2. 1434 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
Fig. 1 (Inset) Setting of the Rheic suture with respect to Variscan and Cadomian Massifs in southeastern Europe (adapted from Nance et al.
2010). An overview of the geology of the South Portuguese and Pulo do Lobo zones (adapted from Braid et al. 2012)
Fig. 2 A summary of the geology of the GMP and host Pulo do Lobo zone, with sample locations shown
3. 1435Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
a classic accretionary complex that records the collision
between these continents (Fig. 1; Eden 1991; Quesada
and Dallmeyer 1994; Onézime et al. 2003; Braid et al.
2011) and separates a portion of Laurussia (South Portu-
guese Zone, SPZ) from Gondwana (Ossa Morena Zone,
OMZ). The SPZ and PDLZ are crosscut by the Sierra Norte
Batholith (Fig. 1), for which published data suggest intru-
sion occurred between ca. 350 and 300 Ma (Dunning et al.
2002, de la Rosa 1992; Braid et al. 2010, 2012).
This study focuses on the composite Gil Marquez pluton
(GMP), an important component of the Sierra Norte Batho-
lith, which intrudes the PDLZ suture zone. The GMP is com-
prised primarily of gabbro, granite, and granodiorite. These
rocks have the potential to elucidate the late-stage tectonic
evolution of this collisional setting and may provide insights
into processes responsible for the generation of magmas
within suture zones, as well as temporal constraints for the
emplacement of the host rocks within the suture zone.
The GMP contains both foliated and nonfoliated com-
ponents suggesting their syn- to postcollision emplacement
(Castro et al. 1995; de la Rosa et al. 2002; Braid et al. 2012).
However, (1) the timing of pluton emplacement, (2) the
timing and origin of the foliation relative to regional defor-
mation, and (3) the age relationships between the internal
phases of the pluton remain poorly understood. In this paper,
we provide new U–Pb laser ablation inductively coupled
plasma mass spectrometry (LA-ICP-MS) analyses of mag-
matic, inherited, and xenocrystic zircons from different com-
ponents of the GMP. Taken together with petrographic and
field observations, these data provide insights into the age(s)
and emplacement mechanism(s) of the GMP, its likely crus-
tal sources, and the relationship between fabric development
in both the pluton and the suture zone host rocks.
Geologic setting
The late Paleozoic collision of Gondwana and Laurus-
sia resulted from the closure of the Rheic Ocean and was
a major event in the formation of the Variscan orogenic
Fig. 3 Field relationships
within the GMP, and with sur-
rounding host rocks. a Unfoli-
ated gabbro intruded by foliated
intermediate phase. b Unfoli-
ated gabbro intruded by biotite
granite. c Parallel foliation
shared between granodiorite
and quartz diorite, demonstrat-
ing coeval emplacement and
supporting magma mingling
processes. d Biotite granite
intruding foliated intermediate
phase, and intersecting the folia-
tion. e Biotite granite intrud-
ing host Pulo do Lobo schist
and transecting the foliation. f
Porphyritic granite intruding a
quartz wacke of the Ribeira de
Limas Formation (high angle to
the intrusive contact)
4. 1436 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
belt and the amalgamation of Pangea (Matte and Ribeiro
1975; Franke 1989, 2000; Matte 2001; Stampfli and Borel
2002; Onézime et al. 2003; Van Der Voo 2004; Mur-
phy and Nance 2008; Braid et al. 2010, 2011; Weil et al.
2010; Gutiérrez-Alonso et al. 2008, 2011; Martínez Cata-
lán 2011). In southern Iberia, the Pangean suture zone is
unusually well exposed and separates the parautochthonous
Ossa Morena Zone (Gondwana) from the South Portuguese
Zone (SPZ) (Laurussia) (Onézime et al. 2002, 2003; Nance
et al. 2010; Braid et al. 2011, 2012). Abundant 355–300 Ma
calc-alkaline magmatism along the southern margin of the
OMZ is interpreted to be genetically linked to subduction
beneath the Gondwanan margin (Jesus et al. 2007; Cas-
tro et al. 2002) marking the oblique closure of the Rheic
Ocean and juxtaposition of the SPZ to the south (Quesada
1991). During this convergence, oceanic metasedimentary
rocks, sedimentary mélange, mafic mélange, and flysch
deposits of the PDLZ are thought to have accreted on the
OMZ upper plate and deformed during continued sinistral
convergence (Fig. 1; Eden 1991; de la Rosa et al. 2002;
Simancas et al. 2005; Braid et al. 2010; Dahn et al. 2014).
However, recent detrital zircon data show that the meta-
sedimentary rocks are not derived from either the SPZ or
the OMZ, suggesting the PDLZ likely had a more complex
tectonic history (Braid et al. 2011).
The exposed geology of the SPZ contains mostly Devo-
nian-Carboniferous sedimentary and bimodal volcanic
sequences of the Iberian Pyrite Belt (IPB), which con-
sists from oldest to youngest: (1) upper Devonian Phyllite
Quartzite (PQ) Group (Braid et al. 2012); (2) Late Famen-
nian to middle Visean age Volcano Siliceous Complex
(VSC), hosting the volcanogenic massive sulfide (VMS)
mineralization (Dunning et al. 2002; Rosa et al. 2008);
and (3) Upper Visean to the Serpukhovian turbiditic flysch
group (Schermerhorn 1971; Oliveira et al. 1986). The PQ
rocks were deposited in a sub-tidal environment in a sand
bar and fan delta system on a shallow-marine continental
platform. Detrital zircon data from PQ host rocks yield age
populations dominated by ca. 1.8–2.3 and ca. 0.5–0.7 Ga,
with minor 2.5–2.9 Ga zircons (Braid et al. 2011). The
Fig. 4 Enclaves, Xenoliths,
and the magmatic aureole of the
GMP. a Ribeira de Limas quartz
wacke Xenolith hosted in foli-
ated granodiorite. The foliation
of the granodiorite wraps the
xenolith and displays a pressure
shadow. b Mafic dyke intruding
unfoliated gabbro and foliated
granodiorite. The gabbro was
previously intruded by the
granodiorite, with a fine-grained
chill margin present. c Mag-
matic enclave hosted in coeval
granodiorite and quartz diorite
providing further evidence of
magma mingling processes.
