Neogene kinematics of the Giudicarie Belt and eastern Southern Alpine orogenic front (northern Italy)
<p>Neogene indentation of the Adriatic plate into Europe led to major modifications of the Alpine orogenic structures and style of deformation in the Eastern and Southern Alps. The Giudicarie Belt is a prime example of this, as it offsets the entire Alpine orogenic edifice; its activity has be...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-06-01
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| Series: | Solid Earth |
| Online Access: | https://se.copernicus.org/articles/12/1309/2021/se-12-1309-2021.pdf |
| Summary: | <p>Neogene indentation of the Adriatic plate into Europe led to major
modifications of the Alpine orogenic structures and style of deformation in
the Eastern and Southern Alps. The Giudicarie Belt is a prime example of
this, as it offsets the entire Alpine orogenic edifice; its activity has
been kinematically linked to strike-slip faulting and lateral extrusion of
the Eastern Alps. Remaining questions on the exact role of this
fold-and-thrust belt in the structure of the Alpine orogen at depth
necessitate a quantitative analysis of the shortening, kinematics, and depth
of decoupling beneath the Giudicarie Belt and adjacent parts of the Southern
Alps. Tectonic balancing of a network of seven cross sections through the
Giudicarie Belt parallel to the local NNW–SSE shortening direction reveals
that this belt comprises two kinematic domains that accommodated different
amounts of shortening during overlapping times. These two domains are
separated by the NW–SE-oriented strike-slip Trento-Cles–Schio-Vicenza
fault system, which offsets the Southern Alpine orogenic front in the south
and merges with the Northern Giudicarie Fault in the north. The SW kinematic
domain (Val Trompia sector) accommodated at least <span class="inline-formula">∼</span> 18 km of
Late Oligocene to Early Miocene shortening. Since the Middle Miocene, this
domain experienced at least <span class="inline-formula">∼</span> 12–22 km shortening, whereas the
NE kinematic domain accommodated at least <span class="inline-formula">∼</span> 25–35 km
shortening. Together, these domains contributed an estimated minimum of
<span class="inline-formula">∼</span> 40–47 km of sinistral strike-slip motion along the Northern
Giudicarie Fault, implying that most offset of the Periadriatic Fault is due
to Late Oligocene to Neogene indentation of the Adriatic plate into the
Eastern Alps. Moreover, the faults linking the Giudicarie Belt with the
Northern Giudicarie Fault reach <span class="inline-formula">∼</span> 15–20 km depth, indicating a
thick-skinned tectonic style of deformation. These fault detachments may
also connect at depth with a lower crustal Adriatic wedge that protruded
north of the Periadriatic Fault and are responsible for N–S shortening and
eastward, orogen-parallel escape of deeply exhumed units in the Tauern
Window. Finally, the E–W lateral variation of shortening across the
Giudicarie Belt indicates internal deformation and lateral variation in
strength of the Adriatic indenter related to Permian–Mesozoic tectonic
structures and paleogeographic zones.</p> |
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| ISSN: | 1869-9510 1869-9529 |