Neotectonic joints

Abstract

Research Article| October 01, 1989 Neotectonic joints PAUL L. HANCOCK; PAUL L. HANCOCK 1Department of Geology, Wills Memorial Building, Queen's Road University of Bristol, Bristol BS8 1RJ, England Search for other works by this author on: GSW Google Scholar TERRY ENGELDER TERRY ENGELDER 2Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1989) 101 (10): 1197–1208. https://doi.org/10.1130/0016-7606(1989)101<1197:NJ>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 PAUL L. HANCOCK, TERRY ENGELDER; Neotectonic joints. GSA Bulletin 1989;; 101 (10): 1197–1208. doi: https://doi.org/10.1130/0016-7606(1989)101<1197:NJ>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 Neotectonic joint systems are the most recent joint systems to form within a region subject to uplift and erosion. An inventory of neotectonic joint attributes was compiled from observations in case study terrains containing flat-lying sedimentary sequences in the platform covers of cratons: the Appalachain Plateau, southeast England-northeast France, the Arabian platform, and the Ebro basin in Spain. Neotectonic joint systems are simple, generally consisting of sets of vertical extension fractures or less commonly steep conjugate fractures striking parallel to, or symmetrically about, the extension fractures. Shallow neotectonic joints propagate within the upper 0.5 km of the crust where effective σ3 is both tensile and horizontal and σ1 - σ3 is small. These shallow joint systems generally form within the upper 0.5 km: of the crust because unloading as a result of denudation and lateral relief consequent on uplift are prerequisites for their propagation. These structures are of potential value for tracking the contemporary stress field in regions where in situ measurements are not available. As a test of this possibility, late-formed joints were studied in the Appalachian Valley and Ridge of Pennsylvania. Outcrop studies showed that late-formed joints have the characteristics of neotectonic joints and, furthermore, propagated parallel to or approximately parallel (N75°-90°E) to directions of contemporary horizontal maximum stress (SH) known from in situ stress measurements or fault-plane solutions of earthquakes. The latter study lends strong support to our notion that late-formed or neotectonic joints in some terrains are likely to reflect the orientation of the neotectonic or contemporary tectonic stress field. 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.