d Enclave hosted in foliated
granodiorite, stretched in the
foliation direction. e Xenoliths
of Ribeira de Limas and Gil
Marquez gabbro in a biotite
granite. f Cordierite growth in
the Ribeira de Limas host rocks,
within the northern magmatic
aureole of the GMP
5. 1437Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
Fig. 5 Petrography of gabbro (ERG66). a–d Photomicrographs dis-
playing medium-grained unfoliated gabbro, comprised of hornblende
(hb), plagioclase (pl), and augite (aug) with minor apatite, zircon (zr),
titanite, skeletal Ilmenite (op), and trace chlorite (chl) and calcite
(cal); the plagioclase exhibits subophitic intergrowths with augite and
hornblende. e Macroscopic field sample of gabbro
Fig. 6 Petrography of quartz diorite (ERG21). a–b Photomicro-
graphs displaying strongly foliated, coarse-grained quartz diorite,
comprised of andesine (pl), biotite (bt), and hornblende with minor
quartz (~10–15 %, (qtz), orthopyroxene, apatite (ap), k-feldspar, zir-
con (zr), and opaque minerals. c–d Myrmekitic texture exhibited by
an intergrowth of quartz and plagioclase. e Macroscopic field sample
of quartz diorite
6. 1438 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
VSC is comprised of mafic and felsic rocks, with tuffites,
siltstones, purple shales, and minor limestones, with the
latter dated by conodonts and cephalopods constraining its
depositional age as upper Famennian-Tournaisian to upper
Visean (Braid et al. 2012).
The PDLZ is comprised of four polydeformed fault-
bounded lithotectonic units (Fig. 1; Braid et al. 2011): (1)
quartz–mica schists and local quartzite mélange of the
Pulo do Lobo Formation; (2) quartz wackes and phyllites
of the Ribeira de Limas Formation (RDL), which con-
tains palynomorphs interpreted as evidence for a Givetian-
Frasnian depositional age (Oliveira et al. 1986; Giese et al.
1988); (3) hectometer- to meter-scale internally deformed
olistostromal quartzites in a polydeformed phyllite–quartz-
ite matrix (Alajar mélange); (4) tectonically emplaced
mafic blocks in a volcaniclastic and schistose matrix of the
Peramora mélange (Eden 1991; Braid et al. 2011, 2012;
Dahn et al. 2014). The age of the protolith of the imbricated
sedimentary sequences in the Peramora mélange is con-
strained by paleontological data (Eden and Andrews 1990)
that yield a Givetian to Famennian age (ca. 390–360 Ma).
The Santa Ira Flysch (SIF) unconformably overlies all four
PDLZ lithotectonic units and is comprised of relatively
simply deformed graywackes, shales, and siltstones (Fig. 1;
Braid et al. 2011). A late Devonian to early Carbonifer-
ous depositional age has been inferred from the spores and
acritarchs (Eden 1991), although Dahn et al. (2014) suggest
that these ages may be misleading.
The PDLZ is intruded by the GMP, which is a compo-
nent of the ca. 350 and 300 Ma Sierra Norte Batholith
(Figs. 1, 2; de la Rosa 1992; Dunning et al. 2002; Braid
et al. 2011). The Sierra Norte Batholith is a voluminous
composite batholith, comprised of granitic, tonalitic, gab-
broic and dioritic compositions, which intruded the PDLZ
and SPZ and is considered to be syn- to posttectonic with
respect to the Variscan deformation in the region (Fig. 1;
Simancas 1986; de la Rosa et al. 1993; Soriano and Casas
2002; Braid et al. 2010). The SNB has been interpreted to
represent either: (1) the plutonic counterpart of coeval VSC
exposed in the SPZ (Soler 1980; Schultz et al. 1987) or (2)
late-orogenic intrusive complexes, unrelated to the VSC
volcanism (Simancas 1986). Based on whole rock Rb–Sr
isotopic data, de la Rosa et al. (1993, 2002) interpreted the
SNB granitoids to be the products of mixing/mingling of
magmas derived from melting of the lithospheric mantle
and the lower crust in an active continental margin setting.
Published age data suggest that the components of the GMP
could range in age from 359 to 325 Ma (Kramm et al. 1991;
Giese et al. 1993; de la Rosa et al. 2002; Braid et al. 2012).
According to de la Rosa (1992), emplacement of the
GMP occurred after the main deformation phase of the
Variscan orogeny. However, the intermediate phases
Fig. 7 Petrography of biotite granite (ERG11). a–b Photomicro-
graphs displaying coarse-grained biotite granite, comprised of quartz
(qtz), albite-oligoclase (pl), microcline, biotite (bt) with minor apatite
(ap), zircon, titanite, and opaque minerals. c Perthitic texture between
albite (ab) and microcline (mc). d Oscillatory zoning in plagioclase. e
Macroscopic field sample of biotite granite
7. 1439Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
display a steep (70–90o
) east–west foliation, which is par-
allel to the main orogenic fabric in the host rocks and is
interpreted to reflect late stages of regional deformation
of the PDLZ during its emplacement and crystallization
(Castro et al. 1995). In this context, intrusion and emplace-
ment of the GMP have been interpreted to be synkinematic
with respect to the final (transpressional) phase of regional
deformation (Castro et al. 1995).
Field relationships
Four main intrusive phases of the GMP were documented
and are from oldest to youngest (Fig. 2): (1) an unfoliated
gabbro that comprises a significant portion of the GMP;
(2) a foliated intermediate phase comprised of quartz dior-
ite, tonalite, and granodiorite, which is the most abundant
phase in the GMP; (3) an unfoliated porphyritic granite;
and (4) an unfoliated biotite granite.
The unfoliated gabbro intrudes the RDL unit of the
PDLZ, and the intrusive contact is exposed in numerous
localities throughout the pluton (Dahn et al. 2014). The
gabbro is intruded by all other phases (Figs. 2, 3), and
xenoliths of gabbro are common in all phases of the GMP,
especially in the biotite granite (Fig. 4e), indicating that
the gabbro is the oldest component of the GMP. The foli-
ated intermediate phases intrude the gabbro, but are cross-
cut by the unfoliated biotite granite (Figs. 2, 3) and by
the porphyritic granite, indicating that these intermediate
phases are older than both granite phases. The composi-
tionally intermediate phases display mingling textures
between mafic and felsic magmas and show evidence of
hybridization, ranging in composition from quartz diorite
to granodiorite. The foliated granodiorite, biotite granite,
and porphyritic granite also intrude the lithologies of the
PDLZ to the north, east, south, west (Figs. 2, 3), and con-
tain abundant xenoliths and enclaves of the PDLZ meta-
sedimentary rocks (Fig. 4a, d). Dahn et al. (2014) define
the contact aureole in further detail. Some, but not all,
enclaves and xenoliths are elongate parallel to the folia-
tion (Fig. 4d). The tectonic foliations are commonly con-
tinuous with the regional foliation in the PDLZ wall rock,
Fig. 8 Concordia plots and SEM photomicrographs of gabbro
(ERG66). a Concordia plot of magmatic age of gabbro. b Macro-
scopic field sample of gabbro. c Concordia plot of inherited zircon
population. d SEM image of a subhedral stubby inherited zircon with
heterogeneous overgrowth zoning, and spot analyses location e SEM
image of an oval ‘soccer ball’ inherited zircon with heterogeneous
zoning, and spot analyses location
8. 1440 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
although local occurrences of the foliation at a high angle
to the wall rock also occur (Fig. 3f, e). Porphyritic granite
intrudes both the gabbro and foliated granodiorite (Figs. 2,
3) and is intruded by the biotite granite phase (Figs. 2, 3),
providing evidence that the biotite granite is the young-
est phase in the GMP. Additionally, alkali granite (Monte
Chico Pluton) intrudes the Peramora Mélange (Fig. 2)
(PDLZ) to the southwest of the town of Aroche (Dahn
et al. 2014). Although an intrusive contact between alkali
granite pluton and the PDLZ is exposed, its contact with
the main GMP pluton is not exposed and the relationship
is poorly understood (Dahn et al. 2014).
