Fluid–rock interactions related to metamorphic reducing fluid flow in meta-sediments: example of the Pic-de-Port-Vieux thrust (Pyrenees, Spain)

Trincal, Vincent; Buatier, Martine; Charpentier, Delphine; Lacroix, Brice; Lanari, Pierre; Labaume, Pierre; Lahfid, Abdeltif; Vennemann, Torsten (2017). Fluid–rock interactions related to metamorphic reducing fluid flow in meta-sediments: example of the Pic-de-Port-Vieux thrust (Pyrenees, Spain). Contributions to mineralogy and petrology, 172(9) Springer-Verlag 10.1007/s00410-017-1394-5

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In orogens, shortening is mainly accommodated by thrusts, which constitute preferential zones for fluid–rock interactions. Fluid flow, mass transfer, and mineralogical reactions taking place along thrusts have been intensely investigated, especially in sedimentary basins for petroleum and uranium research. This study combines petrological investigations, mineralogical quantifications, and geochemical characterizations with a wide range of analytical tools with the aim of defining the fluid properties (nature, origin, temperature, and redox) and fluid–host rock interactions (mass transfers, recrystallization mechanisms, and newly formed synkinematic mineralization) in the Pic-de-Port-Vieux thrust fault zone (Pyrenees, Spain). We demonstrate that two geochemically contrasted rocks have been transformed by fluid flow under low-grade metamorphism conditions during thrusting. The hanging-wall Triassic red pelite was locally bleached, while the footwall Cretaceous dolomitic limestone was mylonitized. The results suggest that thrusting was accompanied by a dynamic calcite recrystallization in the dolomitic limestone as well as by leaching of iron via destabilization of iron oxides and phyllosilicate crystallization in the pelite. Geochemical and physical changes highlighted in this study have strong implications on the understanding of the thrust behavior (tectonic and hydraulic), and improve our knowledge of fluid–rock interactions in open fluid systems in the crust.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Lanari, Pierre

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0010-7999

Publisher:

Springer-Verlag

Language:

English

Submitter:

Pierre Lanari

Date Deposited:

19 Sep 2019 10:53

Last Modified:

23 Oct 2019 18:35

Publisher DOI:

10.1007/s00410-017-1394-5

BORIS DOI:

10.7892/boris.112212

URI:

https://boris.unibe.ch/id/eprint/112212

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