Position
1. Project Title / Job Position title: Geodynamic evolution of the deep magmatic system of ocean volcanoes
2. Area of Knowledge: Physical Sciences, Mathematics and Engineering
3. Group of disciplines: Earth Sciences
4. Research project / Research Group description:
This research project aims to define the behaviour of the deepest part of the magmatic systems of oceanic volcanoes over time. The accumulation of dense mafic phases over time due to repeated magmatic intrusions determines the crustal accretion that brings about the end of magmatism. It would also determine gravitational instability and cause isostatic collapse of the entire volcanic system.
The eventual detachment of the dense part of the magmatic system and its sinking into the mantle could be the cause of the reversal of isostatic motion and the resumption of late magmatic activity along faults.
These dynamics are very well illustrated in the Azores and the Canary Islands. In the former case, islands older than 2 Ma show positive isostasy, while all other, younger islands are subsiding.
In the case of the Canary Islands, the young western islands show frequent magmatism and a total crust thickness > 30 km, the central islands are volcanically inactive or quiescent, while the older deeply eroded eastern islands, show a new recent phase of late magmatism along N50° faults.
This study will therefore include products from Santa Maria Island (Azores), Lanzarote and Fuerteventura islands (Canary) and the Taburiente volcano (La Palma Island, Canary). It will be carried out partly in the laboratories of the Instituto de Investigação em Vulcaologia e Avaliaçao de Riscos and partly in the laboratories of the Laboratoire Magmas et Volcans, Université Clermont-Auvergne (France) and the Istituto Nazionale di Geofisica e Vulcanologia - Naples section (Italy)
The methods to be used include 1) microthermometry of fluid inclusions; 2) microthermometry of glassy inclusions (Fourier-Transform Infrared Spectroscopy, Raman spectroscopy, electron microprobe, SIMS, Laser Ablation-ICPMS); 3) Whole rock and isotopic analysis (mass spectroscopy)
The expected results will highlight the influence of several kilometres of ultramafic crystal mush at the base of the crust and provide an explanation for the isostatic movements of oceanic islands over time and the late resurgence of magmatism, with an alternative model to the mantle plume.
5. Job position description:
The candidate will be integrated into the “Vulcanologia Física e Magmatismo” unit of the Instituto de Investigação em Vulcanologia e Avaliação de Riscos (IVAR) of the University of the Azores, Portugal.
The Portuguese laboratory is equipped for the preparation and petrographic study of samples. There is a Linkam stage for microthermometry of fluid inclusions. This part of the work will occupy 50% of the analytical part, with the study of a large quantity of samples.
The remaining analytical work will be carried out in specialised laboratories in France and Italy through active collaboration.
The candidate should have the following characteristics and scientific knowledge:
- Manual ability to handle sub-millimetre crystals;
- Patience, extreme neatness when working in the laboratory, excellent organisation to keep to the study schedule, flexibility to adapt to the analytical schedules and availability of the various laboratories involved through time;
- Must also have initiative in research management and self-management skills;
- Excellent knowledge of English and optionally French is required;
- A good background in optical petrography is required, as well as knowledge of igneous petrology and mineralogy.
Group Leader
Dr. Vittorio Zanon