1. Studying aerosol formation due to volcanic SO2 emission
The ongoing eruption at Holuhraun, north of Vatnajökull, has, and continuous to, emit great amounts of SO2. Estimates vary, but have been between 20 to 60 thousand tons per day. This has raised concerns regarding the pollution due to the gas, but also due to sulfuric acid (acid rain) and aerosol formation. The interest in aerosol formation related to SO2 emissions from the volcano is both from the theoretical viewpoint and because of health concerns. Theoretical questions concern for instance the rate of aerosol formation, and the health concern for instance the interplay between SO2 gas and aerosols. There are sulfur aerosols coming up with the gas at the eruption site. There is also, although less well known, formation of sulfur aerosols derived from sulfuric acid related to high sulfur dioxide concentrations. The project involves compiling scattered data that exist from various locations and sources, and using theory and modeling to explain those measurements and make predictions.
Main collaborators: Þröstur Þorsteinsson (NordVulk), Andri Stefánsson (NordVulk) and M Boy (University of Helsinki, Finland)
Area: Aerosol formation and dispersal
For more information please contact: ThrosturTh@hi.is
2. Inverting glacier dynamics for subglacial volcano-ice interaction processes
Building upon a unique, existing dataset of glacier deformation due to subglacial volcanic activity, this project focuses on utilizing a "Full Stokes" ice flow model for simulating glacier response to elevated basal geothermal heat flux. The input data sets to be used consist of many surface deformation records along with radar data revealing internal and basal changes acquired from several subglacial geothermal systems in Iceland including very recent data from the ongoing Barðabunga volcano unrest. In addition classical glaciological data such as surface and basal topography along with mass balance measurements and models are available. After establishing the forward simulation capabilities, the project will employ geophysical inversion methods building upon the developed numerical model to study subglacial volcano-ice interaction processes such as changes in geothermal heat flux magnitude and distribution over time, subglacial meltwater storage, and the influence of these subglacial volcanic systems on the dynamics of the overlying glaciers. This project combines state-of the-art numerical methods with worldwide unique data to advance the cutting edge of volcano-ice interaction process understanding. Detailed knowledge of numerical methods as well as a strong geophysics background are essential for a successful application. Postdoc as well as PhD level applications will be considered for the project.
Main collaborators: Alexander H. Jarosch (supervisor), Eyjólfur Magnússon, Magnús Tumi Guðmundsson, Finnur Pálsson (NordVulk) and Thomas Zwinger (CSC/adjunct professor Univ. Helsinki, Finland)
Area: Glaciology/Volcanology
For more information please contact: alex@hi.is
3. How deep is (are) the magma reservoir(s) beneath Hekla volcano?
Before the last eruption of Hekla, the depth to a magma chamber under Hekla was modeled, with various geophysical means, at 5–9km. Later, the crustal deformation network around Hekla was used to model a magma chamber located at 11-km depth under the summit of Hekla. Most recently, synthetic aperture radar (SAR) images acquired prior to and after the 2000 eruption, have been interpreted as the result of pressure increase in a spherical magma chamber at 14–20 km depth (Ofeigsson et al., 2011). Eruptions at Hekla produce basaltic icelandite at the end of each eruption. This magma is derived by fractional crystallization from basaltic magma (Sigmarsson et al., 1992). Clinopyroxene-melt equilibrium is temperature and pressure dependent and has been thoroughly calibrated by melting experiments. In this project, several historical tephra from Hekla will be collected in order to determine the pressure and temperature of clinopyroxene crystallization. The results should reveal the depth(s) of magma reservoir(s) beneath Hekla and its (their) possible migration during historical time.
Main collaborator: Olgeir Sigmarsson (NordVulk)
Area: Petrology
For more information please contact: olgeir@hi.is
4. Tectonic structure at the termination of the Reykjanes Ridge.
In the summer 2013 a 96000 km2 of oceanic bottom was mapped in details at the southern termination of the Reykjanes Ridge (RR). The area is a key area where the RR goes from forming a ridge into valley. Furthermore it connects with the Bight fracture zone in this area, the last active fracture zone along the entire 900 km long RR. The project involves working with bathymetry data in Caris©, magnetic data and gravity data. The dataset offers superior image quality (EM122, Kongsberg). The successful applicant will work on disentangling the tectonic structure in the area.
