Quilichini A., Siebenaller Luc, Nachlas W. O., Teyssier C., Vennemann T. W., Heizler M. T., Mulch A. (2015). Infiltration of meteoric fluids in an extensional detachment shear zone (Kettle dome, WA, USA) : how quartz dynamic recrystallization relates to fluid-rock interaction. In :
Sintubin M. (ed.), De Bresser H. (ed.), Drury M. (ed.), Prior D. (ed.), Wenk H.R. (ed.). Deformation of the lithosphere : how small structures tell a big story. Journal of Structural Geology, 71 (no spécial), p. 71-85. ISSN 0191-8141.
Titre du document
Infiltration of meteoric fluids in an extensional detachment shear zone (Kettle dome, WA, USA) : how quartz dynamic recrystallization relates to fluid-rock interaction
Année de publication
2015
Auteurs
Quilichini A., Siebenaller Luc, Nachlas W. O., Teyssier C., Vennemann T. W., Heizler M. T., Mulch A.
In
Sintubin M. (ed.), De Bresser H. (ed.), Drury M. (ed.), Prior D. (ed.), Wenk H.R. (ed.), Deformation of the lithosphere : how small structures tell a big story
Source
Journal of Structural Geology, 2015,
71 (no spécial), p. 71-85 ISSN 0191-8141
We document the interplay between meteoric fluid flow and deformation processes in quartzite-dominated lithologies within a ductile shear zone in the footwall of a Cordilleran extensional fault (Kettle detachment system, Washington, USA). Across 150 m of shear zone section, hydrogen isotope ratios (delta D) from synkinematic muscovite fish are constant (delta D similar to -130 parts per thousand) and consistent with a meteoric fluid source. Quartz-muscovite oxygen isotope thermometry indicates equilibrium fractionation temperatures of similar to 365 +/- 30 degrees C in the lower part of the section, where grain-scale quartz deformation was dominated by grain boundary migration recrystallization. In the upper part of the section, muscovite shows increasing intragrain compositional zoning, and quartz microstructures reflect bulging reaystallization, solution-precipitation, and microcracking that developed during progressive cooling and exhumation. The preserved microstructural characteristics and hydrogen isotope fingerprints of meteoric fluids developed over a short time interval as indicated by consistent mica Ar-40/Ar-39 ages ranging between 51 and 50 Ma over the entire section. Pervasive fluid flow became increasingly channelized during detachment activity, leading to microstructural heterogeneity and large shifts in quartz delta O-18 values on a meter scale. Ductile deformation ended when brittle motion on the detachment fault rapidly exhumed the mylonitic footwall.
Plan de classement
Sciences de la Terre : généralités [060]
;
Géologie et formations superficielles [064]
Description Géographique
ETATS UNIS
Localisation
Fonds IRD [F B010063995]
Identifiant IRD
fdi:010063995
