Abstract: This study presents geochemical and isotopic analyses of supracrustal and igneous rock from the Money klippe in southeastern Yukon in order to constrain the tectonic evolution of the pericratonic Yukon Tanana terrane. Samples from the supracrustal Nisutlin assemblage indicate that while some rocks are similar to the North American miogeocline, juvenile material also contributed to the Nisutlin provenance. These data support models indicating that the Nisutlin assemblage formed as a distal portion of the miogeocline. Some of the samples from the mafic Anvil assemblage have geochemical characteristics of calc-alkalic basalt, which does not support the correlation of the Anvil assemblage to the ocean floor-dominated Slide Mountain terrane. Geochemistry indicates that the Simpson Range plutonic suite (SRPS) is the product of calc-alkalic continental arc magmatism. U-Pb dating of zircons shows that all SRPS rocks were formed between 344 and 360 Ma. Inherited zircon of broadly Proterozoic age, ND model ages (T (sub DM) = 1.67 to 2.10 Ga), initial Sr ratios (super 87) Sr/ (super 86) Sr = 0.7074 to 0.7099), and (super 207) Pb/ (super 204) Pb, (super 206) Pb/ (super 204) Pb, and (super 208) Pb/ (super 204) Pb ratios in excess of those of the uniform reservoir all show that older crust has contributed significantly to the petrogenesis of the SRPS, although to varying amounts, perhaps depending on the thickness of the intruded crust. These studies are compatible with a model which suggests that the Yukon Tanana terrane consists in part of a Devonian-Mississippian fringing arc built on the distal portion of the North American miogeocline.

This thesis is available online at https://doi.org/10.7939/R3BR8MR3B. A copy of this thesis is available at the EMR library – QE195 G73 1997.

Authors: Grant, S.L.

Citation: Grant, S.L., 1997. Geochemical, radiogenic tracer isotopic, and U-Pb geochronological studies of Yukon Tanana Terrane rocks from the Money Klippe, southeastern Yukon, Canada. MSc Thesis, University of Alberta, 177 p.