, a la expansión del lago.

19 pages; International audience; The volcanic crater lake of Dziani Dzaha in Mayotte is studied to constrain the geochemical settings and the diagenetic processes at the origin of Mg‐phyllosilicates associated with carbonate rocks. The Dziani Dzaha is characterized by intense primary productivity, volcanic gases bubbling in three locations and a volcanic catchment of phonolitic/alkaline composition. The lake water has an alkalinity of ca 0·2 mol l−1 and pH values of ca 9·3. Cores of the lake sediments reaching up to one metre in length were collected and studied by means of carbon–hydrogen–nitrogen elemental analyzer, X‐ray fluorescence spectrometry and X‐ray powder diffraction. In surface sediments, the content of total organic carbon reaches up to 20 weight %. The mineral content consists of aragonite and hydromagnesite with minor amounts of alkaline feldspar and clinopyroxene from the volcanic catchment. Below 30 cm depth, X‐ray diffraction analyses of the

The dolomite reservoirs in the Paleogene Shahejie Formation in the Bozhong area of the Bohai Bay Basin contain a large amount of dolomite cement. Petrologic and mineralogic studies have shown that the dolomite cements can be divided into three types according to their occurrence: coating dolomite (CD), pore-lining dolomite (LD), and pore-filling dolomite (FD). The laser microsampling technique was used to analyze the C and O isotopes in the carbonate minerals. This method is an effective way to produce CO2 gas from a particular carbonate structure in a thin section, and it has a spatial resolution of 20&ndash, 50 &micro, m and an optimal precision of approximately &plusmn, 0.22&sigma, for &delta, 13C and &delta, 18O in carbonate standard materials. The carbon and oxygen isotopic compositions and the oxygen isotopic geothermometer results showed that the dolomitization fluid is mainly low temperature fluid, the lake basin environment is relatively closed, and the salinity index Z value is greater than 120, which indicates the invasion of seawater. CD and early-stage LD crystals were mainly very fine crystals with faint cathodoluminescence, which indicates the early formation of diagenesis. The high temperatures of late-stage LD and FD measured by oxygen isotope thermometers indicates that they formed at a deeper depth. The dolomite cements in the study area may have formed in two stages: seepage-reflux dolomitization during the penecontemporaneous period and burial dolomitization.

International audience; The southern Levant is a Mediterranean climate zone of complex variability in which uncertainty remains in regional palaeoclimate reconstruction. In spite of the proven value of diatoms in circum-Mediterranean palaeoenvironmental research, their potential remains largely unexplored in the southern Levant region. In this study, we generate a new, high-resolution multi-proxy record for the last ca. 9000 cal. yr BP, supported by diatom data and key biological, mineralogical and geochemical indicators preserved in a 17.8-m-long sediment sequence recovered from Lake Kinneret (the Sea of Galilee), Israel. During the Holocene, well-correlated shifts in the diatom, minero-geochemical and palynological data indicate marked lake-level variation over time as well as changes in the trophic state of Lake Kinneret. Our results are particularly important in improving the reconstruction of Holocene lake-level variation, and thus past moisture availability. Diatom-inferred lake-level oscillations correlate well with the output from climatic models from the Levantine region and clarify previous uncertainty concerning regional variation in moisture availability. The Early Holocene (from ca. 9000 to 7400 cal. yr BP) was characterized by lake-level shifts due to fluctuating dry-wet climate conditions. During the mid-Holocene (from 7400 to 2200 cal. yr BP), a stable, deep lake-level phase persisted due to high humidity. The lake level of modern Lake Kinneret not only fluctuates seasonally with available moisture, but has also been influenced for ca. 2000 years by the impacts of water abstraction for human consumption and agriculture. Over the last 9000 cal. yr BP, the trophic state of Lake Kinneret has changed from an oligotrophic to a meso- to eutrophic environment, mainly triggered by increased human impact from around 2200 cal. yr BP onwards. The lake’s ecosystem status was not strongly affected by the documented major changes in human occupation patterns during the mid-Holocene, when a relatively stable environment persisted.

