Lead


Lay summary
This ProDoc project is for a multi-year, interdisciplinary study of the Tertiary Adamello batholith in the southern Alps. Detailed studies on exposed batholiths can provide a crucial link between geophysical observations, geochemical studies in active arcs and processes in magma chambers of active volcanoes. We will address key questions such as: what is the rate and mechanism of batholith growth at convergent plate boundaries ? What are the processes that allow magmas to segregate from its source and migrate upwards ? What are the required rheological boundary conditions for successful models of batholith emplacement in the upper crust ? How is the regional deformation regime controlled by the emplacement of mafic to silicic magmas and how do internal and external stress fields interact in space and time ?Our research goals are to (1) conduct detailed investigations on mafic to intermediate plutonic rocks to determine the 3-dimensional arrangement of fractionation levels in the crust; (2) to accurately determine the emplacement of single magma batches, identify and date accessory phases and thereby better constrain how much of the magmas are crystallizing during decompression and how much might crystallize in-situ; (3) conduct major, trace and isotopic analysis, to delineate how many different liquid lines of descent are represented in the Adamello batholith, which are the volumetrically most important ones, and which can be related to, or are similar to syn- to post-plutonic dike generations; (4) make systematic determinations of T-P-X in contact metamorphic silicic rocks to ultimately quantify the contact aureole in 3-D and use these data as input data for high resolution thermomechanical modelling of the Adamello plutonic rocks; (5) to use the 3-dimensional dataset as initial and boundary conditions for creating detailed high-resolution 3D numerical models, and to provide constraints on the density and viscosity structure of the middle and lower crust during and after cessation of arc magmatism; and (6) to provide boundary conditions to understand subvolcanic magma chambersOur teaching goals are (1) to establish a new program for the formation of PhD students by combining present expertise in solid Earth Science in Switzerland into a single doctoral school aiming at formally integrate inter-disciplinary approaches to Earth sciences at the highest level of education and research. Thereby a significantly larger return on the investment is expected than from the sum of individual projects.