Institut für Geologische Wissenschaften
Subproject 1 of the FG 736: Origin of benthic metazoan ecosystems
Subproject 1 is a joint sedimentological-paleobiological project with a particular focus on precambrian geology, palichnology and (bio)stratigraphy. The aim of our work group is to relate the paleobiological and chemostratigraphic/geochronological projects of the Forschergruppe to each other by providing them with a robust stratigraphic framework. This includes accumulating expertise on correlation, the continuity of the stratigraphic record and diagenetic overprint of the sedimentary rocks.
The fields of work of the group-members are:
- Christoph Heubeck: sedimentology, stratigraphy
- Bernd Weber: ichnofossils, biostratigraphy
- Quentin Scouflaire: ichnofossils, biostratigraphy, sedimentology
Paleobiology and sedimentary geology will work hand in hand to better constrain the the sedimentary environment of several spectacular Pc-C body and trace-fossil locations.
Ediacaran to Cambrian (PC-C) shelf deposits and their fossil record provide insights in initial metazoan evolution because they represent the earliest evidence of complex benthic ecosystems on Earth. The Yangtze Platform and adjacent microcontinents provide unique access to widely undisturbed shallow- and deep-marine deposits of this time interval on a large paleogeographic scale. We intend to study the interaction between sedimentary environment, Ediacaran-Cambrian stratigraphic shelf-margin architecture and paleobiological factors in selected sedimentary sequences.
Here we focus on the occurrence, preservation, taphonomy, facies distribution and interpretation of PC-C body fossils, transitional trace-body fossil types and related microbial mat habitats. The latter likely played a key role in the establishing of lifestyles of benthic metazoans, in Ediacara-type fossil preservation and in the stratigraphic architecture: Whereas phanerozoic marine sediments are usually intensely bioturbated, in the Precambrian the seafloor was covered with a crust of algae/microbes. These biomats efficiently trapped biogenic gases and fluids, thereby changing the sediments' mechanical properties). We therefore want to explore the potential temporal changes of shelf margin stability.
plausible chain of events and causalities at the Pc-C transition:
environmental (geochemical/climatic) changes -> new paleoenvironments -> evolution of life -> increase in bioturbation -> new (modern) properties of sediments, leading to more "modern" (actualistic) processes affecting them
Besides supplying the stratigraphic framework, we will investigate following hypotheses: