GEOLOGY

Lone Tree has historically been classified as an Eocene distal-disseminated system. Mineralization is largely structurally controlled along the N-S striking Powerline fault. Additionally, mineralization is located between the Roberts Mountain and Golconda thrusts in siliciclastic rocks of the Ordovician Valmy Formation and in the Pennsylvanian-Permian Battle Mountain and Edna Mountain Formations, and above the Golconda thrust in siliciclastic and carbonate rocks of the Mississippian to Permian Havallah sequence. Mineralization is also hosted by Eocene rhyolitic dikes, although no large intrusive body has been delineated. The gold is associated with sericitic and argillic alteration of the siliciclastic rocks and dikes and with decarbonatization and Fe carbonate alteration of the carbonate-bearing units, as well as in Fe-As sulfide and fine grained quartz alteration of all rock types. Oxidation affects 30-45% of the deposit, penetrating into the stratigraphy along numerous steeply dipping north-south, east-west, and north-northeast–south-southwest structures.