Submitted by Boris Flegr (boris@uerj.br) on 2021-01-05T15:36:43Z No. of bitstreams: 4 Dissertacao_AnaCarolinaLeonelSartorato_ Cap 1 e 2.pdf: 1088363 bytes, checksum: 370963d6d9e5a7b3e2236913569bb25a (MD5) Dissertacao_AnaCarolinaLeonelSartorato_ Cap 3 e 4.pdf: 2898987 bytes, checksum: c6106ec27c3014a89d6156ae1add6483 (MD5) Dissertacao_AnaCarolinaLeonelSartorato_ Cap 5 ate 5 2.pdf: 2517247 bytes, checksum: b3dbfc2d0163ffd228a18f59384ffbaa (MD5) Dissertacao_AnaCarolinaLeonelSartorato_ Cap 5 5 3 ate anexo.pdf: 3040189 bytes, checksum: dd4d4cb065b3df53442866707047ba9b (MD5) Made available in DSpace on 2021-01-05T15:36:43Z (GMT). No. of bitstreams: 4 Dissertacao_AnaCarolinaLeonelSartorato_ Cap 1 e 2.pdf: 1088363 bytes, checksum: 370963d6d9e5a7b3e2236913569bb25a (MD5) Dissertacao_AnaCarolinaLeonelSartorato_ Cap 3 e 4.pdf: 2898987 bytes, checksum: c6106ec27c3014a89d6156ae1add6483 (MD5) Dissertacao_AnaCarolinaLeonelSartorato_ Cap 5 ate 5 2.pdf: 2517247 bytes, checksum: b3dbfc2d0163ffd228a18f59384ffbaa (MD5) Dissertacao_AnaCarolinaLeonelSartorato_ Cap 5 5 3 ate anexo.pdf: 3040189 bytes, checksum: dd4d4cb065b3df53442866707047ba9b (MD5) Previous issue date: 2018-04-26 The Brazilian marginal basins have extensive lacustrine deposits of apatian age, known as the Pre-Salt section, where large oil accumulations were discovered since 2006. The largest volumes occur in the Barra Velha Formation, in Santos Basin. Detailed sedimentary, stratigraphic and diagenetic studies of these reservoirs are of crucial importance, for they provide subsidies for the exploration of new areas, and enable the production development in the already delimited oil fields. In this sense, the aim of this dissertation consisted in the facies, stratigraphic and diagenetic characterization of a carbonate reservoir of the Barra Velha Formation, and the incorporation of the results in a 3D numerical model. To do so, 265 meters of core, 331 sidewall cores and 221 thin sections from four wells were studied. In addition, cathodoluminescence, scanning electron microscopy, x-ray diffractometry and electron microprobe chemical analyzes were performed in selected samples. As a result of the facies analysis, 15 sedimentary facies were identified. By observing the lithological characteristics of each facies, together with their transition pattern, it was possible to establish an ideal vertical stacking of facies, which is mainly controlled by the lake's water balance (dry and humid periods). Through this pattern, and with the analysis of seismic sections and well logs, a stratigraphic correlation was made between the four wells studied, from which an interval was selected for the diagenetic characterization. This study identified that the main diagenetic minerals are, in order of abundance, dolomite, silica minerals and calcite. These minerals are mainly eodiagenetic and occur in a great diversity of forms that represent different diagenetic phases. The carbonate minerals also have differences in chemical composition. The facies characterization and the systematic quantitative description of minerals and diagenetic processes allowed the numerical modeling of the distribution of sedimentary facies and diagenetic products. With the combination of these models, a reservoir quality numerical model was obtained, which turned to be coherent with the permeability log calculated from the nuclear magnetic resonance log. Thus, it can be concluded that the diagenetic analysis was effective in identifying intervals with better permo-porous quality in the reservoir. As bacias marginais brasileiras apresentam extensos depósitos carbonáticos lacustres, de idade aptiana, conhecidos como a seção Pré-Sal, onde foram descobertas grandes acumulações de óleo, a partir de 2006. Os maiores volumes ocorrem na Formação Barra Velha, Bacia de Santos. Estudos sedimentares, estratigráficos e diagenéticos de detalhe são muito importantes, pois fornecem subsídios para a prospecção de novas áreas, e viabilizam o desenvolvimento da produção nos campos já delimitados. Nesse sentido, o objetivo deste trabalho consistiu na caracterização faciológica, estratigráfica e diagenética de um reservatório carbonático da Formação Barra Velha, e a incorporação dos resultados em um modelo numérico tridimensional. Para tanto, foram descritos 265 metros de testemunho, 331 amostras laterais rotativas e 221 lâminas delgadas provenientes de quatro poços. Além disso, foram realizadas, em amostras selecionadas, análises por catodoluminescência, microscopia eletrônica de varredura, difratometria de raios-x e análises químicas em microssonda eletrônica. Através da análise de fácies, 15 fácies sedimentares foram identificadas. Analisando-se as características litológicas de cada uma delas, juntamente com seu padrão de transição, foi possível estabelecer um empilhamento de fácies ideal, que é principalmente controlado pelo balanço hídrico do lago (períodos secos e úmidos). Através desse padrão, e com a análise de seções sísmicas e perfis elétricos, foi feita a correlação estratigráfica entre os quatro poços estudados, a partir da qual foi selecionado um intervalo para a caracterização diagenética. Através do estudo diagenético, identificou-se que os principais minerais diagenéticos são, em ordem de abundância, a dolomita, minerais de sílica e a calcita. Esses minerais são predominantemente eodiagenéticos, e ocorrem em uma grande diversidade de formas, que representam fases diagenéticas diferentes. Os minerais carbonáticos apresentaram composições químicas também distintas entre si. A caracterização faciológica e a descrição sistemática quantitativa de minerais e processos diagenéticos, possibilitou construir modelos numéricos de distribuição de fácies sedimentares e dos produtos diagenéticos. Com a combinação desses modelos, obteve-se um modelo numérico de categorias de qualidade de reservatório, que nos poços mostrou-se coerente com as curvas de permeabilidade calculadas a partir do perfil de ressonância magnética. Assim, pode-se concluir que a análise diagenética foi eficaz na identificação de intervalos com melhor qualidade permoporosa.

