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Introduction
Geotectonic setting
The Ossa-Morena Zone (OMZ) is a major geotectonic unit lo-
cated in the southern sector of the Iberian Massif (Lötze 1945;
Julivert & Martínez 1983; see Figs. 1 and 2), forming, togeth-
er with the Central-Iberian Zone, the Iberian Autochthon (IA)
of the so-called Iberian Massif (e.g. Ribeiro et al. 1990). The
Iberian Massif, located in the western half of Iberian Peninsu-
la, represents the largest and one of the most complete and
continuous exposures of Variscan Belt in Western Europe.
The OMZ involves a complex tectonic scenario with the de-
velopment and closure of an ophiolitic complex – the so-
called Beja-Acebuches Ophiolitic Complex (BAOC; Fonseca
& Ribeiro 1993; Fonseca et al. 1999; Mateus et al. 1999;
Figueiras et al. 2002). Moreover, the OMZ southern border
comprises highly deformed exotic terranes of an oceanic na-
ture (including the “Pulo do Lobo” Accretionary Terrane
(PLAT) and the BAOC), as complex tectonic melanges
(Almeida et al. 2001; Araújo et al. 2005; Booth-Rea et al.
2006). These formations are rimming an early main Variscan
suture in the southwest of the Iberian Massif and they accreted
to the Iberian Autochthon before the Middle/Late Devonian
times (Fonseca & Ribeiro 1993; Fonseca et al. 1999). The
BAOC separates the OMZ and the South-Portuguese Zone
(SPZ), which is regarded as another exotic terrain, originating
from a so-called “Southern Paleo-continent” and accreted to
the IA during Carboniferous times (Dallmeyer et al. 1993).
The Odivelas Limestone: evidence for a Middle Devonian
reef system in western Ossa-Morena Zone (Portugal)
GIL MACHADO
1*
, JINDŘICH HLADIL
2
, LEONA KOPTÍKOVÁ
2,4
, PAULO E. FONSECA
3
,
FERNANDO T. ROCHA
1
and ARNOŠT GALLE
2
1
GeoBioTec, Geoscience Department, University of Aveiro, 3810-193 Aveiro, Portugal;
*
machadogil@gmail.com; frocha@geo.ua.pt
2
Institute of Geology, Academy of Sciences of the Czech Republic, v.v.i., Rozvojová 269, 165 00 Praha 6 - Lysolaje, Czech Republic;
hladil@gli.cas.cz; koptikova@gli.cas.cz; galle@gli.cas.cz
3
Geology Department and CeGul, Faculty of Sciences of the University of Lisbon, Edifício C6, Campo Grande,
1749-016 Lisbon, Portugal; pefonseca@fc.ul.pt
4
Institute of Geology, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2, Czech Republic
(Manuscript received March 12, 2008; accepted in revised form October 23, 2008)
Abstract: The Odivelas Limestone constitutes one of the few records of Middle Devonian sedimentation in the western
Ossa-Morena Zone. Although deformed and metamorphosed the limestones have an abundant fossil content which
allows their positioning as late Eifelian/early Givetian in age and to relate the reef fauna with the typical Rhenish facies
for the same time period. Magnetic susceptibility analysis was attempted and is in agreement with the biostratigraphy,
but the limited extent of sections and the metamorphism precludes firm correlations. The field evidence, petrographic
and geochemical analysis point to a close paleogeographical relation and dependence of the reef system on volcanic
structures which are included in the Beja Igneous Complex. The age of part of the volcanic and sub-volcanic suite of this
complex is thus constrained.
Key words: Eifelian/Givetian, Paleozoic orogens, Ossa Morena Zone, Beja Igneous Complex, biostratigraphy, reef
fauna, carbonate petrology, magnetic susceptibility.
