Geological setting of retrogressed eclogite and jade in the southern Campbell Range: Preliminary structure and stratigraphy, Frances Lake area (NTS 105H), southeastern Yukon.
Description
The southern Campbell Range is underlain by greenschist facies volcaniclastic, epiclastic and sedimentary units of the Tuchitua River and Money Creek formations. Stratigraphy is deformed by at least three syn- to post-Early Permian folding events. Northwest-striking, high-angle faults imbricate the folded metasedimentary package with sheets of serpentinite. These rocks are juxtaposed against basinal rocks of the Fortin Creek group, to the east, along the Jules Creek fault.
Coarse-grained quartz-muscovite schist with lenses of retrogressed eclogite occurs within serpentinite and also in immediate fault contact with greenschist facies Tuchitua River and Money Creek metasedimentary rocks in the western field area. At the King Arctic mine, nephrite jade is the result of metasomatic replacement of Money Creek chert-pebble conglomerate and serpentinite by microcrystalline tremolite-actinolite along late high-angle faults.