El estudio de las plataformas calcáreas del Mesozoico y de los organismos que han contribuido a su desarrollo ha recibido nuevas e importantes aportaciones como ejemplo de respuesta al supergreenhouse climate (clima de superinvernadero) que caracterizó gran parte del Cretácico.El trabajo se ha centrado en el análisis de las asociaciones de rudistas (Bivalvia, Hippuritoidea) del intervalo Turoniense superior-Campaniense, Cretácico superior, en 12 secciones estratigráficas de plataforma calcárea que afloran en localidades de significado paleontológico y estratigráfico particular de los Apeninos centro-meridionales, Italia y la revisión de colecciones en 12 museos.Se han estudiado cinco géneros de la Familia Radiolitidae: Biradiolites, Bournonia, Distefanella, Lapeirousella y Radiolites; y en particular nueve especies con especial significado para la estratigrafía del área considerada: Biradiolites angulosus (d'Orbigny, 1847), Biradiolites martelli (Parona, 1911), Bournonia excavata (d'Orbigny, 1842), Bournonia fascicularis (Pirona, 1869), Distefanella salmojraghii Parona, 1901, Distefanella montagnei Sli kovic, 1971, Lapeirousella samnitica (Parona, 1901), Radiolites dario (Catullo, 1834) y Radiolites trigeri (Coquand, 1859).Se han reinterpretado los caracteres morfológicos de algunas de estas especies y también de algún género, proponiendo, en consecuencia, nuevas descripciones taxonómicas.El análisis de la valva izquierda en los radiolítidos con valva derecha alargada, ha conducido a reconocer dos morfologías distintas, características de contextos sedimentarios diferentes (Tipo A y Tipo B). El análisis de la tasa de crecimiento de los radiolítidos de valva derecha aIargada y concha delgada y de su relación con la tasa de sedimentación ha conducido a estimar tasas realmente elevadas, por lo que estos radiolítidos se consideran indicadores de elevado acúmulo sedimentario.Se han distinguido dos tipos de biofacies con radiolítidos de valva derecha alargada, Slender Radiolitid Biofacies (SRB) que se desarrollaron en distintas áreas y ambientes de la zona considerada a lo largo del Cretácico superior, caracterizadas por distintas asociaciones de especies (SRB Tipo A y SRB Tipo B). La distribución de las biofacies con radiolítidos alargados (SRB) en los Apeninos centro-meridionales es asimétrica y está en íntima relación con la compleja fisiografía de las plataformas calcáreas aisladas que se desarrollaron en el área mediterránea central del Tethys del Turoniense al Santoniense. Su distribución permite reconocer un modelo paleoecológico general en el que deben considerarse algunos parámetros atmosféricos y oceanográficos ligados al flujo de la Corriente Circumglobal del Tethys.Finalmente, los mecanismos de biomineralización adoptados por los bivalvos actuales permiten suponer que la baja relación Mg/Ca y la asociación proteica específica, debe haber jugado un papel importante en la construcción de la concha de los radiolítidos, como lo hace en los bivalvos actuales. / The central Mediterranean area has been investigated by reconstructing the palaeoclimatologic context following the most recent data in literature. Dataasses that surface boundary conditions in late Cretaceous were much different from that of today: sea level much higher (100-200 m higher), medium temperature (higher 14 °C), higher sea water acidity and pCO2 more than 700 ppmv (today 380 ppmv). All these factors deeply modified the global circulation regime. The palaeobiologic answer had to be much different from that of today's biota: rudists with thick calcite shell as radiolitids were well suited to this panorama and represent a keystone in assessing palaeobiologic conditions in a warm climate of the late Cretaceous.Radiolitid rudist bivalves are widely represented in carbonate successions cropping out in central and southern Italy. In order to analyse rudist assemblages, stratigraphic analysis has been performed in 12 successions from five distant areas.In the Monti d'Ocre the succession is condensate, spanning from the Aptian to the Campanian, with three datum planes, mainly of platform margin setting. Rudist assemblages give a good biostratigraphic control with caprinids of the Aptian "Urgonian facies", lagoonal facies with Sauvagesia and other molluscs in the middle Cenomanian, Biradiolites angulosus horizons overlied by grain-supported high-energy Distefanella salmojraghii and Lapeirousella samnitica facies.In the Monti Simbruini, limestones with prevalent mud-supported texture contain radiolitid assemblages composed of beds of elongate Biradiolites angulosus, Radiolites trigeri, Durania arnaudi of late Turonian-Coniacian age, overlaid by assemblages with elongate Radiolites dario and Bournonia excavata of Santonian age. The sedimentary setting is of inner platform. In the Matese Mountains, carbonates of middle Turonian-Campanian age crop out, this is an historical site where Distefanella was instituted. Bioclastic limestones with grain-supported texture bear Distefanella salmojraghii assemblages and other rudist-rich facies.In the Majella Mountain, the physical scalloped platform margin of the Apulian platform crops out. Well preserved Distefanella assemblages with very elongate specimens (up to 40 cm) in bioclastic grain-supported limestone have been studied in