International audience; A 200-m thick carbonate succession has been deposited in shallow-water, saline lake environments during the Priabonian-Rupelian in the Issirac Basin (South-East France). The palaeoenvironmental and palaeogeographic significance of such saline lake carbonates has been characterized on the basis of a multi-proxy analysis including 1) depositional and diagenetic features, 2) biological components (molluscs, ostracods, benthic foraminifers, characean) and 3) carbon, oxygen and strontium stable isotopes. Biological associations are indicative of dominantly shallow (< 10 m), freshwater to mesohaline (0 to 18‰) environments. The occurrence of evaporites is indicative of periods of hypersalinity. Carbonate production is dominantly associated to microbial activity (planar stromatolites) and micrite precipitation in lakes colonized by macrophyte meadows. The Priabonian-Rupelian carbonates from the Issirac Basin recorded three main cycles of lake transgression, corresponding to the three main sedimentary units (U1, U2 and U3). Relative lake-level, degree of connectivity with surrounding lakes and climate (dry versus humid) are the three key factors controlling the water composition, carbonate production and depositional environments in the Issirac lake. Although the ASCI (Alès-Issirac-Saint-Chaptes) lacustrine system likely represents an athalassic (inland) lake system evolving through times, the stable isotope composition (C, O and Sr) of carbonates strongly suggests the occurrence of transient connections of the ASCI lake water with water bodies influenced by seawater and/or fed with sulfates deriving from Triassic evaporites. The Issirac Basin may be therefore interpreted as a sill area connecting the ASCI lacustrine system with the Rhône valley (Mormoiron and Valence) saline lake systems during maximum flooding periods. Finally, changes in depositional features, biota and stable isotope composition of carbonates in unit U3 suggest a transition from relatively dry to more humid climate during the uppermost Priabonian or earliest Rupelian.