It has been proposed (Crespo-Blanc & Orozco 1988; Fonse-
ca 1995, 1997; Fonseca et al. 1999; Crespo-Blanc 2007) that a
major ocean (Rheic Ocean) was closed by subduction/obduc-
tion leaving some remainder ophiolitic slices: the Lizard su-
ture in SW England and the Beja-Acebuches suture zone,
represent, respectively, the northern and southern branches of
the same ocean (Fonseca et al. 1999; Ribeiro et al. 2007).
Data acquired during different research projects clearly
shows new dismembered ophiolitic slices in the OMZ (Inter-
nal Ossa-Morena Zone Ophiolitic Sequences – IOMZOS,
Fonseca et al. 1999), which corresponds to allochthonous
klippen resting on top of the lower Paleozoic sequences
(Ribeiro et al. 2007).
Upper Paleozoic sedimentation in Ossa-Morena Zone
During the Early Devonian, as well as for most of the early
Paleozoic (except for the Cambrian), the sedimentation in the
OMZ was generally occurring in a passive margin setting
(Quesada 1990; Robardet & Gutiérrez-Marco 1990, 2004).
These rocks occur in wide areas from Portalegre to Cordoba
(Robardet & Gutiérrez-Marco 1990, 2004) and more to the
south in the Barrancos-Estremoz area (Robardet & Gutiérrez-
Marco 1990, 2004; Oliveira et al. 1991; Piçarra 2000), Terena
syncline (Piçarra 2000) and Valle synclines, Venta de Ciervo
and Cerron del Hornillo in Spain (Robardet & Gutiérrez-Mar-
co 1990, 2004). Fine siliciclastics dominate the sequences but
some calcareous levels occur (Robardet & Gutiérrez-Marco
1990, 2004) characterizing proximal deposits to deep fan tur-
GEOLOGICA CARPATHICA, APRIL 2009, 60, 2, 121—137 doi: 10.2478/v10096-009-0008-1
122
MACHADO, HLADIL, KOPTÍKOVÁ, FONSECA, ROCHA and GALLE
Fig. 1. Geological setting of the Cortes locality, Odivelas Reservoir. A – Geotectonic units of European Variscides (adapted from Ribeiro
et al. 1996). B – SW Iberia geotectonic units and the several domains of the OMZ (adapted from San-José et al. 2004; Borrego et al. 2005
and Oliveira et al. 1991); Geotransect line refers to text figure 2. C – Detailed geological map of the Cortes locality.
Fig. 2. SW—NE geotransect through the Ossa Morena Zone in Southern Portugal with the geological location of the Odivelas Limestone
(adapted from Ribeiro et al. 2007).
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MIDDLE DEVONIAN REEF SYSTEM IN OSSA-MORENA ZONE (PORTUGAL)
bidites (Oliveira et al. 1991; Piçarra 2000; Borrego et al.
2005). Reefal sedimentation is known from the Lower Devo-
nian of the OMZ as reported by May (1999) and Rodríguez et
al. (2007). The Middle Devonian is generally absent in the
OMZ. This has been interpreted as a consequence of the first
pulses of the Hercynian orogeny and generalized uplift of this
area during the Middle Devonian (Robardet & Gutiérrez-Mar-
co 1990, 2004; Oliveira et al. 1991). In the Évora-Beja Do-
main, the Pedreira de Engenharia calciturbidite outcrops (near
Montemor-o-Novo) provided Eifelian conodonts (van den
Boogaard 1973), but the relation of these with the surrounding
siliciclastic sediments remains unclear (van den Boogaard
1973; Pereira & Oliveira 2006). The overlying limestone lens-
es interbedded with shales of the Cabrela Complex dated as
Frasnian (van den Boogaard 1983) have been shown to be
olistoliths in Visean shales (Pereira & Oliveira 2003, 2006). In
the same sector and within the Beja Igneous Complex (BIC),
the only known Middle Devonian sediments are the Odivelas
Limestone (Conde & Andrade 1974) which are the subject of
the present work. Other rare occurrences of limestones in the
same domain are reported in the contact area with the South
Portuguese Zone near the Caerinha mine, Pena, Atalaia, Mon-
te das Cortes and Alfund o (Pereira & Oliveira 2006; Oliveira
et al. 2006), but the age of these lenses is unknown and the re-
lation with the surrounding Carboniferous Toca da Moura vol-
cano-sedimentary complex remains obscure.
