<sup>40</sup>Ar/<sup>39</sup>Ar laserprobe dating of mylonitic fabrics in a polyorogenic terrane of NW Iberia
Juan Gómez Barreiro
Jan R. Wijbrans
Pedro Castiñeiras
José R. Martínez Catalán
Ricardo Arenas
Florentino Díaz García
Jacobo Abati
10.6084/m9.figshare.3454295.v1
https://geolsoc.figshare.com/articles/dataset/_sup_40_sup_Ar_sup_39_sup_Ar_laserprobe_dating_of_mylonitic_fabrics_in_a_polyorogenic_terrane_of_NW_Iberia/3454295
<p>The tectonothermal evolution of a polyorogenic terrane in the Variscan belt of NW Spain has been constrained by <sup>40</sup>Ar/<sup>39</sup>Ar laserprobe incremental heating experiments on mylonitic fabrics developed in major structures. Transitional levels between
HP–HT and IP upper units in the Órdenes Complex where metamorphic and structural records demonstrate two cycles of burial
and exhumation were selected for dating. Two groups of ages have been defined: (1) Silurian–Early Devonian, obtained from
mylonites of the Fornás extensional detachment, here considered as the minimum age for the start of tectonic exhumation of
the HP–HT units and an upper age-limit for the HP–HT event itself; (2) Early to Mid-Devonian, from structures related to the
Variscan convergence in the area, which include top-to-the-east thrusts and extensional detachments. A single, younger Carboniferous
age obtained from the uppermost allochthonous sequences possibly reflects the final stages of emplacement of the allochthonous
complexes. Our data indicate a polyorogenic character for a part of the Iberian allochthonous complexes, including Variscan
(<em>sensu stricto</em>) and Early Variscan convergence, as well as an older, Early Palaeozoic cycle.
</p>
2016-06-21 12:01:56
Forn ás extensional detachment
Variscan convergence
HP
Ó rdenes Complex
Iberian allochthonous complexes
exhumation
laserprobe
NW
mylonitic fabrics
polyorogenic terrane
Ar
IP
Geology