situ and found in reprised blocks as olistolithes in the pelagic scaglia.In Cilento area, radiolitids have been found in two distinct assemblages:Radiolites trigeri, Durania arnaudi, Biradiolites martelli, Bournononia gardonica,Biradiolites angulosus (CO Assemblage of late Turonian-Coniacian) and Radiolites dario, Bournonia fascicularis, Sauvagesia tenuicostata (SA assemblage of late Coniacian-Santonian age). Both associations are embedded in mud-supported limestone of inner platform setting and are composed of elongate specimens.Specimens collected in outcrops and others studied in museum's collections allowed to update palaeontologic information on five genera and nine species and to re-describe genus Distefanella. The biomineralization stategy adopted by these extinct bivalves with thick calcite shells, could be analogous to that of living molluscs, eventually involving protein associations with aspein and caspartin.During the Late Cretaceous, different sedimentary contexts show peculiar radiolitid assemblages; the rudist biofacies distribution is strongly influenced by the palaeogeographic setting and by the global palaeo-oceanic circulation pattern that, in the central Mediterranean area, was mainly east-to-west directed.R E S U L T SThe study performed on rudist radiolitid assemblages of the late Turonian-Campanian interval, Late Cretaceous, in 12 stratigraphic sections sampled in the central-southern Apennines, Italy, and the revision of fossil collections in 12 museums, lead to some conclusions on the palaeontology of these bivalves. Nine species with particular significance for the stratigraphy of the considered area, belonging to five genera of the Family Radiolitidae have been studied: Biradiolites angulosus (d'Orbigny, 1847), Biradiolites martelli (Parona, 1911), Bournonia excavata (d'Orbigny, 1842), Bournonia fascicularis (Pirona, 1869), Distefanella salmojraghii Parona, 1901, Distefanella montagnei Sli kovic, 1971, Lapeirousella samnitica (Parona, 1901), Radiolites dario (Catullo, 1834) and Radiolites trigeri (Coquand, 1859).The morphologic features of some of these species, and also of some genera, have been reinterpreted. New taxonomic attributions have been proposed.- Bournonia fascicularis (Pirona, 1869). The species description has been completed as it was poorly known; it has been found in many Coniacian-Santonian successions of Italy. Its generic attribution has been justified.- Biradiolites martelli (Parona, 1911). Two morphotypes have been distinguished: morphotype A with elongate costae and morphotype B with short costae. Its generic attribution has been justified. The revision work lead to consider that the species of genus Milovanovicia Pol ak, 1967 can be ascribed to B. martelli for the whole of its features, so that this genus is unnecessary.- Distefanella Parona 1911. The type material has been revised, reinterpreting the diagnostic features of the genus. It has been ascertained synonymy among species originally ascribed. The study of the whole literature published after, and new collected material allowed to reduce the 25 known species to only two, Distefanella salmojraghii Parona, 1911 and Distefanella montagnei Sli ković, 1971, that are different for the development and grade of invagination of the radial bands.- Its attribution to genus Lapeirousella Milovanović, has been definitively ascertained. The analysis of the left valve in radiolitids with elongate right valve, thin shell, and deeply anchored in the substrate, together with the study of the sediment where they are contained, lead to recognize two distinct morphologies, each typical of different sedimentary context, of inner platform/ramp and platform margin respectively.- Type A, with left valve flat or smoothly concave, provided with a little developed myocardinal apparatus that is considered to be well adapted in environments with moderate to low energy.- Type B, with left valve high, cupuliform, provided with a myocardinal apparatus that, with two teeth very large and myophores laterally well developed, forms a nearly tubular structure that, inserted in the right valve, gives good mechanic strength at the area near the commissure. It is considered well adapted to prevent the accumulation of sediment on the valve itself, moreover to be resistant in an environment under moderate to high energy.The analysis of the growth rate of radiolitids with slender and thin shelled right valve, and their relation with the sedimentation rate, lead to approximate rates really high, up to >4 mm/yr, so that these radiolitids are considered as indicators of high sediment accumulation.Two types of biofacies with slender radiolitids have been recognized, (Slender Radiolitid Biofacies, SRB) that developed in different zones and environments of the considered area in the late Cretaceous, characterized by different species assemblages:- SRB Type A, in limestone with mainly mud-supported texture, frequently of algal-bacterial sedimentation, of inner platform and ramp in the Simbruini Mt., Ausoni Mts. and in Cilento. The carbonate productivity in this context is extremely high if comparing to actual models (up to 20 times higher).In the late Turonian-Coniacian the fossiliferous assemblage is marked by: Biradiolites angulosus d'Orbigny, Biradiolites martelli (Parona) morphotype A, Bournonia excavata (d'Orbigny), Durania arnaudi (Choffat), Radiolites trigeri (Coquand) and Sauvagesia sp. In the Coniacian-Santonian by: Bournonia fascicularis (Pirona) and Radiolites dario (Catullo).