The Upper Devonian and Carboniferous sedimentation is
controlled by the pulses and geometry of the oblique collision
occurring between the South-Portuguese Zone and the OMZ
in a clear synorogenic phase (Quesada et al. 1990). According
to the same authors these sediments can be divided into fore-
land basin flyschs and molasses (mostly Upper Devonian and
Mississippian), synorogenic intermontane terrestrial deposits
(Pennsylvanian) and late orogenic intermontane deposits (up-
permost Carboniferous and Permian), all of which have a
greater development in the eastern areas of the OMZ. Close to
the studied area (western OMZ) the Cabrela and Toca-da-
Moura complexes are the representatives of the Mississippian
foreland basin deposits (Pereira & Oliveira 2006) and the San-
ta Susana Coal Basin of the intermontane Pennsylvanian de-
posits (Sousa & Wagner 1983; Wagner 1983; Wagner &
Sousa 1983).
Other Devonian and Carboniferous sediments (mostly black
shales) are present in the northern parts of the OMZ along the
Porto-Tomar shear zone but their deposition seems to be con-
trolled by a quite different geodynamic setting (e.g. Fernandes
et al. 2001; Chaminé et al. 2003; Fernández et al. 2003;
Vázquez et al. 2007) and will not be dealt with any further in
this work.
Local geological setting
The Odivelas Limestone site near Cortes is composed of
several natural and artificial outcrops and a wide area of abun-
dant loose boulders. The limestone was quarried and pro-
cessed locally as can be seen by the ruins of an old lime mill.
Nearly all the outcrops and most of the loose boulder area are
flooded during the winter season. Although outcrops are
scarce a limestone zonation is observable with bioherm lime-
stones mainly in the centre and calciturbidite with crinoid
fragments on the edges of the body (Fig. 1). Together with
geometric information from bedding planes and foliation it is
possible to infer that the limestone body corresponds to a
small, badly defined, anticline structure.
The main limestone body is surrounded by massive lava
flows and rare pyroclastic deposits comprised in the Rebolado
Basalts (Andrade et al. 1976). The same authors considered
these to be the volcanic equivalents of the Casa Branca Doler-
ites that crop out to the W and SW due to the similar chemis-
try. These dolerites were studied in more detail by Jesus et al.
(2003, 2007) and Mateus et al. (2001) who give the relatively
young ages in the 355—320 Ma interval ( ~ Famennian/Tour-
naisian to Visean).
The chronological relation between the basalts and lime-
stones is unclear. Field evidence of the contacts is scarce, but
the structural interpretation (and also facies) suggests that the
limestones overlay the basalts. The presence of a small dyke in-
truding the limestones is indicative that at least the final part of
the magmatic activity that generated the volcanic and sub-vol-
canic suite of the Beja Igneous Complex is posterior (clearly in-
truding) to the limestone deposition. Chemical analyses show
that the limestones deposited contemporaneously with extrusive
volcanic activity (see geochemical and petrographic analysis).
A second, smaller, sector with limestone occurrences is
present to the SE of the main one (Fig. 1). No outcrops are vis-
ible, just abundant loose limestone boulders, mainly calcitur-
bidites. It is possible that this location is an old quarry or lime
mill filled in with tailings and local detritus.
The Tertiary deposits cover most of the northern area of the
Odivelas reservoir and significant parts of the southern area.
They unconformably overlie the volcanic suite and seem to
have a topographic control leading to a local restriction of
Beja Massif outcrops to valleys and other low land areas.
