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

Lead Research Organisation: University of Exeter
Department Name: Camborne School of Mines


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.


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Beasley C (2021) Evidence of a South Asian Proto-Monsoon During the Oligocene-Miocene Transition in Paleoceanography and Paleoclimatology

Description We have developed a next-generation timescale for part of the early Jurassic based on analysis of existing core samples.

We have determined that there is significant perturbation of ocean chemistry for platinum group isotopes during a 'supergreenhouse' event.

We have determined that there is significant perturbation of ocean chemistry for Mercury elemental content during the same event that can be linked to flood basal volcanism.

We have constructed a next-generation history of magnetic polarity reversals for part of the early Jurassic record.

New clay mineral data show systematic changes in palaeoclimate that may relate to long-cycle orbital forcing.

We have recognized the impact of solar system orbital forcing in the Jurassic carbon cycle expressed in organic matter carbon-isotope data.

We have recovered more than 600 m of high quality core and an extensive suite of downhole geophysical logs form the Prees-2 borehole site
Exploitation Route Useful for modelling of solar system orbital history

Informs knowledge of forcings and feedbacks to the Earth system during extremes of palaeoenvironmental change
Sectors Education,Energy,Environment

Description JET (Further funding for drilling operations)
Amount $150,000 (USD)
Organisation Helmholtz Association of German Research Centres 
Department German Research Centre for Geosciences
Sector Private
Country Germany
Start 01/2019 
End 12/2020
Title Data from: Ocean warming affected faunal dynamics of benthic invertebrate assemblages across the Toarcian Oceanic Anoxic Event in the Iberian Basin (Spain) 
Description The Toarcian Oceanic Anoxic Event (TOAE; Early Jurassic, ca. 182 Ma ago) represents one of the major environmental disturbances of the Mesozoic and is associated with global warming, widespread anoxia, and a severe perturbation of the global carbon cycle. Warming-related dysoxia-anoxia has long been considered the main cause of elevated marine extinction rates, although extinctions have been recorded also in environments without evidence for deoxygenation. We addressed the role of warming and disturbance of the carbon cycle in an oxygenated habitat in the Iberian Basin, Spain, by correlating high resolution quantitative faunal occurrences of early Toarcian benthic marine invertebrates with geochemical proxy data (d18O and d13C). We find that temperature, as derived from the d18O record of shells, is significantly correlated with taxonomic and functional diversity and ecological composition, whereas we find no evidence to link carbon cycle variations to the faunal patterns. The local faunal assemblages before and after the TOAE are taxonomically and ecologically distinct. Most ecological change occurred at the onset of the TOAE, synchronous with an increase in water temperatures, and involved declines in multiple diversity metrics, abundance, and biomass. The TOAE interval experienced a complete turnover of brachiopods and a predominance of opportunistic species, which underscores the generality of this pattern recorded elsewhere in the western Tethys Ocean. Ecological instability during the TOAE is indicated by distinct fluctuations in diversity and in the relative abundance of individual modes of life. Local recovery to ecologically stable and diverse post-TOAE faunal assemblages occurred rapidly at the end of the TOAE, synchronous with decreasing water temperatures. Because oxygen-depleted conditions prevailed in many other regions during the TOAE, this study demonstrates that multiple mechanisms can be operating simultaneously with different relative contributions in different parts of the ocean. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Title Drilling Information System 
Description In collaboration with the ICDP we are developing the expedition Drilling Information System, or mDIS 
Type Of Material Data handling & control 
Year Produced 2020 
Provided To Others? No  
Impact The mDIS system will facilitate data acquisition during drilling and sampling operations for the Prees core 
Title Temperature-related body size change of marine benthic macroinvertebrates across the early Toarcian Anoxic Event 
Description The Toarcian Oceanic Anoxic Event (TOAE, Early Jurassic, ~182 Ma ago) was characterised by severe environmental perturbations which led to habitat degradation and extinction of marine species. Warming-induced anoxia is usually identified as main driver, but because marine life was also affected in oxygenated environments the role of raised temperature and its effects on marine life need to be addressed. Body size is a fundamental characteristic of organisms and is expected to decrease as a response to heat stress. We present quantitative size data of bivalves and brachiopods across the TOAE from oxygenated habitats in the Iberian Basin, integrated with geochemical proxy data (d13C and d18O), to investigate the relationship between changes in temperature and body size. We find a strong negative correlation between the mean shell size of bivalve communities and isotope-derived temperature estimates, suggesting heat stress as a main cause of body size reduction. While within-species size changes were minor, we identify changes in the abundance of differently sized species as the dominant mechanism of reduced community shell size during the TOAE. Brachiopods experienced a wholesale turnover across the early warming phase and were replaced by a virtually monotypic assemblage of a smaller-sized, opportunistic species. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Description Astrogeo 
Organisation Observatory of Paris
Country France 
Sector Academic/University 
PI Contribution Providing input to astronomical model development in deep time
Collaborator Contribution Mathematical and astrophysical knowledge and understanding
Impact None yet
Start Year 2021
Description Jurassic clay mineralogy 
Organisation University of Burgundy
Country France 
Sector Academic/University 
PI Contribution Contribution of sample material and scientific context
Collaborator Contribution Generation of XRD analysis of clay mineralogy for palaeoclimatic, diagenetic, and provenance interpretation
Impact Paper in press: Deconinck et al (in press) Climatic and sea-level control of Jurassic (Pliensbachian) clay mineral sedimentation in the Cardigan Bay Basin, Llanbedr (Mochras Farm) borehole, Wales. Sedimentology.
Start Year 2013
Description Community Engagement 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Through the auspices of the National Museum Wales we organized a community event at the village nearest the project drill site. The event comprised an evening talk on Friday, followed by a whole day activity and Q&A event on the Saturday. The event was attended by local resieents who could find out about the aims of the project and ask any questions of project scientists.
Year(s) Of Engagement Activity 2017
Description Engagement with Prees Parish Council all research borehole site 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Policymakers/politicians
Results and Impact Information for the local community who might otherwise be wary of relatively deep drilling activities
Year(s) Of Engagement Activity 2020
Description Prees community introduction to project in advance of planning application 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Presentation and Q&A session at Prees village, Shropshire, ahead of submission of planning application for scientific research borehole on edge of village
Year(s) Of Engagement Activity 2019
Description Talk to Royal Cornwall Geological Society 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact General interest talk to informed lay people and professionals
Year(s) Of Engagement Activity 2021