Sampling
Samples were selected from the GMP for U–Pb (zir-
con) age dating in order to enhance the understanding of
the intrusive age of different plutonic phases, the age of
foliation development, and the regional significance of
its emplacement into the PDLZ suture zone. Ten samples
(Fig. 2) were selected: (1) two biotite granites (ERG11,
ERG57A) and one porphyritic granite (ERG65) from the
unfoliated phases; (2) one quartz diorite (ERG21) and one
tonalite (ERG29) from the intermediate foliated phases;
(3) four unfoliated gabbro samples (ERG66, ERG81A,
ERG81C, and ERG89); and (4) one unfoliated alkali gran-
ite (ERG62) from the Monte Chico intrusion to the NW of
the main GMP body.
Sample descriptions
Gabbro
The unfoliated gabbro is medium grained and comprised
of hornblende, plagioclase, and augite with minor apatite,
zircon, titanite, skeletal ilmenite, and trace chlorite and cal-
cite. The plagioclase displays sub-ophitic intergrowths with
Fig. 9 Concordia plots and SEM photomicrographs of gabbro
(ERG81A). a Concordia plot of magmatic age of gabbro. b SEM
image of euhedral magmatic zircon with oscillatory zoning, and spot
analyses location. c Concordia plot of inherited zircon population. d
SEM image of morphology’s of zircons present in the gabbro. e Mac-
roscopic field sample of gabbro
9. 1441Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
augite and hornblende (Fig. 5). ERG81A, 81C, and 89 are
fine to medium grained and have the same mineralogy and
textures as ERG66 (with additional minor biotite) and are
interpreted to belong to the same consolidated gabbroic
body. The presence of minor calcite and epidote (Fig. 5)
shows the original gabbro has limited secondary alteration
and/or metamorphism.
Intermediate foliated components
The quartz diorite (ERG21) is strongly foliated, coarse
grained, and comprised of plagioclase (andesine), biotite,
and hornblende, with minor quartz (~15 %), orthopyroxene,
apatite, K-feldspar, zircon, and opaque minerals (Fig. 6).
ERG 21 exhibits myrmekitic texture, pericline polysyn-
thetic twinning, and oscillatory zoning in the plagioclase
(Fig. 6b). The tonalite (ERG29) shows a moderate tectonic
foliation, is coarse grained, and is comprised of plagioclase,
biotite, and quartz, with minor hornblende, apatite, zircon,
and opaque minerals. The foliation is defined by the pre-
ferred orientation of euhedral plagioclase (which exhibits
oscillatory zoning) and K-feldspar megacrysts, along with
interstitial biotite and hornblende.
Porphyritic granite
Porphyritic granite (ERG65) intrudes both the gabbro and
intermediate foliated phases (Fig. 2). The sample has a por-
phyritic texture with phenocrysts of k-feldspar and consists
of quartz, plagioclase, and amphibole with minor apatite,
zircon, titanite, and opaque minerals. Micrographic inter-
growths of quartz and k-feldspar occur in ERG65, along with
albite twinning and oscillatory zoning in the plagioclase.
Biotite granite
The biotite granite (ERG11, 57A) is the youngest phase
and is coarse grained and comprised of quartz, plagioclase
(albite-oligoclase), K-feldspar (microcline), biotite, with
minor apatite, zircon, titanite, and opaque minerals. Per-
thitic texture and oscillatory zoning are common in plagio-
clase (Fig. 7).
Fig. 10 Concordia plots and SEM photomicrographs of gabbro
(ERG81C). a Concordia plot of magmatic age of gabbro. b Macro-
scopic field sample of gabbro. c Concordia plot of inherited zircon
population. d SEM image of subhedral fractured inherited zircon with
no zoning, and spot analyses location. e SEM image of rounded sub-
hedral inherited zircon with no zoning, and spot analyses location
10. 1442 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
Alkali granite
The alkali granite (ERG62) from the Monte Chico plu-
ton, which intrudes the Peramora Mélange (PDLZ), is
medium-coarse grained and comprised of quartz, plagio-
clase (albite), K-feldspar (microcline), biotite, with minor
apatite, zircon, titanite, hornblende, and opaque minerals.
Abundant zoning and twinning is present in the plagioclase.
U–Pb geochronology
Methods
Heavy minerals were separated from samples ERG11, 62,
65, 21, 29, 66, 81A, and 89 by Overburden Drilling Man-
agement Limited (ODM). Samples ERG57A and 81C as
well as duplicate samples ERG 11 and 62 were processed
and separated at the Earth Sciences Mineral Separation
facility at Dalhousie University. Samples sent to ODM
were crushed to <2 mm fraction by Activation Labs in Lan-
caster, ON, and returned to ODM. A cleaner quartz sample
was inserted between each sample during crushing to pre-
vent carryover and contamination of the samples. ODM
screened the crushed material to 1 mm and processed the
<1 mm fractions on a shaking table. The concentrates from
the shaking table were further refined by hand panning.
A rare earth pencil magnet was then used to separate the
magnetic and paramagnetic minerals. Zircon grains were
hand-picked from the nonmagnetic fraction, isolated from
the rest of the sample, and encapsulated in a separate vial.
Samples sent to Dalhousie University were crushed and
sieved on a shaking table into different fractions, with the
finest fraction being <250 micrometers, separating light
and heavy minerals (density separation). Separated heavy
mineral fractions were further subjected to the heavy liquid
(sodium polytungstate) separation, as an additional means
of concentrating Zircons. The remaining concentrate was
separated using a Frantz Isodynamic Magnetic Separator,
to extract remaining heavy minerals (rutile, magnetite, gar-
net). Separation was conducted at 0.4 and 0.8 A with result-
ant fractions encapsulated in separate vials based on mag-
netic and nonmagnetic properties.
