Paleobiodiversity and community structures of Lagerstätten during the Late Paleozoic Ice Age and the response of the marine benthic invertebrate fauna to global cooling

Third party funded individual grant

Start date : 01.07.2014

Project details

Scientific Abstract

Paleo-biodiversity studies have become of increasing interest and numerous manuscripts have been published dealing with global diversity trends throughout the Phanerozoic. However, data used in these studies mostly derive from databases that may contain various biases and therefore distort statistical analysis. Moreover, Fossil Lagerstätten are commonly excluded although the quality of preservation and information is much better than in other deposits - fossil assemblages from Lagerstätten reflect the composition of former living communities to a much higher degree.The Phanerozoic is marked by two long-term cooling events. One of these is the Late Paleozoic Ice Age (LPIA) with its major onset in the middle to late Mississippian (Lower Carboniferous) and ending in the mid-Sakmarian (Permian). This project focuses on the paleo-biodiversity during the Upper Carboniferous (Pennsylvanian), i.e. during a large part of the LPIA. Instead of purely using information from databases three fossil Lagerstätten (here Lagerstätten is used in terms of exceptionally preserved fauna; e.g. original shell material, color patterns, delicate ornamentation, minute larval shells) are sampled. These localities were influenced by the glacio-eustatic regime during the LPIA and are, from the American Midcontinent, the Finis Shale (Virgilian) and the Buckhorn Asphalt Quarry (Desmoinesian) and, from the Appalachian Basin, the Kendrick Shale (Morrowan).One objective of this project is to study true biodiversities and ecological structures within deposits of exceptionally preserved fossils based on the fact that such deposits depict a more complete image of the original fossil assemblage than other localities. Stanley & Powell (2003) found that during the Pennsylvanian the rates of origination and extinction were depressed and that the global biodiversity remained relatively stable, whereas Alroy et al. (2008) found a general decrease in this period. Therefore, as the second objective, it will be tested if these previous results are visible in Lagerstätten from the Pennsylvanian as well: Do we also see depressed origination and extinction rates or decreasing biodiversity or are the results presented by Stanley & Powell (2003) and Alroy et al. (2008) caused by biases in their data, as for example by faunas of less quality of preservation? Furthermore, diversity dynamics will be studied by analyzing the Carboniferous-Permian faunal turnover. Which taxa control the diversities? The local marine paleo-temperatures within each profile will be investigated. Isotope-analyses will be carried out for the Finis Shale, the Buckhorn Asphalt Quarry, and the Kendrick Shale. Temperature and diversity will be cross correlated to shed light on the relation of temperature and biodiversity during the LPIA to answer the question 'How does the living environment react to global cooling?'.


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