Controls of subduction geometry, location of magmatic arcs, and tectonics of arc and back-arc regions

Research Article| June 01, 1982 Controls of subduction geometry, location of magmatic arcs, and tectonics of arc and back-arc regions TIMOTHY A. CROSS; TIMOTHY A. CROSS 1Exxon Production Research Company, P.O. Box 2189, Houston, Texas 77001 Search for other works by this author on: GSW Google Scholar REX H. PILGER, Jr. REX H. PILGER, Jr. 2Department of Geology, Louisiana State University, Baton Rouge, Louisiana 70803 Search for other works by this author on: GSW Google Scholar Author and Article Information TIMOTHY A. CROSS 1Exxon Production Research Company, P.O. Box 2189, Houston, Texas 77001 REX H. PILGER, Jr. 2Department of Geology, Louisiana State University, Baton Rouge, Louisiana 70803 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1982) 93 (6): 545–562. https://doi.org/10.1130/0016-7606(1982)93<545:COSGLO>2.0.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 TIMOTHY A. CROSS, REX H. PILGER; Controls of subduction geometry, location of magmatic arcs, and tectonics of arc and back-arc regions. GSA Bulletin 1982;; 93 (6): 545–562. doi: https://doi.org/10.1130/0016-7606(1982)93<545:COSGLO>2.0.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 Most variation in geometry and angle of inclination of subducted oceanic lithosphere is caused by four interdependent factors. Combinations of (1) rapid absolute upper-plate motion toward the trench and active overriding of the subducted plate, (2) rapid relative plate convergence, and (3) subduction of intraplate island-seamount chains, aseismic ridges, and oceanic plateaus (anomalously low-density oceanic lithosphere) cause low-angle subduction. Under conditions of low-angle subduction, the upper surface of the subducted plate is in contact with the base of the overlying plate, the wedge of low-density asthenosphere is replaced by subducted lithosphere, and the width of the arc-trench gap either is significantly increased or a magmatic arc is not developed within the overlying plate. The fourth factor is age of the subducting lithosphere. Subduction of young lithosphere produces two opposing tendencies: (1) low-angle subduction and increased arc-trench distance, owing to its low density; and (2) decreased arc-trench distance, owing to its higher temperature.Two factors of secondary importance contribute to variation in subduction-zone geometry and arc-trench distance. Accretion of sediment in trenches depresses the upper portion of the subducting oceanic plate and causes the trench axis to migrate seaward. Prolonged subduction thickens the upper plate, depresses the isotherms in the subducted plate, and may create a broader arc. Both factors increase the arc-trench gap.The four primary factors also control development of other tectonic elements, such as regional subsidence (for example, the Amazon basin and a portion of the Cretaceous Interior Seaway of western United States), intra-arc extension (for example, the Basin and Range province), foreland fold and thrust belts, and Laramide-style tectonics. 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.