Fig. 11 Concordia plot, relative probability plot, and SEM pho-
tomicrographs of gabbro (ERG89). a Concordia plot of magmatic
age of gabbro. b SEM image of fractured euhedral magmatic zircon
with heterogeneous zoning, and spot analyses location. c Zircon his-
togram/relative probability plot. d SEM image of oval ‘soccer ball’
inherited zircon with heterogeneous zoning, and spot analyses. e
Macroscopic field sample of gabbro
11. 1443Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
Analysis
Zircon dating (U–Pb), by LA-ICP-MS, was performed at
the University of New Brunswick, Department of Earth
Sciences, using a Resonetics M-50 193 nm excimer laser
system connected, via Nylon tubing, to an Agilent 7700×
quadrupole ICP-MS equipped with dual external rotary
pumps (see Archibald et al. 2013 for details). Zircons
were ablated using 24-μm craters for U–Pb geochronol-
ogy and 33-μm craters for Trace/REE. A 4.5-Hz rep-
etition with the laser energy at the target (fluence) regu-
lated at 3.5 J/cm2
was used for all analysis. An analysis
comprised 20 s of background gas collection followed
by 25 s of ablation. A total of 278 analyses were done on
the cores and rims of zircons in lithologies ranging from
gabbroic to granitic in composition; 52 spot analyses of
zircons from gabbroic samples (ERG66, 12; ERG81A,
21; ERG81C, 11; and ERG89, 8), 40 spot analyses from
foliated phases with intermediate composition (ERG 21,
18; ERG 29, 22), and 186 spot analyses of zircons from
granite samples (ERG11, 105; ERG57A, 20; ERG65,
26; and ERG62, 35). All ages used and uncertainties are
reported at 2σ, or 95 % confidence. Data were reduced
using Iolite 2.15 software, and plots generated using Isop-
lot 3.71 (Ludwig 2003). Data were organized by sample
and rock type then sorted by percent discordance. Dis-
cordance was calculated by the following formula: %
Discordance = 100 % * [(207Pb/206Pb age − 206Pb/238U
age)/207Pb/206Pb age] (Gehrels et al. 2006). A discordance
level of <10 % was chosen as the cutoff for acceptable
error, and such analyses are deemed to be concordant. The
data from all spot analyses are given in the Data Reposi-
tory (Tables EG1-12), but only concordant analyses are
discussed in the following sections. Our interpretations are
largely based on concordant magmatic and inherited age
populations. A population is considered robust if it con-
sists of a cluster of three or more zircons with similar ages
(Gehrels et al. 2006).
Fig. 12 Concordia plot, relative probability plot, and SEM photomi-
crographs of quartz diorite (ERG21). a Concordia plot of magmatic
age of quartz diorite. b SEM image of euhedral magmatic zircon with
oscillatory zoning, and spot analyses location. c Zircon histogram/
relative probability plot. d SEM image of oval ‘soccer ball’ inherited
zircon with heterogeneous zoning, and spot analyses. e Equivalent
Cathodoluminescence image of zircon grain in figure d, where zoning
mimics that of the Backscattered Electron image
12. 1444 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
Results
Gabbro (ERG66, 81A, 81C, 89)
Zircons from the gabbroic samples commonly show mul-
tifaceted terminations, and the majority of the grains have
a euhedral–subhedral stubby morphology, with a minor
amount of zircons having an oval ‘soccer ball’ habit
(Figs. 8, 9, 10, 11). SEM-backscattered electron imaging
reveals (1) zircon cores, which are multifaceted to rounded
and contain heterogeneous overgrowth, oscillatory zoning
overgrowth, or homogenous overgrowth rims or (2) zircons
without cores, which show heterogeneous zoning, oscilla-
tory zoning, or no zoning (Figs. 8, 9, 10, 11).
Sample ERG66 (Figs. 5, 8, Table EG-1): Of 12 spot
analyses (Fig. 8), six are concordant. Of these, two yield
an age of ca. 346.3 ± 7.7 Ma and two yield an older age of
2,668 ± 75 Ma. The remaining two concordant grains yield
ages of 399.5 ± 37 and 2,553 ± 46 Ma. Sample ERG81A
(Fig. 9, Table EG-2): Of 21 spot analyses (Fig. 9a), fifteen
are concordant. Two yielded an age of 355.9 ± 15 Ma, and
four define an older population at 452.7 ± 4.5 Ma. The
remaining nine concordant grains yield ages ranging from
996.3 ± 13 to 1,963 ± 26 Ma. Sample ERG81C (Fig. 10,
Table EG-3): Of 11 spot analyses (Fig. 10), four are concord-
ant. These yield ages from 368.7 ± 9.6 to 522.6 ± 12 Ma.
Sample ERG89 (Fig. 11, Table EG-4): Of 8 spot analyses,
only one is concordant and yields an age of 2,673 ± 35 Ma.
Intermediate foliated components (ERG21, 29)
Zircons from the intermediate phases commonly show mul-
tifaceted terminations with the majority of the grains hav-
ing a euhedral to subhedral stubby morphology, and some
zircons with oval ‘soccer ball’ habits are present (Figs. 12,
13). SEM-backscattered electron imaging reveals (1) zircon
cores, which are multifaceted to rounded and contain heter-
ogeneous overgrowth or oscillatory zoning overgrowth rims
(Fig. 12) or (2) zircons without cores, which show hetero-
geneous or homogeneous zoning, or no zoning (Fig. 13c).
Fig. 13 Concordia plots and SEM photomicrographs of tonalite
(ERG29). a Concordia plot of magmatic age of the tonalite. b SEM
image of stubby euhedral magmatic zircon with faint zoning, and
spot analyses location. c Concordia plot of inherited zircon popula-
tion. d SEM image displaying morphology’s of zircons present in the
tonalite. e Macroscopic field sample of tonalite
13. 1445Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
Sample ERG21 (Figs. 6, 12, Table EG-5): Of 17
spot analyses, nine are concordant. Of these, a cluster
of four zircons define a population and yield an age of
348.5 ± 4.0 Ma. The remaining five concordant grains
range in age from 627.9 ± 10 to 2,717 ± 27 Ma. Sam-
ple ERG29 (Fig. 13, Table EG-6): Of 23 spot analy-
ses, eight are concordant. Of these, three yield an age
of 338.2 ± 4.5 Ma and four a slightly older age of
346.3 ± 3.2 Ma (Fig. 13a). The remaining concordant grain
gives an age of 365 ± 6.5 Ma. Exposed field relationships
of the GMP show that the intermediate phases are coeval,
and therefore, both samples were combined giving an age
of 345.6 ± 2.5 Ma based on eleven concordant grains.
