Skip to main content

Main menu

  • Home
    • Journal home
    • Lyell Collection home
    • Geological Society home
  • Content
    • Online First
    • Issue in progress
    • All issues
    • Thematic Collections
    • Supplementary publications
    • Open Access
  • Subscribe
    • GSL fellows
    • Institutions
    • Corporate
    • Other member types
  • Info
    • Authors
    • Librarians
    • Readers
    • GSL Fellows access
    • Other member type access
    • Press office
    • Accessibility
    • Help
    • Metrics
  • Alert sign up
    • eTOC alerts
    • Online First alerts
    • RSS feeds
    • Newsletters
    • GSL blog
  • Submit
  • Geological Society of London Publications
    • Engineering Geology Special Publications
    • Geochemistry: Exploration, Environment, Analysis
    • Journal of Micropalaeontology
    • Journal of the Geological Society
    • Lyell Collection home
    • Memoirs
    • Petroleum Geology Conference Series
    • Petroleum Geoscience
    • Proceedings of the Yorkshire Geological Society
    • Quarterly Journal of Engineering Geology and Hydrogeology
    • Quarterly Journal of the Geological Society
    • Scottish Journal of Geology
    • Special Publications
    • Transactions of the Edinburgh Geological Society
    • Transactions of the Geological Society of Glasgow
    • Transactions of the Geological Society of London

User menu

  • My alerts
  • Log in
  • My Cart

Search

  • Advanced search
Journal of the Geological Society
  • Geological Society of London Publications
    • Engineering Geology Special Publications
    • Geochemistry: Exploration, Environment, Analysis
    • Journal of Micropalaeontology
    • Journal of the Geological Society
    • Lyell Collection home
    • Memoirs
    • Petroleum Geology Conference Series
    • Petroleum Geoscience
    • Proceedings of the Yorkshire Geological Society
    • Quarterly Journal of Engineering Geology and Hydrogeology
    • Quarterly Journal of the Geological Society
    • Scottish Journal of Geology
    • Special Publications
    • Transactions of the Edinburgh Geological Society
    • Transactions of the Geological Society of Glasgow
    • Transactions of the Geological Society of London
  • My alerts
  • Log in
  • My Cart
  • Follow gsl on Twitter
  • Visit gsl on Facebook
  • Visit gsl on Youtube
  • Visit gsl on Linkedin
Journal of the Geological Society

Advanced search

  • Home
    • Journal home
    • Lyell Collection home
    • Geological Society home
  • Content
    • Online First
    • Issue in progress
    • All issues
    • Thematic Collections
    • Supplementary publications
    • Open Access
  • Subscribe
    • GSL fellows
    • Institutions
    • Corporate
    • Other member types
  • Info
    • Authors
    • Librarians
    • Readers
    • GSL Fellows access
    • Other member type access
    • Press office
    • Accessibility
    • Help
    • Metrics
  • Alert sign up
    • eTOC alerts
    • Online First alerts
    • RSS feeds
    • Newsletters
    • GSL blog
  • Submit

Dense welding caused by volatile resorption

R. S. J. SPARKS, S. R. TAIT and Y. YANEV
Journal of the Geological Society, 156, 217-225, 1 March 1999, https://doi.org/10.1144/gsjgs.156.2.0217
R. S. J. SPARKS
1Department of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK (e-mail: )
  • Find this author on Google Scholar
  • Search for this author on this site
  • For correspondence: Steve.Sparks@bristol.ac.uk
S. R. TAIT
2Laboratoire des Dynamique Systèmes Geologiques, IPGP, 4, place Jussieu, 75252 Paris Cedex 05, France
  • Find this author on Google Scholar
  • Search for this author on this site
Y. YANEV
3Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113 Bulgaria
  • Find this author on Google Scholar
  • Search for this author on this site
PreviousNext
  • Article
  • Info & Metrics
  • PDF
Loading

Abstract

Welding of pyroclastic rocks is generally thought to occur by mechanical expulsion of interstitial gas from a deposit as it compacts under its own weight. We propose here that volatile resorption and compression can also be important factors in welding. We describe densely welded rocks which cannot be explained by loading and re-evaluate the welding process taking into account the effects of volatile resorption into the glassy fragments. Intra-caldera Oligocene ignimbrites from the Rhodope Mountains, Bulgaria, and intrusive tuffs of the Loch Ba ring dyke, Mull in Scotland are intensely welded but some samples lack foliation (eutaxitic texture). Fiamme and glass shards show no preferred orientation in thin section or on outcrop scale. Fiamme are sometimes complexy deformed into U or S shapes. We propose that these textures are the consequence of volatile dissolution in the glass and gas compression. Scaling analysis indicates that there are two regimes for gas behaviour following emplacement of hot pyroclastic deposits which depend on the relative characteristic time-scales of compaction, gas escape and gas resorption: a gas escape regime and a gas retention regime. During explosive eruption, glassy pyroclasts are decompressed to less than one atmosphere pressure and are outgassed. During deposition and subsequent burial in a thick hot deposit, volatiles will be retained and soluble gases (H2O) can be resorbed back into the glass, defining the gas retention regime. Poorly soluble gases (air) are compressed to small fractions of their original volume, resulting in destruction of pore spaces and vesicles in pumice. In some circumstances, such as volcanic vents, the volume changes involve isotropic strain and implosion of the tuff. Resorption of water greatly speeds up welding during compactional loading by reducing the viscosity of the glass. Welding is inhibited not only by lower temperatures but also by entrainment of insoluble atmospheric gases. The two regimes also can explain the common presence of post-emplacement gas escape pipes in non-welded ignimbrites and their rarity in densely welded ignimbrite. Factors that are likely to promote the gas retention regime include fine grain size, low collapsing columns, a large thickness of tuff and incorporation of external water.