Os reservatórios lacustres do Grupo Lagoa Feia, seção rift da Bacia de Campos, margem Leste brasileira, tem mantido há décadas uma expressiva produção a partir de campos localizados em águas rasas. A descoberta de grandes acumulações na seção rift e sag (pré-sal) da Bacia de Santos reativou a exploração por reservatórios análogos na Bacia de Campos e em outras bacias marginais. Um estudo petrográfico e petrofísico sistemático foi executado sobre os reservatórios rift da Formação Coqueiros e sag da Formação Macabu do Norte da Bacia de Campos, com objetivo de caracterizar os principais controles sobre a gênese e evolução daqueles reservatórios não-convencionais e seus sistemas porosos. As principais petrofácies de reservatório reconhecidas foram grainstones e rudstones bioclásticos, arenitos ooidais argilosos e dolomitos na Formação Coqueiros, e crostas coalescentes e não-coalescentes de calcita fascicular, rudstones e grainstones intraclásticos e dolomitos na Formação Macabu. A evolução dos reservatórios bioclásticos foi controlada pelo balanço entre dissolução ou neomorfismo dos bioclastos aragoníticos de bivalves, favorecendo a geração de porosidade móldica pouco conectada, ou a preservação da porosidade interpartícula bem conectada, controlando a permeabilidade dos reservatórios. Os arenitos de oóides de argilas magnesianas sofreram dissolução e substituição por dolomita e sílica, o que gerou sistemas porosos altamente heterogêneos, compostos por poros móldicos, intercristalinos, vugulares e microcristalinos. O crescimento de agregados cristalinos arborescentes nas crostas coalescentes de calcita gerou porosidade de crescimento do arcabouço primária, que foi reduzida principalmente por cimentação dolomítica, ou alargada por dissolução, o que ampliou sua permeabilidade. Crostas nãocoalescentes de calcita mostram forte interação com argilominerais magnesianos, que preenchem interstícios, e/ou estão intercalados com as crostas. Sua porosidade está relacionada com a dissolução das argilas, o que produziu baixa permeabilidade. Rochas intraclásticas comumente mostram matriz argilosa, ou estão compactadas e cimentadas. Onde exibem porosidade interpartícula primária ou dissolução da matriz, podem ter boas porosidades e permeabilidades. A dolomitização heterogênea de ambas as Formações em alguns casos destruiu a porosidade primária ou eodiagenética, ou em outros gerou altos valores de porosidade e permeabilidade nos dolomitos. Relações de substituição e de compactação indicam que muitos dos processos diagenéticos ocorreram durante a eodiagênese, controlados principalmente pela instabilidade da aragonita nos reservatórios bioclásticos da Formação Coqueiros, e dos argilominerais magnesianos na Formação Macabu. Este estudo representa a primeira caracterização petrográfica publicada dos reservatórios carbonáticos não-convencionais do sag, e salienta a importância crucial dos estudos petrográficos sistemáticos para a compreensão e previsão da qualidade de reservatórios complexos. Lacustrine carbonate reservoirs from the Lagoa Feia Group, rift section of Campos Basin, offshore eastern Brazil, have sustained for decades a significant production from shallow water oil fields. The discovery of giant accumulations in the rift and sag (pre-salt) section of the adjacent Santos Basin has reactivated the exploration for equivalent reservoirs in the Campos Basin and in other marginal basins. A systematic petrographic and petrophysical study was performed on the rift Coqueiros Formation and the sag Macabu Formation carbonates from the Lagoa Feia Group in northern Campos Basin, in order to characterize the main controls on the origin and evolution of those unconventional reservoirs and their pore systems. The main types of reservoir petrofacies recognized were grainstones and bioclastic rudstones, magnesian clay ooidal arenites and dolostones from the Coqueiros Formation; coalescent and non-coalescent crusts of fascicular calcite, intraclastic rudstones and grainstones, and dolostones from the Macabu Formation. The evolution of bioclastic reservoirs was controlled by the balance between dissolution and neomorphism of the aragonitic bivalve bioclasts, favoring the generation of poorly-connected moldic porosity or the preservation of well-connected interparticle porosity, which controlled the permeability of the reservoirs. The magnesian clay (stevensite) ooidal arenites suffered dissolution and replacement by dolomite and silica, what generated highly heterogeneous pore systems, composed by moldic, intercrystalline, vugular and microcrystalline pores. The growth of crystal shrubs in coalescent calcite crusts generated growth-framework primary porosity, which was reduced mostly by dolomite cementation, or enlarged by dissolution, what enhanced their permeability. Non-coalescent calcite crusts usually show strong interaction with syngenetic magnesian clay minerals, which fill interstices and/or are interbedded with the crusts. Their porosity is related to dissolution of the clays, what generated poor permeability. Intraclastic rocks usually display clay matrix, or are compacted and cemented. Where they show interparticle primary porosity or matrix dissolution, they may have good porosities and permeabilities. The heterogeneous dolomitization of both formations, either destroyed the primary or early diagenetic porosity, or generated high porosity and permeability values in the dolostones. Relationships of replacement and compaction indicate that most of the diagenetic processes occurred during eodiagenesis, controlled mostly by the instability of the aragonite in the bioclastic Coqueiros reservoirs, and of the magnesian clay minerals in the Macabu Formation. This study represents the first published petrographic characterization of the unconventional sag carbonate reservoirs, and stresses the crucial importance of systematic petrographic studies for the understanding and prediction of the quality of complex reservoirs.

