NSFGEO-NERC: Physical and Chemical Constraints on Large-volume Pyroclastic Blasts: The Campanian Ignimbrite Eruption, Italy
Lead Research Organisation:
University of Oxford
Department Name: School of Archaeology
Abstract
Overview:
The Campanian Ignimbrite was emplaced from a dilute pyroclastic density current that accompanied caldera collapse of the Campi Flegrei. The currents reached over 80 km from the vent area and the fallout covers 3.5 million km2, reaching at least 2500 km from the vent. Abundant gas is needed to produce a current that was apparently more than a kilometer thick, but where did this gas come from? Recent work by the proposing team found that emplacement temperatures of the Campanian Ignimbrite were above 580oC, indicating that the current did not cool off very much during transport, which in turn implies minimal entrainment of atmospheric gases and a very short eruption duration. Magmatic gases are likely important, but very high levels of dissolved gas prior to eruption would be needed if that is the only source. Superheated hydrothermal water (estimated at 500oC at 5 km depth today) may be an additional gas source. We propose 1) detailed field investigations to better characterize the Campanian Ignimbrite stratigraphy, in order to link distal and proximal deposits and to define the relative timing of volcanic events; 2) a detailed petrologic study of Campanian Ignimbrite products, notably by performing complete volatile analysis (H2O, CO2, S, F and Cl) of melt inclusions and apatite microphenocrysts via Fourier Transform Infrared (FTIR) spectroscopy, ion probe, and electron microprobe; and 3) an experimental investigation of the cooling rates of Campanian Ignimbrite eruptive products, using a technique that studies the glass transition temperature at
varying strain rates and residual water contents.
Intellectual Merit:
We propose to test the hypothesis that sustained dilute PDCs may be driven by gas sourced from the magmatic and/or hydrothermal systems, rather than dominantly from atmospheric gases incorporated into the column and flow. This would extend our ability to forecast volcanic hazards by linking field observations and measurements to internal magmatic processes. The Campanian Ignimbrite has proximal and medial/distal deposits that are difficult to correlate. Recent advances in geochemical and magnetic techniques used to correlate the distal fallout will be applied to the ignimbrite and proximal deposits. Cooling histories of clasts will be traced using recently developed methods to analyze glass transition temperatures and rheological changes. Back-calculating volatile concentrations during open-system degassing is a new technique that should reveal much about the Campanian Ignimbrite magma history. Understanding the potential role of hydrothermal fluids in ?supercharging? an eruption would require some re-thinking of current models and interpretations of datasets, as hydrothermal water may not appear in many petrologic measurements of gases.
Broader Impacts:
The Naples area has one of the highest volcanic risks in the world, with about 4 million people living in the area that was affected by the Campanian Ignimbrite (ignoring the people living in the fallout zone - >100 million). Understanding the magmatic/hydrothermal conditions that led to such a high-mobility current would allow a better assessment of the risks as current conditions change. We will be working with personnel from the Osservatorio Vesuviano, so our results will be incorporated into their risk assessments. This proposed NSF/NERC project will foster a significant international collaboration between the US, UK, and Italy and will incorporate the education of underrepresented groups in the form of PhD/MS students and post-doctoral researchers.
The Campanian Ignimbrite was emplaced from a dilute pyroclastic density current that accompanied caldera collapse of the Campi Flegrei. The currents reached over 80 km from the vent area and the fallout covers 3.5 million km2, reaching at least 2500 km from the vent. Abundant gas is needed to produce a current that was apparently more than a kilometer thick, but where did this gas come from? Recent work by the proposing team found that emplacement temperatures of the Campanian Ignimbrite were above 580oC, indicating that the current did not cool off very much during transport, which in turn implies minimal entrainment of atmospheric gases and a very short eruption duration. Magmatic gases are likely important, but very high levels of dissolved gas prior to eruption would be needed if that is the only source. Superheated hydrothermal water (estimated at 500oC at 5 km depth today) may be an additional gas source. We propose 1) detailed field investigations to better characterize the Campanian Ignimbrite stratigraphy, in order to link distal and proximal deposits and to define the relative timing of volcanic events; 2) a detailed petrologic study of Campanian Ignimbrite products, notably by performing complete volatile analysis (H2O, CO2, S, F and Cl) of melt inclusions and apatite microphenocrysts via Fourier Transform Infrared (FTIR) spectroscopy, ion probe, and electron microprobe; and 3) an experimental investigation of the cooling rates of Campanian Ignimbrite eruptive products, using a technique that studies the glass transition temperature at
varying strain rates and residual water contents.
