Fluid migration through thrust faults in the Helvetic nappes (Western Swiss Alps)

Details

Serval ID
serval:BIB_DA7F2C021D68
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Fluid migration through thrust faults in the Helvetic nappes (Western Swiss Alps)
Journal
Contributions to Mineralogy and Petrology
Author(s)
Kirschner D.L., Masson H., Sharp Z.D.
ISSN-L
0010-7999
Publication state
Published
Issued date
1999
Peer-reviewed
Oui
Volume
136
Pages
169-183
Language
english
Abstract
The delta(18)O, delta(13)C and Sr-87/Sr-86 values of calcite and organic
matter were measured for carbonate mylonites from numerous thrusts in
the Helvetic Alps. Carbonate mylonites in most of the thrusts retain
essentially unaltered protolith delta(18)O and delta(13)C values,
consistent with there having been little to no advection of isotopically
distinct fluid through these faults. Only carbonate mylonites from the
basal thrusts of the largest nappes have delta(18)O and/or delta(13)C
values that differ from those of their protoliths. The zone of isotopic
alteration/exchange is confined to c. 10 to 20 meters of these fault
contacts. We propose the fluids that migrated through these faults
contained variable amounts of organically derived carbon and radiogenic
strontium, and were probably derived from dewatering of the sedimentary
rocks and prograde metamorphic reactions in the nappes' root zones.
Apart from the basal thrusts of the largest nappes that behaved as
narrow, laterally extensive conduits for fluids, there is little
isotopic evidence that large quantities of fluids passed through most of
the carbonate-hosted thrusts in the Helvetic Alps.
Create date
07/12/2012 14:51
Last modification date
20/08/2019 15:59
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