Reichenbacher B.,Ludwig Maximilians University of Munich |
Krijgsman W.,University Utrecht |
Lataster Y.,University Utrecht |
Pipperr M.,Ludwig Maximilians University of Munich |
And 14 more authors.
Swiss Journal of Geosciences | Year: 2013
Oligocene-Miocene chronostratigraphic correlations within the Paratethys domain are still highly controversial. This study focuses on the late Early Miocene of the Swiss and S-German Molasse Basin (Late Burdigalian, Ottnangian-Karpatian). Previous studies have published different chronologies for this time interval that is represented by the biostratigraphically well constrained Upper Marine Molasse (OMM, lower and middle Ottnangian), Upper Brackish Molasse (OBM, Grimmelfingen and Kirchberg Formations, middle and upper Ottnangian to lower Karpatian, MN 4a-MN 4b) and Upper Freshwater Molasse (OSM, Karpatian-Badenian, MN 5). Here, we suggest a new chronostratigraphic framework, based on integrated magneto-litho-biostratigraphic studies on four sections and three boreholes. Our data indicate that the OBM comprises chrons 5D.1r and 5Dn (Grimmelfingen Fm), chron 5Cr (lower Kirchberg Fm) and the oldest part of chron 5Cn.3n (upper Kirchberg Fm). The OSM begins during chron 5Cn.3n, continues through 5Cn, and includes a long reversed segment that can be correlated to chron 5Br. The OMM-OSM transition was completed at 16.0 Ma in the Swiss Molasse Basin, while the OBM-OSM changeover ended at 16.6 Ma in the S-German Molasse Basin. As the lower Kirchberg Fm represents a facies of the Ottnangian, our data suggest that the Ottnangian-Karpatian boundary in the Molasse Basin is approximately at 16.8 Ma, close to the 5Cr-5Cn.3n magnetic reversal, and thus 0.4 Myr younger than the inferred age of 17.2 Ma used in recent Paratethys time scales. Notably, this would not be problematic for the Paratethys stratigraphy, because chron 5Cr is mainly represented by a sedimentation gap in the Central Paratethys. We also realise, however, that additional data is still required to definitely solve the age debate concerning this intriguing time interval in the North Alpine Foreland Basin. We dedicate this work to our dear friend and colleague Jean-Pierre Berger (8 July 1956-18 January 2012). © 2013 Swiss Geological Society.
Nio S.D.,ENRES International |
Abdul Aziz H.,ENRES International |
Koopmans J.G.,ENRES International |
Hall J.,ADCO |
2nd EAGE Workshop on Geosteering and Well Placement: Geosteering and the Benefits it Brings to Subsurface Understanding | Year: 2013
We present a real time log processing workflow that allows confident placement of wells, especially in complex carbonate depositional sequences, by exploiting a wealth of stratigraphic information present in conventional logging data. The workflow is based on the spectral analysis of data logs that identifies a hierarchy of sedimentary cycles, controlled by orbitally forced climate change. The INPEFA Log Transform (INPEFA), which is the key process in this workflow, mathematically analyses composite waveforms consisting of various amplitudes, phases and frequencies. Geologically, INPEFA is able to predict lithofacies variability, stratigraphic discontinuities and genetic relationship of depositional sequences. Application of the INPEFA workflow to real time stratigraphy provides a framework to interpret stratigraphic sequences while drilling. The benefits of this workflow includes optimal well placement and drilling operations by using a simplified Bottom Hole Assembly (BHA) solution permitted by minimalised logging requirements. This enables operators to make fast decisions during geosteering, save costs on logging equipment and obtain a higher Dogleg Severity (DLS).
Van Ojik K.,Nederlandse Aardolie Maatschappij |
Bohm A.R.,ENRES International |
Cremer H.,TNO |
Geluk M.C.,Royal Dutch Shell |
And 3 more authors.