The oxygen-isotope composition of local precipitation (d18OP) is reconstructed from carbonate lake-sediment components in a sediment core covering the last 10000 calendar years from Lake Tibetanus, a small, hydrologically open, groundwater-fed lake in the Abisko area, northern Sweden. Comparison of the d18OP history with a pollen-based palaeotemperature record from the same core clearly reveals pronounced deviations from the normally expected temporal d18OP-temperature relation (so-called ‘Dansgaard relation’) that may be a function of changing oceanicity. The transition from relatively moist, maritime conditions in the early Holo cene to a much drier climate after 6500 cal. BP is re‘ ected by major changes in forest extent and composition as recorded by pollen and plant macrofossil data. At the time of maximum in‘ uence of westerly air-mass circulation (high zonal index) c. 9500 cal. BP, brought about by high summer insolation and enhanced meridi onal pressure gradients, d18OP at Lake Tibetanus was about 2‰ higher than would be predicted by the modern isotope-temperature relation. The occurrence of long-term changes in d18OP-temperature relations, which are more sensitive measures of palaeoclimate than either d18OP or temperature alone, needs to be taken into account when extracting palaeoclimatic information from continental oxygen-isotope records.

U ovom radu su opisane miocenske jezerske naslage otoka Paga, čiji se izdanci nalaze duž plaže Crnike, na jugozapadnom dijelu Paškog zaljeva. Miocenske naslage pripadaju burdigalu i ostaci su miocenskog slatkovodnog Paškog jezera. Sedimenti su jezerski karbonati i slititi. Istraživanje u sklopu izrade ovog rada uključivalo je snimanje detaljnog geološkog stupa na terenu (u mjerilu 1:2000), uzorkovanje reprezentativnih litotipova te njihovo analiziranje metodom mikroskopiranja u prolaznoj i reflektiranoj svjetlosti. Opisane su petrološko-sedimentološke značajke analiziranih uzoraka i definirani su slijedeći litotipovi: mikrit, fosiliferni mikrit, siltit, onkoidni vapnenac, pješčenjak i ugljen. Na temelju istih značajki i istog uvjeta nastanka, litotipovi su razvrstani u sedam facijesa na temelju kojih je interpretiran taložni model., Miocene lacustrine deposits of the Pag island are described in this thesis. Deposits are placed along the Crnika beach, on the south-west part of the Pag gulf. Miocene deposits correspond to the Burdigalian Stage of the Early Miocene, and they represent remain of the freshwater Lake Pag. Sediments are mostly lacustrine carbonates and silt. The study started with measuring of detailed geological column (1:2000) in the field that included taking of representative samples for micropetrographical analysis by polarising microscopy. Petrological and sedimentological features are described and following lithotypes are determined: micrite, silt, fossiliferous micrite, oncoide limestone, sanstone and coal. These lithotypes are grouped in seven facies based on their similar characteristics. A depositional model is described at the end of the thesis.