Granites (ERG11, 57A, 65, 62)
Zircons from granite samples dominantly show multifac-
eted terminations with the majority of the grains having
a euhedral to subhedral elongate morphology, although
zircons with oval ‘soccer ball’ and euhedral to subhedral
stubby habits are also present (Figs. 16e, 17e). SEM-back-
scattered electron imaging reveals (1) zircon cores, which
are multifaceted to rounded and contain heterogeneous
overgrowth or oscillatory zoning overgrowth rims or (2)
zircons without cores, which show heterogeneous zoning,
oscillatory zoning, and are homogeneous (e.g., Fig. 17e).
Sample ERG11 (Figs. 7, 14, Table EG-7, 7.1): Of 104
spot analyses, fifty-four are concordant. Several popula-
tions can be defined. A cluster of four zircons define the
youngest population with an age of 336.8 ± 4.0 Ma, with
older populations of 355.4 ± 1.7 Ma (seven zircons),
513.2 ± 2.8 Ma (six zircons), and 2,699 ± 35 Ma (three
zircons). The remaining thirty-three concordant grains
range in age from 433.9 ± 6.5 to 3,533 ± 22 Ma.
Sample ERG57A (Fig. 15, Table EG-8). Of 21 spot
analyses, nine are concordant. Of these, one yields an
Fig. 14 Concordia plots and SEM photomicrographs of biotite gran-
ite (ERG11). a Concordia plot of magmatic age of the biotite granite.
b SEM image of elongate euhedral magmatic zircon with oscillatory
zoning, and spot analyses location. c Concordia plot of inherited zir-
con population age. d SEM image of rounded subhedral inherited zir-
con with heterogeneous zoning, and spot analyses location. e SEM
image of fractured euhedral inherited zircon with oscillatory over-
growth, and spot analyses location
14. 1446 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
age of 336.8 ± 7.3 Ma and the youngest population is a
cluster of three zircons, which collectively yield an age of
494.1 ± 6.7 Ma, while remaining five concordant grains
range in age from 1,400 ± 20 to 1,838 ± 36 Ma. Both bio-
tite granite samples (give sample numbers) are from the
same pluton. Therefore, the data from both samples were
combined giving a population of 335.1 ± 2.8 Ma defined
by a cluster of five concordant grains.
Sample ERG65 (Fig. 16, Table EG-9). Of 26 spot anal-
yses, thirteen are concordant. Of these, a cluster of three
zircons yield an age of 346.5 ± 5.4 Ma and the remaining
ten concordant grains range in age from 361.4 ± 9.0 Ma
to 1,890 ± 19 Ma. Sample ERG62 (Monte Chico Gran-
ite, Fig. 17, Table EG10). Of 35 spot analyses, eight are
concordant. Of these, a cluster of six zircons yield an age
population of 344.8 ± 3.0 Ma, and the other two concord-
ant grains give ages of 341.9 ± 6.6 and 349.2 ± 5.4 Ma
(Fig. 17b).
Interpretation
Magmatic ages of the GMP
The magmatic age for the various phases of the GMP was
determined from euhedral zircon crystals, using spot analy-
ses on rims. The youngest concordant population of three
or more euhedral zircon crystals was used to determine
magmatic age (e.g., Gehrels et al. 2006). Older concordant
populations and individual grains are interpreted as inher-
ited ages and represent either xenocrysts from wall rock, or
residue from the source rock. For a more detailed descrip-
tion on the criteria of how individual zircon grains were
selected to avoid zoning, inclusions, lead loss, etc., see
Corfu et al. (2003).
Field data suggest that unfoliated gabbroic phase is the
oldest component of the GMP. No single sample of gab-
bro contains a cluster of three or more concordant zircons.
Fig. 15 Concordia plots and SEM photomicrographs of biotite gran-
ite (ERG57A). a Concordia plot of magmatic age of the biotite gran-
ite. b SEM image of euhedral magmatic zircon with oscillatory zon-
ing, and spot analyses location. c Concordia plot of inherited zircon
population age. d SEM image of euhedral inherited zircon with het-
erogeneous zoning, and spot analyses location. e SEM image of oval
‘soccer ball’ inherited zircon with faint rim growth, and spot analyses
location
15. 1447Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
However, all gabbro samples were selected from the same
gabbroic body, and the results of all samples were com-
bined to define a population and give a more robust age.
The youngest population is defined by a cluster of four con-
cordant grains and yields an age of 354.4 ± 7.6 Ma. Based
on exposed field relationships, which indicate that the foli-
ated intermediate phases (granodiorite, tonalite) are coeval,
we combined the data from samples ERG21 and ERG29.
A cluster of eleven concordant zircons defines a population
of 345.6 ± 2.5 Ma, which is the interpreted as the age of
crystallization of the various components of the intermedi-
ate phase. In the unfoliated porphyritic granite (ERG65),
the youngest population (348.2 ± 5.4 Ma, three euhedral
zircons) is interpreted as magmatic age (Fig. 16).
The unfoliated biotite granite (ERG11, ERG57A)
contains euhedral zircon grains ranging in age from
336.8 ± 4.0 Ma (Fig. 14) to 342.9 ± 3.5 Ma (Fig. 15).
Both granite samples (ERG11 and ERG57A) show coeval
field relationships; consequently, their crystallization age
is interpreted to be 335.1 ± 2.8 Ma based on a concord-
ant zircon population of 5 grains. The youngest age popu-
lation in the Monte Chico alkali granite is 342.9 ± 3.1 Ma
(Fig. 17), which is interpreted as the intrusive age of the
pluton, based on 6 concordant grains. Although the genetic
link between Monte Chico Pluton and the GMP cannot be
deduced from field observations, these age data suggest a
coeval relationship.
Inherited ages of the GMP
Zircon cores from the GMP samples show multifaceted
or rounded inherited core morphology (Figs. 8b, 17b) and
record numerous inherited age populations, based on three
or more grains (Table 1). The ca. 360–3,533 Ma inherited
ages come from sub-rounded to rounded core analyses
(e.g., Figs. 8d, 11d, 12d, 16e). Multifaceted zircon crystals
typically imply a magmatic protolith (Timmermann et al.
2000; Braid et al. 2012), whereas detrital zircons are well
Fig. 16 Concordia plot, relative probability plot, and SEM photomi-
crographs of porphyritic granite (ERG65). a Concordia plot of mag-
matic age of porphyritic granite. b SEM image of euhedral magmatic
zircon with oscillatory zoning, and spot analyses location. c Zircon
histogram/relative probability plot. d SEM image of subhedral inher-
ited zircon with heterogeneous zoning, and spot analyses. e SEM
image of oval ‘soccer ball’ inherited zircon with no zoning, and spot
analyses location
16. 1448 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
rounded and represent inherited grains from a sedimentary
protolith (Braid et al. 2011, 2012).