Previous work
Several short communications, papers and regional field trip
guides (e.g. Andrade et al. 1991), mention the Odivelas Lime-
stone and also the carbonates that occur near the reservoir wall
but all of them refer to the original work by Conde & Andrade
(1974). This was, therefore, the only work so far that de-
scribed the paleontology and location of the site and proposed
a tentative limestone zonation. The fossil content described in
Conde & Andrade (1974) includes stromatoporoids, corals,
crinoids, brachiopods, bryozoans, conodonts and trilobites.
The presence of fossils compared with Athyris concentrica
and Thamnopora boloniensis (brachiopod and tabulate coral)
was then regarded as evidence of a Middle or Late Devonian
age. The only described conodont taxa was Polygnathus sp.
and no stratigraphical implication for this finding was made.
Lithotypes and stratigraphy
Petrographic and geochemical analyses
Several outcrop samples were cut to produce thin sections
and polished hand samples to be observed optically and to
ã
124
MACHADO, HLADIL, KOPTÍKOVÁ, FONSECA, ROCHA and GALLE
Fig. 3. Outcrop and hand sample images and photomicrographs of thin sections. Legend: bd – bedding (emphasized by first order stylolites);
cr – probable crinoid element fragment; LV – late carbonate vein; pr – black prismatic particle; pu – pumpellyite crystals; sg – sigmoid
structure shadows; st1 – first generation stylolite; st2 – second generation stylolite. A – Natural outcrop and surrounding landscape.
B – Partially undissolved calciturbidite limestone block after acetic acid treatment. Note the black prismatic particles. C – Isolated pris-
matic particles (from acetic acid residue) showing overall shape and texture. Note the inner area and outer envelope in some of the particles.
D – Finner fraction of the acetic acid residue showing the dismembered outer envelope fragments of larger prisms and very small prisms.
E – Thin section image showing the general appearance of the calciturbidite limestone. Note the scattered prismatic particles acting as centers
for delta and sigmoid structures. Late carbonate veins cut all the previous structures. F – Photomicrograph of a sigmoid structure around a
prismatic graphitic particle. Note the latter vein cutting all the previous structures. Calciturbidite limestone. Crossed polars. G – Photomicro-
graph of a large scale stylolite (second generation). Subsidiary stylolites are visible (same stage) and previous ones (marking the bedding
fabric). Crinoid(?) skeletal pieces are visible in the upper part of the image. Bioherm limestone. Crossed polars. H – Photomicrograph of a
pumpellyite rosette surrounded by calcite crystals and a recrystallization area. Crossed polars.
125
MIDDLE DEVONIAN REEF SYSTEM IN OSSA-MORENA ZONE (PORTUGAL)
perform EDX and microprobe analyses. The bioherm lime-
stone is dominated by biogenic particles in a micritic matrix
(see the paleontological record section). The calciturbidite
limestone has a homogeneous crypto- to microcristalline tex-
ture (Fig. 3E). In both lithotypes six main petrographic fea-
tures were observed: 1) lamination (marked by ghosts of often
well recognizable bioclasts and a first generation of stylolites);
2) feldspar sub-euhedral crystals; 3) second generation stylo-
lites (Fig. 3G); 4) white and grey coarsely recrystallized areas
and small veins; 5) pumpellyite/prehnite and quartz rosettes
(Fig. 3H); 6) late generations of veins with carbonate and
feldspar, and finally but only in calciturbidites; 7) prismatic
black particles (Fig. 3B to D and F) in size range from tenths
of millimetre to centimetres. Original sedimentary features
seem to be the abundant, mostly non-authigenic feldspar
crystals and the lamination, later marked by a sub-parallel
generation of stylolites. The WDS microprobe and EDX
analyses indicate that up to 30 % of the finer and darker
limestones are composed of volcanic derived minerals such
as chlorite, albite, oligoclase, microcline, titanite, rare micas
and altered pyrite, although only the feldspars and pyrite
were observed optically.
