Project highlights

  • Two field seasons in Deccan Traps, India logging and studying basaltic pahoehoe flows, their volcanic features and collecting samples
  • Study the volcanic stratigraphy and flow relationships to develop a method using GIS and photogrammetry, to assess the emplacement durations of basaltic flows in large igneous provinces.
  • Geochemical analysis of collected basaltic samples to aid stratigraphic correlations as well as quantifying their compositions and gas content for assessment of environmental impacts.

Overview

The Deccan Large Igneous Province (LIP) is associated with the Cretaceous-Paleogene Boundary (KPB) mass extinction event at 66Ma. However, this is not the only environmental crisis it is linked to. Petersen et al. 2016 show a regional warming and extinction event in Antarctica and Hull et al. 2020 constrain an implied major volcanic outgassing event. Both are ~250,000 years before the KPB. Such events suggest a sustained period of large volume volcanic activity. The Thakurvadi Formation in the Kalsubai Sub-group, Deccan, is a prime candidate for this.

The Thakurvadi Fm (Fig. 1a, b) is up to 600m thick and covers ~80,000km2, although its full extent is not known. The flows of the Thakurvadi form a thick, competent part of the Western Ghats Escarpment (WGE; Fig. 1a), with very few weathering horizons. This and the welded appearance of the lobes indicate rapid emplacement with little pause between eruptions. The continuous emission of gasses could have caused the environmental effect ~250,000 years before the KPB.

Fig 1a, incised cliff face approximately 1 km high, formed of multiple flat lying lava flows. The valleys are forested. Fig 1b, 2.5 m high elephants carved into pahoehoe basalt rock within a Hindu temple. Their trunks have all fallen off at mouth level along a lava flow boundary.
Figure 1a: View north along the Western Ghats escarpment, Deccan LIP, India. The entire cliff face is Thakurvadi formation. Figure 1b, Pāhoehoe lobes picked out in temple carvings, note how the elephant’s trunks have detached along a flow boundary, scale bar is ~ 1m.

Host

The Open University

Theme

  • Climate and Environmental Sustainability
  • Dynamic Earth

Supervisors

Project investigator

Dr Anne Jay, The Open University ([email protected])

Co-investigators

How to apply

Methodology

This project will involve two field seasons. The first will involve logging, photogrammetry and mapping of the Thakurvadi in the WGE to recreate the 3D volcanic architecture and volcanostratigraphy of the welded lobes and establish their size and spatial relationships. Cumulatively, this allows an estimate of the time taken to emplace the entire Thakurvadi Fm. Samples will be collected and analysed using the electron microprobe and SIMS analyses of hosted melt inclusions (pockets of magma trapped in minerals) will enable their sulfur, chlorine, fluorine, carbon and water concentrations to be quantified.

The second field season will establish whether the style of the Thakurvadi continues further east and will help confirm its association with the pre-KPB environmental perturbation. Geochemical analyses (using a combination of electron microprobe, XRF and ICP-MS techniques), particularly incompatible trace elements, will be used to confirm the presence of Thakurvadi flows by comparing their chemistry with the known chemostratigraphy. The identification and interpolation of formation boundaries will help constrain the volume of the Thakurvadi Formation.

Basic modelling will be undertaken to link the new gas emissions data to the perturbations seen 250,000 years before the KPB.

Training and skills

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.

Training will be given in:

  • Logging basaltic lava flows.
  • Basic surveying techniques.
  • Using GIS software for spatial modelling
  • Using photogrammetry and creating 3D images
  • Geochemical analytical techniques and data handling skills.
  • Planning and running a successful field trip.

The successful candidate will be encouraged to attend relevant conferences. They will also be supported in applying for a placement, and to take part in career-enhancing opportunities such as teaching, science communication and understanding policy.

