Computerized tomographic analysis of displacement trajectories and three-dimensional fold geometry above oblique thrust ramps

Abstract

Research Article| May 01, 1992 Computerized tomographic analysis of displacement trajectories and three-dimensional fold geometry above oblique thrust ramps M. Scott Wilkerson; M. Scott Wilkerson 1Department of Geology, University of Illinois, 245 NHB, 1301 West Green, Urbana, Illinois 61801 Search for other works by this author on: GSW Google Scholar Stephen Marshak; Stephen Marshak 1Department of Geology, University of Illinois, 245 NHB, 1301 West Green, Urbana, Illinois 61801 Search for other works by this author on: GSW Google Scholar William Bosworth William Bosworth 2Marathon Oil Company, Box 269, Littleton, Colorado 80160-0269 Search for other works by this author on: GSW Google Scholar Geology (1992) 20 (5): 439–442. https://doi.org/10.1130/0091-7613(1992)020<0439:CTAODT>2.3.CO;2 Article history first online: 02 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 M. Scott Wilkerson, Stephen Marshak, William Bosworth; Computerized tomographic analysis of displacement trajectories and three-dimensional fold geometry above oblique thrust ramps. Geology 1992;; 20 (5): 439–442. doi: https://doi.org/10.1130/0091-7613(1992)020<0439:CTAODT>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 SocietyGeology Search Advanced Search Abstract Computerized tomographic analysis of physical models of fold-thrust structures permits nondestructive, systematic analysis of variations in displacement trajectories and variations in three-dimensional fold geometry as a function of thrust-fault geometry. We studied models in which sand layers with embedded transport-parallel marker lines were shortened incrementally up to a maximum of 24% over rigid, footwall fault templates. These templates simulated a right- stepping oblique ramp connecting two ramps perpendicular to the shortening direction. In response to movement over the oblique-ramp templates, overturned folds formed and marker-fine deflections indicative of out-of-plane strains developed. Marker lines within layers originally truncated by fault templates were deflected leftward away from the right-stepping oblique ramp during deformation, whereas marker lines within sand layers that originally extended across the upper flat of the fault template were deflected in a more radial pattern. Differences in marker-line deflections imply that displacement trajectories within natural thrust sheets may vary as a function of overburden and structural position. Furthermore, our tomographic studies graphically demonstrate that out-of-plane strain and differential rotation of layers within thrust sheets occur in the vicinity of oblique ramps. 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.