Convection clashes: Plume splitting beneath eastern Australia

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Geosciences

Abstract

Convection of the Earth's mantle is a fundamental dynamic process that profoundly influences the surface of our planet, affecting processes as diverse as plate tectonics, long-term sea level change, and climate. Convection requires a balance between material sinking deep into the mantle and rising towards the surface. Whilst we know that downwelling material is dominated by subducting slabs that eventually sink thousands of km into the mantle, the locations, durations, and dynamics of the required deep upwelling material are much more ambiguous. The best-known surface indication of such upwelling is intraplate volcanism (volcanism located far from plate boundaries), classically associated with plumes (or 'hotspots') of hot material rising from the lower mantle. Particularly voluminous examples of intraplate volcanism occur when the broad heads of these plumes reach the surface to produce large igneous provinces (LIPs). These LIPs affect the world's atmosphere via the release of massive amounts of gases like sulphuric acid, changing the climate with damaging effects on the ocean, atmosphere, and biology (i.e., mass extinctions). The trails of hotspot volcanoes that come after the LIP have also proved a powerful tool in discovering the past motions of tectonic plates. For these reasons, understanding the origins and evolution of intraplate volcanism is an important part of Earth science.

The classic example of hotspot intraplate volcanism is Hawaii on the Pacific plate: a series of volcanic islands and submerged undersea mountains ('seamounts') that stretches away to the northwest, becoming progressively older the further they are from the actively erupting island of Hawaii. However, intraplate volcanism on Earth is very diverse. Many localities do not fit the classic model of a hot plume rising from the deep mantle, but instead appear to have been caused by processes in the upper mantle or have a mix of deep and shallow characteristics.

For this project, the seas off Eastern Australia are an ideal region for studying the processes involved in the formation of intraplate volcanism. This region is crossed by not one, but three sub-parallel chains of intraplate volcanoes, which erupted simultaneously between 35 and 6 million years ago. These volcanoes are up to 5 km high and 100 km across, and are almost entirely submerged beneath the ocean. The long life and exceptional age progression of the chains are strong indicators of a classic deep upwelling source, but the configuration of the three chains challenges our understanding of this fundamental driving force of our planet. Neither three closely spaced plumes (~500 km apart) nor an upwelling sheet fit well with our understanding of the underlying physics: they are either unstable or are not observed in models of Earth's mantle convection. Instead, these observations suggest a deep upwelling splitting as it nears the surface, perhaps due to obstacles in the mantle, or eddies in the mantle convection.

This proposal builds on a collaboration with Australia, who has already funded a 28 day voyage (worth ~£1.8 million) to collect rock samples and carry out geophysical studies. The voyage will target the two marine chains, as well as the Louisiade Plateau (a 100,000 square km area of raised seafloor that could be a LIP) north of the Tasmantids. We will study these volcanoes using a multi-faceted approach combining chronology (to determine their ages), chemistry (to determine what type of mantle melted), and geodynamic modelling (to examine the processes in the mantle that formed the volcanoes). The geodynamic models will also be applied to the Canary and Comoros Islands (west and east of Africa, respectively) to examine the mechanisms behind intraplate volcanoes elsewhere on the planet. This project will give us significant insight into the formation of enigmatic intraplate volcanism and how material flowing from deep in the Earth's mantle interacts with obstacles as it rises.

Planned Impact

Public Engagement Impact
Our proposal has strong potential impact via outreach to schools and the general public. Marine science has a powerful natural draw in public interest: it is adventure and exploration in a sense that is rare in the modern, ultra-connected world. In an era where we travel more widely than ever before and can instantly share pictures, video, and conversation with people around the world, the ocean remains unknown, a vastness and mystery familiar to anyone who has been to the seaside. Mapping the usually unseen landscape of the seafloor and recovering rock and biological specimens from deep underwater - which we will disseminate via press releases, a public website, and videoconferences - provides an excellent opportunity to engage with the public's natural curiosity about the ocean and ocean exploration.

Having two educators sail on the 2019 voyage, and our planned outreach activities at UK schools and museums, will provide opportunities for all ages to interact with active scientists, technicians, and ship's crew and be exposed to a part of science not often taught in school. This contributes to both UK's Industrial Strategy and the Scottish Government's STEM Strategy on inspiring young people and adults to study STEM. It also contributes to the Australian government's 'Vision for a Science Nation', including closer links between schools and STEM research/professionals, and to the 'Inspiring Australia' initiative, which highlighted marine science as a key area for increased communication and engagement.