The black acicular prismatic crystal pseudomorphs which
occur only in the calciturbidites can (in some levels only) con-
stitute up to 20 % of the limestone; their length ranges from
0.1 mm to 5 cm long (Fig. 3C and D), but the width of the
largest specimens never exceeds 2.5—3 mm. Simple prisms
prevail, but occasionally complex shapes are also present
(Fig. 3D). The transverse section is square, rhombic or irregu-
larly hexagonal. The microprobe analyses show a core com-
posed of hexagonal platelets of white-mica and phlogopite
retaining, most likely, the original compositions of unknown
mineral precursor as well as a very faint cleavage plane (001)
which is sub-perpendicular to the prism axis. The high content
of Al (up to 25 %) is explained due to nanometric inclusions
or mixed phases between the mica layers, although this could
not be confirmed. This core is interpreted as forming in an ear-
ly heating stage due to the contact metamorphism of the sur-
rounding subvolcanic suite. The core is surrounded by an
irregular, partially hollow cylinder composed of Mg-rich mi-
cas. The outer envelope defining the hexagonal prism is com-
posed of chlorite and tosudite. These two outer layers are in-
terpreted as diachronically forming or pseudomorphosing
during late diagenesis and metamorphism. Some of the prisms
have a porous structure which is filled by calcite, hematite and
other minerals. Semi-graphitic organic matter is often concen-
trated at the surface of these pseudomorphs. Occasionally pla-
nar cracks and fissures (sub-perpendicular to the axis of the
needle) are filled by calcite. This fracturing corresponds to
otherwise plastic shear deformation which is parallel to the
original lamination and can be compared to that which was
observed on rare thin-sectioned conodonts. This deformation
can start as early as with compaction of the rocks and early
burial diagenesis.
The major recrystallization areas and second generation of
stylolites cut or affect the previous features. These represent a
second phase of pressure solution and recrystallization of car-
bonate, contemporaneous with the main deformation phase as
can be seen by the delta and sigmoid structures formed around
the prismatic particles (Fig. 3E and F, Fig. 4). Finally, a sec-
ond generation of veins (carbonates, perthitic alkali feldspars
and rare quartz) cut the entire structure. They are usually
thicker and with a more regular orientation which suggests
fracture filling formed during a late deformational event
(Fig. 3E and F, Fig. 4) or by adiabatic decompression.
Magnetic susceptibility
In one of the artificial outcrops a small mostly undeformed
sequence (ca. 2.4 m) of thin-bedded crinoidal calciturbidites
was preserved. This section was sampled for magnetosuscep-
tibility stratigraphy at ca. 10 cm intervals and for palynology
in widely spaced intervals. The results are summarized in
Fig. 5. According to the structural interpretation the measured
section (light grey shade) would be overlaying the bioherm
beds (dark grey shade, Fig. 5), but the positioning is merely
tentative.
The data obtained from a short section with condensed
stratigraphy can be tentatively assigned to the end-Eifelian
segment 37—43 m of the MS Reference Section Moravian
Fig. 4. Graphical chronology of the observed petrographic features. Solid lines refer to chronologically well defined processes and dashed
lines to doubtful chronologies.
126
MACHADO, HLADIL, KOPTÍKOVÁ, FONSECA, ROCHA and GALLE
Karst (Hladil et al. 2006; Fig. 5 herein). This position seems to
be determined by extremely low MS magnitudes together with
medium amplitude “coarse brush patterns”. The compared
point in the reference section was originally held close to the
base of Polygnathus ensensis stratigraphic correlatives (Hladil
et al. 2006), but the most recent Belgian data (F. Boulvain et
al., pers. commun. 2008) are highly indicative of slightly
younger ages for this point, namely with Polygnathus hemian-
satus age correlatives.
