Abstract: In this paper, we present a preliminary assessment of the lithogeochemical characteristics of meta-volcanic rocks in the Finlayson Lake region. Unit 2 mafic meta-volcanic rocks are subdivided into three suites: 1) low Ti tholeiites and boninites (suite 2a); 2) transitional (oceanic island basalt, OIB?), Light Rare Earth Element (LREE) -enriched tholeiites (suite 2b); and 3) normal mid-ocean ridge basalts (suite 2c; N-MORB). Suite 2a has similarities to rocks formed in ancient suprasubduction zone ophiolites and in forearcs in modern intraoceanic arcs. Unit 3 felsic meta-volcanic rocks comprise two subdivisions: 1) a low Eu/Eu*, Zr/Y, and Ce/Yb N suite (3a); and 2) a higher Eu/Eu*, Zr/Y and Ce/Yb N suite (3b). All unit 3 felsic meta-volcanic rocks have calc-alkalic continental arc signatures. Meta-basaltic rocks of the Campbell Range belt (CRB) fall into three suites: 1) moderately LREE enriched E-MORB type rocks (CRB 1 ); 2) LREE depleted N-MORB t ype rocks (CRB 2 ); and 3) a high Mg#, High Field Strength Elements (HFSE) and LREE-enriched tholeiitic suite (CRB 3 ). All CRB meta-basaltic rocks have features consistent with generation in an ocean basin and/or back-arc/marginal basin setting. The most prospective suites for volcanogenic massive sulphide mineralization in the Finlayson Lake region are 2a, 3a, and CRB 1 and CRB 2 .

Authors: Piercey, S.J., Hunt, J.A., and Murphy, D.C.

Keywords: igneous petrology, volcanic stratigraphy

NTS Mapsheet(s): 105G

Citation: Piercey, S.J., Hunt, J.A., and Murphy, D.C., 1999. Lithogeochemistry of meta-volcanic rocks from Yukon-Tanana Terrane, Finlayson lake region, Yukon: Preliminary results. In: Yukon Exploration and Geology 1998, Roots, C.F. and Emond, D.S (eds.), Exploration and Geological Sciences Division, Yukon Region, Indian and Northern Affairs Canada, p. 125-138.

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