Our research focuses on quantifying the kinematics and dynamics of tectonic, geomorphic, and geodynamic processes using numerical numerical models in combination with field, laboratory and geophysical observations. Some current areas of interest can be found below.
Cratons are the regions that form the geological core of continents. They are largely thought to be stable over timescales of millions of years, but an emerging view suggests these regions may be more dynamic than previously thought, experiencing episodes of burial by kilometers of sediment and later exhumation. This burial and exhumation history is often studied using dating methods based on radioactive decay, but this is challenging as radioactive decay can damage crystals and variably affect the ages of dated minerals. The EXTRACT project (EXploiting Thermochronometer sensitivity to RAdiation damage to quantify rates of Craton exhumation through Time) is funded by the Research Council of Finland and aims to produce a new dataset of mineral ages from the craton in Finland (Fennoscandia) and a new numerical model that simulates the effects of radiation damage to quantify the exhumation history of the craton. Ultimately, the project will link craton exhumation to dynamic processes in the Earth and provide insight to address future societal challenges, such as possible earthquake hazards in these regions and the safe long-term storage of nuclear waste.
Though the present-day Finnish topography might lead you to believe otherwise, the rocks exposed near the surface indicate Finland was once a mountainous region perhaps similar to the Himalaya. One challenge is that much of the evidence of these ancient mountains has been eroded in the past ~1.8 billion years, leaving upper-middle crustal rocks from these ancient mountains exposed at the surface. We're investigating how to understand the evolution of the past mountain system using a combination of metamorphic pressure, temperature, and time histories and geodynamic models of Paleoproterozoic mountain building. We are also investigating possible linkages to processes related to the generation of mineral deposits, which occur across Finland.
The mechanical strength of solid rock is believed to decay exponentially with increasing temperature. In addition, even modest amounts of partial melting of rock (<10%) can lead to a reduction in rock strength by 80-90%. Thus, it is clear that the heating and melting associated with magmatic activity in the Earth will impact the strength of the crust and how it deforms. We are using numerical models to quantify the effects of the intrusion of magmas of various compositions on the integrated strength of the Earth's crust, including the effects of partial melt and the latent heat of crystallization.
The collision of tectonic plates builds mountains, however these collisions rarely occur perpendicular to the margin between two plates. Mountain growth and deformation in the crust in regions of oblique convergence thus involves components of fault motion both perpendicular and parallel to the plate margin on one or more faults or shear zones. Our group uses crustal-scale 3D geodynamic models of continent-continent collision and oblique subduction to understand how deformation is partitioned onto different faults and the implications of different partitioning scenarios for the long-term evolution of mountainous regions.
Erosional processes in mountainous regions produce sediment that moves through the landscape. Using dating methods such as thermochronology to date minerals in the sediment in mountain rivers it is possible to establish the time scale of mountain erosion. By combining these ages with numerical models we can even take a step further and begin to explore where and when sediment is generated in the landscape, as well as which erosional processes may have been dominant and their rates of activity. Current efforts on this topic aim to extract the signal of surface erosional processes from the distribution of thermochronological ages of minerals in mountain rivers, as well as establishing the possible roles other factors that may bias the age distribution, such as variations in the concentrations of datable minerals in the bedrock upstream.
Both the mechanical strength of rock and variations in the rates of surface erosional processes have been proposed to have a role in controlling the width of mountainous regions. The eastern Andes of Bolivia are one region where the width of the region of youngest mountain growth narrows significantly along strike. Unfortunately, this is also a region where there is evidence of large changes in the strength of the rocks that underly the mountains and focussed rainfall and efficient erosion. We are using 3D numerical models with variations in rock strength and rainfall intensity to explore which of these factors might explain the significant change in width of the eastern Bolivian Andes, and whether one factor alone can explain the changes in the rates of rock exhumation that are also highest within the narrowest part of the mountains.
Cosmogenic radionuclides are atoms formed within a few meters of the Earth's surface as a result of interactions between elements in rocks and cosmic rays. Because of their sensitivity to the exposure to cosmic rays, they are a valuable method for studying erosion of the Earth's surface as well as the history of surface exposure to rays between glacial periods. We are developing numerical tools to study cosmogenic radionuclide concentrations in glaciated regions across Finland, as well as how boulders transported by ice may be able to be linked to their source areas using cosmogenic radionuclide dating.
Data visualization is a key part of communicating science to the broader public, but also an important part of sharing scientific findings with the science community. HUGG contributes to geographical data visualization through the development of both visualizations and tools that can be used for data visualization and analysis. These include visualizations of earthquake data in regions of seismic activity and tools for creating swath profiles, for example.
Finally, a key part our work involves the creation and development of software for numerical modeling. We are currently in the process of migrating our software to a new repository platform and will add links once the new platform is ready. For now, you can find some of our software on the HUGG GitHub page.