Tracing wedge-internal deformation by means of strontium isotope systematics of vein carbonates

Dielforder, Armin; Villa, Igor M.; Berger, Alfons; Herwegh, Marco (2022). Tracing wedge-internal deformation by means of strontium isotope systematics of vein carbonates. Geological Magazine, pp. 1-15. Cambridge University Press 10.1017/S0016756821001357

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Radiogenic strontium isotopes (87Sr/86Sr) of vein carbonates play a central role in the tectonometamorphic study of fold-and-thrust belts and accretionary wedges and have been used to document fluid sources and fluxes, for example, along major fault zones. In addition, the 87Sr/86Sr ratios of vein carbonates can trace the diagenetic to metamorphic evolution of pore fluids in accreted sediments. Here we present 87Sr/86Sr ratios of vein carbonates from the Infrahelvetic flysch units of the central European Alps (Glarus Alps, Switzerland), which were accreted to the North Alpine fold-and-thrust belt during the early stages of continental collision. We show that the vein carbonates trace the Sr isotopic evolution of pore fluids from an initial seawater-like signature towards the Sr isotopic composition of the host rock with increasing metamorphic grade. This relationship reflects the progressive equilibration of the pore fluid with the host rock and allows us to constrain the diagenetic to low-grade metamorphic conditions of deformation events, including bedding-parallel shearing, imbricate thrusting, folding, cleavage development, tectonic mélange formation and extension. The strontium isotope systematics of vein carbonates provides new insights into the prograde to early retrograde tectonic evolution of the Alpine fold-and-thrust belt and helps to understand the relative timing of deformation events.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Villa, Igor Maria; Berger, Alfons and Herwegh, Marco

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0016-7568

Publisher:

Cambridge University Press

Language:

English

Submitter:

Marco Herwegh

Date Deposited:

09 Mar 2022 18:44

Last Modified:

09 Mar 2022 18:44

Publisher DOI:

10.1017/S0016756821001357

BORIS DOI:

10.48350/166282

URI:

https://boris.unibe.ch/id/eprint/166282

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