Sporormiella, a genus of coprophilous fungus, is increasingly used as a qualitative proxy for megafaunal density. Decreased spore abundances in Late-Pleistocene and Holocene sediments are thought to signal prehistoric megafaunal population declines and extinctions. However, much remains unknown regarding the dispersal, deposition, and preservation of Sporormiella, hindering interpretation. Here we collected lake-center and lake-margin surface-sediment samples from 24 lakes in a west–east transect across South Dakota, Minnesota, and Wisconsin to test whether Sporormiella abundances varied along a precipitation gradient and areas of varying grazing intensity. Unlike other pollen types, relative abundances and concentrations of Sporormiella spores were uncorrelated between lake-center and lake-margin samples. For lake-margin samples, distance-to-shoreline and county-scale cattle density were significant predictors of Sporormiella relative abundances. Only distance to shoreline was a significant predictor of Sporormiella concentrations. The positive relationship between shoreline proximity and Sporormiella abundances differs from prior reports that Sporormiella concentrations decrease away from shoreline. For lake-center samples, Sporormiella relative abundances were negatively correlated with precipitation and Sporormiella concentrations had no significant predictors. These results suggest that Sporormiella representation in lake sediments is controlled by multiple factors, including but not limited to local megaherbivore density. Sporormiella concentrations appear to be ‘noisier’ than Sporormiella relative abundances, due to within-basin sedimentary effects on pollen and spore accumulation rates. More work on Sporormiella taphonomy is critically needed to better understand the controls on its representation in late-Quaternary sediments.

No abstract

Within the Cenozoic sedimentary section of the Roer Valley Graben ten seismostratigraphic units have been identified. They are closely related to the lithological framework which makes it possible to recognize diem also on well logs in this region. The Lower Tertiary seismic units, representing mainly marine sediments, have a uniform development mat can be correlated over large distances into the German part of the Roer Valley Graben. The marine to continental Upper Tertiary and Quaternary seismic units display a more complex development due to lateral facies changes (including prograding delta systems) and rift tectonics.

The Broad Fourteens Basin is a NW-SE trending Mesozoic structural element that was affected by inversion movements during the Late Cretaceous (Subhercynian Phase) and Early Tertiary (Laramide Phase). Since the overlying Tertiary section of this area is relatively little studied, a multi-disciplinary investigation was initiated using both seismic and well data. The present study is the first phase of that project and deals exclusively with the stratigraphical framework and sedimentary development based on well logs from approximately forty wells.The Tertiary sedimentary section in this area (maximum thickness up to approximately 800 m) consists of siliciclastic rocks that generally correlate well with the established lithostratigraphical framework of the Netherlands. However, the highly variable thickness of these lithological units, illustrated by isopach maps for all units, reflect the intricate pattern of sea level movements, differential vertical movements and the ensuing erosion, that took place in this tectonically active area.Well P06-02, one of the most complete sections in the center of the area, was selected for detailed biostratigraphical analysis to support further stratigraphical subdivision and correlation. This yielded information on both the distribution pattern of various lithological units and the influence of large, partly global, events during basin development. It is concluded that application of detailed sequence stratigraphy in the study area is very problematic and only 2nd and some 3rd order cycles could be recognized.