Geology of the Takhanne River (NTS 115A/2) and Kluhini River (115A/7) map areas, southwest Yukon

Bedrock mapping of the Takhanne River (NTS 115A/2) and Kluhini River (NTS 115A/7) map areas in southwest Yukon extends previous mapping of the Coast plutonic complex from the Haines Junction area south to the British Columbia border. The area is characterized by deformed and metamorphosed rocks of the Yukon-Tanana terrane and other Paleozoic to Mesozoic rocks that occur as roof pendants within the Paleocene Ruby Range plutonic suite. Yukon-Tanana rocks appear to be thrust over the Paleozoic to Mesozoic rocks to the west, possibly during Late Cretaceous shortening. Metamorphic mineral assemblages indicate a southwest decrease in metamorphic grade with rocks of the Yukon-Tanana terrane showing P-T conditions of 635-655oC and 6.3-7.9 kbar and rocks in the southernmost part of the study area exhibiting relatively low (~3.5-4 kbar) pressures related to intrusion of the Ruby Range suite. The regional stratigraphic relationships of the Paleozoic to Mesozoic rocks in the study area are not well constrained. They may be related to one of three regionally significant units: 1) the Jura-Cretaceous Dezadeash Formation; 2) the Triassic and older Bear Creek assemblage; or 3) the Kluane schist.