Marine Reserve Management
The bathymetry and geophysical mapping programme focuses on seamounts, a key habitat for open-ocean ecosystems, and may help identify areas of important conservation value. This is particularly significant for the internationally important Coral Sea Commonwealth Marine Reserve and will contribute to the evidence base for monitoring its geology, geomorphology, and biodiversity. The study area is almost completely unmapped, so this work will provide crucial new high-resolution bathymetry data in the Coral Sea. A small portion of the survey also falls in the Great Barrier Reef Marine Park, a World Heritage Site, for which we will also collect high-resolution bathymetric data. Our results will be disseminated to the Coral Sea and Barrier Reef agencies via our Australian project partners. This mapping will also contribute to commitments under the UN Convention on the Law of the Sea on 'the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction (BBNJ)', as well as areas under the jurisdiction of Australia and neighbouring countries. The UN is currently strengthening its commitment to preserving BBNJ, working toward a treaty to protect marine biodiversity (Preparatory Committee phase complete, Intergovernmental Conference beginning Sept 2018).

Marine Safety and Charting
Limited availability of high-resolution bathymetric mapping means that our data can also contribute to valuable information for maritime regulations and policies in areas such as updating charts, designating shipping routes, and planning search and rescue operations in remote areas. A representative from the Australian Hydrographic Office will sail on the 2019 voyage, providing that agency with direct access to the data.

Resource/Economic Impact
Hydrocarbon Maturation and Basin Evolution
Identification of a plume head impacting the lithosphere along Australia's northeastern margin could provide a critical new constraint on thermal maturation and basin evolution of central and east Australian onshore sedimentary basins, such as the Cooper, Eromanga, and East Australian Coal-Seam Gas Area. Data will be disseminated to industry via the Australian Research Council's 'Industry Transformation Research Hub' on basin genesis via our Australian Project Partners Seton and Williams.
 
Description In addition to the live videoconferencing with schools from on board the ship, material from the research voyage has been developed into two sets of curriculum-linked teaching materials (one for museum workshops, one for classroom teachers) for ongoing use to create a lasting impact. This material has been made freely available via major repository of teaching resources, available to both teacher and parents in need of resources during the covid-19 pandemic. This initiative also provided an unusual continuing professional development opportunity for a museum educator and a secondary school teacher, including first-hand experience of scientific research. As a result of participating in the live videoconferences, the museum educator reported finding that the exposure to real-time science itself, and not just the scientists, left a lasting impression on many pupils and their teachers, and that this had influenced his thinking about how one might offer further opportunities to engage with 'live' scientific research.
First Year Of Impact 2019
Sector Education,Culture, Heritage, Museums and Collections
Impact Types Cultural,Societal

 
Title RV Investigator Voyage IN2019_V04 End of Voyage (EOV) Archive 
Description Description from CSIRO: This record describes the End of Voyage (EOV) archive from the Marine National Facility (MNF) RV Investigator research voyage IN2019_V04, titled "Hotspot dynamics in the Coral Sea: connections between the Australian plate and deep Earth." The voyage took place from Cairns (QLD) to Brisbane (QLD) between August 7 and September 3, 2019. For further information please refer to the voyage documentation links below. Instruments used and data collected include: Regular measurements: Acoustic Doppler Current Profiler (ADCP; 75, 150 KHz ), Lowered ADCP (LADCP), Fisheries echosounder (EK60), Multibeam Echosounder (EM710, EM122), Sub-bottom Profiler (SBP120), Gravimeter, GPS Positioning System, Doppler Velocity Log, Temperature, Humidity, Pressure, Wind and Rain sensors, Photosynthetically Active Radiation (PAR) sensor, Precision Infrared Radiometer (PIR), Precision Spectral Pyranometer (PSP), Nephelometer, pCO2, Condensation Particle Counters (CPC), Cloud Condensation Nuclei counter (CCN), Scanning Mobility Particle Sizers (SMPS), Multiangle Absorption Photometer (MAAP), Starboard and Portside Radiometers, Radon, Ozone and Oxygen sensors, Weather Radar, Greenhouse Gas Analysers (Picarro), Infrared Sea Surface Temperature Autonomous Radiometer (ISAR), Fluorometer, Oxygen optode, Thermosalinographs (TSG), CTD, Hydrochemistry, Expendable Bathythermographs (XBTs). Voyage-specific measurements: Argo floats, Magnetometer, Bird Observations, Sea-mammal Observations. The archive for the IN2019_V04 EOV raw data is curated by the CSIRO Oceans and Atmosphere (O&A) Information and Data Centre (IDC) in Hobart, with a permanent archive at the CSIRO Data Access Portal (DAP, https://data.csiro.au/dap/), providing access to participants and processors of the data collected in the voyage. All voyage documentation is available electronically to MNF support via the local network. Access to voyage documentation for non-CSIRO participants can be made via DataLibrariansOAMNF@csiro.au. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact No notable impacts yet; onshore research is still in its early stages due to covid-19 disruption. 
URL https://data.csiro.au/dap/landingpage?pid=csiro:41558
 
