Magma storage, differentiation, and interaction at Lake City caldera, Colorado, USA

Research Article| May 01, 2016 Magma storage, differentiation, and interaction at Lake City caldera, Colorado, USA Ben Kennedy; Ben Kennedy 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Quebec, H3A 0E8, Canada †Current address: Geological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand, Ben.kennedy@canterbury.ac.nz. Search for other works by this author on: GSW Google Scholar John Stix; John Stix 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Quebec, H3A 0E8, Canada Search for other works by this author on: GSW Google Scholar Ken Hon; Ken Hon 2Geology Department, University of Hawai`i at Hilo, 200 West Kawili Street, Hilo, Hawaii 96720-4091, USA Search for other works by this author on: GSW Google Scholar Chad Deering; Chad Deering 3Department of Geological and Mining Engineering and Sciences, 630 Dow Environmental Sciences, 1400 Townsend Drive, Houghton, Michigan 49931, USA Search for other works by this author on: GSW Google Scholar Sarah Gelman Sarah Gelman 4Institute for Geochemie und Petrologie, NO E 53.1, Sonneggstrasse 5, 8092 Zurich, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information Ben Kennedy †Current address: Geological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand, Ben.kennedy@canterbury.ac.nz. 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Quebec, H3A 0E8, Canada John Stix 1Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Quebec, H3A 0E8, Canada Ken Hon 2Geology Department, University of Hawai`i at Hilo, 200 West Kawili Street, Hilo, Hawaii 96720-4091, USA Chad Deering 3Department of Geological and Mining Engineering and Sciences, 630 Dow Environmental Sciences, 1400 Townsend Drive, Houghton, Michigan 49931, USA Sarah Gelman 4Institute for Geochemie und Petrologie, NO E 53.1, Sonneggstrasse 5, 8092 Zurich, Switzerland Publisher: Geological Society of America Received: 25 Feb 2015 Revision Received: 02 Sep 2015 Accepted: 09 Nov 2015 First Online: 09 Mar 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2015 Geological Society of America GSA Bulletin (2016) 128 (5-6): 764–776. https://doi.org/10.1130/B31305.1 Article history Received: 25 Feb 2015 Revision Received: 02 Sep 2015 Accepted: 09 Nov 2015 First Online: 09 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 Ben Kennedy, John Stix, Ken Hon, Chad Deering, Sarah Gelman; Magma storage, differentiation, and interaction at Lake City caldera, Colorado, USA. GSA Bulletin 2016;; 128 (5-6): 764–776. doi: https://doi.org/10.1130/B31305.1 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 Rocks from the 23 Ma Lake City caldera show diverse chemical affinities attesting to a complex magmatic system beneath the caldera. Field and geochemical data from ignimbrites and intrusions constrain magma storage and magma interactions during the formation of the caldera. Two geochemically distinct magma batches erupted during caldera formation: batch A, consisting of rhyolites and trachytes, and batch B, consisting of dacites and trachyandesites. The ignimbrites of the Lower, Middle, and Upper Sunshine Peak Tuff represent the bulk of erupted batch A magma, with an increasing proportion of trachyte to rhyolite as the eruption progressed. Overall, the observed trends of major and trace elements are consistent with the sequential eruption of a magmatic system with a rhyolitic upper portion and trachytic lower portion. The Middle Sunshine Peak Tuff contains two distinct types of pumice clast, while the Upper Sunshine Peak Tuff contains four distinct pumice clast types, with one type chemically related to batch B magma. The link between the rhyolite and trachyte of batch A is supported by major- and trace-element geochemical modeling of an initially trachytic magma that fractionated and was subjected to crystal/melt segregation following 50%–60% crystallization. Compositional gaps and chemical heterogeneity in the bulk ignimbrite composition show that the proportions of these different magma types varied significantly during eruption. We propose that the fractionating batch A and B magmas formed distinct magma pods, some containing residual magma mush, that were tapped during different phases of caldera formation. After collapse, dacite lavas of batch B were erupted concurrent with resurgent uplift from shallow intrusion of both residual mingled batch A and batch B magma. In summary, our observations suggest (1) a complex magma chamber geometry from two fractionating magma batches, and (2) magma replenishment and accelerated periods of magma reorganization in the shallow magma plumbing system during a single caldera cycle at Lake City. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.