NERC GW4+ DTP Studentship: Where and when did they grow big? Tracing the emergence of super-sized ice sheets across the Mid-Pleistocene Transition

Project Background

Around 1 million years ago (during the Mid Pleistocene Transition, MPT), continental ice sheets began to grow much larger during glacial periods than they had previously, resulting ultimately in the extremely large ice sheets that covered much of the Northern Hemisphere during the Last Glacial Maximum. But it remains a mystery as to what caused this period of growth, with theories ranging from loss of an erodible substrate to changes in the transport of warm surface waters into the far North Atlantic, providing moisture for enhanced snowfall. One of the largest obstacles to constraining which theory might be correct is the lack of information about which ice sheets started growing first. In this project we will study the debris carried by icebergs as they crossed the open North Atlantic and Pacific Oceans during past glacial ages. Our aim is to identify changes in the source regions of icebergs across the MPT that reflect changes in the growth patterns of the major ice sheets during this critical period of climate change. 

Project Aims and Methods

The project will exploit the amazing collection of marine sediment cores recovered by the Integrated Ocean Drilling Program (IODP). Within these cores, we find layers made up of tiny particles of rock which were deposited by melting icebergs as they passed over the core site. These grains, known as Ice rafted Debris (IRD), can be counted to produce records of iceberg calving and we already have many thousands of these samples stretching back to ~1.7Myr ago. Furthermore, individual mineral grains (e.g. hornblendes and feldspars) carry with them an isotopic signature of where they came from i.e. their provenance, which we can trace using state of the art analytical techniques. 

In this project we will employ two such techniques (in addition to basic microscopic mineral identification): Here we will combine Ar/Ar dating of hornblendes (to be carried at in the laboratories of Prof Sidney Hemming at Lamont) with Pb isotopic analysis of feldspars (performed at BGS under the supervision of Dr Matthew Horstwood) to constrain the provenance of IRD taken from key intervals characterising the development of glacial conditions before, during and after the MPT. 

Our current collection of samples comes mainly from ODP Sites 981 and 983 (which were collected from just southwest of Iceland) but we also plan to retrieve samples from other cores from key locations across the North Atlantic and Pacific Oceans. This is an aspect of the project that we expect the successful student to help design. We also expect the student to play an active role in the selection of time intervals to be analysed (all background information required for this selection will be provided and discussed during initial supervisory sessions). 

Candidate requirements 

Some experience in isotope geochemistry or analytical chemistry would be an advantage, as would a background in paleoclimate and or paleoceanography. An interest in Quaternary climate is essential. 

Project partners  

The successful candidate will gain invaluable opportunities to learn state of the art techniques under direction of leaders in their respective fields. They will also have the exciting opportunity to spend time in labs outside of Cardiff (including Lamont, which is located just outside New York City, USA).  

Training 

Full training in the techniques to be employed will be provided. We encourage all our paleoclimate students to apply to sail on a coring expedition (cruise) during their PhD and although the material collected during that cruise may not be used during the PhD it will provide opportunities for future research and collaborations beyond Cardiff. 

Entry requirements

In order to be accepted you would need to have a first-class BSc degree or a second-class degree plus an MSc or good MSci. However, for international students, you would need to have a relevant degree in the subject area and have evidence of an English Language qualification. Further information on the English Language can be found here: https://www.cardiff.ac.uk/study/international/english-language-requirements/postgraduate

How to apply

In order to formally apply for the PhD you will need to go to the following web page: https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/earth-sciences

In the black box on the right of the page please select the following options:

·Doctor of Philosophy

·Full Time

·1st October 2023

Click on ‘Apply now’.

Please ensure that you include the ‘Project Title’ you are applying for and supervisor and that you add ‘NERC DTP’ under the source of funding.

The application deadline is Monday 9 January 2023 at 2359 GMT. Interviews will take place from 22nd February to 8th March 2023. For more information about the NERC GW4+ Doctoral Training Partnership please visit https://www.nercgw4plus.ac.uk.