The Cretaceous (Mercedes Formation) and Paleogene (Queguay Formation) deposits cropping out in W and S Uruguay comprise two terrestrial limestone units that are very rich in trace fossils. The study of these units permits to propose a sedimentological model for palustrine limestones and calcretes in which the distribution of different types of trace fossils is considered. The study units include three main types of deposit: lacustrine limestones, palustrine limestones and calcretes. The lacustrine limestones are relatively homogeneous and contain gastropods, charophytes and ostracods, but no trace fossils. They were deposited in a relatively more perennial lacustrine environment. The palustrine limestones include four different facies: desiccated mudstones, nodular limestones, granular limestones and gravel-sheets. The desiccated mudstones indicate a lesser degree of pedogenic modification and the granular limestones a higher degree. The gravel-sheets are an indication of the reworking of previous limestones deposits during low lakewater levels. Most of the palustrine limestones (except the gravel sheets) contain the same bioclasts as the lacustrine limestones plus a variety of trace fossils such as Rebuffoichnus sciuttoi, Fictovichnus gobiensis and different ichnospecies of Celliforma. The calcretes are either massive (groundwater) or laminar. The massive calcretes are sandy limestones made up of a carbonate matrix and cements. The laminar calcretes (root mats), which contain alveolar septal structures, occur as centimetre-thick layers and can be seen in all types of deposit. They contain the same trace fossil association as the palustrine limestones; the massive calcretes are poorer in such fossils. The distribution of trace fossils in these environments is under strong facies control and provides good evidence of subaerial exposure and semi-arid climates. All the limestones are partially replaced and cemented by opal and quartz, but in all cases the primary structure is preserved. Silicification occurred under groundwater meteoric conditions. Overall, the limestones facies (calcretes, palustrine and lacustrine) and their lateral distribution likely reflect the existence of wetland environments in semiarid to sub-humid climates. These climatic conditions were interrupted by a period of increased precipitations, probably the Early Eocene Climatic Optimum. Fil: Alonso Zarza, Ana M.. Universidad Complutense de Madrid; España Fil: Genise, Jorge Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Verde, Mariano. Universidad de la República. Facultad de Ciencias; Uruguay

The Sinj basin belongs to the southernmost basins of the Miocene Dinaride Lake System. It was formed in a 342 km2 large, rhomboidal, NW-SE elongated pull-apart basin. The basin was initiated in the Early Miocene, following the transpressional regime related to a right-lateral movement along the major northwest-southeast-trending Adriatic strike slip fault system. The basin is located on Croatian Karst (External) Dinarides. The pre-Neogene basement is dominated by the Adriatic Carbonate Platform (AdCP) carbonates along the basin margins, ranging in age from the Upper Triassic to the Eocene. Extensive Permo-Triassic evaporites deposits with a direct sedimentary contact with the basal lake sediments occur beneath the basin. Two partially overlapping sections were logged in detail, representing together a continuous, around 500 m thick record of lacustrine deposits. Their correlation roots in sedimentary cycle pattern and marker bed correspondence. The lake sedimentation is dominated by authigenic carbonates ; the siliciclastic input was insignificant. The uppermost beds include coal seam intercalations, whereas the basal and the middle part of the infill show exclusively carbonate rocks. The whole succession is intercalated occasionally by volcanic ash layers. Following to previous study of the topmost, 140 m thick, coal bearing part of the succession, we concentrate now to its middle and lower parts dominated by limestone deposition and including several limestone types. Those limestones are usually light, thin to medium bedded, and commonly soft and porous. The CaCO3 content varies between 82% and 99%, and it primarily refers to the calcite. Sedimentological analysis and petrography made it possible to distinguish five main microfacies types: A – Lime mudstone – consists of very fine-grained micrites. The deposition of the fine-grained components of lacustrine carbonates is dominantly induced by the photosynthetic activity of macrophytes and microphytes. It belongs to deeper and protected lake parts . B - Detrital limestone – during low stands, much of the clastic material may be derived from cannibalizing fringing older lacustrine and/or palustrine beds, now exposed as mud flats and transported by sheet wash. The calcite crystals with organic matter impurities derived from the disintegration of calcified roots – mostly Microcodium. C - Charophycean mudstone or wackstone - contain degraded, and/or carbonized plant remains, plant encrustations, most commonly related to the stems of the submerged Charophytes and fruits and stems of Damasonium plant. Rooted submerged macrophytes indicate a vegetated littoral environment of the carbonate lake. D - Stromatolite bindstone - alternation of thin micritic laminae, and micrite to microsparite laminae containing calcite grains up to 20µm in diameter. Both laminae types contain micrite-calcified microbial filaments about 0.02mm in diameter. E - Gastropod weckstone and coquinas - the association of gastropods, bivalves, ostracods, plant encrustations and predominantly oxidized macrophyte remains suggests a calm, very shallow fresh-water environment of a carbonate lake while coquinas my represent storm deposits. G - Breccia-conglomerate might have been deposited by sporadic fluvial influence. Isotope analyses were carried out on bulk samples representative of the different microfacies. The wide range of the δ18O (-9, 39 to -2, 79 vs. VPDB) and δ13C (-4, 72 to 2, 80 vs. VPDB) values of the lacustrine system reflects the great variability of paleoenvironments and processes involved in isotope fractionation. Particularly, the wide range in δ18O values suggests that the lake waters did vary significantly through time, what is typical of environments without continuous renewal of water and characterised by significant isotope fractionation induced by evaporation.