  • welded tuff
  • ignimbrite
  • volatiles
  • volcanic geology
  • © Geological Society of London 1999

Please note that if you are logged into the Lyell Collection and attempt to access content that is outside of your subscription entitlement you will be presented with a new login screen. You have the option to pay to view this content if you choose. Please see the relevant links below for further assistance.

INDIVIDUALS

Log in using your username and password

– GSL fellows: log in with your Lyell username and password. (Please check your access entitlements at https://www.geolsoc.org.uk/fellowsaccess)
– Other users: log in with the username and password you created when you registered. Help for other users is at https://www.geolsoc.org.uk/lyellcollection_faqs
Forgot your username or password?

Purchase access

You may purchase access to this article for 24 hours and download the PDF within the access period. This will require you to create an account if you don't already have one. To download the PDF, click the 'Purchased Content' link in the receipt email.

LIBRARY USERS

Log in through your institution

You may be able to gain access using your login credentials for your institution. Contact your library if you do not have a username and password.
If your organization uses OpenAthens, you can log in using your OpenAthens username and password. To check if your institution is supported, please see this list. Contact your library for more details.
If you think you should have access, please contact your librarian or email sales@geolsoc.org.uk

LIBRARIANS

Administer your subscription.

CONTACT US

If you have any questions about the Lyell Collection publications website, please see the access help page or contact sales@geolsoc.org.uk

PreviousNext
Back to top

In this issue

Journal of the Geological Society: 156 (2)
Journal of the Geological Society
Volume 156, Issue 2
March 1999
  • Table of Contents
  • Index by author
Alerts
Sign In to Email Alerts with your Email Address
Citation tools

Dense welding caused by volatile resorption

R. S. J. SPARKS, S. R. TAIT and Y. YANEV
Journal of the Geological Society, 156, 217-225, 1 March 1999, https://doi.org/10.1144/gsjgs.156.2.0217
R. S. J. SPARKS
1Department of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK (e-mail: )
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: Steve.Sparks@bristol.ac.uk
S. R. TAIT
2Laboratoire des Dynamique Systèmes Geologiques, IPGP, 4, place Jussieu, 75252 Paris Cedex 05, France
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Y. YANEV
3Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113 Bulgaria
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Permissions
View PDF
Share

Dense welding caused by volatile resorption

R. S. J. SPARKS, S. R. TAIT and Y. YANEV
Journal of the Geological Society, 156, 217-225, 1 March 1999, https://doi.org/10.1144/gsjgs.156.2.0217
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
Email to

Thank you for sharing this Journal of the Geological Society article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Dense welding caused by volatile resorption
(Your Name) has forwarded a page to you from Journal of the Geological Society
(Your Name) thought you would be interested in this article in Journal of the Geological Society.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
  • Tweet Widget
  • Facebook Like
  • Google Plus One
  • Article
  • Info & Metrics
  • PDF

Related Articles

Similar Articles

Cited By...

More in this TOC Section

  • Repeated tabular injection of high-level alkaline granites in the eastern Bushveld, South Africa
  • Volcanic plume monitoring using atmospheric electric potential gradients
Show more: Article
  • Most read
  • Most cited
Loading
  • Geological Society of London Scientific Statement: what the geological record tells us about our present and future climate
  • Linking surface and subsurface volcanic stratigraphy in the Turkana Depression of the East African Rift system
  • Nature and significance of rift-related, near-surface fissure-fill networks in fractured carbonates below regional unconformities
  • Terrestrial stratigraphical division in the Quaternary and its correlation
  • The Shibantan Lagerstätte: insights into the Proterozoic–Phanerozoic transition
More...

Journal of the Geological Society

  • About the journal
  • Editorial Board
  • Submit a manuscript
  • Author information
  • Supplementary Publications
  • Subscribe
  • Pay per view
  • Alerts & RSS
  • Copyright & Permissions
  • Activate Online Subscription
  • Feedback
  • Help

Lyell Collection

  • About the Lyell Collection
  • Lyell Collection homepage
  • Collections
  • Open Access Collection
  • Open Access Policy
  • Lyell Collection access help
  • Recommend to your Library
  • Lyell Collection Sponsors
  • MARC records
  • Digital preservation
  • Developing countries
  • Geofacets
  • Manage your account
  • Cookies

The Geological Society

  • About the Society
  • Join the Society
  • Benefits for Members
  • Online Bookshop
  • Publishing policies
  • Awards, Grants & Bursaries
  • Education & Careers
  • Events
  • Geoscientist Online
  • Library & Information Services
  • Policy & Media
  • Society blog
  • Contact the Society

Published by The Geological Society of London, registered charity number 210161

Print ISSN 
0016-7649
Online ISSN 
2041-479X

Copyright © 2021 Geological Society of London