Intellectual Merit:
We propose to test the hypothesis that sustained dilute PDCs may be driven by gas sourced from the magmatic and/or hydrothermal systems, rather than dominantly from atmospheric gases incorporated into the column and flow. This would extend our ability to forecast volcanic hazards by linking field observations and measurements to internal magmatic processes. The Campanian Ignimbrite has proximal and medial/distal deposits that are difficult to correlate. Recent advances in geochemical and magnetic techniques used to correlate the distal fallout will be applied to the ignimbrite and proximal deposits. Cooling histories of clasts will be traced using recently developed methods to analyze glass transition temperatures and rheological changes. Back-calculating volatile concentrations during open-system degassing is a new technique that should reveal much about the Campanian Ignimbrite magma history. Understanding the potential role of hydrothermal fluids in ?supercharging? an eruption would require some re-thinking of current models and interpretations of datasets, as hydrothermal water may not appear in many petrologic measurements of gases.
Broader Impacts:
The Naples area has one of the highest volcanic risks in the world, with about 4 million people living in the area that was affected by the Campanian Ignimbrite (ignoring the people living in the fallout zone - >100 million). Understanding the magmatic/hydrothermal conditions that led to such a high-mobility current would allow a better assessment of the risks as current conditions change. We will be working with personnel from the Osservatorio Vesuviano, so our results will be incorporated into their risk assessments. This proposed NSF/NERC project will foster a significant international collaboration between the US, UK, and Italy and will incorporate the education of underrepresented groups in the form of PhD/MS students and post-doctoral researchers.
Planned Impact
The Naples area has one of the highest volcanic risks in the world, with about 4 million people living in the area that was affected by the Campanian Ignimbrite (ignoring the people living in the fallout zone ->100 million). Understanding the magmatic/hydrothermal conditions that led to such a high-mobility current would allow a better assessment of the risks as current conditions change. We will be working with personnel from the Osservatorio Vesuviano, so our results will be incorporated into their risk assessments. This proposed NSF/NERC project will foster a significant international collaboration between the US, UK, and Italy.
People |
ORCID iD |
Victoria Smith (Principal Investigator) |
Publications
Costa A
(2021)
The long and intertwined record of humans and the Campi Flegrei volcano (Italy)
in Bulletin of Volcanology
Murray, A.N.
(2021)
Determining Magmatic Volatile Contributions to the Campanian Ignimbrite, Italy
Smith V
(2023)
Handbook of Archaeological Sciences
Smith, V.C.
(2019)
NERC Scientific Facilities and Technology Ion Microprobe Facility
Vineberg S
(2023)
Insights into the explosive eruption history of the Campanian volcanoes prior to the Campanian Ignimbrite eruption
in Journal of Volcanology and Geothermal Research
Description | We have been working on the stratigraphy of the eruption deposits of the large volume Campanian Ignimbrite eruption deposits. We have generated a geochemical data to trace the deposits close from vent to the distal regions and refined the eruption sequence and dynamics during the eruption. Furthermore, we have used the composition of small blebs of melt and small apatite crystals trapped within large crystals that grew in the magma chamber to understand more about the evolution of the magmatic system and storage of the large volumes of melt. These results are summarised in three papers; one has been submitted, another is in draft form, and there is at least one other that is still to be written. |
Exploitation Route | This will allow us to refine the hazards posed by volcanoes that could generate large eruptions, and modify risk assessments. |
Sectors | Education,Government, Democracy and Justice |
Description | Community Established Best Practice Recommendations for Tephra Studies - from Collection through Analysis. |
Geographic Reach | Multiple continents/international |
Policy Influence Type | Influenced training of practitioners or researchers |
Description | IMF facility access |
Amount | £15,000 (GBP) |
Funding ID | IMF677/1118 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start |
Description | Pianeta Dinamico |
Amount | € 300,000 (EUR) |
Organisation | Government of Italy |
Sector | Public |
Country | Italy |
Start | 03/2023 |
End | 03/2025 |
Description | NSF partner |
Organisation | Northern Arizona University |
Country | United States |
Sector | Academic/University |
PI Contribution | Professor Michael Ort is the PI of the NSF part of this project. We have been working together on this project and he has 3 Masters students involved in the research. |
Collaborator Contribution | Sampling and sample processing. |
Impact | Conference presentations |
Start Year | 2018 |
Description | Natural History Museum volcano outreach event |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | We had a stand at the volcanoes public outreach event in the Natural History Museum, London on Monday 7th January. Our team had a stand focussed on 'Dating the Past', with actives and information on ways in which we date sedimentary sequences and events (such as tephrochronology, radiocarbon dating). We had a game that challenged participants to arrange 3-5 events in chronological order, e.g., building of the Egyptian pyramids, advent of farming, first ceramics; and we had slices of wood for children to work out how old the tree was when it was cut down that they could decorate. More than 180 slices were handed out and decorated. |
Year(s) Of Engagement Activity | 2023 |
URL | https://twitter.com/OxfordTephra/status/1612374919777501185 |