Late Cenozoic volcanism in the Aleutian Arc: Information from ash layers in the northeastern Gulf of Alaska

Abstract

Research Article| October 01, 1975 Late Cenozoic volcanism in the Aleutian Arc: Information from ash layers in the northeastern Gulf of Alaska K. F. SCHEIDEGGER; K. F. SCHEIDEGGER 1School of Oceanography, Oregon State University, Corvallis, Oregon 97331 Search for other works by this author on: GSW Google Scholar L. D. KULM L. D. KULM 1School of Oceanography, Oregon State University, Corvallis, Oregon 97331 Search for other works by this author on: GSW Google Scholar Author and Article Information K. F. SCHEIDEGGER 1School of Oceanography, Oregon State University, Corvallis, Oregon 97331 L. D. KULM 1School of Oceanography, Oregon State University, Corvallis, Oregon 97331 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1975) 86 (10): 1407–1412. https://doi.org/10.1130/0016-7606(1975)86<1407:LCVITA>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 K. F. SCHEIDEGGER, L. D. KULM; Late Cenozoic volcanism in the Aleutian Arc: Information from ash layers in the northeastern Gulf of Alaska. GSA Bulletin 1975;; 86 (10): 1407–1412. doi: https://doi.org/10.1130/0016-7606(1975)86<1407:LCVITA>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 A sequence of ash layers recovered from site 178 of the Deep Sea Drilling Project in the Gulf of Alaska was studied to determine the nature of highly explosive volcanic eruptions associated with the Aleutian Arc and Alaskan Peninsula during the last 8 m.y. The major-element chemistry of 25 distinct ash layers was determined. When the analyses are plotted on conventional major-element variation diagrams, the unusual, highly evolved, calc-alkalic characteristics of the ashes are apparent. Perhaps more significantly, there is a good correlation of certain indices of the degree of chemical evolution of each ash (SiO2 content and Larsen index) with sample age. Both parameters vary cyclically, with maximum values of both indices occurring at present, 2.5, and about 5.0 m.y. ago. The cause of the cyclic activity, as well as discontinuous volcanic activity reported for other areas by other investigators, is not precisely known. However, we suggest that variable rates of subduction provide a viable hypothesis for discontinuous volcanic activity associated with convergent plate boundaries. 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.