Emplacement temperatures of unsorted and unstratified deposits of volcanic rock debris as determined by paleomagnetic techniques

Research Article| July 01, 1979 Emplacement temperatures of unsorted and unstratified deposits of volcanic rock debris as determined by paleomagnetic techniques RICHARD P. HOBLITT; RICHARD P. HOBLITT 1U.S. Geological Survey, Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar KARL S. KELLOGG KARL S. KELLOGG 1U.S. Geological Survey, Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Author and Article Information RICHARD P. HOBLITT 1U.S. Geological Survey, Federal Center, Denver, Colorado 80225 KARL S. KELLOGG 1U.S. Geological Survey, Federal Center, Denver, Colorado 80225 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1979) 90 (7): 633–642. https://doi.org/10.1130/0016-7606(1979)90<633:ETOUAU>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 Email Permissions Search Site Citation RICHARD P. HOBLITT, KARL S. KELLOGG; Emplacement temperatures of unsorted and unstratified deposits of volcanic rock debris as determined by paleomagnetic techniques. GSA Bulletin 1979;; 90 (7): 633–642. doi: https://doi.org/10.1130/0016-7606(1979)90<633:ETOUAU>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 Unsorted and unstratified deposits of volcanic rock debris typically flank recently active stratovolcanoes. It is often difficult, using standard geologic procedures, to establish whether a particular deposit was emplaced by a pyroclastic flow, lahar, rock avalanche, or glacier. Determination of the emplacement temperatures of clasts contained in the deposit aids in discriminating among some of these possibilities. The emplacement temperature of a clast can be estimated by analyzing its thermoremanent magnetization. To do this, oriented samples of the clasts are submitted to progressive thermal demagnetization; the directions and magnitudes of the resulting residual remanent vectors provide the information necessary to estimate the temperatures at which the clasts were emplaced. Studies of samples that were given artificial emplacement temperatures reveal that estimates are within ±25 °C of the actual values. The temperature range within which estimates are possible depends on the thermoremanent magnetization acquisition curve of a clast. Data obtained from deposits of volcanic rock debris from Mount St. Helens, Washington, indicate that for andesitic and dacitic rocks, the range is roughly 100 to 550 °C. The procedure probably can be applied to other geologic problems that require temperature information. 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.