Integrated Understanding of the Early Jurassic Earth System and Timescale (JET)

Lead Research Organisation: University of Oxford
Department Name: Earth Sciences


We propose a large-scale, multi-faceted, international programme of research on the functioning of the Earth system at a key juncture in its history - the Early Jurassic. At that time the planet was subject to distinctive tectonic, magmatic, and solar system orbital forcing, and fundamental aspects of the modern biosphere were becoming established in the aftermath of the end-Permian and end-Triassic mass extinctions. Breakup of the supercontinent Pangaea was accompanied by creation of seaways, emplacement of large igneous provinces, and occurrence of biogeochemical disturbances, including the largest magnitude perturbation of the carbon-cycle in the last 200 Myr, at the same time as oceans became oxygen deficient. Continued environmental perturbation played a role in the recovery from the end-Triassic mass extinction, in the rise of modern phytoplankton, in preventing recovery of the pre-existing marine fauna, and in catalysing a 'Mesozoic Marine Revolution'. However, existing knowledge is based on scattered and discontinuous stratigraphic datasets, meaning that correlation errors (i.e. mismatch between datasets from different locations) confound attempts to infer temporal trends and causal relationships, leaving us without a quantitative process-based understanding of Early Jurassic Earth system dynamics.

This proposal aims to address this fundamental gap in knowledge via a combined observational and modelling approach, based on a stratigraphic 'master record' accurately pinned to a robust geological timescale, integrated with an accurate palaeoclimatic, palaeoceanographic and biogeochemical modelling framework. The project has already received $1.5M from the International Continental Drilling Programme towards drilling a deep borehole at Mochras, West Wales, to recover a new 1.3-km-long core, representing an exceptionally expanded and complete 27 My sedimentary archive of Early Jurassic Earth history. This core will allow investigation of the Earth system at a scale and resolution hitherto only attempted for the last 65 million years (i.e. archive sedimentation rate = 5 cm/ky or 20 y/mm). We will use the new record together with existing data and an integrative modelling approach to produce a step-change in understanding of Jurassic time scale and Earth system dynamics.

In addition to order of magnitude improvements in timescale precision, we will: distinguish astronomically forced from non-astronomically forced changes in the palaeoenvironment; use coupled atmosphere-ocean general circulation models to understand controls on the climate system and ocean circulation regime; understand the history of relationships between astronomically forced cyclic variation in environmental parameters at timescales ranging from 20 kyr to 8 Myr, and link to specific aspects of forcing relating to solar energy received; use estimated rates and timing of environmental change to test postulated forcing mechanisms, especially from known geological events; constrain the sequence of triggers and feedbacks that control the initiation, evolution, and recovery from the carbon cycle perturbation events, and; use Earth system models to test hypotheses for the origins 'icehouse' conditions. Thirty six project partners from 13 countries substantially augment and extend the UK-based research.

Planned Impact

We identify three groups on whom the research will impact: the oil and gas industry, school students, and the wider public.

The oil and gas industry will significantly benefit from this work because detailed analysis of the Mochras record will facilitate the more effective prediction of oil and gas reservoir and source rock occurrence and properties regionally and globally. The Early Jurassic includes world-class (i.e. rich and widespread) hydrocarbon source rocks due to significant carbon cycle perturbations at the time. Furthermore, the multi-fossil group biostratigraphy will enhance stratigraphical resolution throughout the Early Jurassic which will help in both the exploration and production phases. The Industry Advisory Group comprising four experts from the hydrocarbon industry and chaired by PI Hesselbo will ensure that this economically-important focus is maintained. The science team also plan two industry workshops in years three and five to derive feedback and to disseminate findings.

We will significantly contribute to the development of curriculum resources for KS2/3 and KS5 school students through the science generated by this project and will engage and inspire school pupils in the earth sciences. These resources will be developed in consultation with project scientists with the National Museum of Wales, and be evaluated by teachers prior to release. The resources will include activities based on scientific data from the project, will be bilingual (Welsh/English) and placed online.

The science party will embark on a public engagement programme in the area around the drill site to promote the context of, and explain the science behind, the project. The target audience will be local communities because it is important that they understand the fundamental science motivations of the project. The activities will comprise public meetings, and drill site visits, and displays. Public lectures/events at local venues such as village halls and community centres to explain different aspects of the JET drilling and science programme will be held. We will actively build public accessibility into the design of the drill site so as to allow visitors to safely view the drilling and core logging activities. This will include a covered area to bilingually (Welsh/English) display information about the project.

The science team will interact with the wider general public to communicate the general themes of the research and more specific details of the project. We will achieve this across four principal themes. The first is a dedicated project website and a Quick Response (QR) code infrastructure. The team anticipate that the project will be a test example for an interactive and flexible means of accessing information at geoscience sites consisting of QR codes on information boards. In this case this will be the drill site display, which will be connected via a QR code web infrastructure to the project website. This can be used to link static information at a site to more detailed and up-to-date information on the www using smartphone technology. The team will deliver presentations and displays on the project at regional science and fossil events such as the Lyme Regis and Scarborough Fossil Festivals. We will also provide QR code links from the stand to access the project website and web feedback form.

The project scientists will work with the communications teams at our respective organisations to issue press releases and social media communications for important project deliverables/milestones and publications. The landowners at the site have expressed their support for the project. The area is a campsite between March and September, and is one of the largest in Europe. It has thousands of Twitter and Facebook followers, which will provide platforms for positive international publicity for the project.
Description We have analysed a suite of samples, from an archived borehole, from a period in the Earth's past, about 180 million years ago, when the world's oceans were characterised by widespread anoxia. This anoxia enabled the preservation of organic carbon during burial that forms the basis of many economically important hydrocarbon deposits. Our work has uncovered a series of reversals of the Earth's magnetic field that span this interval that provide new constraints on the timing and duration of the oceanic anoxic event (OAE) at a higher resolution that has previously been documented. The reversals also enable us to explore possible links between major periods of volcanism at this time and the development of these OAE's. We have proposed that our reversal stratigraphy should form the basis of a new global standard for this interval of geological time. This work was published in 2018.

In October to December 2020 we were finally able to complete drilling of a 656m deep borehole near Press in Shropshire. This was a major goal of this project, which was co-funded by the International Continental Scientific Drilling Program (ICDP). The cored material from this hole was transported to the Core Repository at the British Geology Survey, in Keyworth, where it was subjected to a full suite of core analyses. The core was then split into two halves; one of which is being archived for future use, and a working half which is available to project scientists for sampling. We collected some 1200 sub-samples from the core for magnetic analysis in July-August 2021. These analyses have been carried out in palaeomagnetic laboratories at Oxford and Southampton, and all the analyses will be complete by the summer of 2024.
Exploitation Route Our findings will be mainly of use to stratigraphers, who specialise in the correlation of rock sequences. In particular they will provide a framework in time of when major environmental perturbations took place in the early Jurassic and how long they lasted. This will also provide a time-frame for environmental change in response to major driving events such as the release of CO2 and other volaites into the atmosphere ay the time.
Sectors Education


Description JET Project Collaboration 
Organisation Camborne School of Mines
Country United Kingdom 
Sector Academic/University 
PI Contribution This is a collaboration within the framework of the original proposal, whihc is a multi-partner project looking at the environments and timescales of a particular part of geological time about 180 million years ago. My group has been providing a timeline to their study of the changing environments at this time.
Collaborator Contribution My collaborators at the Cambourne School of mines have been developng the basic stratigraphy for the material we are analysing.
Impact We published one paper in 2018, and are set to commence the major portion of the project in 2019 with the drilling of a deep borehole/
Start Year 2014