Project Details
Projekt
The climate development of Gondwana during the Jurassic
Applicant
Dr. Matthias Alberti
Subject Area
Palaeontology
Term
from 2015 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 283866124
Older studies claim an ice-free Jurassic world with equable warm climate conditions and weak latitudinal temperature gradients. However, this view was challenged since by a series of climate reconstructions pointing to several warmer and colder intervals, some even with short polar glaciations. Many of these studies were based on stable isotope analyses of fossil shells resulting in absolute water temperature data. Nevertheless, most of the analyzed material has been collected from Laurasian localities and often it is unknown to which extent the reconstructed temperature curves depict global or only regional events (possibly even changes in water depth at the sample localities). Climate conditions of other regions, such as the southern supercontinent Gondwana, are much less known. Furthermore, most of the available reconstructions are based on stable isotope analyses of belemnites, as these are often common in the sedimentary successions and large amounts of sample material can be extracted from their massive rostra. Research during the last few years, however, has shown that the use of belemnites often leads to an underestimation of temperatures with results being lower than those from shells of the benthic fauna. The proposed project aims to reconstruct the Jurassic climate development for a series of localities of Gondwana. Fossil material has been or will be collected from Tunisia, Egypt, Jordan, India, Madagascar, Chile, and Argentina. In many cases, the project will result in the first absolute temperature data available for these localities. Furthermore, the project will rely mainly on oysters and impunctate rhynchonellid brachiopods, thereby gaining a more reliable picture of local temperature conditions compared to results from belemnites. Water temperatures will be calculated based on stable isotope, clumped isotope, and trace element analysis. High-resolution stable isotope and trace element analyses of bivalve shells will enable an estimation of the degree of seasonality at the different localities as well as the reconstruction of other environmental parameters (e.g., the presence of upwelling currents). Combining the results, latitudinal temperature gradients will be calculated for Gondwana at different time intervals in the Jurassic. Possibly the most interesting application of the dataset assembled in the proposed project lies in a comparison with latitudinal gradients of marine invertebrate diversity. This would allow to identify whether temperatures were a major controlling factor of marine faunal patterns. As the Jurassic was a period with generally warmer climate conditions and elevated CO2-concentrations in the atmosphere compared to recent times, the results might benefit the current global warming debate. Therefore, a special focus is directed at Jurassic climate conditions along the equator, where elevated temperatures might have depleted the faunal diversity.
DFG Programme
Research Grants
International Connection
Argentina, India, USA