The post-evaporitic Messinian in the northern sector of the Adriatic foredeep is characterized by the occurrence of abundant terrigenous deposits which have been subdivided into two allostratigraphic units (p-ev1, p-ev2) separated by an erosional unconformity of regional importance. The p-ev1 consists of basal complex of resedimented evaporites overlain by monotonous succession of mudstone/siltstone alternations (thin bedded turbidites) with an overall coarsening and shallowing upwards trend. It is possibly related to the rapid basin infill after the end of the salinity crisis. The upper unit (p-ev2) shows, in the most marginal areas, a clear cyclical stacking pattern made up of three fining-up sequences with fan-delta conglomerates at the base of each cycle. Here, a peculiar feature of the p-ev2 deposits is the occurrence of three distinct laminated limestone horizons (termed colombacci) interbedded with fine grained, varved mudstones. These limestones are abiotic, despite the occurrence of abundant Ostracod assemblages (Lago–Mare fauna) in the interbedding pelites, and are interpreted as inorganically precipitated, deposited in a relatively deep-water environment, possibly anoxic and related to permanent stratification of water mass events during periods of lake level maxima. The combination of petrographical and geochemical observations on carbonate layers reveals that they correspond to events characterized by significant variations of environmental conditions. However, δ18O (−5.30/+0.2) and δ13C (−9.28/+1.68) signatures suggest that the precipitation of low-Mg calcite often occurred in a non-marine environment and that meteoric water input had a considerable influence on late Messinian sedimentation. Moreover, the limestones have a uniform 87Sr/86Sr composition (0.70864–0.70875) in the range of other Lago–Mare sediments from elsewhere in the Mediterranean, suggesting that some of the major Mediterranean basins were likely interconnected during the Lago–Mare phase. A strongly reduced rate of hydrological exchange with the ocean is also possible, but the possibility of marine influence during this stage is not completely excluded.

The isotopic features of lacustrine carbonates from three Tertiary basins of Spain are compared. In the Campins and Bicorp basins the 8’3C and 8wO values of the lacustrine carbonates display different clusters that are related to the carbonate mineralogy. The stable isotope data of the primary carbonate minerals of Campins and Bicorp basins (taking into account the normalization of the dolomite with respect to calcite) show an approximate covariance trend between 8'3C and 8wO, suggesting that the lacustrine carbonates were formed in closed basins. The preliminary data for the Rubielos de Mora basin does not show differential clustering and there is no correlation between the main three carbonate minerals (calcite, Mg-calcite and aragonite) and the evaporation degree deduced from the 8,sO values