Description Australian Marine Volcanism Collaboration 
Organisation James Cook University
Country Australia 
Sector Academic/University 
PI Contribution Prior to this grant (work that laid the foundations for this grant): - Expertise and intellectual input in preparing bid for shiptime funding (first applied in 2016, revised proposal funded by MNF CSIRO in 2017); led the funding application for this NERC grant for associated onshore research During this grant: - Participation (PDRA and two students) in 2019 research voyage; PDRA led volcanic sampling and description team onboard; remote input on geophysical survey lines by PI (did not sail due to maternity leave) - Implemented a UK-based version of the 'Educator on Board' programme run by MNF to embed a UK education professional in the research voyage team to videoconference with UK schools live from the ship and prepare curriculum-linked teaching materials based on the voyage - Lead on the geochemistry and geochronology analyses of the samples, including associated IODP legacy samples (currently in progress, significantly delayed by covid-19 lockdowns)
Collaborator Contribution Prior to this grant (work that laid the foundations for this grant): - Expertise and intellectual input in preparing bid for shiptime funding (first applied in 2016, revised proposal funded by MNF CSIRO in 2017, via the University of Tasmania); led funding application to the Australian Research Council for associated onshore research During this grant: - Led the 2019 research voyage (University of Tasmania), and provided the rest of the voyage science team including both experienced senior researchers and students/PDRAs (all partners) - Led further funding application to Australian IODP legacy funding for analysis of IODP samples from the Coral Sea (University of Sydney)
Impact - Publications: IN2019_V04 voyage report - Databases: IN2019_V04 voyage data in MNF repositories - Further funding: IODP legacy funding - Engagement: Educator on Board blog/social media; live videoconferencing with school from the ship; development of curriculum-linked teaching materials based on the voyage
Start Year 2016
 
Description Australian Marine Volcanism Collaboration 
Organisation University of Sydney
Department School of Geosciences
Country Australia 
Sector Academic/University 
PI Contribution Prior to this grant (work that laid the foundations for this grant): - Expertise and intellectual input in preparing bid for shiptime funding (first applied in 2016, revised proposal funded by MNF CSIRO in 2017); led the funding application for this NERC grant for associated onshore research During this grant: - Participation (PDRA and two students) in 2019 research voyage; PDRA led volcanic sampling and description team onboard; remote input on geophysical survey lines by PI (did not sail due to maternity leave) - Implemented a UK-based version of the 'Educator on Board' programme run by MNF to embed a UK education professional in the research voyage team to videoconference with UK schools live from the ship and prepare curriculum-linked teaching materials based on the voyage - Lead on the geochemistry and geochronology analyses of the samples, including associated IODP legacy samples (currently in progress, significantly delayed by covid-19 lockdowns)
Collaborator Contribution Prior to this grant (work that laid the foundations for this grant): - Expertise and intellectual input in preparing bid for shiptime funding (first applied in 2016, revised proposal funded by MNF CSIRO in 2017, via the University of Tasmania); led funding application to the Australian Research Council for associated onshore research During this grant: - Led the 2019 research voyage (University of Tasmania), and provided the rest of the voyage science team including both experienced senior researchers and students/PDRAs (all partners) - Led further funding application to Australian IODP legacy funding for analysis of IODP samples from the Coral Sea (University of Sydney)
Impact - Publications: IN2019_V04 voyage report - Databases: IN2019_V04 voyage data in MNF repositories - Further funding: IODP legacy funding - Engagement: Educator on Board blog/social media; live videoconferencing with school from the ship; development of curriculum-linked teaching materials based on the voyage
Start Year 2016
 
Description Australian Marine Volcanism Collaboration 
Organisation University of Tasmania
Country Australia 
Sector Academic/University 
PI Contribution Prior to this grant (work that laid the foundations for this grant): - Expertise and intellectual input in preparing bid for shiptime funding (first applied in 2016, revised proposal funded by MNF CSIRO in 2017); led the funding application for this NERC grant for associated onshore research During this grant: - Participation (PDRA and two students) in 2019 research voyage; PDRA led volcanic sampling and description team onboard; remote input on geophysical survey lines by PI (did not sail due to maternity leave) - Implemented a UK-based version of the 'Educator on Board' programme run by MNF to embed a UK education professional in the research voyage team to videoconference with UK schools live from the ship and prepare curriculum-linked teaching materials based on the voyage - Lead on the geochemistry and geochronology analyses of the samples, including associated IODP legacy samples (currently in progress, significantly delayed by covid-19 lockdowns)
Collaborator Contribution Prior to this grant (work that laid the foundations for this grant): - Expertise and intellectual input in preparing bid for shiptime funding (first applied in 2016, revised proposal funded by MNF CSIRO in 2017, via the University of Tasmania); led funding application to the Australian Research Council for associated onshore research During this grant: - Led the 2019 research voyage (University of Tasmania), and provided the rest of the voyage science team including both experienced senior researchers and students/PDRAs (all partners) - Led further funding application to Australian IODP legacy funding for analysis of IODP samples from the Coral Sea (University of Sydney)
Impact - Publications: IN2019_V04 voyage report - Databases: IN2019_V04 voyage data in MNF repositories - Further funding: IODP legacy funding - Engagement: Educator on Board blog/social media; live videoconferencing with school from the ship; development of curriculum-linked teaching materials based on the voyage
Start Year 2016
 
