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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. • Caria-Vila da Ponte Variscan biotite-rich granites (Sernancelhe, Northern Portugal). • Emplacement of the late-to post-tectonic asymmetric laccolithic pluton tectonically controlled. • Petrographic and petrophysic studies allowed similar features for both granites, which outcrop in two distinct bodies. • Deep root feeder zone inferred from anisotropy of magnetic susceptibility. [ABSTRACT FROM AUTHOR]

The Santa Eulália Plutonic Complex (SEPC), located in the Ossa Morena Zone (south Portugal), is composed of a medium- to coarse-grained pink granite (G0-type) and a central grey medium-grained biotite granite (G1-type). Available Rb–Sr data indicates an age of 290 Ma. An emplacement model for the SEPC is proposed, taking into account magnetic fabric, 2D gravity modelling and fluid inclusion planes studies. The G0 and G1 types demonstrate different magnetic behaviour: G0 is considered a magnetite-type granite and G1 is an ilmenite-type granite. The formation of G0 required oxidized conditions related to the interaction of mafic rocks with a felsic magma. The 2D gravity modelling and subvertical magnetic lineations show that the feeder zone of the SEPC is located in the eastern part of the pluton, confirming the role of the Assumar and Messejana Variscan faults in the process of ascent and emplacement. The magma emplacement was controlled by ENE–WSW planar anisotropies related to the final brittle stages of the Variscan Orogeny. The emplacement of the two granites was almost synchronous as shown by their gradational contacts in the field. The magnetic fabric however suggests emplacement of the G0-type first, closely followed by emplacement of the G1-type, pushing the G0 laterally which becomes more anisotropic towards the margin. The G1-type became flattened, acquiring a dome-like structure. The SEPC is a nested pluton with G0-type granite assuming a tabular flat shape and G1-type forming a rooted dome-like structure. After emplacement, SEPC recorded increments of the late Variscan stress field documented by fluid inclusion planes in quartz. [ABSTRACT FROM AUTHOR]