GSA Bulletin: Structural and kinematic evolution of the Yukon-Tanana upland tectonites, east-central Alaska: A record of late Paleozoic to Mesozoic crustal assembly: Discussion and Reply: Discussion
We welcome the efforts of Hansen and Dusel-Bacon (1998) in synthesizing sparse and apparently inconsistent structural data sets from widely separated areas of the poorly exposed Yukon-Tanana Uplands. However, we consider that credible extrapolation of such a synthesis southward to include a 300 × 80...
| Main Authors: | , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1045.5294 http://www.d.umn.edu/dees/research/planetaryLab/documents/HansenOliverGSAB.Reply1999.pdf |
| Summary: | We welcome the efforts of Hansen and Dusel-Bacon (1998) in synthesizing sparse and apparently inconsistent structural data sets from widely separated areas of the poorly exposed Yukon-Tanana Uplands. However, we consider that credible extrapolation of such a synthesis southward to include a 300 × 800 km region of the Canadian Cordillera is unwarranted. We clarify here points of terrane definition and discuss the implications for tectonic models for the Yukon-Tanana terrane in the Canadian Cordillera. TERRANE AND ASSEMBLAGE CLARIFICATIONS The emplacement of allochthonous terranes (upper plate) over parautochthonous North America (lower plate) has been known for decades from the recognition of obvious klippen of Slide Mountain and YukonTanana terranes resting on North American strata (e.g., Sylvester allochthon and St. Cyr and Stewart Lake klippen, The metamorphic-structural focus of the Hansen and Dusel-Bacon study diverts attention from the fundamental geological criteria of terrane definition: rock types and protoliths, ages and contact relationships. Ideas of Hansen and Dusel-Bacon (1998) appear to be an outgrowth of those presented by |
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