Modelling Partial Melting in the Himalaya and Trans-Hudson belts
Anatectic melts can be viewed as the end product of peak Barrovian-type metamorphism in continent-continent collisional orogens and serve as a record of the spatial distribution of thermal energy and internal heat production. The generation, emplacement and crystallisation of anatectic melts have important implications for the distribution of strain during the making of collisional mountain belts, such as the Himalaya and the Canadian Trans-Hudson orogens. Hall Peninsula, Arctic Canada exposes a superb section of crustal anatexis in the exhumed core of the Precambrian Trans-Hudson, with melt generated along several reaction pathways during continued collisional tectonics. Whereas the Greater Himalayan Sequence in northern Nepal exposes the partially molten middle crust of an active orogeny that offers researchers the chance to compare old orogenic belts with active tectonic characteristics i.e. seismogenic depth, far-field strain distribution, magnetotellurics, satellite interferometrics.
With the data and samples collected in the field we use thermodynamic modelling to constrain the mineral reactions and reaction pathways that have produced what is observed in the field. Some questions the project aims to answer are: (1) to what extent does partial melting weaken the middle-crust? (2) How does the segregation and crystallisation of melt strengthen the middle crust? (3) What is the timing and duration of partial melting in collisional belts and does melt composition have an effect on the source retention of partial melts? (4) What are the thermodynamic and kinetic controls on melt generation and migration? (5) What controls the depletion of melt reservoirs ? are all high-grade migmatitic paragneisses restitic?