Partners and collaboration

The project will collaborate with Prof. Stephen Self (University of Berkley, California) a world leading expert in the emplacement of LIPs, who will be present for at least part of the field trips. To provide expertise in India: Dr Gauri Dole (Savitribai Phule Pune University), Dr Vivek Kale at (Advanced Center for Water Resources Development and Management, Pune; India), both Deccan volcanostratigraphical experts. 2 week placement is available at CASP (Cambridge) with use of their AZTEC Mineral SEM.

Further details

Applicants should have a strong background in, and enthusiasm for, field geology. An interest in volcanology, detailed logging of stratigraphically sequences (any logging, volcanological is not necessary) and knowledge of GIS software (e.g. QGIS, ArcPro, ArcMap) would be advantageous.

The successful student will join a well-established team researching Dynamic Earth processes at the Open University  (http://www.open.ac.uk/science/environment-earth-ecosystems/research/dynamic_earth)

Please contact Dr Anne Jay, [email protected]  for further information.

If you wish to apply to the project, applications should include:

  • A CV with the names of at least two referees (preferably three and who can comment on your academic abilities)

Applications to be received by the end of the day on Wednesday 11th January 2023.

Possible timeline

Year 1

Literature review on the Deccan Traps and Thakurvadi Fm in particular. Collate information on its current extent and exposure.  First field trip to India in January/February including detailed fieldwork training with supervisors. Analyse data from fieldwork using GIS. Start analyses on glass inclusions.

Year 2

Second Field trip to India. Attend VMSG conference. Analyse data from fieldwork including geochemistry, and write up manuscript on Emplacement of Thakurvadi Fm. Use GIS to estimate volume of the Thakurvadi Fm. Two week placement at CASP.

Year 3

Finish interpretation, assess impact of Thakurvadi Fm on Pre-KPB environment, prepare thesis and further manuscripts. Presentation at an international conference. Possibly suspend PhD studies for several months to complete internship.

Further reading

Hull, P. M., Bornemann, A., Penman, D. E., Henehan, M. J., Norris, R. D., Wilson, P. A., Blum, P., Alegret, L., Batenburg, S. J., Bown, P. R., Bralower, T. J., Cournede, C., Deutsch, A., Donner, B., Friedrich, O., Jehle, S., Kim, H., Kroon, D., Lippert, P. C., … Zachos, J. C. (2020). On impact and volcanism across the Cretaceous-Paleogene boundary. Science, 367(6475), 266–272. https://doi.org/10.1126/science.aay5055

Jay, A. E., Marsh, J. S., Fluteau, F., & Courtillot, V. (2018). Emplacement of inflated Pāhoehoe flows in the Naude’s Nek Pass, Lesotho remnant, Karoo continental flood basalt province: use of flow-lobe tumuli in understanding flood basalt emplacement. Bulletin of Volcanology, 80(2). https://doi.org/10.1007/s00445-017-1189-6

Kale, V. S., Dole, G., Shandilya, P., & Pande, K. (2019). Stratigraphy and correlations in Deccan Volcanic Province, India: Quo vadis? Geological Society of America Bulletin.

Li, S., Grasby, S.E., Zhao, X., Chen, J., Zheng, D., Wang, H., Fang, Y., Zhang, Q., Yu, T., Tian, J. and Du, S., 2022. Mercury evidence of Deccan volcanism driving the Latest Maastrichtian warming event. Geology, 50(10), pp.1140-1144.

Petersen, S. V., Dutton, A., & Lohmann, K. C. (2016). End-Cretaceous extinction in Antarctica linked to both Deccan volcanism and meteorite impact via climate change. Nature Communications, 7, 9. https://doi.org/10.1038/ncomms12079

COVID-19

If respiratory and contact infection pandemic prevented overseas fieldwork the project could study the geochemical evolution of the Thakurvadi Formation by analysing pre-existing geochemical data, new geochemical and petrographically data from existing rock samples. Or a GIS could be built to analyse pre-existing data of the Deccan. If UK field work is possible, the project could focus on the physical volcanology of the extrusives of the North Atlantic Igneous Province as a comparison with the Deccan, possibly using drones to create 3D data sets. We will work with the successful applicant to build a project that interests them.