Although the latter is quite concordant with the paleonto-
logical record, several concurrent problems exist. A crude vi-
sual estimation of the proportion of the small black prisms in
the magnetic susceptibility samples show a good correlation
with the obtained MS curve. The measured MS values in iso-
lated prims vary from 7.9 for complete specimens to 84.6
(
×10
—9
[m
3
· kg
—1
]) for the minute flakes composing their outer
envelopes (Fig. 3D). Additionally, the not negligible propor-
tion of fine-grained, mostly altered volcanic admixture (?vol-
canic ash and recycled microdetrital material) is expected to
modify the MS record. In this context, however, the mean MS
values which are smaller than 1
×10
—9
are very surprising and
we explain this by early diagenetic trapping of iron by pyrite
and its late weathering alteration to iron oxyhydroxidic sub-
crystalline mixtures. Metamorphism, although low grade
probably adds other noise or overprints the sedimentary MS
variations. The obtained curve can, therefore, reflect the com-
bination of several processes which may have modified the
comparability of the original, wide regional to global (climati-
cally induced) magnetosusceptibility stratigraphic record.
Paleontological record
Macrofauna
Crinoids
Very common columnals of the crinoid genus Cupresso-
crinites are visible on the weathered rock surfaces or in slabs
of the limestone sampled from relatively well preserved layers
and boudins. These remarkable fossils are present across all
discernible original sedimentary facies of the Odivelas Lime-
stone in its type occurrence outcrops (i.e. from bioherms to
calciturbidites). The largest about 5—7 mm wide columnals
were regularly found with the coral-crinoid-brachiopod bio-
herm and biostrome relict structures. The large and medium
sized columnals can be compared, according to their rough
morphology, with Cupressocrinites cf. crassus? (Goldfuss,
1831) or at least very similar forms – Fig. 6A—C. Some of
small columnals with well separated peripheral canals may
Fig. 5. Sampled section for magnetic susceptibility and palynology with reference to the sampled horizons and possible correlation with the
already published magnetic susceptibility curves for the same time interval (Hladil et al. 2006) and estimated conodont zone time equiva-
lents (still under improvement by interregional correlation). The biostratigraphic correlatives for the indicated point (base of Polygnathus
ensensis Zone) can be updated by means of the most recent Belgian results (slightly younger, in Pol. hemiansatus Zone; Bultynck et al.,
pers. commun. 2008).
127
MIDDLE DEVONIAN REEF SYSTEM IN OSSA-MORENA ZONE (PORTUGAL)
also be compared with Cupressocrinites sp. M ? Le Menn,
1999 (in Ureš et al. 1999). The columnals having similarity to
the latter taxon are found mainly in tempestites—calciturbidites
which are interpreted as an original cover of the underlying
biohermal-biostromal facies. These Cupressocrinites species
occur together, for example, in the lowermost Givetian part of
the Čelechovice Limestone in Moravia, Czech Republic (e.g.
Bouček 1931; Remeš 1939; Ureš et al. 1999; V. Petr, internet
comments on the C. crassus 2007). They are especially abun-
dant in the Middle Devonian and particularly Eifelian—
Givetian strata worldwide (i.e. among North Gondwana,
South Baltica, Urals and Siberia basins and terranes) but they
typically mark the Rhenish facies together with parallel, close-
ly adjacent Variscan facies-tectonic belts on the inner side of
the former and having a partial resemblance to pre-closure
Rheic passages. Such a high abundance of Cupressocrinites
remnants coupled with the presence of dark grey coloured cor-
al and stromatoporoid limestones is, therefore, a not negligible
indication that these sediments deposited in the middle of
Variscan belts, and according to stratigraphic position close to
the Eifelian/Givetian stratigraphic boundary. In spite of the
predominance of these crinoid columnals, the presence of oth-
er crinoid genera is quite possible. Most of these genera, how-
ever, cannot be seriously determined on the basis of the
random sections, due to imperfectly preserved features of fac-
et, areola, latus, etc. The only exception is for Gasterocoma?
sp. because its “rounded, double-axial-canal” in columnals
and cirral ossicles which is clearly visible in the sections.
