Project Details
Projekt
Late Paleocene to early Eocene (~57 – 52 Ma) calcareous nannoplankton paleoecology and biostratigraphy: new insights from the high-latitude Southern Hemisphere
Applicant
Heather Jones, Ph.D.
Subject Area
Palaeontology
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 527717172
A key objective of scientific ocean drilling is to understand palaeoecological responses to tipping points over different spatial and temporal scales, so as to better predict how future marine communities will be affected by ongoing environmental change. Calcareous nannoplankton - a dominant group of microscopic algae - leave a rich, globally-distributed fossil record in deep sea sediment cores, which is ideal for exploring how ecosystems responded to environmental change in the geological past. The early Eocene (~57 to 52 Ma) is considered a particularly good analogy for future climate change if carbon dioxide emissions continue to rise. Periodic disruption of the carbon-cycle during this interval drove a series of transient warming events (hyperthermals), which leave a distinctive signature in the geochemical record. As each of these hyperthermals are of a different magnitude, they provide a unique opportunity to explore whether nannoplankton exhibited a scaled or threshold response to carbon-cycle perturbations. However, most previous studies only focus on the largest warming event: the Paleocene-Eocene Thermal Maximum (PETM). Although a few records do span multiple hyperthermals, they are heavily biased towards the low- and mid- latitudes. Therefore, to better understand community-level responses to environmental change over different spatial scales, more palaeoecological records are needed from the high-latitudes. The proposed research takes advantage of a new early Eocene record from International Ocean Discovery Program (IODP) Site U1514, which was located at a high paleolatitude ~50 Ma. Nannoplankton community composition will be reconstructed across 9 hyperthermal events at Site U1514, greatly improving our understanding of how high-latitude ecosystems responded to different-magnitude carbon-cycle perturbations. Site U1514 also benefits from having an astronomically-tuned early Eocene age model: one of the first from the high-latitude Southern Hemisphere. This makes it ideal for constraining calcareous nannofossil biozone datums, which are mostly based on low-to mid-latitude assemblages, and are often problematic at high-latitude sites. Therefore, the proposed research will astronomically-calibrate existing and new nannofossil bio-events to the Site U1514 age model. To ensure that the newly-defined datums can be correlated throughout the high-latitudes, detailed biostratigraphy will also be conducted on sediments from several Ocean Drilling Program (ODP) sites that span all the major ocean basins. Age models for each site will be constructed by correlating new and existing high-resolution carbon isotope records to the orbital-age model of Walvis Ridge. Therefore, the proposed research will both improve high-latitude nannoplankton zonation schemes and identify legacy ODP sites that might be critical for future studies on the early Eocene hyperthermals.
DFG Programme
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