Main collaborator: Ármann Höskuldsson
Area: Tectonics
For more information please contact: armh@hi.is
5. Off rift volcanism in and around the Bight fracture zone
In the summer 2013 a 96000 km2 of oceanic bottom was mapped in details at the southern termination of the Reykjanes Ridge (RR). The area is a key area where the RR goes from forming a ridge into valley. Further it connects with the Bight fracture zone in this area, the last active fracture zone along the entire 900 km long RR. The project involves working with bathymetry data in Caris©, magnetic data and gravity data. Data set offers superior image quality (EM122, Kongsberg). The successful applicant shall work on the distribution of monogenetic volcanic edifices in the area and compare with on rift volcanism.
Main collaborator: Ármann Höskuldsson
Area: Tectonics
For more information please contact: armh@hi.is
6. Iron, copper and sulfur isotope systematics in volcanic hydrothermal systems
Sulfur is among the major elements in volcanic geothermal systems. It is found in the various fluids including liquid and vapor as well as in various alteration minerals like sulfides. It may have variable origin including crustal magma, mantle and source fluid and is found in all phases of the system like liquid vapor and liquid as well as primary rocks and secondary minerals. The project aims at tracing the source and reactions of sulfur in volcanic geothermal systems in Iceland in particular in relation to formation of various magmatic and geothermally formed sulfides using Cu, Fe and S isotopes.
Main collaborators: Andri Stefánsson and Sæmundur Ari Halldórsson (NordVulk)
Area: Isotope geochemistry
For more information please contact: as@hi.is or saemiah@hi.is
7. Magma hydrothermal fluid interaction in the Earth‘s crust
Magma intruded in to the crust interacts with the surrounding ground water systems resulting in formation of hydrothermal fluids commonly of meteoric or seawater origin. Such interaction may lead to contact metamorphism and elemental transport with elemental and isotope gradients from mantle to surface sources. Recent work suggest that the surface fluids may be a key part of the metamorphsm to very high temperatures or around 450-600°C, suggesting that classical contact metamorphic reactions (crustal hornfells) may be a result of magma-hydrothermal fluid interaction rather than magma-magmatic fluid interaction. In this project we aim at using isotopes to trace these contact metamorphic processes by using natural analogs from fossil magma chambers/geothermal systems of eastern Iceland and comparison with xenolithic material in the Askja 1875 eruption and the Þórsmörk Ignimbrite layer.
Main collaborators: Andri Stefánsson and Sæmundur Ari Halldórsson (NordVulk)
Area: Isotope geochemistry
For more information please contact: as@hi.is or saemiah@hi.is
8. Eruption dynamics and lava emplacement processes in a basaltic fissure eruption: A case study involving the 1961 event at the Askja volcano North Iceland.
The 1961 Askja eruption is a basaltic fissure eruption where existing data indicates a direct link between changes in magma discharge, style of fountaining at the vents and modes of lava emplacement. The principal aim of this project is to investigate and quantify these changes. This will be achieved by: (i) measuring key physical properties of the tephra fall deposit (e.g. distribution, volume, grain size and pyroclast properties) ; (ii) determining the initial and residual volatile contents via measurements of H2O, CO2, S, Cl, F in melt inclusions and groundmass glass in tephra and lava selvages from the 1961 Askja eruption in order to quantify the role of degassing-induced crystallization in modifying the properties (i.e. viscosity and yield strength) of the magma upon venting; (iii) undertake systematic textural analysis of glassy tephra and lava selvages in order to investigate the thermal history of a’a versus pahoehoe lavas during emplacement and their role in determining flow length.
