Analysis of a regional middle Paleozoic unconformity along the distal southeastern Laurentian margin, southernmost Appalachians: Implications for tectonic evolution

Abstract

Research Article| September 01, 1998 Analysis of a regional middle Paleozoic unconformity along the distal southeastern Laurentian margin, southernmost Appalachians: Implications for tectonic evolution James F. Tull James F. Tull 1Department of Geology, Florida State University, Tallahassee, Florida 32306 Search for other works by this author on: GSW Google Scholar Author and Article Information James F. Tull 1Department of Geology, Florida State University, Tallahassee, Florida 32306 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1998) 110 (9): 1149–1162. https://doi.org/10.1130/0016-7606(1998)110<1149:AOARMP>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation James F. Tull; Analysis of a regional middle Paleozoic unconformity along the distal southeastern Laurentian margin, southernmost Appalachians: Implications for tectonic evolution. GSA Bulletin 1998;; 110 (9): 1149–1162. doi: https://doi.org/10.1130/0016-7606(1998)110<1149:AOARMP>2.3.CO;2 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 SocietyGSA Bulletin Search Advanced Search Abstract The highly allochthonous Talladega belt in the southernmost Appalachian orogen of Alabama and Georgia represents the most completely preserved outboard fragment of the early Paleozoic Laurentian continental margin in this part of the orogen. Palinspastic restoration indicates that this Alleghanian thrust sheet was originally located at or near this continental margin. The Talladega belt is within a structural recess (Alabama recess) in the orogen, which is interpreted to have originated as a continental promontory during the opening and initial closing of the Iapetus ocean. Because continental promontories protrude oceanward along a continental margin, any significant early deformation of this margin should be recorded within this thrust sheet. Regional geologic mapping has revealed a middle Paleozoic regional unconformity within this belt, and distortion of this unconformity by late Paleozoic regional folding provides for examination of subcrop geometries below the unconformity over a large area (∼640 km2). Retrodeformation of the late Paleozoic folds indicates that only very mild deformation predated the unconformity. The origin of this early deformation is unclear. Possibilities include very mild contractional deformation during the Taconic orogeny, or folding associated with wrench or extensional faulting during Silurian(?)-Devonian Acadian successor-basin formation. If the latter is the case, then no vestiges of Taconic deformation can be found in this outboard fragment of the margin, implying that a major continental promontory at the southwesternmost Laurentian margin may have escaped any significant effects of this orogeny. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.