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Full-Text Articles in Physical Sciences and Mathematics
U-Pb And Hf Isotopic Evidence For An Arctic Origin Of Terranes In Northwestern Washington, Elizabeth R. Schermer, Eric A. Hoffnagle, Edwin H. Brown, George E. Gehrels, William C. Mcclelland
U-Pb And Hf Isotopic Evidence For An Arctic Origin Of Terranes In Northwestern Washington, Elizabeth R. Schermer, Eric A. Hoffnagle, Edwin H. Brown, George E. Gehrels, William C. Mcclelland
Geology Faculty Publications
New field, U-Pb, and Lu-Hf zircon data constrain the geologic history, age, and origin of the Yellow Aster Complex (YAC) in northwestern Washington, providing insight into the tectonic history of this and related Paleozoic arc terranes of the western North American Cordillera. Mapping shows that the oldest YAC rocks consist of quartzofeldspathic paragneiss (meta-arkose) and quartzose calc-silicate paragneiss (metacalcareous siltstone) in gradational contact. Paragneisses are cut by syn-tectonic and post-tectonic intrusions and faulted against granitic orthogneiss. U-Pb zircon results show that (1) maximum depositional ages of paragneisses are Silurian to Early Devonian (432– 390 Ma); (2) detrital zircons from quartzose …