Main collaborator: Þorvaldur Þordarson (NordVulk)
Area: Physical volcanology
For more information please contact: torvth@hi.is
9. Petrogenesis of the Trölladyngja lava shield
Located only a few km west of the on-going eruption in front of Dyngjujökull, the Trölladyngja lava shield represents one of Iceland’s most spectacular shield formations. With an estimated volume of about 15 km3, it is comparable to the well-studied, large-volume fissure eruptions, such as the historical Laki and Eldgjá lava flows. However, preliminary datasets available at Nordvulk suggest that, in contrast to these recent events, the Trölladyngja eruption products reveal significant chemical heterogeneity, which straddles the primitive spectrum of Icelandic basalts in general. The principal aim of this project is to unravel the magma plumbing system of the Trölladyngja lava shield through a systematic study involving (i) fluid and melt inclusions, (ii) mineralogical data (e.g., cpx geobarometry) to constrain depth of magma equilibration and timescales associated with ascent from possible deep-crustal reservoirs. A key observation in this regard is the fact that, unlike most large-volume fissure eruptions, phenocryst (ol, plag and cpx) content is significant, opening up the exciting prospect of better constraining where Icelandic magmas reside and evolve between source and surface. Additionally, the degree of heterogeneity among the mantle sources of Trölladyngja will be assessed by means of radiogenic isotopes.
NordVulk is already in possession of an extensive set of samples from Trölladyngja, and with analytical equipment that includes a new electron microprobe, MC-ICP-MS, FTIR instrument and stages for high- and low-temperature thermometry. This project has the potential of developing into a full PhD research project focused on the petrogenesis of basaltic magmas near the center of the Iceland mantle plume.
Main collaborators: Enikő Bali, Guðmundur Guðfinnsson, Sæmundur Ari Halldórsson and Þorvaldur Þórðarson (NordVulk)
Area: Igneous Geochemistry
For more information please contact: saemiah@hi.is
10. Origin of flank zone magmas in Iceland: the case of Esjufjöll and Snæfell, eastern Iceland
The initial aim of this project is centered on the petrogensis of magmas from two volcanoes, Esjufjöll and Snæfell, which are part of the Öræfajökull flank zone, and are, to a large extent covered by Iceland’s largest glacier, Vatnajökull. Preliminary dataset available at Nordvulk have shown that these two volcanoes have generated a continuous spectrum of igneous rocks, ranging from primitive basalts to rhyolites. However, the core of this project involves the use of radiogenic (Sr-Nd-Hf-Pb) and stable isotopes (e.g., oxygen) to assess petrogenetic processes responsible for generating a full spectrum of magmas, at significant distance from the active spreading axis in Iceland.
This project has the potential of developing into a full PhD research project centered on the petrogenesis of flank zone magmas in eastern Iceland.
Main collaborators: Sæmundur Ari Halldórsson (NordVulk) and Reidar Trønnes (University of Oslo, Norway)
Area: Igneous Geochemistry
For more information please contact: saemiah@hi.is
11. Intrusive growth and magma transport in central volcanoes - How do cone-sheets form?
Swarms of thousands of cone sheets, cone-shaped dykes, make up the interior of many of the eroded central volcanoes in Iceland, which stresses the significance of cone sheets in magma transport from the shallow magma reservoir. Furthermore, the abundance of cone sheets indicates that cone-sheet emplacement is an important mechanism of edifice growth. However, the dynamic emplacement of cone-sheets is still controversial.
The main aim of this 1-2 year project is to analyse cone-sheet emplacement by combining systematic structural mapping, statistical analysis, state-of-the-art 3D modelling with (for an optional 2nd year) measurements of the magnetic fabric (through AMS) in cone sheets of the Thingmuli central volcano in Eastern Iceland. The shallow magmatic plumbing system of Thingmuli is well exposed and suitable for structural field work and sampling.
Main collaborators: Morten S. Riishuus, Steffi Burchardt
Area: Structural volcanology
For more information please contact: riishuus@hi.is or steffi.burchardt@geo.uu.se