We use the term “Cupressocrinites” because we have no
solid data on possible exoplacoid layer covering the plates of
cup and arms (cf. also Robustocrinites and Abbreviatocrinites
Bohatý, 2005, newly defined but considerably sympatrical
forms). In spite of general uncertainty about the crinoid co-
lumnal determination, the illustrated morphology is consider-
ably different in comparison with any older (Emsian-Eifelian)
or younger (Givetian-Frasnian) crinoid columnals which pos-
sess four accessory canals, e.g. “Tetraptocrinus”, “Tetraxoni-
crinus” or similar forms. In addition, it is particularly
important that rich and diversified columnals assemblages of
both the older and younger ages are completely absent in reef-
collar biostromal/biohermal and upper slope facies at this vol-
canic elevation. The cupressocrinitid columnals strongly
predominate.
Tabulate corals
Owing to the local thickening of originally calcite corallite
walls the branches of Thamnopora tabulate corals belong to
the most spectacular fossils which can be found in the less de-
formed layers and boudins of biohermal limestone facies. The
whitish colour and positive weathering surfaces of these corals
are eyecatching during collecting of the fossils, and this may
lead to a slight overestimation of their relative abundances in
comparison with other coral-stromatoporoid fauna of softer,
Mg-calcite or aragonitic and thus less preservable skeletons.
The present analysis of newly collected Thamnopora speci-
mens does not confirm the previous determinations (Conde &
Andrade 1974) but suggests that majority of these branched
coralla and their fragments most likely belong to Thamnopora
cf. irregularis Lecompte, 1939 (Fig. 6D—L). The main evi-
dence for the revision of the previous determination as T. bol-
oniensis (Gosselet, 1877) lies in the capability of this coral for
frequent rejuvenations and irregular arrangement of the coral-
lites as well as irregular budding and often imperfectly devel-
oped (or missing) separation of the thick-walled peripheral
zone. The other supportive arguments for this determination
are based on full agreement of the coralla and corallite shapes
and mural pore dimensions with the type populations of T. ir-
regularis which were described from the “Gia” levels
(Lecompte 1939) [in the present stratigraphic terms: Hanonet
Formation/Trois Fontaines Member in the Dinant Synclinori-
um, Belgium ~ Polygnathus hemiansatus Zone]. Besides this
dominant species, some small and rare forms and one medi-
um-sized form are also present, but their determination is very
difficult. These forms resemble in some of their poorly pre-
served features T. cf. compacta minima? Sharkova, 1981, T. cf.
incerta perpussila Hladil, 1984, T. cf. vermicularis? (McCoy,
1850) and T. cf. bilamellosa? Ermakova, 1960. Although the
presence of these species remains highly problematic, it is in-
teresting that all these possible links are also focused in the
Eifelian—Givetian ages, and are also indicative of the same pa-
leogeographical space as the above mentioned high abun-
dance of the Cupressocrinites crinoid remains.
Other prominent component among tabulatomorphic (but
not tabulate) corals are colonies of Heliolites. Domical and
short cylindrical colonies prevail. Also the colonies with sev-
eral centimeters thick overgrowths by undetermined massive
coenostea of stromatoporoids are commonly seen in the bio-
herm-biostrome facies in the central part of the Odivelas
Limestone type occurrence outcrops, but their subtle skeletons
were often and considerably damaged by recrystallization. A
few uncoated colonies with at least partial preservation of visi-
ble internal structures (Fig. 2A—F) were classified as Heliolites
cf. porosus bilsteinensis? Iven, 1980, but we must also consid-
er a certain similarity to Heliolites “Typus C” Hubmann, 1991
and partly also to the youngest forms of the problematically
defined H. cf. vulgaris Tchernyshev, 1951 (e.g. Hladil & Lang
1985). The morphologies like H. porosus bilsteinensis, and
considering also these three morphologically related forms are
quite indicative of the Eifelian—Givetian and particularly the
earliest Givetian ages. On the other hand, there is no evidence
for the presence of the typical septate heliolites as H. porosus
porosus (Goldfuss, 1826) or H. “intermedius” Le Maître, 1947
which are also typical for these stratigraphic levels but occur
rather in thicker limestones around platforms than in thin
limestone layers on volcanic substrates. In spite of a certain
tendency toward the reduction of coenenchymatic tubulae, the
possible comparison with H. barrandei Penecke, 1887 is hin-
dered by the absence of rudimentary but thickened bases of
septa as well as local thickenings of the parts of the skeleton as
a whole (compare, e.g. Fernández-Martínez 1999).
