No description available.

High-resolution lithostratigraphic data from rock sequences known as the Indidura Formation near Parras de La Fuente, Coahuila, NE Mexico, led to achieve a significant improvement of our knowledge of that Formation. The results of this study indicate for the first time that the sequence at Parras de La Fuente developed from the deposition of calcareous cyanobacterial microspheroids that accumulated under perennial blooms during the Late Cenomanian through the Middle Turonian. Multi-proxy analyses included sedimentological, petrographical, scanning electron microscopy, stable isotope, trace element geochemistry, and paleontological data. The combined results allowed the correlation of δ13C and anomalies in Mo, V, and Cr with the abundance and predominance of calcareous cyanobacterial microspheroids, which were the main suppliers of the carbonate components and the organic matter throughout deposition of the Indidura Formation in the Parras de la Fuente area, under dysoxic/anoxic conditions. Conspicuous interbeds of dark and light-gray laminated marly calcilutites, and dark-gray marlstones that characterize the stratigraphic sequence formed in response to external forcing climatic factors of millennial-scale Milankovitch cycles (ca. 20 ka precession). At the microscopic level, the prominent dark and light-gray laminae were formed during cycles similar to the 10 to 15 years solar irradiance maximum, and represent alternating periods of high and low calcareous cyanobacterial microspheroids productivity.

Quatre coupes ont été étudiées dans les séries marno-calcaires de talus et de bassin profond de la "fosse vocontienne" au Cénomanien. Le travail effectué à partir de plus de 800 échantillons dans lesquels les associations de foraminifères planctoniques et benthiques ont été étudiées a montré des particularités biostratigraphiques, et paléogéographiques. En effet, il existe un diachronisme dans l’extension verticale de Thalmanninella reicheli et dans l’apparition du marqueur de la base du Cénomanien supérieur (Rotalipora cushmani). T. reicheli a une extension verticale courte, mais située dans le Cénomanien inférieur peu élevé d’après les faunes d’ ammonites associées; R. cushmaniapparait avant les ammonites marquant le Cénomanien moyen (Acanthoceras). Les chutes du niveau marin relatif enregistrées par des discontinuités lithologiques dans la coupe de la marge du talus au Cénomanien basal, dans la partie moyenne du Cénomanien, et au passage Cénomanien-Turonien sont également repérées par la dominance des assemblages de foraminifères benthiques opportunistes, d’abord dans les coupes de marge et de plate-forme méridionale, ensuite dans les coupes de bassin profond. Ces passages correspondent aussi à des évènements dysoxiques, liés à l’anomalie du δ13C. L’évolution des foraminifères benthiques s’avère très sensible à profondeur de l’eau et à la dysoxie,leur réponse étant plus rapide que la variation du δ13C. La régression forcée au passage Cénomanien-Turonien correspond à des dépôts de black shales dans la coupe du bassin le plus profond, traduisant l’événement anoxique OAE2. La fin de l’ extension de Rotalipora cushmani, définit le sommet de l’étage dans les 4 coupes. / A detailed lithologic and biostratigraphic framework was determined for 4 Cenomanian sections, allowing correlations from the boarder of the upper slope to the platform and the lower slope of the vocontian basin. Over 800 samples provided planktonic and benthic foraminifera associations for a biostratigraphic and paleogeographic succession. There was a diachronisme between the ammonites and the foraminifera biozonation. Indeed, Thalmanninella reicheli, the marker of the middle Cenomanian substage had a short extension,overlapping with the Mantelliceras mantelli, ammonite of the Inferior Cenomanian. Moreover Rotalipora cushmani, the foraminifer marker for the Upper Cenomanian,appeared before Acanthoceras, an ammonite of the Middle Cenomanian. Basal Cenomanian, Middle Cenomanian, and CTB were registered by local lithologic discontinuities resulting from the lowering of the relative sea level in the boarder of the upper slope section. Correlated with the lithologic events, the benthic opportunist foraminifera dominated the associations from the Inferior Cenomanian of the upper slope and platform sections, and from the middle part of the Upper Cenomanian of the deep sea sections. Dysoxic periods (Albian-Cenomanian boundary, MCE, and OAE2) as detected by δ13C anomalies, also corresponded to the regression levels. Benthic Foraminifera responsiveness to sea water depth and anoxia was faster than δ13C variations. CTBE was lithologically registered by black shakes deposits in the deep sea section, but the end of the Rotalipora extension was the marking event in all sections.

