Abstract: Two tills and related deposits are the products of at least two ice advances over the Tintina Trench near Ross River, Yukon Territory. These ice advances are termed the McConnell and pre-McConnell glaciations. Erosional remnants provide evidence of the pre-McConnell glaciation and indicate that the ice was flowing to the west or northwest. The onset of McConnell glaciation was marked by an early ice advance out of the Lapie River valley, which was followed by a general ice flow toward the west or northwest along the Tintina Trench. During the retreat of the McConnell glacier, an ice tongue advanced up the Lapie River valley, blocking the drainage and forming a glacial lake.

To develop and apply drift prospecting techniques in the Tintina Trench, 204 till samples were collected over the study area. The silt plus clay size fraction was analysed for Au and the clay fraction was analysed for 30 elements. Only Au, Ag, Hg and Sb results are discussed in this paper. The geochemical data for till down-ice from the Grew Creek Au-Ag mineralization (MINFILE 105K 009) show a dispersal train for gold, but not for pathfinder elements such as Ag, As, Hg and Sb. A possible relationship between Au and Tertiary volcanic rocks is illustrated. However, closer-spaced samples would have to be taken to verify this hypothesis, since the length of the Au dispersal train is about 500 m, much smaller than the sampling interval.

Authors: Plouffe, A. and Jackson, L.E., Jr.

Citation: Plouffe, A. and Jackson, L.E., Jr., 1992. Drift prospecting for gold in the Tintina Trench. In: Yukon Geology Volume 3, T.J. Bremner (ed.), Exploration & Geological Services Division, Indian & Northern Affairs Canada, p. 196-213.

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