Structural paragenesis of the Pogo Deposit, Alaska

Challenge:
The overall paragenetic evolution and processes responsible for gold introduction and remobilisation at Pogo remain poorly constrained.

Aim:
To document the successive stages of gold introduction and their spatial relationships, to better understand the formation of high-grade gold mineralisation at Pogo.

Approach:
The study combines detailed structural analysis, petrography, and in-situ geochemical, isotopic, and nanoscale investigations to establish a metallogenic model for the deposit.

Expected Outcomes:
Define the structural architecture and mineral paragenesis of the deposit, determine their relationship to gold distribution, and evaluate whether Pogo’s endowment reflects multiple mineralising events or progressive refinement of a single episode. The results will refine understanding of the deposit’s evolution and inform future exploration strategies.

Context:
The Pogo Au deposit is the largest gold occurrence in eastern interior Alaska. Gold mineralisation is hosted in quartz veins within biotite–quartz feldspar orthogneiss and paragneiss of Devonian to Carboniferous age. Deformation across the region is complex and spans from the mid-Palaeozoic to the Early Cretaceous, with vein formation interpreted to be paragenetically late and associated with regional extension. Quartz veins at Pogo vary in texture and thickness and contain sparse sulfides (<1%), including pyrite, pyrrhotite, and arsenopyrite, with gold commonly associated with bismuth and tellurium phases. Gold occurs in several paragenetic stages, from fine-grained inclusions in early quartz and arsenopyrite to coarser grains in later high-grade veinlets.

Involvement

Project Coordinator:

• Nico Thébaud

Investigators:

• Alex Edgar

Additional Information

Participating Partner Research Orgs: USGS Curtin University

Industry Participants: Northern Star