No description available.

The Eagle Ford Shale and equivalent Boquillas Formation (Late Cretaceous) contain abundant volcanic ash beds of varying thickness. These ash beds represent a unique facies that displays a range of sedimentary structures, bed continuity, and diagenetic alteration. They are prominent not only in West Texas outcrops, but also in the subsurface of South Texas where hydrocarbon production is actively occurring. The ash beds have the potential to be used for stratigraphic correlation for understanding early diagenesis and — most importantly — for obtaining high-resolution geochronology, which can then be used for defining depositional rates and chronostratigraphy. Study of the ash beds was conducted at outcrops along U.S. 90, west of Comstock, Texas, the subsurface in Atascosa and Karnes County, and at a construction site in South Austin. Bed thicknesses range from 0.1–33 cm and were collected throughout the entirety of the Eagle Ford succession. Mineral separation yielded abundant non-detrital zircons for U-Pb dating. Dating was conducted using LA-ICP-MS at The University of Texas at Austin, to attain a base level understanding of the age range for the Eagle Ford. High-resolution ages for the base and top of the Eagle Ford were obtained, in addition to radioisotopically defining the Cenomanian-Turonian boundary within the section. U-Pb ages for the Eagle Ford Shale range from Early Cenomanian to Late-Coniacian near Comstock, Mid-Cenomanian to the Turonian-Coniacian boundary in the subsurface, and Early Cenomanian to Late Turonian in Austin area. These findings contrast with many of the regional biostratigraphic studies across the Eagle Ford and indicate a more prolonged period of Eagle Ford deposition than previously observed. / text

The diploma thesis presents an overview of the extinct representatives of Blattidae, the still living cockroach family. Six already described species, belonging to three genera, have been confirmed. All of them lived during Cenozoic. Eight new morphotypes from Myanmar amber were recognized. Cenomanian Burmite with its exceptional state of preservation, allows a detailed study of the morphology of the inclusions. Six morphototypes belong to the family Blattidae. One morphotype belongs to the derived family Olidae studied herein. One female morphotype belongs to the still living family Ectobiidae, based on the presence of an attached ootheca. The work specifies the previous molecular analysis (J2-K1) and determines the divergence of Blattidae during Early Cretaceous. Any evidence and interpolations before 127Ma is not substantiated. Phylogenetic analysis confirmed Blattidae being parafyletic in respect to the family Olidae. The work emphasizes the need for changes in systematics of the Mesoblattinidae, the stem of the Blattidae. Amber is confirmed as the product of coniferous trees of the Araucariaceae family. Key words: Blattidae, taxonomy, phylogeny, Cenomanian, Myanmar amber

This work is focused on systematic research of cephalopod jaws from the Late Cretaceous. Samples of 147 newly recorded nautiloid rhyncholites from the Bohemian Cretacoeus Basin and one new ammonite rhyncholite from Řepov village were systematically analyzed. The new collection of lower ammonite jaws (aptychi) consists of 32 specimens. Nautiloid rhyncholites from localities Turkaňk, Úpohlavy, and Dreisen were determined as Nautilorhynchus simplex. Conchorhynchs from locality Vinary u Vysokého Mýta belong to the species Conchorhynchus cretaceous, which is associated with the commonmost species Eutrephoceras sublaevigatum. Ammonite rhyncholite is left in the open nomenclature due to its uncertain systematic position and it is not assigned to any ammonite species. Records of aptychi from the locality of Úpohlavy and Pecínov represent mainly species of heteromorphic ammonites - baculitids (Baculites, Sciponoceras). The total diversity of species from both localities reaches 20 ammonite species. The two jaw morphotypes (2 species of aptychi) are reported from the Bohemian Cretaceous Basin for the first time herein. Of the high importance, it is a record of ammonite Prionocyclus germari from Úpohlavy with associated lower jaws in situ within the body chamber. Aptychus of this taxon has never been...

