Research

EXTREME (ERC Funded)

The EXTREME project quantifies how the 3D properties (e.g., geometric stiffness) of plate subductioninfluence deformation in the overriding plate and how this deformation then influences the evolution of climate and erosion. These objectives encapsulate cutting edge interdisciplinary Earth System Science research by linking atmospheric and solid Earth processes. Within the duration of this project we will: (1) develop state of the art linked atmospheric, surface processes, and thermomechanical models that utilize advances in cutting edge high performancecomputing, and (2) collect new, and integrate existing, thermochronometer and cosmogenic isotope observations of deformation and erosion along transects parallel and perpendicular to the strike/geometry of plate corners.

This project challenges the geoscience ‘tectonic aneurysm’ paradigm that rapid deformation and erosion at plate corners is initiated from the “top down” by localized precipitation, and erosion. Rather, we hypothesize that these processes are 1) initiated from the “bottom up” by the 3D geometry of the subducting plate; and 2) require a threshold rate of both “bottom up” deformation and surface erosion to initiate a feedback between climate and tectonics.

Working Hypotheses Evaluated:

1. Rapid erosion, deformation, and high topographic relief at plate corners are initiated by the 3D geometry of the subducting plate as well as the evolution of paleoclimate during topographic development.
2. The geometry of subduction, rheology of the upper and lower plates, and paleoclimate must exceed threshold conditions, or tipping points, to develop a positive feedback between climate and tectonics.

EarthShape (DFG - SPP 1803)

A common Geoscience paradigm holds that the Earth surface is shaped mainly by climate (eroding soil) and tectonics (building mountains). The EarthShape project challenges this paradigm to explore how in addition biologic processes form soil, influence topography, and thereby shape the Earth surface and modulates the impact of climate change on the Earth surface. The influence of microorganisms, plants, and animals on the formation of soils and the shape of topography is still poorly understood, but new scientific technology now allows to identify their role. Research into biologic controls on topography is particularly important for understanding how future climate and biologic changes will impact the Earth’s surface.

Scientific Goals:

The scientific goals of the EarthShape program are to investigate four linked processes and one modeling cluster. Individual projects within the EarthShape project are encouraged to investigate one or more these components in the Chilean field sites. For details see webpage at www.earthshape.net.

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Alpine Glaciers and Continental Ice sheets

Ice sheets and glaciers form the landscape by eroding material at their base. The vast majority of today's freshwater reserves is locked up in the Greenlandic and Antarctic ice sheets. In the last glacial, North America and Scandinavia were also covered by ice, and alpine glaciers extended much longer into adjacent valleys than what is observed today. We study the impact of glaciers and ice sheets on the landscape evolution using observations from LiDAR, RADAR, thermochronology, and cosmogenic isotopes. These observations are interpreted using paeloclimate modelling over glacial/interglacial cycles, coupled with theoretical simulations about glacier mechanics, sedimentation, and erosion.

Our research group is interested in applying our knowledge of active tectonics, climate change, and surface processes to address societally relevant problems. To do this, we employ a mixture of remote sensing/GIS, geologic, and geophysical techniques to understand a range of geologic hazards. Ongoing studies we are active in include:

1. The Central Asia Fault Database (CAFD) allows users to access information on active faults that are located in Central Asia and the surrounding regions. The interactive map displays two different datasets related to seismic hazards in Central Asia including (1) 1196 faults that are linked to an online database that displays detailed information and references about each fault, and (2) the locations of historic earthquakes. The database search tool permits simple search options (e.g., by fault name or location) and more complex queries (e.g., by seismic and structural characteristics). Ongoing research related to this involves including other geologic hazards (e.g. mass wasting, extreme climate events) into the database. Users can download data formatted for use in ESRI ArcMap (.shp) and Google Earth (.kml). For education and outreach materials related to this project, please click here.

2. Rockfalls are one of the principal mechanisms of erosion in alpine landscapes. The steep limestone walls of the Lauterbrunnen Valley located in the Bernese Oberland, Switzerland, experience many rockfalls each year. Using an Optech ILRIS-LR terrestrial light detection and ranging (lidar) scanner, our research group has been documenting the timing, location, and volume of rockfalls as well as ice volumes from frozen waterfalls since 2012. From these observations, we derive modern and long-term rates of rock wall retreat, calculate correlations with environmental triggers of rockfall, and investigate the role of fractures in rockfall events.