Magnetic Reversal Stratigraphy of the Lower Triassic Moenkopi Formation of Western Colorado

Abstract

Research Article| December 01, 1969 Magnetic Reversal Stratigraphy of the Lower Triassic Moenkopi Formation of Western Colorado CHARLES E HELSLEY CHARLES E HELSLEY University of Texas at Dallas (formerly Southwest Center for Advanced Studies), P. O. Box 30365, Dallas, Texas 75230 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1969) 80 (12): 2431–2450. https://doi.org/10.1130/0016-7606(1969)80[2431:MRSOTL]2.0.CO;2 Article history received: 03 Mar 1969 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 CHARLES E HELSLEY; Magnetic Reversal Stratigraphy of the Lower Triassic Moenkopi Formation of Western Colorado. GSA Bulletin 1969;; 80 (12): 2431–2450. doi: https://doi.org/10.1130/0016-7606(1969)80[2431:MRSOTL]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 Oriented cores, taken at stratigraphic intervals of 9 to 12 inches, have been collected from the basal 500 feet of the Moenkopi Formation along the Dolores River in western Colorado. The NRM and the demagnetized data from these samples indicate that the Lower Triassic magnetic field is characterized by at least eleven reversals. Samples from the normal polarity intervals are initially well clustered and remain so after AC or thermal demagnetization. Samples with reversed polarity are initially scattered and remain so after AC demagnetization. However, after thermal demagnetization to 500° C, they become well clustered and have a direction approximately 180° from that of the normal intervals.All samples belong to either the normal or reversed groups, and no samples transitional between normal and reverse were observed.A tentative correlation of the resulting polarity reversal sequence with that from the Chugwater Formation of Wyoming is proposed. A magnetic anomaly pattern similar to this polarity reversal sequence is observed in magnetic profiles at sea, indicating that polarity reversal sequences may be a useful means of both regional correlation and calibration of the sea-floor spreading rates postulated for the ocean basins. 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.

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Affiliated Institutions

• Southwest Center for Educational Excellence US
• The University of Texas at Dallas US

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