Description STEM Learning engagement collaboration 
Organisation National STEM Learning Centre
Country United Kingdom 
Sector Private 
PI Contribution - Development of curriculum-linked lesson plans related to the voyage
Collaborator Contribution - Assistance in publicising placement opportunity for education professional to join research voyage - Review/quality assessment and hosting of curriculum-linked lesson plans related to the voyage
Impact - Hosting (and increasing the reach) of a series of 7 curriculum-linked lesson for early secondary school maths and geography based on the research voyage
Start Year 2019
 
Description Scottish Maritime Museum engagement collaboration 
Organisation Scottish Maritime Museum
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution - Provided high-quality professional development opportunity for museum STEM Learning Officer to be embedded in research voyage, including supporting funding - Collaborated on development of curriculum-linked teaching materials related to the voyage
Collaborator Contribution The embedded museum staff member: - Provided expertise in communicating the voyage's scientific objectives to a range of audiences - Led public engagement (blogs, twitter, videoconferences) whilst on board ship, including using existing networks to advertise opportunity such as the videoconferences to reach a wide range of schools - Led development of curriculum-linked teaching materials related to the voyage, and in collaboration with other members of museum staff, trialed delivery of these at the museum and refined them based on that experience
Impact - Set of 6 curriculum-linked workshops for primary and early secondary pupils on STEM topics linked to the research voyage for ongoing delivery at the Scottish Maritime Museum (as covid-19 restrictions permit)
Start Year 2019
 
Description University of Melbourne - iron isotope geochemistry 
Organisation University of Melbourne
Country Australia 
Sector Academic/University 
PI Contribution - Provided sample material for analyses, expertise in choose appropriate samples, and interpretation of results in the regional context (PDRA)
Collaborator Contribution - World-leading lab for iron isotope analyses aimed at determining the source rock and melting conditions of the volcanism
Impact - Submitted paper
Start Year 2019
 
Description Research voyage social media 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Social media associated with research voyage to the Coral and Tasman Seas in August-September 2019, led by the two Educators on Board (one from the UK, one from Australia), including the official CSIRO Educator on Board blog (https://research.csiro.au/educator-on-board/category/in2019_t04/), a small University of Edinburgh based blog (https://blogs.ed.ac.uk/oceanvolcanoes/), and the UK educator's twitter account.
Year(s) Of Engagement Activity 2019
URL https://research.csiro.au/educator-on-board/category/in2019_t04/
 
Description School videoconferences from the R/V Investigator 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Over 600 pupils from 19 primary schools across Scotland attended live videoconferences with the science party on board the R/V Investigator (videoconferences led by UK-based Educator on Board) including a tour of the ship and introduction to the research being done, followed by questions and discussion afterwards. The schools reported high engagement with the sessions (and a jump in interest in being a volcanologist). Some also coordinated the session with other STEM activities and/or featured the virtual visit on their Twitter feeds.
Year(s) Of Engagement Activity 2019
 
Description Teaching Resources (Sam) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact A set of seven lessons for early secondary maths and geography was developed based on the research voyage (development led by a shore-based secondary teacher in collaboration with the PI and on board scientists; see placements). In addition to being used at the teacher's own secondary school, these resources are also freely available to teachers and others such as home-educating parents on TES (https://www.tes.com/teaching-resource/mysteries-of-the-deep-earth-exploring-australia-s-underwater-volcanoes-12360139) and STEM Learning (https://www.stem.org.uk/resources/collection/484555/mysteries-deep-earth). In trialling the lessons with his own classes, the teacher reported high levels of engagement and lots of related questions.
Year(s) Of Engagement Activity 2020,2021
URL https://www.stem.org.uk/resources/collection/484555/mysteries-deep-earth
 
Description Workshops at the Scottish Maritime Museum 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Approximately 100 pupils attended the first delivery of a set of workshops at the Scottish Maritime Museum based around the research voyage and linked to the Scottish curriculum. The set of 6 workshops were then refined based on the initial delivery experience and other museum staff were also trained in delivering the workshops for ongoing use at the museum (as covid restrictions allow).
Year(s) Of Engagement Activity 2019,2020