The isotopic features of lacustrine carbonates form three Tertiary basins of Spain are compared. In the Campins and Bicorp basins the and values of the lacustrine carbonates display different clusters that are related to the carbonate mineralogy. The stable isotope data of the primary carbonate minerals of Campins and Bicorp basins (Taking into account the normalization of the dolomite with respect to calcite) show an approximate covariante trend between and , suggesting that the basin does not show differential clustering and there is no correlation between the main three carbonate minerals (Calcite, Mg-calciete and aragonite) and the evaporation degree deduced form the values

Sedimentary processes and dynamics of filling up in the Jurassian lakes are studied from investigations of presently settling deposits and from Lateglacial and Holocene infilling stratigraphies. Several lithofacies and types of carbonate concretions are identified from the shore to the profundal zone, and lead to define several sedimentary sequences. Three phases are distinguished during the filling up : the first is characterized by allochton detrital sediment (Old Dryas) ; the second, by autochton carbonate deposits ; and the third, by organic infillings. The development processes of the platform bench testify the dynamics of centripetal filling up. Lateral and vertical distribution of lithofacies or concretions shows disturbances due to lake-level fluctuations building regressive and transgressive sequences., Les processus sédimentaires et la dynamique de comblement des lacs jurassiens sont discutés à partir de l'analyse des dépôts qui s'y forment actuellement et de la stratigraphie de leurs remplissages tardiglaciaires et holocènes. Plusieurs lithofaciès et différents types de concrétions carbonatées sont reconnus de la rive à la zone profonde et conduisent à définir des séquences sédimentaires. Trois phases sont distinguées dans le comblement de ces cuvettes : la première est caractérisée par une sédimentation détritique allochtone, la seconde par une sédimentation carbonatée autochtone, et la troisième par une sédimentation organique. La formation de la plate* forme littorale témoigne de la dynamique centripète de comblement. Enfin, les fluctuations du niveau de l'eau perturbent la distribution verticale et latérale des lithofaciès et des concrétions, entraînant la formation de séquences régressives et transgressées., Magny Michel. Sédimentation et dynamique de comblement dans les lacs du Jura au cours des 15 derniers millénaires. In: Revue d'Archéométrie, n°16, 1992. pp. 27-49.

Sedimentological and petrological analysis of the Gorafe-Huélago formation (pliocene) permits to distinguish some different facies types which characterize the following subenvironments of lacustrine carbonate sedimentation: lutitic plain (silts, carbonatic silts and sands), swamps (coaly marls), carbonatic marshy rim (root-bioturbated limestones, nodulzar lemistones, paleosols, calcareous crusts and nodular marls) and lacustrine zone (algal limestones, fossiliferous limestones, marly limestones and marls). The distribution of this facies was strongly controlled by the tectonics (Negratin accident), which delimited a southern sunken block, predominantly with terrigenous facies (lutitic plain and swamps) and a northern uplifted block in which there is a greater development of carbonatic lacustrine sediments. Finally, these facies are organized in retractive, expansive or expansive-retractive sequences which mark the sedimentological evolution of the formation.El análisis sedimentológico y petrológico de los materiales carbonatados de la formación de Gorafe-Huélago (Plioceno), ha permitido diferenciar diversas facies que caracterizan varios subambientes de sedimentación carbonatada dentro de un sistema deposicional tluvio-lacustre: llanura lutítica (limos, limos carbonatados y arenas), zonas de encharcamiento palustre (margas carbonosas), orla palustre carbonatada (calizas bioturbadas por raíces, calizas nodulosas y paleosuelos, costras calcáreas y margas nodulosas) y zona lacustre (calizas algales laminadas y oncolíticas, calizas fosilíferas, calizas margosas y margas). La evolución y distribución de las facies están controladas por el accidente tectónico del Negratin, fundamentalmente transcurrente y que atraviesa la zona de estudio con una dirección NE-SW. En el bloque levantado (sector N) tiene lugar una sedimentación carbonatada lacustre, mientras que en el bloque hundido (sector S) la sedimentación es fundamentalmente terrígena. Los materiales carbonatados que caracterizan la sedimentación lacustre se relacionan entre sí y con otras facies terrígenas en determinadas secuencias sedimentológicas lacustres: secuencias de retracción, secuencias de expansión y secuencias de expansión-retracción.