A calcareous block made of algo-laminated (stromatolitic) material exhibits at its upper surface a foot print of a Dinosaurian. A vertical section (sawing) and a thin section allow to make detailed observations. The early diagenesis permits the preservation of the deformations caused by the foot print.
Als ich in diesem Jahre meine Sammlung einer genaueren Durchsicht unterwarf, fand ich, dass in derselben genügendes Material vorhanden war, um dasselbe für einen kleineren Beitrag zur Paläontologie der Juraformation verwerten zu können. Nicht allein zeigte es sich, dass manche Species, wenn auch schon beschrieben, doch von neuen Fundorten vorlagen, und dass andere noch ganz neu für die jurassischen Schichten des nordwestlichen Deutschland waren, sondern die Untersuchung des vorliegenden Materials gab auch für die Kenntnis und Auffassung mancher bekannter Species neue Gesichtspunkte an die Hand. In dem folgenden ersten Theile, der Versteinerungen des unteren und teilweise des mittleren Jura (bis zu den Coronaten - Schichten inclus.) behandelt, habe ich in Bezug des geognostischen Vorkommen der Species die Einteilung des Jura den Werken von Brauns (der untere Jura im nordwestlichen Deutschland 1871, der mittlere Jura 1869) entnommen. Um eine spätere Kritik zu ermöglichen, ist bei den Species das Werk angegeben, nach dem dieselben bestimmt sind. Von Fundorten sind meistens nur die neuen angeführt....
Seit dem Erscheinen von O. WEBER'S Tertiärflora der niederrheinischen Braunkohleformation im 2. und 4. Bande der Palaeontographica (1852 und 1856) sind zwar von verschiedenen Seiten Mitteilungen über Funde fossiler Pflanzen aus dem niederrheinischen Tertiärgebiete gemacht worden, immerhin aber war die Zahl neuer Pflanzenfunde gering; es war daher zu begrüßen, daß im Laufe der letzten Jahre eine größere Anzahl von Pflanzenresten in den Besitz der Königlich Preußischen Geologischen Landesanstalt bzw. der geologischen Sammlung der Technischen Hochschule in Aachen gelangte, welche im Folgenden beschrieben werden sollen....
Die Foraminiferen-Fauna der miocänen und oligocänen Ablagerungen, die der übrigen auf der West- und Nordseite der Westfälischen Kreideformation auftretenden Ablagerungen werden namentlich mit der von Dingden verglichen.
Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project provides a comprehensive data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe to determine the major and minor element contents of fossil and modern molar enamel, cement and dentin from Hippopotamids. Most of the studied specimens are from different ecosystems in Eastern Africa, representing modern and fossil lacustrine (Lake Kikorongo, Lake Albert, and Lake Malawi) and modern fluvial environments of the Nile River system. Secondary alteration effects - in particular FeO, MnO, SO3 and F concentrations – are 2 to 10 times higher in fossil than in modern enamel; the secondary enrichment of these components in fossil dentin and cement is even higher. In modern and fossil enamel, along sections perpendicular to the enamel-dentin junction (EDJ) or along cervix-apex profiles, P2O5 and CaO contents and the CaO/P2O5 ratios are very constant (StdDev ∼1%). Linear regression analysis reveals tight control of the MgO (R2∼0.6), Na2O and Cl variation (for both R2>0.84) along EDJ-outer enamel rim profiles, despite large concentration variations (40% to 300%) across the enamel. These minor elements show well defined distribution patterns in enamel, similar in all specimens regardless of their age and origin, as the concentration of MgO and Na2O decrease from the enamel-dentin junction (EDJ) towards the outer rim, whereas Cl displays the opposite trend. Fossil enamel from Hippopotamids which lived in the saline Lake Kikorongo have a much higher MgO/Na2O ratio (∼1.11) than those from the Neogene fossils of Lake Albert (MgO/Na2O∼0.4), which was a large fresh water lake like those in the western Branch of the East African Rift System today. Similarly, the MgO/Na2O ratio in modern enamel from the White Nile River (∼0.36), which has a Precambrian catchment of dominantly granites and gneisses and passes through several saline zones, is higher than that from the Blue Nile River, whose catchment is the Neogene volcanic Ethiopian Highland (MgO/Na2O∼0.22). Thus, particularly MgO/Na2O might be a sensitive fingerprint for environments where river and lake water have suffered strong evaporation. Enamel formation in mammals takes place at successive mineralization fronts within a confined chamber where ion and molecule transport is controlled by the surrounding enamel organ. During the secretion and maturation phases the epithelium generates different fluid composition, which in principle, should determine the final composition of enamel apatite. This is supported by co-linear relationships between MgO, Cl and Na2O which can be interpreted as binary mixing lines. However, if maturation starts after secretion is completed, the observed element distribution can only be explained by equilibration of existing and addition of new apatite during maturation. It appears the initial enamel crystallites precipitating during secretion and the newly formed bioapatite crystals during maturation equilibrate with a continuously evolving fluid. During crystallization of bioapatite the enamel fluid becomes continuously depleted in MgO and Na2O, but enriched in Cl which results in the formation of MgO, and Na2O-rich, but Cl-poor bioapatite near the EDJ and MgO- and Na2O-poor, but Cl-rich bioapatite at the outer enamel rim. The linkage between lake and river water compositions, bioavailability of elements for plants, animal nutrition and tooth formation is complex and multifaceted. The quality and limits of the MgO/Na2O and other proxies have to be established with systematic investigations relating chemical distribution patterns to sedimentary environment and to growth structures developing as secretion and maturation proceed during tooth formation....