Thermal impact of dykes on ignimbrite and implications for fluid flow compartmentalisation in calderas

Publikationen: Beitrag in FachzeitschriftArtikelForschung(peer-reviewed)

Autoren

  • Ben M. Kennedy
  • Michael J. Heap
  • Steffi Burchardt
  • Hugh Tuffen
  • H. Albert Gilg
  • Jonathan Davidson
  • Neryda Duncan
  • Elodie Saubin
  • Einar Bessi Gestsson
  • Marzieh Anjomrouz
  • Philip Butler

Externe Organisationseinheiten

  • University of Canterbury
  • Institut Terre et Environnement de Strasbourg
  • Institut Universitaire de France
  • Uppsala University
  • University of Lancaster
  • Technische Universität München
  • MARS Bioimaging Ltd
  • Icelandic Meteorological Office

Abstract

Ignimbrites within calderas host intrusions with hazardous and/or economically significant hydrothermal systems. The Hvítserkur ignimbrite at Breiðuvík caldera, north-eastern Iceland, is intruded by basaltic dykes. Our data show that the ignimbrite immediately adjacent to the dyke is hard, dark-coloured, recrystallised quartz, plagioclase, and alkali feldspar with a low permeability and porosity and frequent macrofractures. At 1-2 m from the dyke, the ignimbrite is hard, dominantly glassy with pervasive perlitic microfractures, has high permeability, but low porosity and frequent macrofractures. A narrow zone of pervasive unlithified clay exists 2 m from the dyke. Beyond this, the ignimbrite is soft and zeolite-rich, has low permeability, high porosity and fewer macrofractures. The dyke intrusion promoted a narrow zone of welding, fracturing and perlitisation in the ignimbrite resulting in high permeability and focussed alteration. Our study shows how intrusions and their thermal aureoles create vertical pathways for, and horizontal barriers to, geothermal fluid flow.

Details

OriginalspracheEnglisch
Seiten (von - bis)75-93
Seitenumfang19
FachzeitschriftVolcanica
Jahrgang5.2022
Ausgabenummer1
DOIs
StatusVeröffentlicht - 4 Feb 2022