A Late Cretaceous polygonal fault system in central North America

Abstract

Research Article| May 01, 2017 A Late Cretaceous polygonal fault system in central North America Andy St-Onge Andy St-Onge 1PFS Interpretations Ltd., 427 28 Avenue NW, Calgary, Alberta T2M 2K7, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Andy St-Onge 1PFS Interpretations Ltd., 427 28 Avenue NW, Calgary, Alberta T2M 2K7, Canada Publisher: Geological Society of America Received: 23 May 2016 Revision Received: 28 Oct 2016 Accepted: 04 Dec 2016 First Online: 06 Jul 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2017 Geological Society of America GSA Bulletin (2017) 129 (5-6): 582–593. https://doi.org/10.1130/B31582.1 Article history Received: 23 May 2016 Revision Received: 28 Oct 2016 Accepted: 04 Dec 2016 First Online: 06 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Andy St-Onge; A Late Cretaceous polygonal fault system in central North America. GSA Bulletin 2017;; 129 (5-6): 582–593. doi: https://doi.org/10.1130/B31582.1 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 SocietyGSA Bulletin Search Advanced Search Abstract Polygonal fault systems (PFS) have been interpreted worldwide using seismic data imaging sedimentary strata. Normal faults initiate over a large area in fine-grained subaqueous strata soon after deposition. As they continue to grow laterally and vertically, their fault traces intersect to form polygons in plan view. These polygons are difficult to image without three-dimensional (3-D) seismic data. The faulting is initiated during sediment dewatering and mud particle consolidation that can be independent of external stresses. In the past 20 years, hundreds of basins worldwide have been interpreted to contain polygonal faults.This paper presents a PFS interpretation for fine-grained sediments deposited in the Late Cretaceous Western Interior Seaway of the Great Plains of North America. The faulted strata have been observed as a PFS at depths ranging from ∼2750 m subsurface to outcrop. Seismic dataset interpretations and borehole analyses corroborate previously published outcrop analyses and seismic interpretations. The larger observed faults are mesoscale in size, with throws up to 80 m, and strike lengths up to ∼1.5 km. Potentially encompassing over 2,000,000 km2, observational averages imply 107 or more mesoscale-size faults, with an order of magnitude greater number of smaller faults. At shallow depth and outcrop, the PFS model of extensive normal faulting could help to explain Late Cretaceous shale faulting attributed to other causes such as deeper sediment dissolution or glacial processes. In the subsurface, faulting and fracturing consistent with a PFS model can help to explain fault geometries observed in well control and 3-D seismic data. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.