Overview

Project Highlights:

  • Address fundamental questions about global cooling and environmental change in the oceans in the middle Miocene
  • Training and application of traditional and advanced organic geochemistry techniques
  • Join a vibrant research group of leading palaeoclimate researchers applying multiple proxy-based techniques across different scales in space and time.

 

The middle Miocene records one of the four major cooling steps in the last 66 million years of Earth history, as the Earth’s climate system moved from the greenhouse conditions of the early Eocene to the icehouse conditions of today. The cooling (Middle Miocene Climate Transition; MMCT) resulted in major growth and consolidation of the East Antarctic Ice Sheet (EAIS) and a significant increase in sea ice in the Arctic.

Stratigraphically complete records of the middle Miocene are rare due to strengthening of current activity during the MMCT and this has hampered our understanding of this critical period of Earth history. One stratigraphically near-complete and important record is the Monterey Formation in California. This project will use samples from the Monterey Formation now housed at the Open University. These were collected from a stratigraphically complete deep marine section of the middle Miocene that is undisturbed by either bioturbation or mass flow deposits. The deposits are rich in organic-carbon from high productivity in this upwelling zone, and we are already in possession of substantial datasets (δ13Corg and δ13Ccarbonate) which will feed directly into the proposed research.

Changes in sedimentary facies can be linked to changes in the palaeoclimate. This study will investigate the organic geochemistry of these deposits in detail and establish the links between local, regional and global changes the Earth’s carbon cycle and climate during this critical interval in Earth history. Organic geochemical proxy-based measurements of terrestrial and marine temperature (using GDGT-based proxies such as the TEX86, MBT/CBT), ocean productivity and terrestrial runoff, will be combined with isotope-based traces of the global carbon cycle to elucidate the dynamics of the climate system during the middle Miocene.

Summary of the change in temperature over the last 66 Ma showing the middle Miocene cooling.

Methodology

Construct a record of changes in palaeotemperature on both a million-year and millennial timescale across the MMCT cooling and the Monterey carbon isotope excursion using the TEX86 proxy measured from the organic molecular fossils extracted from the Monterey Formation samples.

Assess changes in ocean productivity and local land runoff using carbonate, isotope and organic geochemical techniques.

Determine the link between local, regional and global changes in the Earth’s climate system by combining novel and traditional organic and isotope-based measurements.

Training and Skills

In addition to a wide range of generic training from CENTA2 and the Open University, the student will be trained in a number of subject specific skills. These include stratigraphy, sedimentology and organic geochemistry which has a wide range of applications. There will be the opportunity to work in state-of-the-art geochemistry labs with access to hyphenated mass spectrometry techniques. The successful candidate will be encouraged and supported in applying for a paid internship of a month or more and to take part in career-enhancing opportunities such as teaching, science communication and understanding policy.

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

Timeline

Year 1: Review literature on Miocene climate change, train in organic geochemistry labs with supervisors. Select and process pilot set of samples from Miocene collection at the OU.

Year 2: Analyse further set of samples based on initial results. Write manuscript.

Year 3: Finish interpretation, prepare thesis and further manuscripts. Possibly take a formal study break for several months to complete internship.

Partners and collaboration (including CASE)

The project will provide the opportunity to work within the international community of scientists working on palaeoclimate science, and work alongside scientists applying organic geochemistry to diverse questions including climate change, proxy development, and the search for extra-terrestrial life.

Further Details

Applicants should have a strong background in, and enthusiasm for laboratory work and the ability to work independently after initial training. The student will join a well-established team researching palaeoenvironmental change at the Open University (http://www.open.ac.uk/science/environment-earth-ecosystems/research/palaeoenvironmental-change). If you would like to apply or require further information please contact Marcus Badger at the Open University (Marcus. Badger@open.ac.uk).

Applications should include: