Preliminary observations on the geology of the southern Big Salmon Range, south-central Yukon (parts of NTS 105C/13,14, 105F/4 and 105E/1)

Penetratively deformed rocks of the Yukon-Tanana terrane and Semenof block, and unfoliated Jurassic-Cretaceous intrusions are exposed in the southern Big Salmon Range of south-central Yukon. A newly mapped area, centred on the Boswell River, is divided into three structural panels by two regional-scale discontinuities, the Little Bear fault and the Sidney Creek fault. The panel on the northeastern side of the Little Bear fault includes units dominated by metasedimentary rocks (Slate Mountain succession), mafic volcanic and volcaniclastic rocks (Wiley succession), and a varied metasedimentary/metavolcaniclastic unit (Livingstone Creek succession). Each of these is crosscut by intermediate-mafic intrusions of the Simpson Range suite and is therefore Early Mississippian or older. Fossiliferous limestone is interpreted to unconformably overlie phyllite of the Slate Mountain succession. Other units that crop out in this region are Permian augen schist and Cretaceous plutons, including Late Cretaceous quartz monzonite that hosts the Red Mountain Mo porphyry deposit. The central part of the area, between the Little Bear and Sidney Creek faults, is dominated by mafic volcanic and…

Publisher

Government of Yukon

Resources

4

Catalogue metadata updated

2026-08-26