SEPM Special Publications | Year: 2011
Due to the nature of the depositional environment and most importantly the lack of (bio) stratigraphic control, it remains difficult to establish a robust and reliable stratigraphic framework for the Upper Rotliegend which can be used as a guideline to better understand the internal architecture. The most important challenges encountered are the identification of the large-scale basin architecture and basin fill, the identification of a sequence stratigraphic model for (semi-) arid continental deposits, and the relationship between the distribution of Upper Rotliegend sediments and the underlying Variscan structural framework. Based on the present-day knowledge and status of particular stratigraphic aspects, it can be concluded that a single "silver bullet" solution does not exist for providing a more profound understanding of the depositional model. It is evident that none of the methods available should be used in isolation but rather integrated in the framework of sequence stratigraphy providing the petroleum geologist a genetic and predictive geological model. Copyright © 2011 SEPM (Society for Sedimentary Geology).
Kirscher U.,Ludwig Maximilians University of Munich |
Kirscher U.,Geoscience Australia |
Kirscher U.,Curtin University Australia |
Prieto J.,Ludwig Maximilians University of Munich |
And 6 more authors.
Newsletters on Stratigraphy | Year: 2016
Chronostratigraphic correlation and dating of terrestrial, especially mammal bearing, sediments of the European Neogene are still problematic and highly debated. In particular, absolute ages for important vertebrate assemblages are often not available making correlation during the continental Miocene across Europe so ambiguous. Here we present a detailed magnetostratigraphic study on a paleontological key section of the Middle to Late Miocene transition in the North Alpine Foreland Basin (NAFB) in Bavaria (Hammerschmiede) and a neighboring drill core, which has a total length of 150.4 m and includes, stratigraphically, the fossil site. We identify three complete normal polarity intervals, which have been correlated based on biochronologic constraints to chrons C5An.1n, C5r.2n and C5r.2r-1n. At least two major hiatuses probably occurred within the interjacent reversed chrons, for which geological indications are present and might be relatable to isochronic features in the Vienna basin. Inferred upper limits of the accumulation rate vary between 10 and 30 cm/kyr. This correlation determines the age of the Hammerschmiede vertebrate level HAM 5 to be about 11.62 Ma, making it an ideal biochronologic tie-point for the base of the Tortonian and Pannonian stages in terrestrial settings. Additionally, we date the youngest freshwater molasse lithostratigraphic unit of the Bavarian part of the NAFB, the Obere Serie, to between 13.8 and 11.1 Ma. Following our correlation, the lack of hipparion horses in the Bavarian part of the NAFB has stratigraphic rather than ecologic reasons and the 'Hipparion datum' seems to be a single bio-event at 11.1 Ma in Western Eurasia. © 2016 Gebrüder Borntraeger, Stuttgart, Germany.
Hilgen F.J.,University Utrecht |
Hinnov L.A.,Johns Hopkins University |
Abdul Aziz H.,ENRES International |
Abels H.A.,University Utrecht |
And 11 more authors.
Geological Society Special Publication | Year: 2015
The Milankovitch theory of climate change is widely accepted, but the registration of the climate changes in the stratigraphic record and their use in building high-resolution astronomically tuned timescales has been disputed due to the complex and fragmentary nature of the stratigraphic record. However, results of time series analysis and consistency with independent magnetobiostratigraphic and/or radio-isotopic age models show that Milankovitch cycles are recorded not only in deep marine and lacustrine successions, but also in ice cores and speleothems, and in eolian and fluvial successions. Integrated stratigraphic studies further provide evidence for continuous sedimentation at Milankovitch time scales (104 years up to 106 years). This combined approach also shows that strict application of statistical confidence limits in spectral analysis to verify astronomical forcing in climate proxy records is not fully justified and may lead to false negatives. This is in contrast to recent claims that failure to apply strict statistical standards can lead to false positives in the search for periodic signals. Finally, and contrary to the argument that changes in insolation are too small to effect significant climate change, seasonal insolation variations resulting from orbital extremes can be significant (20% and more) and, as shown by climate modelling, generate large climate changes that can be expected to leave a marked imprint in the stratigraphic record. The tuning of long and continuous cyclic successions now underlies the standard geological time scale for much of the Cenozoic and also for extended intervals of the Mesozoic. Such successions have to be taken into account to fully comprehend the (cyclic) nature of the stratigraphic record. © 2015 The Author(s).