High-temperature, low-pressure metamorphism in the Kisseynew domain, Trans-Hudson orogen: crustal anatexis due to tectonic thickening?
The Kisseynew domain within the central Trans-Hudson orogen constitutes a high-temperature (T) and low- to mediumpressure (P) metasedimentary belt characterized by uniform peak metamorphic conditions of 750 ± 50 °C and 56 kbar (1 kbar = 100 MPa). To investigate the thermal evolution of the Kisseynew domain 1-dimensional thermal modelling was conducted for a range of thermal parameters, including the effects of exhumation and incorporating current information about the crustal architecture. The results show that tectonic thickening of the sedimentary pile to ~40 km, consistent with present-day thickness estimates and erosional levels, is capable of producing enough crustal heating to melt the base of the sedimentary pile, advect heat to shallower crustal levels, and produce the observed PT conditions. Deep-seated mantle heat sources, though not excluded, are not required.