Paleomagnetic Criteria for Volcanic Breccia Emplacement

Research Article| August 01, 1971 Paleomagnetic Criteria for Volcanic Breccia Emplacement ROBERT A CHADWICK ROBERT A CHADWICK Department of Earth Sciences, Montana State University, Bozeman, Montana 59715 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1971) 82 (8): 2285–2294. https://doi.org/10.1130/0016-7606(1971)82[2285:PCFVBE]2.0.CO;2 Article history received: 13 Aug 1970 rev-recd: 09 Mar 1971 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ROBERT A CHADWICK; Paleomagnetic Criteria for Volcanic Breccia Emplacement. GSA Bulletin 1971;; 82 (8): 2285–2294. doi: https://doi.org/10.1130/0016-7606(1971)82[2285:PCFVBE]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 Measurements of NRM directions in clasts from selected volcanic breccia units of the Gallatin Range of Montana show that magnetization directions may be near-parallel from clast to clast, or near-random. Near-parallel directions are found in clasts from a unit formed by autobrecciation of a flow; this is to be expected in breccias which come to rest while heated above the average of blocking temperatures of the constituent ferromagnetic grains. Near-random directions are present in a breccia exhibiting field and petrographic characteristics of a mudflow or debris flow; such randomization should take place as breccia clasts are rotated while below the blocking temperature. Paleomagnetic measurements thus help distinguish between Gallatin Range volcanic breccias emplaced at relatively high versus relatively low temperature. The technique should have wide application in rocks of these types. 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.