Transport and emplacement of granitoids

Over the past three decades, a growing amount of research has determined that granitoid plutons are constructed incrementally, heterogeneous at all scales, and the result of multiple end member lithospheric reservoirs. Teasing out petrogenetic mechanisms responsible for the production of heterogeneity during magma transport and emplacement requires linking potential syn-kinematic and post emplacement structural contributions to geochemical and isotopic attributes in an igneous system. Transport of igneous material through the crust is dependent on several factors including lithologic rigidity, strength of contact between layers, stress orientations, and to a lesser extent diapirism. Melt flux and conductive heat loss will in turn control the longevity and partial melt content of a growing plutonic system, limiting intrapluton hybridization and fractional crystallization. It follows that all plutonic systems vary, and attributing petrologic response(s) to unique catalysts persists as a major challenge in determining cause and effect in any one plutonic system. My research on pluton growth and possible structural controls is focused on two main general processes: 1) the role of extensional strain to accommodate granitic plutonism in the middle continental crust (Adirondack Mountain research and Para autochthonous North America structurally below accreted terranes of the Yukon Tanana terrane), and 2) Eocene plutonism along the Denali fault focused on determining the viability of a long-lived and lithospheric-scale structure to tranport arc magmas vertically through the crust.

Student Jalen Cox and Sean Regan collecting a sample from the Eocene Schist Creek pluton positioned along the Denali Fault
Disrupted migmatitic xenoliths in a leucogranitic intrusion – northern SK.

Locations:

Eocene plutonism along the Denali Fault

Lyon Mountain granite – Adirondack Mountains