ERG66 has a population at 2,668 ± 75 Ma. ERG81A
has a population at 452.7 ± 4.5 Ma, and individual grains
ranging in age from 996 to 1,891 Ma. ERG81C has a
population at 374.2 ± 7.7, and individual grains rang-
ing in age from 399 to 523 Ma. ERG89 has no distinct
populations (Table EG-4). ERG21 has individual zircons
ranging 382–628 Ma and 2,309–2,717 Ma. ERG29 has
a population at 346.3 ± 3.2 Ma, with individual grains
ranging from 353 to 365 Ma. ERG11 has populations of
355.4 ± 1.7 Ma, 513.2 ± 2.8 Ma, and 2,699 ± 35 Ma,
with individual zircons ranging from 434 to 497 Ma, 543
to 547 Ma, and 1,034 to 1,815 Ma. ERG57A has a popu-
lation of 494.1 ± 6.7 Ma, with individual zircons rang-
ing from 1,223 to 1,838 Ma. ERG65 has individual zir-
cons ranging from 361 to 467 Ma and 1,849 to 1,890 Ma.
ERG62 has no distinct inherited populations (Table
EG-10).
Discussion
The U–Pb (zircon) crystallization ages reported herein are
consistent with field relationships, which indicate that the
gabbro is the oldest component and the unfoliated bio-
tite granite is the youngest component of the GMP. These
data also indicate that the Monte Chico pluton is coeval
with the emplacement of the GMP plutonic complex.
Taken together, these data imply that the GMP was part
of an active magmatic system for ca. 20–30 Ma, during
which time mafic to felsic rocks intruded the PDLZ. The
range in ages (354.4 ± 7.6 to 335.1 ± 2.8 Ma) is consist-
ent with interpretations that the GMP is part of the com-
posite ca. 350–308 Ma SNB (de la Rosa et al. 2002; Dun-
ning et al. 2002; Braid et al. 2011, 2012). Other possible
correlatives include an upper Devonian bimodal volcanic
series (IPB) of the SPZ and sub-volcanic rocks of the SNB
(Soler 1980). The northern volcanic rocks of the IPB and
the Campo Frio suite of the SPZ contain zircons dated at
Fig. 17 Concordia plot, relative probability plot, and SEM photomi-
crographs of alkali granite (ERG62). a Concordia plot of magmatic
age of alkali granite. b SEM image of euhedral magmatic zircon with
heterogeneous zoning, and spot analyses location. c Zircon histo-
gram/relative probability plot. d SEM image displaying zircon mor-
phology’s present in the alkali granite. e Macroscopic field sample of
alkali granite
17. 1449Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
349.8 ± 0.90 and 346.3 ± 0.8 Ma, respectively (Barrie
et al. 2002). The volcanic rocks of the IPB are similar in
age to the GMP gabbro. The Campo Frio suite is similar
in age to the intermediate phase and porphyritic granite of
the GMP. The different phases of the GMP contain a range
of inherited age populations spanning from 355.4 ± 1.7 to
2,699 ± 35 Ma (Table 1), including an important Mesopro-
terozoic inherited component.
These inherited ages are inconsistent with those from
the OMZ crust, which lacks Mesoproterozoic zircons
(Braid et al. 2011). Instead, our data suggest that GMP
traversed through SPZ and PDLZ crust during emplace-
ment. A quartzite from the PDLZ bordering the GMP has
zircon populations of 1.0–1.5 and 1.6–1.9 Ga (Braid et al.
2011), which are comparable with inherited populations
found in the GMP granites (Table 1, EG7-9), suggesting
the PDLZ quartzites may be the source of these popula-
tions in the GMP. A nonfoliated granite sample from the
SNB contains Neoproterozoic (ca. 561–647 Ma) and Mes-
oproterozoic ages (ca. 1.08–1.12 Ga (Braid et al. 2012).
Both these inherited ages populations also occur within
the GMP (Table 1, EG1-12), suggesting the GMP and the
composite SNB intruded similar crustal sources. In both
bodies, the younger zircons are pristine and multifaceted,
whereas the older zircons have an oval shaped morphol-
ogy (Braid et al. 2011). The ages of the inherited zircons
are consistent with derivation from the SPZ and the PDLZ.
The oldest known exposed unit of the SPZ is the Phyllite
Quartzite Group (PQ), which has a max depositional age
of 438.7 ± 4.38 Ma, and contains inherited zircons popula-
tions of Archean age ca. 2.5–3.0 Ga (Braid et al. 2011).
The 355–335 Ma intrusion of the GMP provides a mini-
mum age for the components of the suture zone. The ca.
345 Ma emplacement of the late kinematic foliated phases
constrains the age of late-stage strike slip deformation
within the PDLZ. The steep foliation in the intermediate
phases is parallel to the main orogenic fabric in the host
rocks and is interpreted to reflect late stages of regional
deformation of the PDLZ during its emplacement. The foli-
ation probably reflects northward-directed oblique conver-
gence and associated regional sinistral shear (Castro et al.
1995). The emplacement of the intermediate phases along
a shear zone attests to the heterogeneous style of deforma-
tion. The lack of a foliation in the older gabbro indicates
that is was not proximal to a shear zone neither at the
time of emplacement, nor during its subsequent history.
The GMP is a magmatic plumbing system that was active
for ca. 20 Ma, during which time it intruded the Variscan
Table 1 Summary of the results of the geochronological data from this study
For details on each sample, see electronic files Tables EG-1 to EG-13
a
Ages reported in Ma; 206/238 for Zircons <1 Ga and 207/206 for Zircons >1 Ga (Gehrels et al. 2006)
b
Ages in italics represent a population of ≥2 grains. Individual Zircon ranges in normal font
Samples Rock type Latitude Longitude Interpreted agea,b
Inherited age(s)a,b
ERG11 bt-Granite 37.853954 −6.810555 339 ± 6.6 355.4 ± 1.7, 513.2 ± 2.8, 2,699 ± 35
ca.434–497, ca.543–547, ca.1,034–1,815, ca.2,485–3,533
ERG57A bt-Granite 37.853013 −6.812671 342.9 ± 3.5 494.1 ± 6.7
ca.1,223–1,838
ERG11/57A bt-Granite n/a n/a 335.1 ± 2.8
ERG65 Porphyritic granite 37.856512 −6.803243 346.5 ± 5.4
ca.361–467, ca. 1,849–1,890
ERG62 Alkali granite 37.916659 −7.066271 342.9 ± 3.1
ERG21 qtz-Diorite 37.849355 −6.8338 348.5 ± 4.0
ca.382–628, ca. 2,309–2,717
ERG29 Tonalite 37.850384 −6.833535 338.2 ± 4.5 346.3 ± 3.2
ca.353–365
ERG21/29 Intermediate phases n/a n/a 345.6 ± 2.5
ERG66 Gabbro 37.854138 −6.805176 346.3 ± 7.7 2,668 ± 75
ca. 399.5
ERG81A Gabbro 37.855515 −6.836935 355.9 ± 15 452.7 ± 4.5
ca.492, ca.996–1,891, ca.2,702
ERG81C Gabbro 37.855515 −6.836935 351.8 ± 2.9 374.2 ± 7.7
ca.399–523
ERG89 Gabbro 37.854077 −6.835998 2,673 ± 35
ERG66,81A,
81C,89
Gabbro n/a n/a 354.4 ± 7.6
18. 1450 Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
suture zone throughout the final stages of continental colli-
sion between the OMZ (Gondwana) and SPZ (Laurussia).