The diploma thesis presents an overview of the extinct representatives of Blattidae, the still living cockroach family. Six already described species, belonging to three genera, have been confirmed. All of them lived during Cenozoic. Eight new morphotypes from Myanmar amber were recognized. Cenomanian Burmite with its exceptional state of preservation, allows a detailed study of the morphology of the inclusions. Six morphototypes belong to the family Blattidae. One morphotype belongs to the derived family Olidae studied herein. One female morphotype belongs to the still living family Ectobiidae, based on the presence of an attached ootheca. The work specifies the previous molecular analysis (J2-K1) and determines the divergence of Blattidae during Early Cretaceous. Any evidence and interpolations before 127Ma is not substantiated. Phylogenetic analysis confirmed Blattidae being parafyletic in respect to the family Olidae. The work emphasizes the need for changes in systematics of the Mesoblattinidae, the stem of the Blattidae. Amber is confirmed as the product of coniferous trees of the Araucariaceae family. Key words: Blattidae, taxonomy, phylogeny, Cenomanian, Myanmar amber

No description available.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work were analyzed the Spatangoids Echinoids of the species Mecaster batnensis (Coquand, 1862), Mecaster fourneli (Agassiz & Desor, 1847) and Mecaster africanus (Coquand, 1862) from the Sergipe sub-basin of the Fundação Paleontológica Phoenix collection. Among the specimens studied, there were found exemplars of the species Mecaster texanus (Roemer, 1849), that were recorded for the first time in the Sergipe Cretaceous. It was observed that the species M. batnensis and M. africanus, distributed from the Cenomanian to the Turonian showed a lower number of pore pars in the ambulacra III when compared to the others Mecaster species in this same interval. This data could indicate that this species lived in lower depths in the sediment, since the podia of those pores would be sparser. On the other hand, M. fourneli and M. texanus distributed between the Turonian and Coniacian showed a higher number of pore pairs in the ambulacra III, what could indicate that these species lived at more profound depths in the sediment and their contacts with the water-sediment interface through the podia were more effective. All the Mecaster species were present at the basin during the Turonian where they had occupied different habitats, M. batnensis and M. africanus on the other hand would search more profound places where they would live borrowed closer to the water-sediment interface and protected from predators. M. fourneli and M. texanus would prefer shallow environments where they would ride from their predadors burrowed deeply in the sediment. / Neste trabalho foram analisados os equinoides espatangoides Mecaster batnensis (Coquand, 1862), Mecaster fourneli (Agassiz & Desor, 1847) e Mecaster africanus (Coquand, 1862) provenientes da sub-bacia de Sergipe e depositados nas coleções de Invertebrados fósseis da Fundação Paleontológica Phoenix. Entre os espécimes estudados foram encontrados exemplares de Mecaster texanus (Roemer, 1849) sendo esta espécie registrada pela primeira vez para o Cretáceo de Sergipe. Foi observado que as espécies Mecaster batnensis e M. africanus distribuídos do Cenomaniano ao Turoniano apresentaram um número menor de pares de poros no ambulacro III do que as demais espécies neste mesmo intervalo, o que poderia indicar que teriam tido a capacidade de se enterrar a uma menor profundidade no sedimento, já que os pódios destes poros seriam mais espaçados. As espécies Mecaster fourneli e M. texanus foram distribuídas entre o Turoniano e o Coniaciano e apresentaram um maior número de pares de poros no ambulacro III, podendo indicar que estas espécies teriam se enterrado mais profundamente e seu contato com a interface água/sedimento através dos pódios mais efetivo. Todas as espécies de Mecaster estiveram presentes na bacia durante o Turoniano, onde teriam ocupado habitat distinto. Enquanto Mecaster batnensis e M. africanus teriam procurado locais talvez mais profundos onde teriam vivido enterrados mais próximo da interface sedimento/água e afastados de prováveis predadores, M. fourneli e M. texanus teriam preferido ambientes mais rasos onde teriam driblado seus predadores se enterrando mais profundamente no sedimento.