Audio-frequency magnetotelluric and gravity traverse across the crest of the Purcell anticlinorium, northwestern Montana

Abstract

Research Article| May 01, 1977 Audio-frequency magnetotelluric and gravity traverse across the crest of the Purcell anticlinorium, northwestern Montana Jeffrey C. Wynn; Jeffrey C. Wynn 1U.S. Geological Survey, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar M. Dean Kleinkopf; M. Dean Kleinkopf 1U.S. Geological Survey, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Jack E. Harrison Jack E. Harrison 1U.S. Geological Survey, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Author and Article Information Jeffrey C. Wynn 1U.S. Geological Survey, Denver, Colorado 80225 M. Dean Kleinkopf 1U.S. Geological Survey, Denver, Colorado 80225 Jack E. Harrison 1U.S. Geological Survey, Denver, Colorado 80225 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1977) 5 (5): 309–312. https://doi.org/10.1130/0091-7613(1977)5<309:AMAGTA>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Jeffrey C. Wynn, M. Dean Kleinkopf, Jack E. Harrison; Audio-frequency magnetotelluric and gravity traverse across the crest of the Purcell anticlinorium, northwestern Montana. Geology 1977;; 5 (5): 309–312. doi: https://doi.org/10.1130/0091-7613(1977)5<309:AMAGTA>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 SocietyGeology Search Advanced Search Abstract A series of audio-frequency magnetotelluric (AMT) and gravity measurements were made across the Purcell anticlinoriurn of the Belt basin in Montana. The purpose of the study was to gain information about the electrical properties of the Belt Supergroup strata before using techniques that probe deeper but are more expensive. The Bouguer gravity data indicate an anomaly of about 20 mgal that can be modelled as a block uplifted 11 km above a flat basement surface that lies at a depth of 17 km. The AMT measurements did not penetrate to the crystalline basement, but they did delineate several intermediate structural features, including a deep layer of unusually high conductivity. Both the uplifted block and the conductive unit are positioned beneath the crest of the anticlinoriurn, approximately beneath the outcrop of the Prichard Formation. 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.