The unfoliated porphyritic granite and unfoliated biotite
granite cut the foliation of the intermediate phases, during
the waning stages of collision. The biotite granite intrudes
the porphyritic granite and the SIF (Fig. 2), which uncon-
formably overlies all other units of the PDLZ and has a
maximum depositional age of 345–350 Ma (Braid et al.
2011, 2012). The relatively simple style of deformation
exhibited by the SIF probably reflects the latest stages of
deformation within the PDLZ, and the ca. 335 Ma age of
the granite provides a tight constraint for the age of that
deformation.
Acknowledgments We thank Ricardo Arenas and Vaclav Kachlik
for their constructive and insightful reviews and Jarda Dostal for edi-
torial handling. This research was funded by the Natural Sciences and
Engineering Research Council of Canada (NSERC) Discovery grants
to JAB and JBM.
References
Archibald DB, Barr SM, Murphy JB, White CE, MacHattie TG,
Escarraga EA, Hamilton MA, McFarlane CRM (2013) Field
relationships, petrography, and tectonic setting of the Ordovician
West Barneys River plutonic suite, southern Antigonish High-
lands, Nova Scotia. Can J Earth Sci 50:727–745
Barrie CT, Amelin Y, Pascual E (2002) U–Pb geochronology of
VMS mineralization in the Iberian Pyrite Belt. Mineral Deposita
37:684–703
Braid JA (2011) Dynamics of allochthonous terranes in the Pangean
suture zone of southern Iberia. Ph.D. thesis, Dalhousie University
Braid JA, Murphy JB, Quesada C (2010) Structural analysis of an
accretionary prism in a continental collisional setting, the Late
Paleozoic Pulo do Lobo Zone, Southern Iberia. Gondwana Res
17:422–439
Braid JA, Murphy JB, Quesada C, Mortensen J (2011) Tectonic
escape of a crustal fragment during the closure of the Rheic
Ocean: U–Pb detrital zircon data from the Late Palaeozoic Pulo
do Lobo and South Portuguese zones, southern Iberia. J Geol Soc
Lond 168:383–392
Braid JA, Murphy JB, Quesada C, Bickerton L, Mortensen JK (2012)
Probing the composition of unexposed basement, South Por-
tuguese Zone, southern Iberia: implications for the connections
between the Appalachian and Variscan orogens. Can J Earth Sci
49:591–613
Castro A, de la Rosa JD, Fernandez C, Moreno-Ventas I (1995)
Unstable flow, magma mixing and magma-rock deformation in
a deep-seated conduit: the Gil-Marquez Complex, south-west
Spain. Geol Rundsch 84:359–374
Castro A, Corretgé LG, de la Rosa J, Enrique P, Martínez FJ, Pascual
E, Lago M, Arranz E, Galé C, Fernández C, Donaire T, López
S (2002) Palaeozoic magmatism. In: Gibbons W, Moreno T
(eds) The geology of Spain. The Geological Society, London, pp
117–153
Corfu F, Hanchar JM, Hoskin PWO, Kinny P (2003) Atlas of zircon
textures. Rev Mineral Geochem 53(1):469–500
Dahn DRL, Braid JA, Murphy JB, Quesada C, McFarlane CRM
(2014) Geochemistry of the Peramora Melange and Pulo do Lobo
Schist: Geochemical investigation and Tectonic Interpretation of
mafic mélange in the Pangean suture zone, Southern Iberia. Int J
Earth Sci, this volume
de la Rosa JD (1992) Petrologia de las Rocas Basicas y Granitoides
del batolito de la Sierra Norte de Sevilla, Zona Surportuguesa,
Macizo Iberico. Ph.D. Thesis, Universidad de Sevilla
de la Rosa JD, Rogers G, Castro A (1993) Relaciones 87Sr/86Sr de
Rocas Basicas y Granitoides del batolito de la Sierra Norte de
Sevilla. Revista de la Sociedad Geologica de Espana 6:141–149
de la Rosa J, Jenner J, Castro A (2002) A study of inherited zircons
in granitoid rocks from the South Portuguese and Ossa-Morena
Zones, Iberian Massif: support for the exotic origin of the South
Portuguese Zone. Tectonophysics 352:245–256
Dilek Y (2006) Collision tectonics of the Mediterranean region:
causes and consequences. Geol Soc Am Spec Papl 409:1–13
Dunning GR, Diez MA, Matas J, Martin PLM, Almarza J, Donaire M
(2002) Geocronologia U/Pb del volcanismo acido y granitoides
de la Faja Piritica Iberica (Zona Surportuguesa). Geogaceta
32:127–130
Eden CP (1991) Tectonostratigraphic analysis of the northern extent
of the oceanic exotic terrane, Northwestern Huelva Province,
Spain. Ph.D. thesis, University of Southampton, England
Eden CP, Andrews JR (1990) Middle to upper Devonian mélanges
in SW Spain and their relationship to the Meneage formation in
south Cornwall. Proc Ussher Soc 7:217–222
Franke W (1989) Tectonostratigraphic units in the Variscan belt of
central Europe. Geol Soc Am Spec Papl 230:67–90
Franke W (2000) The mid-European segment of the Variscides: tec-
tonostratigraphic units, terrane boundaries and plate tectonic evo-
lution. Geol Soc Lond Spec Publ 179:35–61
Gehrels GE, Valencia V, Pullen A (2006) Detrital zircon geo-chro-
nology by Laser–Ablation Multicollector ICPMS at the Arizona
LaserChron Center. In: Olszewski T, Huff W (ed) Geochro-
nology: emerging opportunities, paleontological society short
course. Paleontological Society Pap,er12:1–10
Giese U, Reitz E, Walter R (1988) Contribution to the stratigraphy of
the Pulo do Lobo succession in southwest Spain. Comunicações
dos Serviços Geológicos de Portugal 74:79–84
Giese U, Glodny J, Kramm U (1993) The Gil Marquez intrusion, SW
