Result of our detailled cartography of Alpe Larecc
(2001-2002) |
A detail cartographic*
study has allowed to highlight a discordant*
contact between the Campo Tencia mass metasediments and the subjacent
amphibolites. This could either represent a
tectonic*,
or a sedimentary
contact* with perhaps a time-gap. The latter interpretation is
compatible with an episode of rifting*
and sedimentation in a system of tilted
blocks*. The contact between amphibolite and augen
gneiss* of the Verzasca complex is delimited by a sheared border
facies of the augen gneiss (alpine or variscian deformation).
Other maps "home-made"
here!!! |
The geochemistry*
of Alpe Larecc amphibolites denotes an E-MORB*
or OIB* signature.
Their close association with a quartzo-feldspathic*
series and the gradual transition from levels more or less rich in amphiboles
led us to interpret them as a volcanogenic*
series, emplaced in a context of rifting, at the foot
of the margin*. The caledonian*
age of the underlying granites (450 My, Köppel et al. 1980 [reference])
suggests that these amphibolites are related to the Paleotethys* rifting. |
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