The NTS is a large-scale alteration/deformation zone within the Red Lake Greenstone Belt and is one of three principal areas within the Belt recognized for widespread iron-carbonate alteration. The other two principal areas exhibiting similar geological characteristics are the Red Lake Mine and the East Bay Deformation Zone – host to Rubicon's Phoenix zone. The scale and style of alteration within the NTS is considered to be associated with large, multi-stage hydrothermal systems with sources deep in the earth's crust. High-grade gold mineralization is associated with silica, sulphide minerals, and magnetite replacement of the iron-carbonate zones. These high-grade zones can often form distinct lenses or shoots of high-grade gold mineralization with extensive down-dip continuity and are often associated with wider zones of lower-grade gold mineralization.