Spain: syntectonic intrusion, magma mixing and deformation in
a transpressive regime. GSA Annual Meeting, Boston. Abstract
with Programs, 25(7):A-342
Gutiérrez-Alonso G, Fernandez-Suarez J, Weil AB, Murphy JB,
Nance RD, Corfu F, Johnston ST (2008) Self-subduction of the
Pangaean global plate. Nat Geosci 1:549–553
Gutiérrez-Alonso G, Fernandez-Suarez J, Jeffries TE, Johnston ST,
Pastor-Galan D, Murphy JB, Franco MP, Gonzalo JC (2011)
Diachronous post-orogenic magmatism within a developing oro-
cline in Iberia, European Variscides. Tectonics, 30:TC5008. doi:
10.1029/2010TC002845
Jesus A, Munhá J, Mateus A, Tassinari C, Nutman A (2007) The Beja
layered gabbroic sequence (Ossa-Morena Zone, Southern Portu-
gal): geochronology and geodynamic implications. Geodin Acta
20:139–157
Kramm U, Giese D, Zhuravlev D, Walter R (1991) Isotope equilibra-
tion of magmatis and metamorphic rocks of the Ara-cena Meta-
morphic Belt. In: XI Reunión sobre la Geología del Oeste Penin-
sular, Univ. de Sevilla, Huelva, España
Ludwig KR (2003) Isoplot 3.00: a geochronological toolkit for
Microsoft Excel: Berkeley Geochronological Centre Special Pub-
lication 4
Martínez Catalán JR (2011) Are the oroclines of the Variscan
belt related to late Variscan strike-slip tectonics? Terra Nova
23:241–247
Matte P (2001) The Variscan collage and orogeny (480–290 Ma) and
the tectonic definition of the Armorica microplate: a review. Terra
Nova 13:122–128
19. 1451Int J Earth Sci (Geol Rundsch) (2014) 103:1433–1451
1 3
Matte P, Ribeiro A (1975) Forme et orientation de l’éllipsoide de
déformation dans la virgation hercynienne de Galice. Rélations
avec le plissement et hipothèses sur la génèse de l’arc Ibero-
Armoricain. Comptè Rendus de l’Académie des Sciences de la
Terre Paris 280:2825–2828
Murphy JB, Nance RD (2008) The Pangea conundrum. Geology
36(9):703–706
Nance RD, Gutierrez-Alonso G, Keppie JD, Linnemann U, Murphy
JB, Quesada C, Strachan RA, Woodcock NH (2010) Evolution of
the Rheic Ocean. Gondwana Res 17:194–222
Oliveira JT, Cunha T, Streel M, Vanguestaine M (1986) Dating the
Horta da Torre Formation, a new lithostratigraphic unit of the
Ferreira-Ficalho Group, South Portuguese Zone: geological con-
sequences. Communicações dos Serviços Geológicos de Portugal
72:26–34
Onézime J, Charvet J, Faure J, Chauvet A, Panis D (2002) Structural
evolution of the southernmost segment of the West European
Variscides: the South Portuguese Zone (SW Iberia). J Struct Geol
24:451–468
Onézime J, Charvet J, Faure M, Bourdier JL, Chauvet A (2003) A
new geodynamic interpretation for the South Portuguese Zone
(SW Iberia) and the Iberian Pyrite Belt genesis. Tectonics 22(4):
TC001387
Pereira MF, Ma Chichorro, Silva JB, Ordonez-Casado B, Lee
JKW, Williams IS (2012) Early carboniferous wrench-
ing, exhumation of high-grade metamorphic rocks and basin
instability in SW Iberia. Tectonophysics 558–559:8–44.
doi:10.1016/j.tecto.2012.06.020
Quesada C (1991) Geological constraints on the Paleozoic tectonic
evolution of tectonostratigraphic terranes in the Iberian Massif.
Tectonophysics 185:225–245
Quesada C, Dallmeyer RD (1994) Tectonothermal evolution of the
Badajoz-Cordoba shear zone (SW Iberia): characteristics and
40Ar–39Ar mineral age constraints. Tectonophysics 231:195–213
Rosa DR, Finch AA, Andersen T, Inverno CM (2008) U–Pb geochro-
nology and Hf isotope ratios of magmatic zircons from the Ibe-
rian Pyrite Belt. Mineral Petrol 95:47–69
Schermerhorn LJG (1971) An outline stratigraphy of the Iberian
Pyrite Belt. Boletín Geológico y Minero 82:239–268
Schultz W, Ebneth J, Meyer KD (1987) Trondhjemites, tonalities and
diorites in the South Portuguese Zone and their relations to the
volcanics and mineral deposits of the Iberian Pyrite Belt. Geol
Rundsch 76(1):201–212
Simancas JF (1986) La deformación en el sector oriental de la zona
Sudportuguesa. Boletín Geológico y Minero 97:148–159
Simancas JF, Tahiri A, Azor A, Gonzalez Lodeiro F, Martinez Poy-
atos DJ, El Hadi H (2005) The tectonic frame of the Variscan-
Alleghanian orogen in Southern Europe and Northern Africa.
Tectonophysics 398:181–198
Soler E (1980) Spilites et metallogenic: La province pyrite-cuprifere
de Huelva (SW Espagne). Mem Sci Terre Nancy 39:1–461
Soriano C, Casas JM (2002) Variscan tectonics in the Iberian pyrite
belt, South Portuguese Zone. Int J Earth Sci 91:882–896
Stampfli GM, Borel GD (2002) A plate tectonic model for the Pale-
ozoic and Mesozoic constrained by dynamic plate boundaries
and restored synthetic oceanic isochrons. Earth Planet Sci Lett
196:17–33
Timmermann H, Parrish RR, Noble SR, Kryza R (2000) New U–Pb
monazite and zircon data from the Sudetes mountains in SW
Poland: evidence for a single-cycle Variscan orogeny. J Geol Soc
157(2):265–268
Van der Voo R (2004) Paleomagnetism, oroclines, and growth of the
continental crust: presidential address. GSA Today 14:4–9
Weil A, Gutierrez-Alonso G, Conan J (2010) New time constraints on
lithospheric-scale oroclinal bending of the Ibero-Armorican Arc:
a palaeomagnetic study of earliest Permian rocks from Iberia. J
Geol Soc Lond 167:127–143
