Owen Davis, BSc

O. Davis¹, B. Lafrance^1 
1Harquail School of Earth Sciences, Laurentian University, Sudbury, Ontario, Canada 

The aim of this project is to characterize the lithologies, structures, and alteration mineral assemblages along a newly exposed segment of the Larder Lake-Cadillac Deformation Zone (LLCDZ) along strike and within the footprint of the world-class Kerr-Addison gold mine in the southern Abitibi subprovince, Ontario, Canada. The LLCDZ straddles the contact between metavolcanic rocks of the ca. 2705 Ma Larder Lake Group and metasandstone of the ca. 2676 to ca. 2669 Ma Timiskaming assemblage. Structural mapping along this new segment suggests that folding of the Timiskaming metasandstone north of the LLCDZ is associated with the formation of a regional east-west striking cleavage. This cleavage is more pronounced and parallel to bedding adjacent to the LLCDZ and becomes the main structure within mafic and ultramafic metavolcanic rocks of the Larder Lake group along the LLCDZ, where it is parallel to lithological contacts. A steeply plunging (~65 to the east) mineral stretching lineation lies along the cleavage and formed during dip-slip movement along the deformation zone. Later dextral transcurrent reactivation of the LLCDZ produced narrow shear zones with a shallowly-plunging mineral lineation, S-C fabrics, and steeply-plunging Z-shaped folds. Mineralized quartz veins cut across the cleavage in the Timiskaming metasandstone but are also folded, suggesting that they were emplaced during deformation. This well-exposed segment of the LLCDZ is easily accessible and promises to become a regular stop during field trips across the Abitibi.