Reactive mass transport modelling of a three-dimensional vertical fault zone with a finger-like convective flow regime

Alt-Epping, Peter; Zhao, Chongbin (2010). Reactive mass transport modelling of a three-dimensional vertical fault zone with a finger-like convective flow regime. Journal of Geochemical Exploration, 106(1-3), pp. 8-23. Elsevier 10.1016/j.gexplo.2009.12.007

[img] Text
alt-epping_zhao_JGE_2010.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (3MB) | Request a copy

For a three-dimensional vertically-oriented fault zone, we consider the coupled effects of fluid flow, heat transfer and reactive mass transport, to investigate the patterns of fluid flow, temperature distribution, mineral alteration and chemically induced porosity changes. We show, analytically and numerically, that finger-like convection patterns can arise in a vertically-oriented fault zone. The onset and patterns of convective fluid flow are controlled by the Rayleigh number which is a function of the thermal properties of the fluid and the rock, the vertical temperature gradient, and the height and the permeability of the fault zone. Vigorous fluid flow causes low temperature gradients over a large region of the fault zone. In such a case, flow across lithological interfaces becomes the most important mechanism for the formation of sharp chemical reaction fronts. The degree of rock buffering, the extent and intensity of alteration, the alteration mineralogy and in some cases the formation of ore deposits are controlled by the magnitude of the flow velocity across these compositional interfaces in the rock. This indicates that alteration patterns along compositional boundaries in the rock may provide some insights into the convection pattern. The advective mass and heat exchanges between the fault zone and the wallrock depend on the permeability contrast between the fault zone and the wallrock. A high permeability contrast promotes focussed convective flow within the fault zone and diffusive exchange of heat and chemical reactants between the fault zone and the wallrock. However, a more gradual permeability change may lead to a regional-scale convective flow system where the flow pattern in the fault affects large-scale fluid flow, mass transport and chemical alteration in the wallrocks

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geological Sciences > Rock-Water Interaction

UniBE Contributor:

Alt-Epping, Peter

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0375-6742

Publisher:

Elsevier

Language:

English

Submitter:

Peter Alt-Epping

Date Deposited:

26 Sep 2014 15:36

Last Modified:

10 Aug 2015 11:15

Publisher DOI:

10.1016/j.gexplo.2009.12.007

Web of Science ID:

000280119400003

BORIS DOI:

10.7892/boris.57657

URI:

https://boris.unibe.ch/id/eprint/57657

Actions (login required)

Edit item Edit item
Provide Feedback