Experimentally Produced Devitrification Textures in Natural Rhyolitic Glass
1971; Geological Society of America; Volume: 82; Issue: 1 Linguagem: Inglês
10.1130/0016-7606(1971)82[111
ISSN1943-2674
Autores Tópico(s)Geological formations and processes
ResumoResearch Article| January 01, 1971 Experimentally Produced Devitrification Textures in Natural Rhyolitic Glass GARY LOFGREN GARY LOFGREN Department of Geology, Stanford University, Stanford, California 99304 PRESENT ADDRESS: GEOLOGY BRANCH TN6, NASA MANNED SPACECRAFT CENTER, HOUSTON, TEXAS 77058 Search for other works by this author on: GSW Google Scholar Author and Article Information GARY LOFGREN PRESENT ADDRESS: GEOLOGY BRANCH TN6, NASA MANNED SPACECRAFT CENTER, HOUSTON, TEXAS 77058 Department of Geology, Stanford University, Stanford, California 99304 Publisher: Geological Society of America Received: 12 Jun 1970 Revision Received: 14 Aug 1970 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1971, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1971) 82 (1): 111–124. https://doi.org/10.1130/0016-7606(1971)82[111:EPDTIN]2.0.CO;2 Article history Received: 12 Jun 1970 Revision Received: 14 Aug 1970 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 GARY LOFGREN; Experimentally Produced Devitrification Textures in Natural Rhyolitic Glass. GSA Bulletin 1971;; 82 (1): 111–124. doi: https://doi.org/10.1130/0016-7606(1971)82[111:EPDTIN]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 Experimental devitrification of natural rhyolitic glass was undertaken in an attempt to produce, under known conditions, analogs of naturally devitrified rocks. The results should facilitate the recognition and interpretation of devitrification textures. Previous studies have shown that alkali-rich aqueous solutions increase devitrification rates sufficiently to produce solid pieces of devitrified obsidian in the laboratory, but none of these has provided a systematic study of experimentally produced devitrification textures.Cylinders of natural volcanic glass, 4.6 mm in diameter and 10 to 20 mm long, were sealed in 5-mm-diameter gold capsules, along with either pure water or alkali-rich solutions. Runs were made in externally heated pressure vessels in the temperature range 240° to 700°C and in the pressure range 0.5 to 4 kb. Textures recognized in the products of the runs closely resembled hydration and devitrification texture s in some rhyolitic rocks. Although hydration fronts and strain birefringence were developed during some experimental runs, no perlitic fractures were observed. Devitrified products contained spherulites, micropoikilitic quartz, orb texture, axiolites, and miarolitic cavities.Two stages of devitrification are distinguished. The glassy stage is characterized by glassy or felsitic textures with isolated spherulites, and the spherulitic stage by spherulitic textures and micropoikilitic quartz. A hypothetical third stage in this succession, not represented in products from this study, most likely has a granophyric or granitic texture, with no evidence of glassy precursors. 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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