- SRB Type B, in limestone with texture mainly grain-supported, bioclastic, of platform margin in the Matese Mts. and in the Majella Mt. The carbonate productivity can be compared to that recorded in the actual most productive barrier reefs. In the late Turonian-Santonian the fossiliferous assemblage is marked by: Distefanella salmojraghii Parona and Lapeirousella samnitica (Parona).It has been ascertained that the slender radiolitid biofacies distribution (SRB) in the central-southern Apennines is asymmetric:- T- he SRB Type A crop out in the Simbruini Mts., Ausoni Mts. and in the Cilento area, localized in the western side of the Apenninic belt.- The SRB Type B is well developed in the bioclastic successions that crop out in the Monti d'Ocre, Matese Mts. and in the Majella Mt., localized in the eastern side of the belt.Both the SRB Type A and SRB Type B are intimately linked to the complex physiography of the isolate carbonate platforms that developed in the central Mediterranean area of the Tethys from the Turonian up to the Santonian. Its distribution allows to recognize a general palaeoecologic model where, to explain the asymmetry, some oceanographic and atmospheric parameters must be considered, linked to the Tethys Circumglobal Current flux that, in the Late Cretaceous, was from the East to the West in the latitude corresponding to the central Mediterranean area (between 15° and 25° of latitude).The examination of the biomineralization mechanisms adopted by the living bivalves allow to hypothesize that the low Mg/Ca ratio and the specific protein assemblage have had a key role in the formation of the radiolitid shell, as it is in the living bivalves. Particularly, aspein and caspartin might have acted as amplifiers in calcite shell biomineralization process and as palaeobiologic response of these bivalves to the supergreenhouse climate context of the Cretaceous.

Magíster en Ciencias, Mención Geología. Geólogo / La Cuenca Pre-Andina, ubicada en el norte de Chile entre los 21°S y 27°S, contiene un registro estratigráfico completo desde el Cretácico Superior hasta tiempos recientes; sin embargo, la mayoría de las investigaciones se han concentrado en el margen oeste de la cuenca del salar de Atacama (~23°S), manteniendo dudas respecto a sus variaciones espaciales y correlaciones estratigráficas hacia el sur, norte y este. A su vez, aún persisten preguntas con respecto a su relación con la tectónica andina y el desarrollo de las fases tectónicas Peruana, K-T e Incaica. Esta tesis se realizó en los depósitos sedimentarios cretácico-paleógenos, ubicados ~90 km al sur del salar de Atacama, en las cercanías de los salares Imilac y Punta Negra (24°-24°30 S), con un enfoque estratigráfico y sedimentológico, los cuales fueron apoyados por nuevos datos geocronológicos. Para llevarla a cabo, se realizaron 4 campañas de terreno en conjunto con el SERNAGEOMIN, donde se midieron 5500 m de columnas estratigráficas de alta resolución. Se identificaron 12 litofacies, 8 asociaciones de facies y 3 ambientes sedimentarios. Además, se realizaron conteos modales de clastos en los conglomerados, 282 mediciones de paleocorrientes y 7 dataciones radiométricas U-Pb en circones. Se determina que el relleno de la Cuenca Pre-Andina se inició en el Maastrichtiano con la depositación con flujos axiales norte-sur de la Formación Quebrada Pajonales, cuyas facies fluviales meándricas iniciales (Miembro Quebrada Vizcachas) gradaron a facies fluviales trenzadas contenidas en un megaciclo granocreciente (Miembro Quebrada Gentilar). Posteriormente, el relleno continuó sin gradaciones importantes durante el Paleoceno (~57 Ma), con las facies fluviales trenzadas este-oeste de la Formación Naranja. Luego la acumulación sedimentaria se reanudó en el Eoceno (~40 Ma), con la depositación de las facies de abanicos aluviales de la Formación Loma Amarilla, las cuales cubren en discordancia de erosión a la Formación Naranja. Presenta un megaciclo de gradación inversa, seguido de un megaciclo de gradación normal (Miembros Cordillera Agua Amarga y Pampa Imilac, respectivamente). El aumento de clastos granitoides, durante la depositación del Miembro Pampa Imilac, sumado a las paleocorrientes desde el oeste, permiten inferir un destechamiento de la Cordillera de Domeyko. Finalmente, desde el Oligoceno tardío (~28 Ma), se depositó en discordancia angular la Formación Quebrada Tambores, en facies de abanicos aluviales retrogradantes. Se concluye que existió un control estructural sobre la cuenca, de los eventos tectónicos K-T e Incaico, durante la deposición de las Formaciones Quebrada Pajonales y Loma Amarilla, ocurriendo entre ellos una etapa de quietud tectónica en el Paleoceno, durante la acumulación de la Formación Naranja. Se propone que la Formación Quebrada Tambores estaría relacionada a un evento transtensivo en el Oligoceno superior-Mioceno inferior, previo al alzamiento del altiplano. Además, se concluye que los relieves heredados del Arco Transpampeano, en conjunto con la Cordillera de Domeyko, fueron la principal fuente de recursos de sedimentos.

