The continental crust of the Austroalpine Domain : the record of multiple rejuvenation of an orogenic scar
Abstract
Data di Pubblicazione:
2014
Citazione:
The continental crust of the Austroalpine Domain : the record of multiple rejuvenation of an orogenic scar / M.I. Spalla, F. Delleani, A.M. Marotta, G. Rebay, A. Regorda, M. Roda, F. Salvi, D. Zanoni, M. Zucali, G. Gosso. - In: RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA. - ISSN 2035-8008. - 31:Suppl. 1(2014 Sep), pp. 687-687. (Intervento presentato al convegno Congresso SGI-SIMP tenutosi a Milano nel 2014).
Abstract:
In the Alpine continental crust structural, metamorphic, sedimentary and igneous signatures indicate that orogenic
scars are weak lithospheric zones of recurring tectonic and metamorphic rejuvenation during successive convergent and
divergent plate dynamics. Fortunately, the overprint related to Alpine subduction and collision in the Austroalpine
domain has not completely erased the markers of the transition from Variscan convergence to Permian – Triassic
lithospheric thinning, making this domain a key repository to investigate the recycling of passive margins in subduction
environments. Due to the fact that subduction–collision zones are characterized by the amalgamation and
disaggregation of lithospheric slices, in these domains the determination of contours for thermally and structurally
characterized units is crucial to accurately exploit the rock memory (i), and define the variations in sizes of crustal slices
involved in the dynamic evolution of an active margin (ii). The dimensions of these structural entities evolve over time
and can be reconstructed using the structural and metamorphic evolution of the basement rocks as tracers. These
tectono-metamorphic units (TMUs) represent discrete portions of the orogenic crust influenced by a sequence of
metamorphic and textural changes and their translational trajectories and shape changes can be derived from a joint
reconstruction of quantitative P-T-d-t paths. This analytical approach offers the opportunity to test the physical
compatibilities of the interconnected variables constraining numerical modelling, such as density, viscosity, and heat
transfer, with structural, petrologic and geochronological data. Comparison between modelling predictions and natural
data, obtained by this analytical approach, helped to solve longstanding ambiguities on the pre-Alpine and Alpine
geodynamic evolution of Central and Western Austroalpine units and to explore the crustal levels of protolith
derivation.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
pre-Alpine rifting; Alpine subduction; geophysical modeling
Elenco autori:
M.I. Spalla, F. Delleani, A.M. Marotta, G. Rebay, A. Regorda, M. Roda, F. Salvi, D. Zanoni, M. Zucali, G. Gosso
Link alla scheda completa: