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Article Structure of the Granitic Pegmatite Field of the Northern Coast of Portugal—Inner Pegmatite Structures and Mineralogical Fabrics

Cristiana Faria *,† and Carlos Leal Gomes † Lab2PT—Universidade do Minho, 4710-057 Braga, Portugal; [email protected] * Correspondence: [email protected]; Tel.: +351-916-087-223 † These authors contributed equally to this work.



Received: 8 December 2018; Accepted: 21 January 2019; Published: 24 January 2019


Abstract: On the coastline of Northern Portugal, metamorphic formations and pegmatites were the subject of structural analysis with the main goal of understanding Variscan kinematics and related pegmatite intrusion. This study also aims to discriminate, select and characterize relevant aspects of the structure and the paragenesis of pegmatites, well exposed as a result of coastal erosion, justifying its inclusion in the geological heritage of the Northern coast of Portugal. The pegmatite bodies show distinctive internal and external structures that are attributable to different modes of emplacement and subsequent deformation. The pegmatitic implantation in the areas of Moledo and Afife occurs in an intragneissic and perigranitic environment, for the first area, and perigneissic and perigranitic environment, for the second. In Pedras Ruivas predominates the implantation into an exo-gneissic to exo-granitic domain. The Moledo veins show evidence of multiphase open/filling, revealing positions, shapes, attitudes, sizes and internal structures that change as a function of the host lithology and host structure, but mainly due to the dilation and the cycles number of local telescoping. The structural analysis of the pegmatite bodies allows the deduction of a local fulcrum of expansion that hypothetically overlaps a hidden stock of parental granite. In Afife and Pedras Ruivas, some pegmatitic lenses are specialized and mineralized in Li, Cs and Ta, with spodumene and tantalite ± cassiterite. Spodumene occurs as giant crystals, centimetric to pluri-decimetric in length, which mark very clearly the structures of in situ or in flow crystallization inside the pegmatites (primary structures) and also the secondary structures resulting from deformation. The geometric analysis of fabrics helps the individualization of well-defined stages of progressive evolution of the deformation of the pegmatites, allowing its correlation with major D2–D3 episodes of regional Variscan deformation.

Keywords: pegmatites; dilation; spodumene; fabric; geological heritage

1. Introduction This seeks sought to explore the geometric analysis of intra-pegmatitic fractionation structures, in a typical dilational context, aiming to contribute to the kinematic interpretation of the internal structures of the pegmatite bodies and their vein fields in intra- and peri-granitic contexts. It also tries to establish the reliability of the use of typomorphic minerals as kinematic markers, in the study of the primary internal pegmatite fabrics, either fluidal or deformational. In fact, it can contribute to accessing the temporal and chronological correlation and influence of the different phases of regional deformation over different lithological supports, complementing the approaches that consider other mega-crystalline phases. This approach is similar to that proposed in [1]. A logical implication and corollary are the attribution of a relative age of the chronological framework of implantation of these pegmatitic assemblages in the context of the structure of the

Heritage 2019, 2, 315–330; doi:10.3390/heritage2010021 www.mdpi.com/journal/heritage Heritage 2019, 2 316

Pegmatite Belt of the Central and Iberian Variscan Province. It will also allow the establishment of a chronological sequence of Li, Cs and Ta (LCT) mineralizations, at least in this sector of the Variscan Orogene. As an associated goal and application, the study tries to discriminate, select and characterize relevant aspects which are well exposed as a result of coastal erosion, suitable for inclusion in the regional geological heritage considering the structure and the paragenesis of pegmatites. The intertidal pegmatite and gneiss outcrops reveal some astonishing peculiarities of lithium bearing pegmatites in a situation or statute of land management that does not allow mining. However they are extremely interesting in what concerns good representative values (mineralogical, petrological, geomorphological and archaeological) and good exposure, suitable for inclusion in the set of sites of geological interest, with didactic and touristic importance, attributed to the geological heritage of the Northern coast of Portugal [2–6]. In the coastal zone between Caminha and Viana do Castelo, a network of aplite-pegmatitic bodies do occur, being more concentrated in a gneissic host-rock in the Northern Sector, especially in the key location—Moledo. In the metasedimentary host-rocks that predominate to the south of the mentioned range, the sill and dyke network is much less dense and its conformation is more dependent on shear deformation, tangential to transcurrent. It is known that the position, shape, orientation, and to some extent, the size of pegmatitic bodies, are controlled by a complex interaction between pegmatitic fluid pressure, rheological state of the host rock, lithostatic and directed strain, porous pressure, anisotropies of the lodging lithologies and dilatational directions. In the upper crust, where fragile deformation conditions prevail, the combination of lithostatic and directional stresses with preexisting anisotropies of resistance to deformation, such as fractures, cleavages, pressure shadows or even stratifications, give rise to preferential attitudes of minimum strength. The pegmatites that occur in these circumstances tend to be tabular and have a preferential orientation, according to those directions. At deeper levels of the crust, generally characterized by states of ductile deformation, pegmatitic intrusions usually assume irregular morphologies. According to [7], the modification of the forms and attitudes of the pegmatites can be interpreted using theoretical models developed for the different combinations of the factors referenced above. Considering the differentiation of evolutionary stages of the implantation of parental plutons, the diversity of veins attitudes can interpreted by adopting the conceptual matrix of Phillips [8,9] and Roberts’s [10] vein setting, which explains the distribution and attitude of tabular to lenticular bodies around circumscribed plutonic stocks. In conjunction with these reference models, originally adjusted to the sequence and hierarchy of attitudes of intrusive tabular bodies in anorogenic (permissive and isotropic) subvolcanic environments, a lateral and apical expansion of the parental plutonisms explains, more generally, the geometries of the pegmatites that cross the contacts between granitoids and hosting formations. Pegmatites assume the configuration of sills with subparallel directions to the contacts between granite and hosting lithologies. In distal locations, they are horizontal. In proximal positions, they show attitudes of deep with a centripetal trend (for proximal sills and cone-sheet in peri-granitic swarms). In areas near parental massifs, the preponderant effect of the configuration of the magmatic chamber in distal sectors and a greater influence of the tensile regional field, help to better understanding of the set of strikes and deeps. In the Northern Coast Pegmatitic Field (NCPF), the positions and attitudes of the proximal pegmatite groups adjust better to the Brisbin models for medium-depth intrusion in ductile/fragile conditions, under the major influence of the local stress field [7]. The arrangement of the sets of pegmatites in a distal situation suggests a greater preponderance of the field of regional tensions [11]. The pegmatites identified were classified into two sets, according to the criteria of [12]. Some are characterized by the presence of beryl and columbite; the remainder are included in the LCT family specialized in lithium, cesium and tantalum, having spodumene or spodumene and tourmaline [11]. Heritage 2019, 2 317

The former have a predominantly aluminous and potassic geochemical feature and the latter are sodium–lithium hyperaluminous. They organized into sets that can be designated as groups, according to [13]. Some show early crystallization of spodumene in large crystals, with an extension following the c-axis of a few centimeters to several decimeters and centimetric width in a and b. The habit of the crystals is prismatic elongated and, therefore, allows registering of all the variations and local displacement, as a consequence of the action of the fields of regional strength that eventually affect the pegmatites’ evolution. It is therefore reasonable to use spodumene as a mineralogical and geometric marker to estimate the progressive displacement and deformation during the intrusion of the pegmatites, from early dilation stages to deformation that overlaps the later crystallization. The fact that the genesis of spodumene is early in the paragenetic sequence potentiates its use as a marker of deformation.

2. Geological and Tectonic Framework In the geological framework of the studied areas, we used the information in sheet 1 of the geological map of Portugal at the 1:200,000 scale [14] and Caminha geological map—1C at the 1:50,000 scale, reviewed in [15]. On the Northern coast of Portugal, according to [16], the structure of the Iberia Variscan Chain shows three main folding phases (D):

• 1st folding phase (D1) is marked by folds with vertical axial planes and a metamorphic surface, with the same attitude, established in a ductile regime; • 2nd folding phase (D2), characterized by the generation of recumbent folds, associated with significant tectonic transport, laminating the previous structures, especially at the inverse fold flanks and a metamorphic surface, with the same attitude, established in a ductile regime; • 3rd folding phase (D3), generation of folds with subvertical axial planes, with a trajectory subparallel to the Ibero-Armorican Arc, occasionally producing a metamorphic flow and axial plane surface, also very inclined to vertical.

According to Lotze’s [17] tectonostratigraphy and paleogeography, modified by [18] and [19], this area is included in Central-Iberian Zone (CIZ) and Galicia-Trás-os-Montes Zone (TMGZ) (Figure1a). The first geotectonic unit is represented by autochthonous terrenes; the second is constituted by parautochtonous terrenes; both are Paleozoic. According to the same authors the evolution of these terrenes depended on the geodynamic evolution of Iberia, with the following major episodes [16,20]:

• Opening of the Rheic ocean, between Gondwana and Avalony—Cambrian-Ordovician (500–470 Ma); • Subduction of the SE margin of the Rheic ocean associated with the retro-arc opening of the ocean Paleothetys—Ordovician to the Silurian (430–390 Ma); • Separation of Armórica/Iberia, by opening of Paleothetys—distensive context; • Closing of the oceans Rheic and Paleotethys (Low to Medium Devonian, 390–370 Ma) and collision due to the Variscan Orogeny, between Iberia and Armorica; • Collision of Avalonia with Gondwana—end of Variscan Orogeny.

The high-resolution cartography of the Northern coast is in good agreement with its inclusion in Central-Iberian Zone of the Variscan chain, considered by [21] as a Central-Iberian Pegmatite Belt in the sense of [13]. According to [21], the Central-Iberian Zone of the Variscan chain includes a great diversity of compositional and structural types of pegmatites that were implanted from endo-granitic to exo-granitic positions and are genetically related, more or less clearly, with the different types of Variscan granites. Heritage 2019, 2 318 Heritage 2018, 2, x FOR PEER REVIEW 4 of 17 Heritage 2018, 2, x FOR PEER REVIEW 4 of 17 In the NCPF, the pegmatites are distributed from endo-gneissic, such as in the Moledo area, In the NCPF, the pegmatites are distributed from endo-gneissic, such as in the Moledo area, where HeritagewhereIn 2018thethe ,hosting 2NCPF,, x FOR PEERoccurs the REVIEW pegmatites in gneissic units, are distributedto exo-gneissic from positions, endo-gneissic, such as in Pedrassuch as Ruivas in the (Viana4 ofMoledo 17 area, the hostingwheredo Castelo), the occurs hosting where in the occurs gneissic pegmatites in gneissic units, occur to insideunits, exo-gneissic ato quartz exo-gnite eissicunit positions, surrounded positions, such by such chiastoltic as as in in Pedras Pedras mica schists. RuivasRuivas (Viana (Viana do Castelo),do Castelo), whereIn the NCPF, thewhere pegmatites the the pegmatites pegmatites occur are occur insidedistributed inside a quartzite froma quartz endo-gneissic,ite unit unit surrounded surrounded such as in bythe chiastoltic chiastolticMoledo area, mica mica schists. schists. where the hosting occurs in gneissic units, to exo-gneissic positions, such as in Pedras Ruivas (Viana do Castelo), where the pegmatites occur inside a quartzite unit surrounded by chiastoltic mica schists.

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Pegmatite F3,sin—F3, medium medium to fine to grained ripplemuscovite-biotitic,Granitic marks pegmatites and bilobites. of the class muscovite-biotitic,rippleGranitic marks pegmatites and bilobites. of the class conglomerates.8. Pegmatites Granitic Pegmatite pegmatites of the PegmatiteGranitic pegmatites Pegmatite of the References fine grained. occasionallywith rarewith metals, garnet LCT and family occasionally with with with rare metals,garnet LCTand family with 8. 8.Pegmatites Pegmatites class with Pegmatite rare spodumenemetals, LCT and Pegmatiteclass with rare Pegmatite metals,spodumene LCT and References tourmaline. tourmaline. tantalite-columbite, beryl and tantalite-columbite, beryl and 1.References Doblas, M. Slickenside8. Pegmatites kinematic indicators.familyGranitic with Tectonophysics pegmatites spodumene of1998 theand, 295 , 187–197.familyGranitic with pegmatites spodumene of theand 1. Doblas, M. Slickenside kinematic indicators. 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Lima,Laxe:Lousal:Methodologically,Detailed 1998,F.; Lousal, Leal geometricpp. Gomes, 23,Portugal, 89–99. the C.analysis Locais 1998.development de (high Interesse resolution of Geológico the presen cartography) e Arquelógico-Mineirot study contemplates of pegmatites no Noroeste the and following de internal, Minho ;procedures IGMlinear e CMand Laxe: 1998, pp. 23, 89–99. 6.5.and Lousal:Lima,stages:planar F.; Lousal, fabricsLealLeal Gomes,Gomes, Portugal, of spodumene; C.C. Actas1998.Cadernos do I Semináriodo Laboratório Sobre Xeolóxico Património de GeológicoLaxe; Cadernos Português do ;Laboratório IGM: Alfragide, Xeolóxico Portugal, de 6.• Lima, F.; Leal Gomes, C. Actas do I Seminário Sobre Património Geológico Português; IGM: Alfragide, Portugal, 5.• Lima,1999;Laxe:DetailedGeometric p. 1998,F.; 6. Leal geometricpp. analysisGomes, 23, 89–99. analysisC. of Cadernos the (highvariability do Laboratório resolution of Xeolóxicothe cartography) pegmatite de Laxe of; Cadernosinner pegmatites structure do Laboratório and internal,and the Xeolóxico linearfabric and deof 1999; p. 6. 7.6. Laxe:Brisbin,Lima,planarspodumene 1998,F.; W.C. fabricsLeal pp. MechanicsGomes, 23,lodged of 89–99. spodumene; C. Actas oftherein, pegmatite do I Seminárioin intrusion.distinct Sobre Am. sectPatrimónio Mineral.ors of Geológico 1986NCPF,, 71, Português644–651. which ; areIGM: considered Alfragide, Portugal, to be 7. Brisbin, W.C. Mechanics of pegmatite intrusion. Am. Mineral. 1986, 71, 644–651. 6.8.• Lima,Phillips,1999;Geometricrepresentatives p. F.; 6. W.J.Leal Hydraulic analysisGomes, of this C. fracturing ofActas variability—the the do variabilityI Seminárioand mineralization. Moledo Sobreof thePatrimónio to pegmatite J.Afife Geol. GeológicoSector Soc. Lond.inner to Português the 1972 structure North,, 128; IGM:, 337–359. where and Alfragide, the the pegmatites fabric Portugal, of 7.8. Brisbin,Phillips, W.C.W.J. HydraulicMechanics fracturing of pegmatite and intrusion. mineralization. Am. Mineral. J. Geol. 1986 Soc. ,Lond. 71, 644–651. 1972, 128 , 337–359. 9. 1999;Phillips,spodumeneare hostedp. 6. W.J. Thein lodgedtwo dynamic mica therein, emplacementgneisses in with distinct of tourmalincone sheets.sectorse Tectonophysicsand of garnet,NCPF, and 1974which ,the 24, Pedras69–84.are considered Ruivas Sector, to bein 8.9. Phillips, W.J. HydraulicThe dynamic fracturing emplacement and mineralization. of cone sheets. J. Tectonophysics Geol. Soc. Lond. 1974 1972, 24, 128, 69–84., 337–359. 7.10. Brisbin,Roberts,representativesthe southern W.C.J.L. The Mechanics part, intrusion of thiswhere of variability—the of pegmatite magmathe pegmatites into intrusion. brittle Moledo were Am.rocks. toimMineral. Mech.Afifeplanted IgneousSector1986 in, 71 quartzites toIntrusion, 644–651. the North, 1970 and, where2 meta-quartzphyllite, 287–338. the pegmatites 9.10. Phillips,Roberts, W.J.J.L. The The intrusion dynamic ofemplacement magma into of brittle cone rocks.sheets. Mech. Tectonophysics Igneous Intrusion 1974, 24 1970, 69–84., 2, 287–338. 8.11. Phillips,Lealare(Figure Gomes,hosted W.J. 1 and C.;Hydraulicin LopestwoTable mica Nunes, 1); fracturing gneisses J.E. Análise and with mineralization. paragenética tourmalin eJ.e classificaçãoandGeol. garnet,Soc. Lond. dos and 1972 pegmatitos the, 128 Pedras, 337–359. graníticos Ruivas da Sector, Cintura in 10.11.• Roberts,Leal Gomes, J.L. TheC.; Lopes intrusion Nunes, of magma J.E. Análise into paragenéticabrittle rocks. Mech.e classificação Igneous Intrusiondos pegmatitos 1970, 2 ,graníticos 287–338. da Cintura 9. Phillips,HercínicatheInterpretation southern W.J. Centro-Ibérica. The part, ofdynamic structures where In emplacement A the Geologia resulting pegmatites de of Engenharia from cone were sheets.im posedime os plantedTectonophysics Recursos and insuperimposed Geológicos quartzites 1974,; 24I. da, and69–84. U.deformation, demeta-quartzphyllite Coimbra: fromCoimbra, the 11. LealHercínica Gomes, Centro-Ibérica. C.; Lopes Nunes, In A J.E. Geologia Análise de paragenéticaEngenharia e os e classificaçãoRecursos Geológicos dos pegmatitos; I. da U. degraníticos Coimbra: da Coimbra, Cintura 10. Roberts,Portugal,(Figurepoint of J.L. 12003; view and The pp. Tableofintrusion 85–109.displacement 1); of magma kinematics, into brittle consideringrocks. Mech. Igneous the rheological Intrusion 1970 behavior, 2, 287–338. of host rocks in HercínicaPortugal, 2003;Centro-Ibérica. pp. 85–109. In A Geologia de Engenharia e os Recursos Geológicos; I. da U. de Coimbra: Coimbra, 11.12.• LealCerny,different Gomes, P.; Ercit, deformational C.; LopesT. The Nunes, classificati regimes. J.E. onAnálise of granitic paragenética pegmatites e classificação revisited. Can. dos pegmatitosMiner. 2005 graníticos, 43, 2005–2026. da Cintura 12. Cerny,Interpretation P.; Ercit, T. of The structures classificati resultingon of granitic from pegmatites imposed revisited. and superimposed Can. Miner. 2005 deformation,, 43, 2005–2026. from the 13. HercínicaCerny,Portugal, P. 2003;AnatomyCentro-Ibérica. pp. 85–109.and classification In A Geologia of de granitic Engenharia pegmatites. e os Recursos Granitic Geológicos Pegmatites; I. da Sci. U. Ind. de Coimbra:1982, 1–39. Coimbra, 13. Cerny,point P.of Anatomyview of displacementand classification kinematics, of granitic consideringpegmatites. Granitic the rheological Pegmatites behaviorSci. Ind. 1982 of ,host 1–39. rocks in 12.4. StructuralPortugal,Cerny, P.; 2003;AnalysisErcit, pp. T. The 85–109. of classificati the Pegmatiteson of granitic Network pegmatites revisited. Can. Miner. 2005, 43, 2005–2026. 13. Cerny,different P. Anatomy deformational and classification regimes. of granitic pegmatites. Granitic Pegmatites Sci. Ind. 1982, 1–39. 12. Cerny, P.; Ercit, T. The classification of granitic pegmatites revisited. Can. Miner. 2005, 43, 2005–2026. 13. Cerny, P. Anatomy and classification of granitic pegmatites. Granitic Pegmatites Sci. Ind. 1982, 1–39. 4.4.1. Structural Moledo Analysis of the Pegmatites Network The Moledo site was considered as representative of the pure dilational lodging and so was 4.1.considered Moledo suitable to a systematic survey of the internal pegmatitic structures characterized by the fabricsThe of Moledomega feldspar, site was tourmaline, considered garnetas representati and, rarelyve ofbut the more pure conspicuously, dilational lodging spodumene. and so Thiswas considereddetailed geometric suitable analysis to a systematic was guided survey by ofphotographic the internal pegmatiticimages (aerial structures views of characterized vertical incidence) by the fabricsobtained of throughmega feldspar, short-haul tourmaline, flights of garnetan unmanned and, rarely aerial but vehicle more (UAVconspicuously, or drone). spodumene. This detailedThe geometricintegration analysis of the two was approaches guided by photographicallowed the correlation images (aerial between views internal of vertical structures incidence) and obtainedmodes of throughintrusion. short-haul The contrasting flights conformationof an unmanned in dikes aerial or vehicle sills was (UAV explained, or drone). comparing domains of differentiatedThe integration dilation of the that two are approaches located in Figureallowed 2. the correlation between internal structures and modesThe of relationshipsintrusion. The between contrasting the extensionconformation (E) and in dikes the pitch or sills (P) was (measured explained, in meters),comparing and domains the E/P ofratios, differentiated presented dilationin Figure that 3, show are located that the in conditions Figure 2. most favorable to the diversification of internal structuresThe relationships occur when thebetween magnitude the extension of expansion (E) and is maximum,the pitch (P) i.e., (measured when the in thickness meters), of and the the in situE/P ratios,differentiation presented is largerin Figure and, 3 ,espe showcially that when the conditions E/P decreases, most favorablea tendency to that the culminatesdiversification in the of fulcruminternal structures occur when the magnitude of expansion is maximum, i.e., when the thickness of the in situ

differentiation is larger and, especially when E/P decreases, a tendency that culminates in the fulcrum

Heritage 2019, 2 319

3. Methods Methodologically, the development of the present study contemplates the following procedures and stages:

• Detailed geometric analysis (high resolution cartography) of pegmatites and internal, linear and planar fabrics of spodumene; • Geometric analysis of the variability of the pegmatite inner structure and the fabric of spodumene lodged therein, in distinct sectors of NCPF, which are considered to be representatives of this variability—the Moledo to Afife Sector to the North, where the pegmatites are hosted in two mica gneisses with tourmaline and garnet, and the Pedras Ruivas Sector, in the southern part, where the pegmatites were implanted in quartzites and meta-quartzphyllite (Figure1 and Table1); • Interpretation of structures resulting from imposed and superimposed deformation, from the point of view of displacement kinematics, considering the rheological behavior of host rocks in different deformational regimes.

4. Structural Analysis of the Pegmatites Network

4.1. Moledo The Moledo site was considered as representative of the pure dilational lodging and so was considered suitable to a systematic survey of the internal pegmatitic structures characterized by the fabrics of mega feldspar, tourmaline, garnet and, rarely but more conspicuously, spodumene. This detailed geometric analysis was guided by photographic images (aerial views of vertical incidence) obtained through short-haul flights of an unmanned aerial vehicle (UAV or drone). The integration of the two approaches allowed the correlation between internal structures and modes of intrusion. The contrasting conformation in dikes or sills was explained, comparing domains of differentiated dilation that are located in Figure2. The relationships between the extension (E) and the pitch (P) (measured in meters), and the E/P ratios, presented in Figure3, show that the conditions most favorable to the diversification of internal structures occur when the magnitude of expansion is maximum, i.e., when the thickness of the in situ differentiation is larger and, especially when E/P decreases, a tendency that culminates in the fulcrum of maximum expansion that is indicated in Figure2. In fact, structural arrangements, indicating a maximum of internal evolution, such as line-rocks or pillow-type structures and the more developed comb-structures, occur precisely in these situations. According to Figure3, there appears to be an extensional magnitude from which the in situ and in flow crystallization differentiates itself. In a vast set of veins whose internal geometry was analyzed, comb-type structures prevail in a number of one to three dilational/coaxial reactivations. Thus, it can be deduced that during the consolidation, the in situ crystallization processes predominated. For greater percentages of extension (>40%) and larger dilational volumes, conditions of occurrence for more than three dilational reactivations are gathered, and in addition to comb structures, line-rocks, albite-pillows and convoluted linear and planar flow fabrics do occur (Figure4). In addition to in situ crystallization, structures with crystallization in flow were observed. Also from the detailed geometric analysis of the Pegmatitic Group of Moledo, the possibility of defining planimetric domains with differentiated dilation arises. In fact, the pure dilation components are much more materialized than the dilation associated with shear. Consequently, the typological differentiation of the pegmatites may be related to kinematic criteria. Heritage 2018, 2, x FOR PEER REVIEW 6 of 17 of maximum expansion that is indicated in Figure 2. In fact, structural arrangements, indicating a maximum of internal evolution, such as line-rocks or pillow-type structures and the more developed Heritagecomb-structures,2019, 2 occur precisely in these situations. According to Figure 3, there appears to be 320an extensional magnitude from which the in situ and in flow crystallization differentiates itself.

Heritage 2018, 2, x FOR PEER REVIEW 7 of 17 FigureFigure 2.2. InterpretationInterpretation of of high-resolution high-resolution cartography cartography at at the the Moledo Moledo Pegmatite Pegmatite Group Group and and zoning zoning of distinct dilation domains. Different colors distinguish magnitudes and number of dilation stages. of distinct dilation domains. Different colors distinguish magnitudes and number of dilation stages.

Figure 3. Dilation analysis—magnitude and multistage character. Colors identify the outcrops representedFigure 3. Dilation in the high-resolution analysis—magnitude map in Figureand multistage2. character. Colors identify the outcrops represented in the high-resolution map in Figure 2.

In a vast set of veins whose internal geometry was analyzed, comb-type structures prevail in a number of one to three dilational/coaxial reactivations. Thus, it can be deduced that during the consolidation, the in situ crystallization processes predominated. For greater percentages of extension (>40%) and larger dilational volumes, conditions of occurrence for more than three dilational reactivations are gathered, and in addition to comb structures, line-rocks, albite-pillows and convoluted linear and planar flow fabrics do occur (Figure 4). In addition to in situ crystallization, structures with crystallization in flow were observed.

(a) (b) (c)

Figure 4. Structural arrangements and fabrics of internal fractionation in situ and in flow (in this case, essentially gravitational) resulting from different numbers of coaxial dilation pulses. (b) drill core of a sill polar structure (the drill core was obtained at the border of the pegmatite field). (a) gravitational polar structure in sill -comb structure to the roof and line-rock to the foot-wall; and (c) Symmetrical structure in dikes - comb layering.

Also from the detailed geometric analysis of the Pegmatitic Group of Moledo, the possibility of defining planimetric domains with differentiated dilation arises. In fact, the pure dilation components are much more materialized than the dilation associated with shear. Consequently, the typological differentiation of the pegmatites may be related to kinematic criteria. Such a system reflects the diversification of internal structures in function of magnitude and time of rock-volume expansion and the prevalence of progressive or multistage dilation (Figure 5) relative to shear dilation at different regimens and alternating repeated dilation/shortening textures (Figure 6).

Heritage 2018, 2, x FOR PEER REVIEW 7 of 17

Figure 3. Dilation analysis—magnitude and multistage character. Colors identify the outcrops represented in the high-resolution map in Figure 2.

In a vast set of veins whose internal geometry was analyzed, comb-type structures prevail in a number of one to three dilational/coaxial reactivations. Thus, it can be deduced that during the consolidation, the in situ crystallization processes predominated. For greater percentages of extension (>40%) and larger dilational volumes, conditions of occurrence for more than three dilational reactivations are gathered, and in addition to comb structures, line-rocks, albite-pillows Heritageand2019 convoluted, 2 linear and planar flow fabrics do occur (Figure 4). In addition to in situ 321 crystallization, structures with crystallization in flow were observed.

(a) (b) (c)

FigureFigure 4. Structural 4. Structural arrangements arrangements and and fabrics fabrics ofof internal fractionation fractionation in insitu situ and and in flow in flow (in this (in case, this case, essentiallyessentially gravitational) gravitational) resulting resulting from from different different numbers numbers of coaxial dilation dilation pulses. pulses. (b) ( bdrill) drill core core of of a a sill polar structure (the drill core was obtained at the border of the pegmatite field). (a) gravitational sill polar structure (the drill core was obtained at the border of the pegmatite field). (a) gravitational polar structure in sill -comb structure to the roof and line-rock to the foot-wall; and (c) Symmetrical polar structure in sill-comb structure to the roof and line-rock to the foot-wall; and (c) Symmetrical structure in dikes - comb layering. structure in dikes-comb layering. Also from the detailed geometric analysis of the Pegmatitic Group of Moledo, the possibility of Suchdefining a system planimetric reflects domains the diversification with differentiated of internal dilation structures arises. in functionIn fact, ofthe magnitude pure dilation and time of rock-volumecomponentsHeritage 2018 expansion ,are 2, x muchFOR PEER more and REVIEW thematerialized prevalence than of the progressive dilation associated or multistage with shear. dilation Consequently, (Figure5)8 relativethe of 17 Heritage 2018, 2, x FOR PEER REVIEW 8 of 17 to sheartypological dilation differentiation at different regimens of the pegmatites and alternating may be related repeated to kinematic dilation/shortening criteria. textures (Figure6). Such a system reflects the diversification of internal structures in function of magnitude and time of rock-volume expansion and the prevalence of progressive or multistage dilation (Figure 5) relative to shear dilation at different regimens and alternating repeated dilation/shortening textures (Figure 6).

(a) (b) (a) (b) Figure 5. Geometric and mineralogical expressions of different stages and magnitudes of dilation - FigureFigureprogressive 5. 5.Geometric Geometric or multistage and and mineralogical mineralogical dilation expressionsstructures expressions in of contrastingdifferent of different stages dilation and stages magnitudesdomains. and ( aof magnitudes) dilationDefined - or of dilation—progressiveprogressiveprogressive or monotypicmultistage or multistage dilation,dilation dilation twostructures stages—independent structures in contrasting in contrasting veindilation fills; dilation domains.and domains.(b) Polytypic(a) Defined (a) Defineddilation or or progressiveprogressivemultiple monotypic stages—common monotypic dilation, dilation, or two coalescing stages—independenttwo stages—independent vein fills. vein vein fills; fills; and and (b) Polytypic(b) Polytypic dilation dilation multiple multiple stages—common or coalescing vein fills. stages—common or coalescing vein fills.

(a) (b) (a) (b) FigureFigure 6. Typology 6. Typology of dilatationalof dilatational pegmatite pegmatite stages—diversi stages—diversityty of internal of internal structures structures associated associated with Figure 6. Typology of dilatational pegmatite stages—diversity of internal structures associated with with differentdifferent reactivations:reactivations: (a) dilation/shorteningdilation/shortening structures, structures, dilation dilation I and I and II IIwith with telescoping telescoping different reactivations: (a) dilation/shortening structures, dilation I and II with telescoping open/filling—mineralogicalopen/filling — mineralogical markers: markers: orthoclase orthoclase plumose plumose and and schorlschorl stretched and and segmented; segmented; (b) (b) open/fillingshear controlled — mineralogical expansion structures:markers: orthoclase dilation II—crac plumosek-seal and and schorl stretching; stretched dilation and segmented; III—dilation (b and) shear controlled expansion structures: dilation II—crack-seal and stretching; dilation III—dilation and shearsinistral controlled shear. expansion structures: dilation II—crack-seal and stretching; dilation III—dilation and sinistralsinistral shear. shear. 4.2. Afife 4.2. Afife The pegmatite set of Afife, like that of Moledo, is also hosted in gneissic rocks composed of a faciesThe of pegmatite two micas set with of Afife, garnet like and that tourmaline, of Moledo, to iswhich also hostedthere are in sometimesgneissic rocks associated composed xenoliths, of a faciesleucocratic of two micassegregations with garnet and schlieren-likeand tourmaline, restites. to which In the there Afife are location,sometimes the associated vein emplacement xenoliths, is leucocraticcontrolled segregations by a pure dilation and schlieren-like and the pegmatites restites. areIn thelodged Afife according location, to the permissive vein emplacement conditions, is or controlledinstead, theby adilation pure dilation lodging and is relatedthe pegmatites with shear, are whichlodged happens according in topull-a-part permissive amplifications conditions, orand instead,volumes. the dilation lodging is related with shear, which happens in pull-a-part amplifications and volumes. 4.3. Pedras Ruivas 4.3. Pedras Ruivas The pegmatite group of Pedras Ruivas, unlike those already considered, is implanted in quartziteThe pegmatite and quartz-phyllite group of Pedrashost-rocks, Ruivas, the rheolounlikegical those contrast already between considered, the quartzite is implanted and quartz- in quartzitephyllite and unit, quartz-phyllite being determinant host-rocks, for its selectivethe rheolo emgicalplacement, contrast with between a competent the quartzite response and to quartz- ductile- phyllitefragile unit, deformation being determinant in contrast for with its selective the surroundi emplacement,ng horizons with aof competent high-fissile response phyllits to andductile- shale fragileformations, deformation including in contrastthe alluded with chiastolite the surroundi mica scnghists horizons that appear of high-fissile more to the phyllits West. Theand attitudeshale formations,of the pegmatites including is conditionedthe alluded chiastoliteby the generation mica sc histsof volumes that appear of expansion more to associated the West. Thewith attitude the shear of processesthe pegmatites (Figure is conditioned7). by the generation of volumes of expansion associated with the shear processes (Figure 7).

Heritage 2019, 2 322

4.2. Afife The pegmatite set of Afife, like that of Moledo, is also hosted in gneissic rocks composed of a facies of two micas with garnet and tourmaline, to which there are sometimes associated xenoliths, leucocratic segregations and schlieren-like restites. In the Afife location, the vein emplacement is controlled by a pure dilation and the pegmatites are lodged according to permissive conditions, or instead, the dilation lodging is related with shear, which happens in pull-a-part amplifications and volumes.

4.3. Pedras Ruivas The pegmatite group of Pedras Ruivas, unlike those already considered, is implanted in quartzite and quartz-phyllite host-rocks, the rheological contrast between the quartzite and quartz-phyllite unit, being determinant for its selective emplacement, with a competent response to ductile-fragile deformation in contrast with the surrounding horizons of high-fissile phyllits and shale formations, including the alluded chiastolite mica schists that appear more to the West. The attitude of the pegmatites is conditioned by the generation of volumes of expansion associated with the shear processes (Figure7). Heritage 2018, 2, x FOR PEER REVIEW 9 of 17

FigureFigure 7.7. High-resolutionHigh-resolution cartography cartography of of the the Pedr Pedrasas Ruivas Pegmatite Group andand kinematickinematic interpretationinterpretation ofof megamega andand mesoscalemesoscale deformationaldeformational episodes.episodes.

5.5. Modes of Occurrence of Spodumene TheThe occurrenceoccurrence ofof spodumenespodumene inin pegmatitespegmatites includesincludes thethe followingfollowing texturaltextural architecturesarchitectures (Figures(Figure 88,– 11Figure): 9, Figure 10 and Figure 11): • CombComb structurestructure duedue toto centripetalcentripetal growthgrowth nucleatednucleated atat thethe pegmatitepegmatite contact;contact; • DisseminationDissemination ofof phenocrysts phenocrysts in ain magmatic a magmatic flow, highlighting flow, highlighting the planar the and planar linear imbricationsand linear accordingimbrications to theaccording fluidalities’ to motionthe fluidalities’ in the fine motion granular in matrix,the fine sometimes granular typically matrix, aplitic;sometimes • Occurrencetypically aplitic; as mega to giga-crystals of sheared spodumene, due to orthogonal shortening or • extensionOccurrence associated as mega with to giga-crystals shear in low viscosityof sheared state spodumene, or in a ductile due regime to orthogonal after the crystallizationshortening or extension associated with shear in low viscosity state or in a ductile regime after the crystallization of the surrounding mesostasis—spodumenes present contours according to the surrounding c / s surfaces.

(a) (b) (c)

Figure 8. Types of pegmatites with spodumene and differentiation of tabular bodies with early comb spodumene: (a) dyke—narrow tabular bodies with early comb spodumene—with symmetrical inner structure; (b) sill—narrow tabular bodies with early comb spodumene—asymmetric polar inner structure resulting from differentiated crystallization from roof-wall to foot-wall; and (c) sill with same characteristics of (b).

There is geometric evidence that the early crystallization of spodumene may occur in situ or in flow (Figure 9 and Figure 10). Deformation can be imposed to the consolidation of the host

Heritage 2018, 2, x FOR PEER REVIEW 9 of 17

Figure 7. High-resolution cartography of the Pedras Ruivas Pegmatite Group and kinematic interpretation of mega and mesoscale deformational episodes.

5. Modes of Occurrence of Spodumene The occurrence of spodumene in pegmatites includes the following textural architectures (Figure 8, Figure 9, Figure 10 and Figure 11): • Comb structure due to centripetal growth nucleated at the pegmatite contact; • Dissemination of phenocrysts in a magmatic flow, highlighting the planar and linear

Heritageimbrications2019, 2 according to the fluidalities’ motion in the fine granular matrix, sometimes323 typically aplitic; • Occurrence as mega to giga-crystals of sheared spodumene, due to orthogonal shortening or ofextension the surrounding associated mesostasis—spodumenes with shear in low viscos presentity state contours or in according a ductile to regime the surrounding after the Heritage 2018, 2, x FOR PEER REVIEW 10 of 17 c/scrystallization surfaces. of the surrounding mesostasis—spodumenes present contours according to the HeritageHeritage 2018, 2 2018, x FOR, 2, xPEER FOR REVIEWPEER REVIEW 10 of 1710 of 17 surrounding c / s surfaces. pegmatites, affecting them when they are in different states or rates of crystallization, or can be pegmatites,superimposedpegmatites, affecting affecting them them when afterwhen they the theyare total in are differencrysta in differenllizationt statest states oror evenrates or afterratesof crystallization, theof crystallization,metasomatism. or can or It be canwas be superimposedpossiblesuperimposed to distinguishaffecting affecting them in them structuralafter afterthe total theterms totalcrysta the crystallization pegmatitesllization or even withor evenafter spodumene, afterthe metasomatism. the metasomatism.attributing It towas thisIt was possiblestructuralpossible to distinguishdiscrimination to distinguish in thestructural in following structural terms major terms the terms pethegmatites ofpe parageneticgmatites with withspodumene, diversity spodumene, (Figure attributing 9,attributing Figure to 10this toand this structuralFigurestructural 11 discrimination): discrimination the following the following major major terms terms of paragenetic of paragenetic diversity diversity (Figure (Figure 9, Figure 9, Figure 10 and 10 and FigureFigure 11): 11): • Type I – narrow tabular bodies with spodumene in early comb-structures (Figure 8); • • Type• Type TypeI – IInarrow –I tabular– narrow tabular bodies tabular bodies with bodies with metrical withspodumene width spodumene wi inth early spodumene, in earlycomb-structures comb-structures tourmaline, (Figure garnet (Figure 8); and 8); apatite - • Type• megacrysts TypeII – tabular II – oftabular spodumenebodies bodies with werewith metrical observmetrical widthed width in wi combth wispodumene, thand spodumene, flow structures tourmaline, tourmaline, (Figure garnet garnet9 );and apatite and apatite - - • megacrystsTypemegacrysts III –of tabular( spodumenea) of spodumene to lenticular were wereobserv bodies observed inof (edcombbvari) inable comb and thickness, flow and structuresflow with structures very (Figure( c deformed()Figure 9); 9); spodumene • Type• III – tabular to lenticular bodies of variable thickness, with very deformed spodumene Figure (cataclasticType 8 8.. TypesTypes III to–of oftabular miloniticpegmatites pegmatites to and lenticularwith with pseudomorphic spodumene spodumene bodies and of and differeinvari phyllosilicates) differentiationablentiation thickness, of tabular of associated tabularwith bodies very bodies withwith deformed early withwell-defined comb early spodumene c/s (cataclastic to milonitic and pseudomorphic in phyllosilicates) associated with well-defined c/s spodumene:comb(shear)(cataclastic spodumene: structures (a) dyke—narrow to (a )milonitic dyke—narrow(Figure tabular 11and); pseudomorphic tabular bodies bodies with early with in comb early phyllosilicates) combspodumene—with spodumene—with associated symmetrical with symmetrical well-defined inner c/s • structure;(shear)innerType(shear) structure; structures IV (b )– structuressill—narrow lenticular (b) sill—narrow (Figure ( Figure bodiestabular 11); tabular 11 withbodies); bodies spodumene with with early early combunits comb spodumene—asymmetricin spodumene—asymmetric late dilations, constituting polar polar inner pull-apart • • structureType structures TypeIV resultingresulting– IVlenticular. – fromlenticularfrom differentiated bodiesdifferentiated bodies with crystallization with spodumenecrysta spodumenellization fromunits from roof-wall units inroof-wall late in to dilations,late foot-wall; to foot-wall;dilations, andconstituting (andc )constituting sill (c with) sill pull-apart samewith pull-apart samestructurescharacteristics structurescharacteristics. of.( b). of (b).

There is geometric evidence that the early crystallization of spodumene may occur in situ or in flow (Figure 9 and Figure 10). Deformation can be imposed to the consolidation of the host

(a) (b) (c) (a) (a) (b) (b) (c) (c) Figure 9. Spodumene mesoscopic fabrics—flow crystallization structure. (a) exposure parallel to c of FiguretheFigure spodumene 9. SSpodumenepodumene 9. Spodumene + rossmanite; mesoscopic mesoscopic mesoscopic (b fabrics—flow) fabrics—flow fabrics—flow rossmanite crystallization crystallization c-axis—defines crystallization structure. structure. a structure.rotational (a) exposure (a )( deltoida exposure) exposure parallel in aplitic parallel parallel to flow—c toof to c of thec ofrotation spodumene thethe spodumene spodumene under + rossmanite;low ++ viscosity rossmanite;rossmanite; (b )and ( bmagmatic )) rossmanite rossmanite flow; c-axis—defines and c-axis—defines c-axis—defines (c) cut perpendicular a rotational a a rotational rotational deltoid to c deltoid of deltoid in the aplitic spodumenein in aplitic flow— aplitic flow— + rotationflow—rotationrossmanite.rotation under under underlow viscosity low viscosity and magmatic andand magmaticmagmatic flow; flow; flow;and and( cand) cut (c )( c cutperpendicular) cut perpendicular perpendicular to c to of cto ofthe c theof spodumene the spodumene spodumene + + +rossmanite. rossmanite.rossmanite.

Spodumene c axis - comb growth Spodumene Spodumene c axis c- axiscomb - combgrowth growth

FigureFigure 10. 10.Spodumene Spodumene mesoscopic mesoscopic fabrics–in fabrics – situ in situ crystallization crystallization structure. structure. Pegmatite Pegmatite sill sill with with comb comb FigurespodumenespodumeneFigure 10. Spodumene growing10. growing Spodumene from mesoscopic from the mesoscopic the intermediate intermediate fabrics fabrics – zonein situzone – to in crysta the tositu the quartz crystallization quartz corellization corestructure. (Afife). (Afife). structure. Pegmatite Pegmatite sill with sill combwith comb spodumenespodumene growing growing from thefrom intermediate the intermediate zone tozone the toquartz the quartz core (Afife). core (Afife).

Heritage 2019, 2 324 Heritage 2018, 2, x FOR PEER REVIEW 11 of 17

(a)

(b)

FigureFigure 11. 11.Spodumene Spodumene mesoscopicmesoscopic fabricsfabrics (Pedras(Pedras Ruivas).Ruivas). (a (a) )Ductile Ductile imposed imposed deformation. deformation. (b) (b)Pegmatite Pegmatite sill sill hosted in low angle reversereverse faultfault withwith c/s c/s andand severalseveral spodumene spodumene fish-like fish-like structures. structures.

6. DiscussionThere is geometric evidence that the early crystallization of spodumene may occur in situ or in flow (Figures9 and 10). Deformation can be imposed to the consolidation of the host pegmatites, affecting The integration of the results of the detailed structural analysis allowed the differentiation of them when they are in different states or rates of crystallization, or can be superimposed affecting meso-scalar fabric domains, which depend very much on the different rheological behavior of the them after the total crystallization or even after the metasomatism. It was possible to distinguish pegmatite host-rocks. The lodging of pegmatites inside gneissic rocks, in the Moledo case (Figure 12 in structural terms the pegmatites with spodumene, attributing to this structural discrimination the and Figure 13) and Afife example (Figure 14 and Figure 15), produces inner structures clearly following major terms of paragenetic diversity (Figures9–11): distinguishable from those occurring in pegmatites lodged inside quartzite strata, which is the case • of TypePedras I—narrow Ruivas (Figure tabular 16 bodies and Figure with spodumene 17). in early comb-structures (Figure8); • TypeThe II—tabularvariation in bodies space withand time metrical of the width regional with stress spodumene, fields combined tourmaline, with garnet the physical and propertiesapatite-megacrysts of the host-rocks of spodumene had a strong were observedinfluence inon comb the structural and flow organization structures (Figure of the9); pegmatitic bodies. Reciprocally, it allows the deduction of the main trajectories of strength, acting in the time lapse of the pegmatites’ permissive emplacement (Figure 12, Figure 13, Figure 16 and Figure 17).

Heritage 2019, 2 325

• Type III—tabular to lenticular bodies of variable thickness, with very deformed spodumene (cataclastic to milonitic and pseudomorphic in phyllosilicates) associated with well-defined c/s (shear) structures (Figure 11); • Type IV—lenticular bodies with spodumene units in late dilations, constituting pull-apart structures.

6. Discussion The integration of the results of the detailed structural analysis allowed the differentiation of meso-scalar fabric domains, which depend very much on the different rheological behavior of the pegmatite host-rocks. The lodging of pegmatites inside gneissic rocks, in the Moledo case (Figures 12 and 13) and Afife example (Figures 14 and 15), produces inner structures clearly distinguishable fromHeritage those 2018, occurring2, x FOR PEER in REVIEW pegmatites lodged inside quartzite strata, which is the case of Pedras Ruivas12 of 17 (FiguresHeritage 16 2018 and, 2, 17x FOR). PEER REVIEW 12 of 17

FigureFigure 12.12. MoledoMoledo location: location: geometry geometry of of sills sills and and dykes, dykes, enhanced enhanced in in a a vertical drone image. Figure 12. Moledo location: geometry of sills and dykes, enhanced in a vertical drone image. MorphometryMorphometry andand morphoscopymorphoscopy ofof thethe dykes (yellow bands)bands) inin the horizontal projectionprojection atat seasea level.level. Morphometry and morphoscopy of the dykes (yellow bands) in the horizontal projection at sea level.

FigureFigure 13.13. Conceptual sketch blocks for Moledo location. (a) Conjugated apicalapical impulseimpulse ofof aa parentalparental stock,stock,Figure superimposedsuperimposed 13. Conceptual to to the sketchthe asymmetrical asymmetrical blocks for regional Moledo regional dilation. location. dilation. (b) ( Isopacsa) Conjugated(b) ofIsopacs linear apical dilationof linear impulse and dilation anomalous of a parental and magnitudeanomalousstock, superimposed respondingmagnitude toresponding locallyto the asymmetricasymmetrical to locally dilation, asymmetric regional white dilation.dilation, lines; simplified white(b) Isopacs lines; distention simplifiedof linear trajectories distentiondilation are and representedtrajectoriesanomalous are in blackmagnituderepresented dashed responding in lines. black dashed to locally lines. asymmetric dilation, white lines; simplified distention trajectories are represented in black dashed lines.

Heritage 2018, 2, x FOR PEER REVIEW 13 of 17 Heritage 2019, 2 326 Heritage 2018, 2, x FOR PEER REVIEW 13 of 17

Figure 14. Afife pull-apart: (a) drone image, with delimitation of the dilation volumes; (b) perspective fromFigure the 14. south, AfifeAfife with pull-apart: horizontal ( a) drone drone projection image, of with the centripetaldelimitation growth of the dilationvectors involumes; the comb-structure (b) perspective of geminatedfrom the south,south, Baveno withwith giga-feldspars. horizontalhorizontal projection of thethe centripetal growth vectors in the comb-structure of geminated Baveno giga-feldspars.

Figure 15. Three-dimensional sketch blocks including spodumene structures from pegmatites hosted Figure 15. Three-dimensional sketch blocks including spodumene structures from pegmatites hosted in gneisses. The corresponding outcrop is located in Afife. inFigure gneisses. 15. Three-dimensional The corresponding sketch outcrop blocks is located including in Afife. spodumene structures from pegmatites hosted in gneisses. The corresponding outcrop is located in Afife.

Heritage 2019, 2 327 Heritage 2018, 2, x FOR PEER REVIEW 14 of 17

Heritage 2018, 2, x FOR PEER REVIEW 14 of 17

Figure 16. Evidence of shortening followed by transcurrent shear deformation, superimposed over Figure 16. Evidence ofof shorteningshortening followed followed by by transcurrent transcurrent shear shear deformation, deformation, superimposed superimposed over over the the internal consolidation in a sill pegmatite body from Pedras Ruivas. theinternal internal consolidation consolidation in a in sill a pegmatitesill pegmatite body body from from Pedras Pedras Ruivas. Ruivas.

Figure 17. Three-dimensional sketch blocks for spodumene structures observed in pegmatites intruded Figure 17. Three-dimensional sketch blocks for spodumene structures observed in pegmatites in quartziteintruded units in quartzite from Pedras units from Ruivas. Pedras The Ruiv correspondingas. The corresponding outcrops outcrops are located are located in Figurein Figure1. Note:1. DiscontinuitiesNote: Discontinuities attributable attributable to the first to deformationthe first deform phaseation (D1)phase tend (D1) totend be to coincident be coincident to those to those related with therelated third with deformation the third deformation phase (D3). phase (D3). Figure 17. Three-dimensional sketch blocks for spodumene structures observed in pegmatites

intruded in quartzite units from Pedras Ruivas. The corresponding outcrops are located in Figure 1. Note: Discontinuities attributable to the first deformation phase (D1) tend to be coincident to those related with the third deformation phase (D3).

Heritage 2019, 2 328 Heritage 2018, 2, x FOR PEER REVIEW 15 of 17

7. ConclusionsThe variation in space and time of the regional stress fields combined with the physical properties of theThe host-rocks permissive had emplacement a strong influence of the aplite-pegmati on the structuraltes at organization the Moledo beach, of the marked pegmatitic by internal bodies. Reciprocally,structures of itin allows situ crystallizat the deductionion and of the centripetal main trajectories fractionation, of strength, essentially acting depends in the time on the lapse dilation of the pegmatites’along an N–S permissive axis. The emplacementmost penetrative (Figures foliation 12, 13of, the16 andgneisses 17). lies between the azimuths N–S and N25° W. The dilation may have as fulcrum a circumscribed and concealed protuberance of parental 7. Conclusions granite. TheIn the permissive case of the emplacement Moledo Group of the and aplite-pegmatites possibly in many at the pegmatites Moledo beach, generated marked in by dilational internal structuresenvironments, of in the situ diversity crystallization of internal and structures centripetal varies fractionation, according essentially to the magnitude depends and on thethe dilationnumber alongof dilation an N–S episodes. axis. The The most hierarchy penetrative and the foliation attribution of the of gneissesa chronology lies betweenfor the deformation the azimuths events N–S andaffecting N25◦ eachW. ThePegmatitic dilation Group may haveis influenced as fulcrum by th ae circumscribed antecedent factors and concealedsuch as the protuberance structure of the of parentalhost-rock. granite. InThe the rheological case of the behavior Moledo of Groupthe host-rock and possibly at the in intrusion many site pegmatites has also a generated strong influence in dilational on the environments,current orientation the diversity of the ofvein internal structures structures and varieson their according response to the to magnitudeoverlapping and deformation; the number ofconsequently, dilation episodes. the spodumene The hierarchy fabric andand thethe attributioncrystal forms of and a chronology shapes are foraffected the deformation and might register events affectingdifferentiated each stages Pegmatitic or variations Group in is magnitude influenced of by the the progressive antecedent deformation. factors such In as the the studied structure region, of thethe host-rock.crystals of spodumene and the pegmatites that carry them denote the action of at least two importantThe rheological and independent behavior episodes of the of host-rock coaxial defo at thermation, intrusion from site crystallization has also a strong to evolution influence under on thesubsolidus current conditions. orientation of the vein structures and on their response to overlapping deformation; consequently,In all pegmatites the spodumene North of fabric Pedras and Ruivas, the crystal the pl formsanar-linear and shapes setting are of affected spodumene and might is affected register by differentiatedthe same deformation stages or that variations generates in magnitude de most penetrative of the progressive foliation deformation. of the host gneisses. In the studied region, the crystalsAt the ofmega spodumene scale, the and results the pegmatitesof the petrofab thatric carry study them reflect denote the thedifference action ofin at rheological least two importantbehavior between and independent meta-quartzofilites episodes of and coaxial gneisses. deformation, It also indicates from crystallization that the lithium to evolution mineralization under subsolidusin the form conditions.of spodumene is synchronous or precedes the last ductile-fragile structuring of quartzite- metaquartzphylliteIn all pegmatites of North Pedras of PedrasRuivas Ruivas,and succeed the planar-linears to the genesis setting of spodumenethe Afife gneisses. is affected This by theassumption same deformation suggests that that Li generates mineralization de most can penetrative be earlier foliation than what of the is generally host gneisses. assumed [15] and still influencedAt the mega by the scale, deformation the results attributed of the petrofabric to D2 (Figure study 18 and reflect Table the 2 difference), Variscan infolding rheological phase. behaviorThe betweenmetallogenic meta-quartzofilites implications of and this gneisses. study led It alsoto the indicates conclusion that that the lithiumthe NCPF mineralization has a great inimportance the form in of what spodumene concerns is the synchronous geological heri or precedestage of Northern the last Portugal, ductile-fragile not only structuring due to the of quartzite-metaquartzphyllitepeculiarity and rarity of the mineralogical of Pedras Ruivas and pegmatitical and succeeds exposures to the genesis and its of geomorphology the Afife gneisses. and Thisinduced assumption coastal suggestslandscape, that but Li mineralizationalso because it can allowed be earlier the than deduction what is generallyof a conceptual assumed model [15] and of stillemplacement, influenced bywhich the deformationrepresents attributedsome of tothe D2 ol (Figuredest and 18 and well-expressed Table2), Variscan evidence folding of phase. Li–Ta metallogenesis in the context of Iberia, particularly in the Central Iberian Pegmatite Belt.

FigureFigure 18.18. ConceptualConceptual profilesprofiles discriminatingdiscriminating contrastingcontrasting stylesstyles ofof pegmatitepegmatite emplacement.emplacement. LegendLegend completedcompleted TableTable2 .2.

Heritage 2018, 2, x FOR PEER REVIEW 4 of 17

In the NCPF, the pegmatites are distributed from endo-gneissic, such as in the Moledo area,

Heritagewhere 2018the ,hosting 2, x FOR PEERoccurs REVIEW in gneissic units, to exo-gneissic positions, such as in Pedras Ruivas (Viana4 of 17 do Castelo), where the pegmatites occur inside a quartzite unit surrounded by chiastoltic mica schists. In the NCPF, the pegmatites are distributed from endo-gneissic, such as in the Moledo area, where the hosting occurs in gneissic units, to exo-gneissic positions, such as in Pedras Ruivas (Viana do Castelo), where the pegmatites occur inside a quartzite unit surrounded by chiastoltic mica schists.

Figure 1. Location and orogenic setting of pegmatite key sites submitted to detailed structural analysis. (a) Structural arrangement of North-western Iberia (adapted from [16]); (b) geological sketch Heritage 2018, 2, x FOR PEER REVIEW 16 of 17 Heritagemap 2018 modified, 2, x FOR PEERfrom REVIEW[14]. Legend completed in Table 1. 16 of 17 Heritage 2018, 2, x FOR PEER REVIEW 16 of 17 TableFigure 2. 1.Lithological Location and correspondences orogenic setting between of pegmatite sketches keyof geological sites submitted map and to detailedprofile. Note:structural the Heritage 2019TableTable, 2 2. 1. LithologicalLegend of the correspondences geological map beof tweenPortugal sketches at the 1:200,000of geological scale map[14] andand Caminha profile. Note:geological the 329 HeritagetourmalineTableanalysis. 2018 , 2.2, xLithological ( FORa rocks) Structural PEER and REVIEW correspondencesthe arrangement metasomatic of North-westerntourmalinitesbetween sketches as Iberia well of (adapted geologicalas the pegmatite from map [16]); and and ( bprofile. ) aplite-pegmatitegeological Note: sketch the16 of 17 map—1C at the 1:50,000 scale, reviewed in [15], applicable to Figure 1. tourmalineoutcropsmap modified do rocks not from have and [14]. thea definite Legendmetasomatic cartographic completed tourmalinites in expression Table as1. well at this as thescale. pegmatite Recent andand quaternaryaplite-pegmatite units LithologiesoutcropswereTable not 2. includedLithologicaldo notin Cartographichave in the correspondencesa definiteoutline ofcartographic theIdentified altimetric between expression Lithologies profilessketches for atof easethisandgeological scale.of Adopted reading. Recent map Designations and and profile.quaternary Note: on units Sheet the Table 2. Lithological correspondences between sketches of geological map and profile. Note: the weretourmalineTable not 1. includedLegend rocks ofand in the the the geological outline metasomatic of mapthe altimetric tourmalinitesof Portugal profiles at asthe wellfor 1:200,000 ease as the of scale reading.pegmatite [14] and and Caminha aplite-pegmatite geological LithologiesSketch According in Cartographic to [14]. Sketch Correspondence1-C Reviewed In The Extended by [15]. Interpretative tourmalineoutcropsmap—1C do rocksat notthe have1:50,000 and a the definite scale, metasomatic reviewed cartographic in tourmalinites[15], expression applicable at to asthis Figure well scale. as1. Recent the pegmatite and quaternary and aplite-pegmatiteunits LithologiesAccording in Cartographic to [14]. Sketch CorrespondenceMoledo In TheProfiles. Extended Afife e PedrasInterpretative Ruivas outcropswere not do included not have in the a definite outline of cartographic the altimetric expressionprofiles for ease at this of reading. scale.Recent and quaternary units were LithologiesAccording 1.in Recent Cartographic to and [14] . Identified Lithologies and AdoptedProfiles. Designations on Sheet not includedAccording in the outline to [14] of. the altimetric Profile profiles AB for ease Profile ofProfiles. reading. CD Profile EF LithologiesSketchHolocene—deposits According1. Recent in Cartographic and to [14]Holocene—. Sketch Correspondence Profile AB1-C Reviewed In Profile The Extended by CD [15] . Interpretative Profile EF Lithologies According1. in depositsRecent Cartographicof dunes and ofto and dunes[14]Holocene— Sketch . and According toMoledo Correspondence Profiles.in theAfife Extended e Pedras Interpretative Ruivas Profiles.

beaches—sandbeaches—sanddeposits[ 14of]. dunes oror gravel. and Profile AB Profile CD Profile EF deposits1. Recent of and dunes and Profile AB Profile CD Profile EF Holocene—deposits1.beaches—sand2. RecentOldgravel. quaternary—river and Holocene— or gravel. 2.1. Old Recent quaternary—river and Holocene—deposits of 2.2. Olddeposits andOldof dunes quaternary— marinequaternary—river of and dunes deposits. and dunesand marine and beaches—sand deposits. or gravel. beaches—sandriverand andmarine marine deposits. or gravel. Chiastolite Heritage 2018 , 23., 2.x 2.Cambrian—alternation FOR Old Olddeposits. gravel.PEER quaternary—river REVIEW and of marine MicaChiastolite schist 5 of 17 Chiastolite 3. Cambrian—alternationdeposits. of Mica schist Chiastolite 3.2.carbonaceous Cambrian—alternationOldand quaternary— marine phyllitedeposits. and of MicaLayered schist schistsChiastolite to chiastolític Lithologies carbonaceous in Cartographic phyllite andIdentified Lithologies and Adopted DesignationsMicaChiastolite onschist Sheet carbonaceousriver3. Cambrian— andsiltite. marine phyllite and ChiastoliteContact Chiastolite metapsamytes HeritageSketch 2018 , 2 ,According x FOR PEER REVIEWto [14]. Tourmalinites—1-C Reviewed by [15]. Mica schist 5 of 17 3. Cambrian—alternationalternationdeposits.3. Cambrian—alternationsiltite. of of of TourmalinitesMicaContact schist Mica schist Chiastolite prototurmalinites and Chiastolite carbonaceous4.carbonaceous Lower Ordovician— phyllite phyllite and and siltite. Moledo TourmalinitesLayered AfifeTourmalinites—Contact schists e Pedras to chiastolíticRuivas Mica schist Lithologies in Cartographic Identifiedcontact Lithologiestourmalinites. and AdoptedTourmalinites DesignationsMica onschist Sheet 5.phyllite Two4.quartzites,3. Lower Cambrian— mica andsiltite. Ordovician— granites siltite.schists and Contactprototourmalinites metapsamytes and Sketch According to [14]. 1-C Reviewed by [15]. Quartzite quartzites,4. Lower Ordovician—quartzites, schists and Tourmalinites— contact tourmalinites. quartzites,alternationsin—F3,quartz fine matrix,schists of and Tourmalinites Porphyritic Quartzite granite of quartzschists andmatrix, quartz matrix,prototurmalinitesMoledo and Afife e PedrasQuartzite Ruivas Quartzite 4.carbonaceous Lower4.grained,conglomerates.quartz Lower Ordovician— matrix, Tourmalinites—Carreço 5. Two micaconglomerates. granites contactQuartzite tourmalinites. to Quartzite to 5.phyllite quartzites,TwoOrdovician—porphyritic..conglomerates. mica and granitessiltite.schists and sin— Porphyritic Porphyriticprototourmalinites Porphyritic and 5.sin—F3, Two mica fine granites sin—F3,metaquartzphyllite fine Porphyritic with two PorphyriticmetaquartzphyllitePorphyritic granite Quartzitegranite withPorphyritic of granite 6.5.quartzites, Two TwoF3,quartz mica mica fine schistsgranites granitesgrained,matrix, sin— Porphyritictwo micas Porphyriticgranite contactof tourmalinites.Porphyriticgranite of grained,grained, porphyritic.fissility and graymicas levels granite with fissilityof and CarreçoCarreço gray levels withof Carreço andsin—F3, quartzF3,conglomerates.porphyritic.. fine coarse matrix, grained, twogranite micas graniteCarreço of graniteCarreço of F3,4. Lower fine grained, ripple markstwo micas and bilobites. graniteripple of marks andgranite bilobites. of porphyritic..porphyritic.. Quartzitegranite to Carreço QuartziteCarreço to 6.5.6. conglomerates.TwoOrdovician— Twograined. porphyritic..mica mica granites granites sin—F3,sin— coarsePorphyriticgranite PorphyriticCarreço GranitesPorphyriticCarreço withGranites with two 6.6. Two Two mica mica granites granites sin—metaquartzphyllite with metaquartzphylliteGranites with 6.quartzites, TwoF3,F3, micacoarse fine schists granitesgrained, grained. sin— Gneissestwo with micas schlierenitic, granite Gneisses of withGranitestwo graniteschlierenitic, micas with of micas sin—F3,F3, coarse coarse grained. fissility and gray levels with fissility and gray two levels micas with 7.7.and Two TwoF3, quartz mica porphyritic..micacoarse matrix,granites granites grained. sin— supermicaceous,granite with restitic Carreçosupermicaceous, twoCarreço with micas restitic 7.grained. Two mica granites sin—F3,ripple marksGneiss and bilobites. Gneissripple marks and bilobites. F3,sin—F3,7.6. conglomerates.Two medium mica medium togranites fine to grained sin— muscovite-biotitic,Gneiss muscovite-biotitic, GneissGranites with 7. Two mediummica granites to fine sin— grained Gneiss Gneiss F3, mediumfine grained. to fine grainedoccasionallyGneisses withGneiss with schlierenitic, garnet and GneissoccasionallyGneisses with with schlierenitic, garnet and F3, mediumF3, coarse to grained.fine grained two micas 7. Two 8.mica Pegmatites granites supermicaceous,tourmaline. Pegmatite with restitic Pegmatite supermicaceous, tourmaline. Pegmatite with restitic 7. Two8. mica Pegmatites8. granites Pegmatites sin— Pegmatite Pegmatite Pegmatite Pegmatite Pegmatite Pegmatite sin—F3,8. mediumPegmatites to muscovite-biotitic, PegmatiteGneiss PegmatiteGneiss muscovite-biotitic, Pegmatite F3, medium to fine grainedGranitic pegmatites of the Granitic pegmatites of the References fine grained. occasionallyclass with rare with metals, garnet LCT and occasionallyclass with rare with metals, garnet LCT and 8. Pegmatites Pegmatite Pegmatite Pegmatite References 8. Pegmatites family withtourmaline. spodumene and family withtourmaline. spodumene and 1. Doblas, M. Slickenside kinematic indicators. Tectonophysics 1998, 295, 187–197. The metallogenic implicationstantalite-columbite,Granitic of this pegmatites study ledberyl of tothe and the tantalite-columbite, conclusionGranitic pegmatites that theberyl of NCPFthe and has a great 1. Doblas, M. Slickenside kinematic indicators. Tectonophysics 1998, 295, 187–197. 2.1. Lima,Doblas, F. M. Itinerários Slickenside Geológicos kinematic do indicators. classAlto-Minho—Estudo with Tectonophysics rare metals, de 1998 LCTlocais, 295 ,de 187–197. classInteresse with Geológico. rare metals, MSc LCT Thesis, importanceReferences in what concerns the geologicalamblygonite. heritage of Northernamblygonite Portugal, not only due to the 2. Lima,Universidade F. Itinerários do Minho, Geológicos Gualtar, do Portugal, Alto-Minho—Estudo 1996; p. 215. de locais de Interesse Geológico. MSc Thesis, peculiarity and rarity8. Pegmatites of the mineralogicalfamily with and spodumene pegmatitical and exposuresfamily with andspodumene its geomorphology and and 3.1. UniversidadeLima,Doblas, F. M. Caracterização Slickenside do Minho, kinematic Gual e Estratégiastar, indicators.Portugal, de 1996; TectonophysicsValori p. zação215. Sustentável1998, 295, 187–197. de Ocorrências Geológicas com 3. Methods tantalite-columbite, beryl and tantalite-columbite, beryl and induced3.2. Lima,Importância coastal F.F. ItineráriosCaracterização Patrimonial. landscape, Geológicos Ph.D.e butEstratégias Th do alsoesis, Alto-Minho—Estudo Universidade becausede Valorização it do allowed Minho, deSustentável locais Gualtar, the de deInteresse deduction Portugal, Ocorrências Geológico. 2006; of p.Geológicas a336. conceptualMSc Thesis, com model of 3. Lima, F. Caracterização e Estratégias deamblygonite. Valorização Sustentável de Ocorrênciasamblygonite Geológicas com emplacement,4. ImportânciaLima,UniversidadeMethodologically, F.; whichLeal Patrimonial. doGomes, Minho, represents theC. Gual LocaisPh.D.developmenttar, somedeTh Portugal,Interesseesis,of Universidade of the Geológico 1996;the oldest presen p. 215.e doArquelógico-Mineiro andt Minho,study well-expressed contemplates Gualtar, Portugal,no Noroeste the evidence 2006;following de Minho p. 336. of ;procedures Li–TaIGM e CM metallogenesis in the4.3.and context Lima,Lousal:stages: F.;F. Lousal, of LealCaracterização Iberia, Gomes, Portugal, particularly C. Locais 1998.e Estratégias de Interesse in thede Geológico CentralValori zaçãoe Arquelógico-Mineiro Iberian Sustentável Pegmatite de no Ocorrências Noroeste Belt. de MinhoGeológicas; IGM e comCM 3. MethodsLousal: Lousal, Portugal, 1998. 5.• Lima,ImportânciaLousal:Detailed F.; Lousal, Leal geometric Patrimonial. Gomes, Portugal, analysisC. 1998.CadernosPh.D. Th(high esis,do Laboratório resolution Universidade Xeolóxico cartography) do Minho, de Laxe Gualtar, of; Cadernos pegmatites Portugal, do Laboratório and 2006; internal, p. 336. Xeolóxico linear and de 5. Lima, F.; Leal Gomes, C. Cadernos do Laboratório Xeolóxico de Laxe; Cadernos do Laboratório Xeolóxico de Author4.5. Contributions:Laxe:Lima,Methodologically,planar 1998,F.; fabricsLeal pp. Gomes, 23, of Formal89–99. spodumene; the C.C. Locais Cadernosdevelopment analysis, de Interessedo Laboratório C.F. of Geológico andthe presen C.L.G.Xeolóxico e Arquelógico-Mineirot study de Laxe contemplates; Cadernos no Noroestedo the Laboratório following de Minho Xeolóxico ;procedures IGM e CM de Laxe: 1998, pp. 23, 89–99. 6.and• Lima,Lousal:Laxe:stages:Geometric 1998,F.; Lousal, Leal pp. analysisGomes, 23,Portugal, 89–99. C. of Actas1998. the do variabilityI Seminário Sobreof thePatrimónio pegmatite Geológico inner Português structure; IGM: and Alfragide, the fabric Portugal, of Funding:6.• Lima,This F.; research Leal Gomes, received C. Actas no do externalI Seminário funding. Sobre Património Geológico Português; IGM: Alfragide, Portugal, 5.6. 1999;Lima,Detailedspodumene p. F.; 6. Leal geometric Gomes, Gomes,lodged C.analysisC. Actastherein,Cadernos do (high I Semináriodoin Laboratório resolutiondistinct Sobre Xeolóxico sectPatrimóniocartography)ors deof GeológicoLaxe NCPF, of; Cadernos pegmatites Português which do ;Laboratório andareIGM: internal,considered Alfragide, Xeolóxico linear Portugal, to and debe 1999; p. 6. Conflicts7. Brisbin,Laxe:1999;planarrepresentatives of Interest:p.1998, 6. W.C.fabrics pp. Mechanics 23,The of of89–99. spodumene; authorsthis of variability—the pegmatite declare intrusion. no conflictMoledo Am. oftoMineral. Afife interest. Sector1986, 71 to, 644–651. the North, where the pegmatites 7.8.• Brisbin,Phillips, W.C.W.J. HydraulicMechanics fracturing of pegmatite and intrusion. mineralization. Am. Mineral. J. Geol. 1986 Soc. ,Lond. 71, 644–651. 1972, 128 , 337–359. 6.7. Lima,Brisbin,Geometricare hosted F.; W.C. Leal inMechanicsanalysisGomes, two mica C. ofActasof pegmatitegneissesthe do variabilityI Seminário withintrusion. tourmalin Sobreof Am. thePatrimónio Mineral. pegmatitee and Geológico1986garnet, , 71inner, andPortuguês644–651. structurethe Pedras; IGM: and Alfragide, Ruivas the Sector,fabric Portugal, ofin 8. Phillips, W.J. Hydraulic fracturing and mineralization. J. Geol. Soc. Lond. 1972, 128, 337–359. 9.8. Phillips,1999;spodumene p. 6. W.J. HydraulicThe lodged dynamic fracturingtherein, emplacement andin mineralization.distinct of cone sheets.sectors J. Tectonophysics Geol. of Soc.NCPF, Lond. 1974 1972which, 24, 128, 69–84.are, 337–359. considered to be References9. Phillips,the southern W.J. The part, dynamic where emplacement the pegmatites of cone were sheets. im plantedTectonophysics in quartzites 1974, 24, and69–84. meta-quartzphyllite 10.7.9. Roberts,Brisbin,Phillips,representatives W.C.W.J.J.L. The TheMechanics intrusion dynamic of this of variability—the of emplacementpegmatite magma into intrusion. of brittle Moledocone rocks.Am.sheets. toMineral. Mech.Afife Tectonophysics IgneousSector1986, 71 toIntrusion, 644–651.1974 the ,North, 24 1970, 69–84., where2, 287–338. the pegmatites 10. Roberts,(Figure J.L. 1 and The Tableintrusion 1); of magma into brittle rocks. Mech. Igneous Intrusion 1970, 2, 287–338. 1. 11.8.10.• Doblas, LealPhillips,Roberts,are Gomes,hosted M. W.J.J.L. Slickenside The C.;Hydraulicin Lopes twointrusion mica Nunes, kinematicfracturing of gneisses magma J.E. Análise and indicators. intowith mineralization. paragenéticabrittle tourmalin rocks.Tectonophysics eMech.eJ. classificaçãoandGeol. Igneous garnet,Soc. 1998Lond. Intrusiondos and, 1972295 pegmatitos the, 128 187–197.1970 Pedras, 337–359., 2 graníticos, 287–338. Ruivas [CrossRef da Sector, Cintura] in 11. LealInterpretation Gomes, C.; Lopes of structures Nunes, J.E. resulting Análise paragenética from imposed e classificação and superimposed dos pegmatitos deformation, graníticos da from Cintura the 9.11. HercínicaPhillips,Lealthe Gomes,southern W.J. Centro-Ibérica. C.; The part,Lopes dynamic where Nunes, In emplacement A the J.E. Geologia pegmatitesAnálise de of paragenéticaEngenharia cone were sheets. ime os e planted TectonophysicsclassificaçãoRecursos in Geológicos quartzites dos 1974 pegmatitos,; 24I. da, and69–84. U. demeta-quartzphyllitegraníticos Coimbra: da Coimbra, Cintura 2. Lima,Hercínicapoint F. Itinerof Centro-Ibérica.viewários of displacement Geol óIngicos A Geologia do kinematics, Alto-Minho—Estudo de Engenharia considering e os Recursos the de Geológicosrheological locais de; I. Interesseda behavior U. de Coimbra: Geolof hostógico. Coimbra,rocks Master’s in Thesis, 10. Portugal,Roberts,Hercínica(Figure J.L. 12003;Centro-Ibérica. and The pp. Tableintrusion 85–109. 1); In of A magma Geologia into de Engenhariabrittle rocks. e os Mech. Recursos Igneous Geológicos Intrusion; I. 1970da U., 2 de, 287–338. Coimbra: Coimbra, UniversidadePortugal,different 2003; deformational do pp. Minho, 85–109. Gualtar, regimes. Portugal, 1996; p. 215. 12.11.• Cerny,LealPortugal, Gomes, P.; 2003;Ercit, C.; pp. LopesT. The 85–109. Nunes, classificati J.E. onAnálise of granitic paragenética pegmatites e classificação revisited. Can. dos pegmatitosMiner. 2005 graníticos, 43, 2005–2026. da Cintura Interpretation of structures resulting from imposed and superimposed deformation, from the 3. 12.13.Lima, Cerny,Hercínica F. CaracterizaçP.;P. AnatomyCentro-Ibérica.Ercit, T. The andão classificati classification e In Estrat A Geologiaéongias of of graniticde granitic Engenharia Valorizaç pegmatites pegmatites. eã oso SustentRecursos revisited. Granitic áGeológicosvel Can.Pegmatites de Miner. Ocorr; I. da Sci. 2005ê U.ncias Ind. de, 43 Coimbra:1982, Geol 2005–2026., 1–39.ógicas Coimbra, com Importância 4. Structuralpoint of Analysisview of displacement of the Pegmatites kinematics, Network considering the rheological behavior of host rocks in 13.Patrimonial. Cerny,Portugal, P. Anatomy2003; Ph.D. pp. 85–109.Thesis,and classification Universidade of granitic do pegmatites. Minho, Gualtar, Granitic Portugal, Pegmatites 2006;Sci. Ind. p. 1982 336., 1–39. different deformational regimes. 12. Cerny, P.; Ercit, T. The classificatiLocaison de of Interesse granitic Geolpegmatitesógico erevisited. Arqueló gico-MineiroCan. Miner. 2005 no, 43 Noroeste, 2005–2026. deMinho 4. 4.1.Lima, Moledo F.; Leal Gomes, C. ; IGM e CM