No description available.

Aquesta tesi té com a objectiu fonamental la caracterització taxonòmica, biostratigràfica i paleoecològica de les associacions de caròfits de les fàcies lacustres i transicionals del Garumnià basal (Cretaci superior) de les Conques de Vallcebre, Coll de Nargó, Tremp i Àger. L’altre objectiu d’aquesta tesi és la caracterització tafonòmica i paleoecològica de les restes fòssils de plantes vasculars productores dels lignits garumnians. La flora de caròfits del Garumnià basal està constituïda per girogonits de Feistiella malladae, Peckichara cancellata, P. sertulata, Microchara cristata, M. parazensis, Platychara caudata, P. turbinata i Dughiella obtusa, i utricles de Clavator brachycerus. Pel que fa als òrgans vegetatius les calcàries garumnianes son molt riques en tal•lus de grans dimensions de Charaxis sp. associats a Peckichara sp., i de tal•lus més gràcils de Clavatoraxis microcharophorus Villalba-Breva et Martín-Closas 2011, portadors de Microchara sp. També és freqüent la presència de Munieria grambastii associada a vegades a Clavator brachycerus. Des del punt de vista biostratigràfic, les associacions de caròfits de les conques d’Àger i Vallcebre pertanyen a la biozona de caròfits Peckichara cancellata (Campanià superior - Maastrichtià inferior basal), mentre que les associacions de caròfits de les conques de Coll de Nargó i Tremp pertanyen a la biozona Septorella ultima (Maastrichtià inferior). En base a l’estudi estratigràfic i sedimentològic i l’anàlisi de microfàcies s’ha determinat que la sedimentació a la Conca d’Àger està formada majoritàriament per calcàries lacustres organitzades en centenars de seqüències de somització, que van des de fàcies lacustres profundes, passant per ambients marginals, ben il•luminats dominats per herbeis de caràcies, fins a fàcies de vora de llac dominades per herbeis de clavatoràcies. A les conques de Vallcebre, Coll de Nargó i Tremp, la sedimentació del Garumnià basal està organitzada en diversos cicles, els quals comencen amb dipòsits salabrosos formats per margues amb mol•luscs eurihalins a la base, seguits per lignits i calcàries d’ambients salabrosos dominades per porocaràcies, i calcàries d’aigua dolça amb caràcies i clavatoràcies. Les diferències en el registre sedimentari i la flora de caròfits mostren que les conques sud pirinenques presentaven una polaritat de fàcies sud-nord durant l’inici de la sedimentació continental del Cretaci superior, i que aquesta continentalització va començar al sud i desprès va continuar al nord, d’est a oest. L’estudi de la macroflora del Garumnià basal de les conques de Vallcebre, Coll de Nargó i Tremp indica que la comunitat vegetal dels aiguamolls del Maastrichtià inferior estava dominada per la conífera queirolepidiàcia Frenelopsis, que va ser la planta productora de la matèria orgànica precursora del lignit. Associada a aquestes coníferes hi havia la palmera Sabalites longirhachis, i en alguns casos altres angiospermes d’aiguamoll, representades per les seves llavors, especialment Bergacarpon viladricii Marmi, Gomez, Villalba-Breva et Martín-Closas 2012. Altres plantes vasculars significatives encara que menys abundants eren les falgueres, cicadals i pandanals. / This thesis aims to characterize the taxonomy, biostratigraphy and palaeoecology of charophyte assemblages of lacustrine and transitional facies from the basal Garumnian (Late Cretaceous) of the Vallcebre, Coll de Nargó, Tremp and Àger basins. The other objective of this study is the taphonomic and palaeoecological characterization of the precursory vascular plants of the Garumnian lignite. The charophyte flora of the basal Garumnian consists of gyrogonites of Feistiella malladae, Peckichara cancellata, P. sertulata, Microchara cristata, M. parazensis, Platychara caudata, P. turbinata and Dughiella obtusa, and utricles of Clavator brachycerus. Regarding the vegetative organs, Garumnian limestones are rich in large thalli of Charaxis sp. associated to Peckichara sp., and smaller thalli of Clavatoraxis microcharophorus Villalba-Breva et Martín-Closas 2011, with attached Microchara sp. Also Munieria grambastii thalli are abundant, associated sometimes with Clavator brachycerus. From a