Diagenesis and the K-Ar Dating of Shales and Clay Minerals

Abstract

Research Article| May 01, 1974 Diagenesis and the K-Ar Dating of Shales and Clay Minerals EDWARD A. PERRY, JR. EDWARD A. PERRY, JR. 1Department of Geology and Marine Science Program, University of Massachusetts, Amherst, Massachusetts 01002 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1974) 85 (5): 827–830. https://doi.org/10.1130/0016-7606(1974)85<827:DATKDO>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 MailTo Tools Icon Tools Get Permissions Search Site Citation EDWARD A. PERRY; Diagenesis and the K-Ar Dating of Shales and Clay Minerals. GSA Bulletin 1974;; 85 (5): 827–830. doi: https://doi.org/10.1130/0016-7606(1974)85<827:DATKDO>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 Gulf Coast sediments were obtained from an oil well drilled in coastal Louisiana, and their diagenesis was documented by the mineralogic changes in mixed layer illite/smectite. Samples were selected to represent varying degrees of diagenesis and separated into four size ranges for K-Ar analysis; bulk shale samples were also analyzed.The measured K-Ar ages of the mixed layer illite/smectite become progressively younger with increasing depth of burial because of the diagenetic addition of potassium caused by conversion of smectite layers to illite layers. Detrital illite and feldspar are destroyed to provide potassium for the diagenetic illite layers, and the detrital phases have lowered ages because of the greater loss of radiogenic argon relative to potassium. As a result of both processes, the measured ages of whole shale also decrease with increasing diagenesis, and radiogenic argon is lost from the system. 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.