Eocene plutonism along the Denali Fault zone, AK

Map modified from Reed and Lanphere, 1974 showing the interpreted piercing point in red. Detrital zircon results from catchments draining each pluton shown in lower right. Research from our group at UAF has demonstrated that this piercing point is no longer valid.

A link between strike-slip faults and magmatism has been well documented in the field of volcanology, (e.g. Pe-Piper et al., 2005; Tibaldi et al., 2009; Mathieu et al., 2011). Given that all volcanoes have an associated intrusive-plutonic reservoir(s), there is a clear association of magmas with arc-parallel strike slip systems(not strictly on faults) by extension. However, the signature of and mechanism(s) for the transport of melt and possible fault controls on magma ascent and emplacement from the middle to upper continental crust is understudied and controversial.The well exposed suite of Eocene plutons along the Denali Fault system was emplaced synchronous with strike-slip motion along the fault (e.g. Trop et al., 2019) and our main objective is to discern if faults play a passive (pathway), active (kinematically-controlled), or no role during incremental arc pluton assembly. Hence, a geochemical, petrophysical (micro-structure and magnetic susceptibility), and geochronological spatial evaluation of Eocene plutons along the Denali Fault paired with a published thermochronologic backdrop make an ideal setting to evaluate this long-standing problem of the role(s) strike-slip faults play in pluton construction with implications for continental arc systems globally.

Eocene plutonism along the Denali Fault. Modified from S. Roeske
View of the Schist Creek pluton adjacent to the Denali Fault
Hypersolidus foliation developed in the East Susitna batholith adjacent to the Denali Fault