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Tightening the Belt: Paleomagnetic-stratigraphic constraints on deposition, correlation, and deformation of the Middle Proterozoic (ca. 1.4 Ga) Belt-Purcell Supergroup, United States and Canada

2002; Geological Society of America; Volume: 114; Issue: 5 Linguagem: Inglês

10.1130/0016-7606(2002)114 2.0.co;2

1943-2674

Donald P. Elston, Randolph J. Enkin, J. Baker, D. Kisilevsky,

High-pressure geophysics and materials

Research Article| May 01, 2002 Tightening the Belt: Paleomagnetic-stratigraphic constraints on deposition, correlation, and deformation of the Middle Proterozoic (ca. 1.4 Ga) Belt-Purcell Supergroup, United States and Canada D.P. Elston; D.P. Elston 16300 Country Club Drive, Flagstaff, Arizona 86004, USA Search for other works by this author on: GSW Google Scholar R.J. Enkin; R.J. Enkin 2Geological Survey of Canada–Pacific, Sidney, British Columbia V8L 4B2, Canada Search for other works by this author on: GSW Google Scholar J. Baker; J. Baker 2Geological Survey of Canada–Pacific, Sidney, British Columbia V8L 4B2, Canada Search for other works by this author on: GSW Google Scholar D.K. Kisilevsky D.K. Kisilevsky 3Petrel Robertson Consulting, Ltd., Calgary, Alberta T2P 3C4, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information D.P. Elston 16300 Country Club Drive, Flagstaff, Arizona 86004, USA R.J. Enkin 2Geological Survey of Canada–Pacific, Sidney, British Columbia V8L 4B2, Canada J. Baker 2Geological Survey of Canada–Pacific, Sidney, British Columbia V8L 4B2, Canada D.K. Kisilevsky 3Petrel Robertson Consulting, Ltd., Calgary, Alberta T2P 3C4, Canada Publisher: Geological Society of America Received: 05 Dec 2000 Revision Received: 25 Oct 2001 Accepted: 19 Nov 2001 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2002) 114 (5): 619–638. https://doi.org/10.1130/0016-7606(2002)114 2.0.CO;2 Article history Received: 05 Dec 2000 Revision Received: 25 Oct 2001 Accepted: 19 Nov 2001 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation D.P. Elston, R.J. Enkin, J. Baker, D.K. Kisilevsky; Tightening the Belt: Paleomagnetic-stratigraphic constraints on deposition, correlation, and deformation of the Middle Proterozoic (ca. 1.4 Ga) Belt-Purcell Supergroup, United States and Canada. GSA Bulletin 2002;; 114 (5): 619–638. doi: https://doi.org/10.1130/0016-7606(2002)114 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 The Belt-Purcell Supergroup crops out in Montana, Idaho, Washington, British Columbia, and Alberta. It is the largest and most intensively studied Middle Proterozoic succession in North America. A major paleomagnetic survey of the Belt-Purcell basin in Montana was carried out by the U.S. Geological Survey between 1975 and 1985, but only partial results have been published. We reanalyze these data and add new data from the Canadian part of the basin. Results come from >2700 samples (mostly red beds) from 93 localities, spanning 13 formations or members of formations. They typically exhibit stable magnetizations carried by hematite in detrital specularite grains and pigment. Coherent paleomagnetic directions have either southwest declinations and moderate positive inclinations (normal polarity) or northeast declinations and moderate negative inclinations (reverse polarity). These directions clearly pass fold and reversal tests. A stratigraphically coherent directional swing and a reproducible polarity zonation indicate that the stable magnetization is primary and was acquired during the course of deposition. U-Pb dates suggest an ∼50 m.y. duration of deposition of the upper part of the Belt-Purcell Supergroup. The limited amount of apparent polar wander and the few polarity reversals recorded in the Belt- Purcell deposits are similar to the rate of polar wander and a long interval of stable polarity observed for the middle Cretaceous. An apparent incompatibility between early Middle Proterozoic (Elsonian) paleomagnetic poles from different regions of North America is now resolved; the Belt- Purcell poles are middle Elsonian in age and form the southern extreme point on a hairpin loop of the 1500–1400 Ma part of a refined Elsonian apparent polar wander path. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.