Sealing, healing and fluid flow in clay rocks: Insights on episodic flow events in fault zones

Ville Nenonen, P. Dick, Juuso Sammaljärvi, B. Johansson, Mikko Voutilainen, Marja Siitari-Kauppi

Forskningsoutput: Kapitel i bok/rapport/konferenshandlingKonferensbidragVetenskapligPeer review


The porosity distribution and mineralogical changes in a clay-rich fault core from the Tournemire underground research laboratory are analyzed to determine the mechano-chemical processes in a small-scale vertical strike-slip fault. The results display significant spatial variations in porosity and mineralogy along different gouge zones due to a polyphased tectonic history combined with complex paleo-fluid migrations. Porosity values increase from the center of the gouges to their borders indicating diffusive sealing/healing effects and past hydrothermal activities. The healing and thus the strengthening of the fault is marked by an increase of calcium content, which is concurrent with lower porosities around the gouge zone. Chemical mapping in the gouges reveal clay alteration, iron zonality and the presence of zinc sulphide as well as barium sulphate inside the gouge, further suggesting past hydrothermal activity. Finally, even though the observed porosity variations only occur in subcentimeter-thick gouge bands, the higher porosity sections are pathways for fluid flow during fault activity. © 5th International Conference on Fault and Top Seals 2019. All Rights Reserved.
Titel på värdpublikation5th International Conference on Fault and Top Seals 2019 : Proceedings of a meeting held 8-9 September 2019, Palermo, Italy
Antal sidor5
ISBN (elektroniskt)978-1-5108-9236-1
StatusPublicerad - 2019
MoE-publikationstypA4 Artikel i en konferenspublikation
Evenemang5th International Conference on Fault and Top Seals 2019 - Palermo, Italien
Varaktighet: 8 sep. 20199 sep. 2019
Konferensnummer: 5


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