Evolution of the Murphy synclinorium,southern Appalachian Blue Ridge,USA |
| |
| Institution: | 1. Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA;2. Department of Physics, Astronomy, and Geosciences, Valdosta State University, Valdosta, GA 31698, USA;1. Department of Geological Engineering, Gümü?hane University, TR-29000 Gümü?hane, Turkey;2. Department of Geological Engineering, Karadeniz Technical University, TR-61080 Trabzon, Turkey;3. Rare Earth Elements Application and Research Center, Munzur University, TR-62000 Tunceli, Turkey;4. School of Physical Sciences, STEM Faculty, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK;1. Unit of Sustainable Forest Management, Department of Vegetal Production, University of Santiago de Compostela, E-27002 Lugo, Spain;2. Subdirección General de Recursos Forestales, Xunta de Galicia, E-15704 Santiago de Compostela, Spain;3. Department Forest Inventory and Remote Sensing, Georg-August-Universität Göttingen, Büsgenweg 5, D-37077 Göttingen, Germany;4. Department of Soil Science and Agricultural Chemistry, University of Santiago de Compostela, E-27002 Lugo, Spain;1. School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata, 807-8555, Kitakyusyu, Japan;2. The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, 252-5210, Japan;1. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3 prosp. Akad. Koptyuga, Novosibirsk 630090, Russia;2. Zavaritskii Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences, 7 per. Pochtovii, Ekaterinburg 620151, Russia;3. Novosibirsk State University, Department of Geology and Geophysics, 2 Pirogova str., Novosibirsk 630090, Russia |
| |
| Abstract: | The western Blue Ridge allochthon of the southern Appalachians is dominated by the >180 km-long Murphy synclinorium, paired with anticlinoria to the northwest. These are first generation, northwest overturned, doubly plunging, large amplitude and wavelength (>10 km) isoclinal folds contemporaneous with peak Neo-Acadian orogeny (Visian, ～335–345 Ma) regional metamorphism. The synclinorium folds a regional unconformity separating Neoproterozoic rift and lower Paleozoic drift sequences from a younger successor-basin sequence. Strain analysis of metaconglomerates from lithologic groups above and below the unconformity indicates coaxial, low to moderate, oblate to nearly plane strain in both groups. The synclinorium evolved via NNW-SSE-crustal shortening (～32%), combined with orthogonal NNE-SSW-sub-horizontal flow (stretching) (～35–45%) sub-parallel to the developing fold axes. Differences in metamorphic grade and paleodepth (～10–17 km) of the exposed synclinorium had essentially no effect on strain magnitudes. Retrodeformation of the embedded regional unconformity reveals a very broad synclinal warping of the rift and drift-facies units predating superposition of the Murphy synclinorium, suggesting tectonic inheritance in the latter structure's origin. The earlier mild deformation is post-Early Cambrian and may represent the only vestige of the dynamic effects of the Middle Ordovician Taconic orogeny to be found in this region. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