biostratigraphic point of view, charophyte assemblages of Vallcebre and Àger basins belong to the Peckichara cancellata biozone (Late Campanian – Earliest Maastrichtian), while charophyte assemblages of Coll de Nargó and Tremp basins belong to the Septorella ultima biozone (Early Maastrichtian). Based on the sedimentological and stratigraphic studies and microfacies analyses, the sedimentation in the Àger Basin is organised into hundreds of small order sedimentary cycles corresponding to lacustrine infilling sequences, ranging from deep lacustrine facies, through marginal environments dominated by characean meadows, to lakeshore facies dominated by clavatorecean meadows. In the Vallcebre, Coll de Nargó and Tremp basins, the deposits of the basal Garumnian are organized into small number of cycles that show a transition from brackish deposits formed by marls with euryhaline molluscs, lignites and limestones with porocharaceans, to lacustrine limestones with characeans and clavatoraceans. The differences in the sedimentary record and in the charophyte flora show that the Southern Pyrenean Basin displayed a south to north shift of facies during the onset of the Upper Cretaceous continental sedimentation and that this continentalisation began in the south and then continued to north, from east to west. The study of megafossil plant remains from the basal Garumnian of the Vallcebre, Coll de Nargó and Tremp basins indicates that the cheirolepidiacean conifer Frenelopsis was the main component of the wetlands vegetation associated with Sabalites longirhachis palms, and in some cases with other angiosperms, such as the plant bearing Bergacarpon viladricii Marmi, Gomez, Villalba-Breva et Martín-Closas 2012, probably a commelinid.

Southern Pyrenees has provided an abundant fossil record of dinosaur eggs and eggshells. Historically, the oofamily Megaloolithidae has shown its predominance over any other group of fossil eggs in this region. In addition, this oofamily is world-wide distributed being represented by, at least, four oogenus and 20 oospeices. Considering that the eggshell is a high stable structure, this number of Megaloolithus‘s oospecies is too high for such a relatively short time-interval (Campanian to Maastrichtian; less than 7 My). The structural characters used to define these oospecies are critically revised. As a consequence, three structural groups have been identified, and only ten oospecies have been considered valid. Four of those oospecies have been recognized in Southern Pyrenees: M. aureliensis, M. sirugei, M. mamillare and M. baghensis. The oogenus Cairanoolithus, historically included in Megaloolithidae oofamily, is reevaluated. All evidences suggest that this type of fossil egg is, definitively, different from any other Megaloolithus. Consequently, a new oofamily is erected (Cairanoolithidae oofam. nov), which emphasizes the singularity of cairanoolithid eggs. Phylogenetical analysis also suggests that the eggs of Cairanoolithidae oofam. nov. could be laid by ornithischian dinosaurs. New oological material is described here, including the first spheroolithid oospecies (Spheroolithus oosp. nov.) from the Upper Cretaceous of Europe. Several oospecies of Prismatoolithus (Prismatoolithus oosp. nov, Prismatoolithus cf. levis, Prismatoolithus oosp. indet.) and few eggshells of ratite-morphotype (cf. Ageroolithus fontllonguensis) have been identified. In addition, the great number of specimens attributed to Pseudogeckoolithus oogenus allows re-describing and re-assigning this ootaxon to Mesozoic lizards. The space-temporal variation of the oological diversity in the Southern Pyrenees could be a consequence of environmental changes during the end-Cretaceous or even due to preferences in the nesting-site of each group of dinosaurs. Finally, biostratigraphical studies based on the successions of megaloolithid oospecies have been performed in Coll de Nargó and Àger-Tremp basins, and the European Megaloolithus succession has been updated. As a result, three oozonones have been described: M. aureliensis + Cairanoolithus oozone dates the Late Campanian, M. siruguei oozone the Early Maastrichtian and M. mamillare + M. baghensis oozone the Late Maastrichtian.