Constraining lithologic variability along the Alleghanian detachment in the southern Appalachians using passive-source seismology

Abstract

Research Article| May 01, 2015 Constraining lithologic variability along the Alleghanian detachment in the southern Appalachians using passive-source seismology E. Horry Parker, Jr.; E. Horry Parker, Jr. 1Department of Geology, University of Georgia, Athens, Georgia 30602, USA Search for other works by this author on: GSW Google Scholar Robert B. Hawman; Robert B. Hawman 1Department of Geology, University of Georgia, Athens, Georgia 30602, USA Search for other works by this author on: GSW Google Scholar Karen M. Fischer; Karen M. Fischer 2Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Lara S. Wagner Lara S. Wagner 3Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, D.C. 20015, USA Search for other works by this author on: GSW Google Scholar Geology (2015) 43 (5): 431–434. https://doi.org/10.1130/G36517.1 Article history received: 10 Dec 2014 rev-recd: 13 Feb 2015 accepted: 20 Feb 2015 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation E. Horry Parker, Robert B. Hawman, Karen M. Fischer, Lara S. Wagner; Constraining lithologic variability along the Alleghanian detachment in the southern Appalachians using passive-source seismology. Geology 2015;; 43 (5): 431–434. doi: https://doi.org/10.1130/G36517.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Polarities and amplitudes of intracrustal P-SV conversions (P waves converted to vertically polarized shear waves) in receiver functions from the Southeastern Suture of the Appalachian Margin Experiment array and USArray Transportable Array provide new constraints on the origin of seismic reflectivity delineating the Alleghanian detachment in the southern Appalachians(eastern United States). Forward modeling of receiver functions is consistent with a 3.5-km-thick, high shear-wave velocity (Vs = 3.9 km/s) section of deformed Paleozoic platform metasedimentary rocks beneath the Blue Ridge at 3–6.5 km depth. In the Inner Piedmont, conversions from the top and base of a low-Vs zone (3.1 km/s) at depths of 5–9 km are interpreted as a package of metasedimentary rocks or a shear zone characterized by radial anisotropy. The detachment continues to the southeast beneath the Carolina terrane, where high-amplitude negative conversions at 10–13 km depth are consistent with arc rocks (Vs = 4.0 km/s) overlying sheared rocks with lower Vs (3.2 km/s). Southeast-dipping conversions at 5–10 km depth mark the boundary between the Inner Piedmont and Carolina terrane. This study demonstrates that relatively high-frequency receiver functions (up to ∼3 Hz), though still lower in frequency than P-wave energy analyzed for reflection profiling (>20 Hz), can provide important links between surface geology and active-source experiments to better constrain models of crustal structure. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.