- Constrain short-term benthic ecosystem responses to climatic change
- Expert training in calcareous micropalaeontology
- Working as part of international, multidisciplinary research network
The Triassic-Jurassic boundary interval witnessed a marked global extinction with profound consequences for all ecosystems. Significant diversification occurred after this event but the pattern and process of recovery in marine shelf environments, particularly over the short-term, is not well known. The earliest Jurassic in Britain is often characterised by cyclical sedimentation, considered to reflect astronomically-driven climate variability. These sediments contain abundant and diverse assemblages of calcareous microfossils, i.e. ostracods (microscopic Crustacea) and foraminifera (Protista) that will be used to quantify the biotic response to Jurassic cyclic climate changes for the first time. Pilot studies on cycles within the Blue Lias Formation, SW England (see photo below) have shown that microfossil assemblages display marked changes on a centimetric-decimetric scale within these cycles. However, to examine these interactions in greater detail and understand the benthic ecosystem response to these cycles requires (i) relatively expanded sedimentary sequences, (ii) complimentary geochemical records and (iii) relatively abundant and diverse faunal assemblages, all three requirements are met by this project.
Working alongside the ICDP/NERC funded JET project (Hesselbo et al., 2013), the student will have access to a new ~850m core from Prees (Cheshire Basin) through this interval. The project will benefit from synergies created by working with this diverse, multinational research network while contributing important chronostratigraphic and palaeoenvironmental data to JET objectives. The project will include a comparative study of the Carnduff-1 & 2 cores from the Larne Basin, Northern Ireland, thanks to ongoing collaboration with BGS colleagues at GSNI (the Geological Survey of Northern Ireland) and outcrops such as Dorset. Investigating these events from different depositional basins will help understand the spatial variability in their response while the high-resolution faunal sampling through cycles in the Prees & Carnduff cores, will elucidate benthic ecosystem responses during all stages of these climate cycles, in particular linkages to surface water productivity.
In collaboration with partners at Merlin Energy Resources Ltd, the student will also develop an understanding of how these microfossils can be used to establish correlations and, for the first time, develop microfossil-derived sequence stratigraphic frameworks for the Early Jurassic using industry-standard software.
The project will be based on high-resolution sediment sampling for microfossils through cycles from both the Prees and the Carnduff cores. The latter already has a well-constrained biostratigraphic and stable isotope framework (Boomer et al. in review). Additional sampling throughout the late Triassic and Early Jurassic sediments at Prees will establish a working foraminiferal biozonation for this interval (Copestake & Johnson, 2014). Quantitative relationships between microfossil assemblages and parallel chemical & physical proxies from the same cores will help constrain the environmental controls on assemblage composition. Outcrop sampling of the Blue Lias Formation in SW Britain will also investigate lateral, within-bed, assemblage variability to assess ecological patchiness, not possible in the cores due to limited material.
Training and Skills
Training will be provided in micropalaeontological techniques and , the student will also learn to use Scanning Electron Microscope facilities at the University of Birmingham. The student will gain experience in taxonomic identification and imaging of early Jurassic benthic foraminifer and ostracods, and in applying geochemical and sedimentological datasets to understand the drivers of biological change. The student will also develop skills in multivariate statistical techniques for palaeobiological analyses.
In addition to standard software, training can be arranged to use biostratigraphic management software (Stratabugs) and well-correlation software (ODM/IC).
Year 1: Sampling of the 2 main cores from GSNI (Belfast) and BGS (Keyworth). Field site sampling, SW England. Determining optimum processing techniques, establishing familiarity with key microfossil taxa. Establish JF foram Zonation scheme for Prees core.
Year 2: Detailed microfaunal analysis across climatic cycles, correlation to core chemistry & physical properties (submit as publication)
Year 3: Establish models to explain assemblage changes. Test against other parts of the same cores using chemistry/physical properties to predict assemblage composition (possible publication). Begin Thesis write up.
Partners and collaboration (including CASE)
Merlin Energy Resources Ltd. Phil Copestake will provide taxonomic advice throughout the project and there may be an opportunity to work at the Merlin offices regarding the sequence stratigraphic interpretation of the microfossil assemblages.
GSNI. Provides access to the Carnduff cores, Rob Raine brings his expertise in sedimentology and elemental chemistry (XRF) to the project and access to some BGS facilities.
JET Project team. Undertaking multi-proxy study of the Prees Core that will support interpretation of microfossil records generated here (and vice versa) as well as offering considerable networking opportunities.
GEES Palaeoclimates Research Group
Dr Kirsty Edgar