13.4.Lousal: StructuralCerny, Lousal, P. AnatomyAnalysis Portugal, and of theclassification 1998. Pegmatites of granitic Network pegmatites. Granitic Pegmatites Sci. Ind. 1982, 1–39. The Moledo site was considered as representative of the pure dilational lodging and so was 5. Lima, F.; Leal Gomes, C. Locais de Interesse Para a Arqueologia Mineira do Alto Minho (N. de Portugal) considered suitable to a systematic survey of the internal pegmatitic structures characterized by the 4.1.Estado Moledo Actual-m étodos de Caracterização e Estratégias de Aproveitamento. Cadernos do Laboratório Xeolóxico fabrics of mega feldspar, tourmaline, garnet and, rarely but more conspicuously, spodumene. This detailedde LaxeThe geometric1998Moledo, 23 ,site 89–99.analysis was considered was guided as by representati photographicve of images the pure (aerial dilational views oflodging vertical and incidence) so was 6. consideredobtainedLima, F.; through Leal suitable Gomes, short-haul to a C.systematicActas flights do surveyof I Semin an unmanned ofário the Sobre internal aerial Patrim pegmatitic vehicleónio Geol (UAV structuresógico or Portugudrone). characterized ê s; IGM: Alfragide, by the Portugal, fabrics1999;The p.of integration 6.mega feldspar, of the tourmaline, two approaches garnet allowed and, rarely the correlationbut more conspicuously, between internal spodumene. structures Thisand 7. detailedmodesBrisbin, of geometric intrusion. W.C. Mechanics analysisThe contrasting ofwas pegmatite guided conformation by intrusion. photographic in dikesAm. Mineral. imagesor sills was (aerial1986 explained,, 71views, 644–651. of comparing vertical incidence) domains obtainedof differentiated through dilation short-haul that flights are located of an inunmanned Figure 2. aerial vehicle (UAV or drone). The relationshipsintegration of between the two theapproaches extension allowed (E) and th thee correlation pitch (P) (measured between internalin meters), structures and the andE/P modesratios, presentedof intrusion. in FigureThe contrasting 3, show that conformation the conditions in dikes most or favorable sills was toexplained, the diversification comparing of domains internal ofstructures differentiated occur whendilation the that magnitude are located of expansion in Figure 2is. maximum, i.e., when the thickness of the in situ differentiationThe relationships is larger between and, espe thecially extension when E/P (E) decreases,and the pitch a tenden (P) (measuredcy that culminates in meters), in theand fulcrum the E/P ratios, presented in Figure 3, show that the conditions most favorable to the diversification of internal structures occur when the magnitude of expansion is maximum, i.e., when the thickness of the in situ differentiation is larger and, especially when E/P decreases, a tendency that culminates in the fulcrum

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8. Phillips, W.J. Hydraulic fracturing and mineralization. J. Geol. Soc. Lond. 1972, 128, 337–359. [CrossRef] 9. Phillips, W.J. The dynamic emplacement of cone sheets. Tectonophysics 1974, 24, 69–84. [CrossRef] 10. Roberts, J.L. The intrusion of magma into brittle rocks. Mech. Igneous Intrusion 1970, 2, 287–338. 11. Leal Gomes, C.; Lopes Nunes, J.E. Análise paragenética e classificação dos pegmatitos graníticos da Cintura Hercínica Centro-Ibérica. In A Geologia de Engenharia e os Recursos Geológicos; I. da U. de Coimbra: Coimbra, Portugal, 2003; pp. 85–109. 12. Cerny, P.; Ercit, T. The classification of granitic pegmatites revisited. Can. Miner. 2005, 43, 2005–2026. [CrossRef] 13. Cerny, P. Anatomy and classification of granitic pegmatites. Granitic Pegmatites Sci. Ind. 1982, 1–39. 14. Pereira, E. Folha 1—Minho—Carta geológica de Portugal à escala 1:200.000. Serv. Geol. Portugal. 1989. 15. Leal Gomes, C. Minuta (SINGULAR) de revisão da Folha 1C-Caminha. Carta geológica de Portugal na escala 1: 50 000. 2008. Available online: https://repositorium.sdum.uminho.pt/handle/1822/33593 (accessed on 24 January 2019). 16. Dias, R.; Araújo, A.A.; Terrinha, P.; Kullberg, J.C. Geologia de Portugal, Volume I, Geologia Pré-mesozóica de Portugal; Escolar Editora: Maputo, Mozambique, 2013. 17. Lotze, F. Zur Gliederung der Varisziden der Iberischen Meseta. Geotekt. Forschg 1945, 6, 78–92. 18. Julivert, M.; Fontboté, J.; Ribeiro, A.; Conde, L. Memória explicativa del Mapa Tectónico de la Península Ibérica y Baleares. Escala 1/100000. Inst. Geol. Min. España Madrid 1974, 133. 19. Farias, P.; Gallastegui, G.; Lodeiro, F.G.; Marquinez, J.; Parra, L.M.M.; Catalán, J.R.M.; Maciá, J.G.P.; Fernandez, L.R. Aportaciones al conocimiento de la estratigrafía y estrutura de Galicia Central. Mem. An Fac. Cien. Univ. Porto 1987, 1, 411–431. 20. Ribeiro, A.; Munhá, J.; Dias, R.; Mateus, A.; Pereira, E.; Ribeiro, L.; Fonseca, P.; Araújo, A.; Oliveira, T.; Romão, J.; et al. Geodynamic evolution of the SW Europe Variscides. Tectonics 2007, 26.[CrossRef] 21. Leal Gomes, C. Estudo Estrutural e Paragenético de um Sistema Pegmatóide Granítico–o Campo Aplito-Pegmatítico de Arga Minho, Portugal. Unpublished Ph.D. Thesis, Minho University, Gualtar, Portugal, 1994.

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