Metamorphism and Polyphase Deformation of the Zinc Sulfide Orebodies of the Balmat-Edwards Mining District, NW Adirondacks, NYS. A Record of Shawinigan through Ottawan Orogenic Events In the Grenvillian Orogenic Cycle
High temperature remobilization postdates earlier deformation of perhaps early Shawinigan age or older and may have occurred late Shawinigan. Grenvillian cooling paths for the Lowlands suggest that perhaps as much as 200 million years may have elapsed between remobilization and development of durchbewegung textures, perhaps during Ottawan time.
Shear folds of durchbewegung ore exhibit pervasive top-side-East asymmetric senses suggesting bulk transport consistent with Lowlands rocks having been thrust back towards the Adirondack massif, again during Ottawan time. The last major deformational phase produced the Sylvia Lake syncline, a nappe-like fold hosting the orebodies of the Balmat-Edwards district and one of several responsible for the NE-SW regional grain of the Lowlands. Tentative correlation of these folds with dated events in the BLSZ suggests a major Ottawan component of deformation in the Lowlands.