Gonçalves, A., Sant’Ovaia, H., Noronha, F., 2019. Emplacement mechanism of Caria-Vila da Ponte Pluton (Northern Portugal): Building and internal magmatic record. J Struc Geol 124, 91-111.
The late to post-tectonic biotite granites from Caria–Vila da Ponte area were studied for their mineralogical, microstructural and petrophysical standpoint using anisotropy of magnetic susceptibility coupled to petrography and scanning electron microscopy. One main direction, N339°-345°E, of stretching magnetic lineations, was found indicating that the emplacement of these granites was tectonically controlled. Although, the Caria – CA (on the W) and Vila da Ponte -VP (on the E) granites outcrops in distinct bodies, the results pointed out similar petrographic and petrophysical characteristics for both. Thus, it is suggested that both granites belong to only one asymmetric laccolith with a deep root feeder zone located in VP massif. A five-stage model is proposed: (I) passive magma ascent along NNW-SSE deep faults and in situ doming emplacement recorded in the magnetic/magmatic fabric; (II) after total crystallization of the pluton, a late alteration most evident in the VP granite, promoted a normal zoning of the magnetic susceptibility; (III) NNW-SSE to NNE-SSW regional faults promoted the uplift of the CA relatively to VP; (IV) laying of quartz veins implied the development of an intense sericitization, most evident in the CA; (V) circulation of later hot fluids implied alteration and concentration of metallic phases.
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