The small favositid-like, nodularly or domically shaped
centimeter-sized coralla often have characteristics of caliapor-
ids (rotation of parallel corallites, presence of battens, indica-
tions of squamulae). However, the presence of Calipora
battersbyi (Milne-Edwards & Haime, 1851), Mariusilites cha-
etetoides (Lecompte, 1939) or their Eifelian precursor species
lack unambiguous evidence in this recrystallized coral materi-
128
MACHADO, HLADIL, KOPTÍKOVÁ, FONSECA, ROCHA and GALLE
Fig. 6. A—C – Cupressocrinites sp. remains, echinoderms. A – A wide but low columnal has an extremely opened lumen that originated
due to interconnection of the axial and four peripheral canals. The specimen shape is indicative of a distal internodal. The obliteration of the
articular facet was caused by recrystallization of the calcite-filled skeleton tissue, as well as by recent corrosion/erosion of the rock surface.
The porous, 1—5 mm thick, dark grey coloured fossils with positive relief are silicified fragments of amphiporid stems. B – A middle sized
but high crinoid columnal corresponds to a nodal from a middle part of the stem. Cirrus with dichotomically branched cirral canals was in-
serted on the latus. This nodal was embedded in packstone where detritus of shelly fauna, crinoids and corals prevail. C – Assemblage of
numerous, small cupressocrinitid and/or gasterocomids columnals, accompanied by less abundant Gasterocoma, together with detritus of
other, mainly brachial crinoid parts.
129
MIDDLE DEVONIAN REEF SYSTEM IN OSSA-MORENA ZONE (PORTUGAL)
al. In contrast to this, several colony remains (perhaps ran-
domly preserved?) provided sufficient indications that one of
these caliaporids can be labelled as Caliapora? cf. pla-
giosquamata Hladil, 1981 (Fig. 7G—I). This coral has all the
evident though moderately reduced Caliapora type features.
Its occurrence is typical of the Givetian stage, ranging in
Moravia from the Eifelian—Givetian to Middle Givetian strata.
Many observed and analysed colonies must likely be en-
compassed within the alveolitids, specifically between the
genera Squameoalveolites and Spongioalveolites. The best
evidence was found for several coating to low domical colo-
nies of relatively compact skeleton which were determined
as Squameoalveolites cf. fornicatus (Schlüter, 1889) –
Fig. 7J—M. Corallites have a clear alveolitid shape where
densely spaced and well opened mural pores are on the later-
al sides and are regularly alternated by couples of thick,
tongue-shaped skeletal protrusions which resemble forma-
tions of “squamulae or spines”. Again, the species is very
typical for the Eifelian—Givetian and lowermost Givetian
strata worldwide and especially in the Rhenish and adjacent
marine basins.
Other fossils apparent among well preserved, thick skeleton
branched tabulate corals are scolioporids with subdominant
Scoliopora denticulata denticulata (Milne-Edwards & Haime,
1851) cf. alpha morfotype Hladil, 1984 – Fig. 8A—D. The
corallites elongated in the transverse section have flattened,
rounded-rectangular to bean shapes, and despite and in spite
of the corallite rotation after the budding they tend again to be
sub-parallel near the colony surface. Septal ridges are always
clearly visible, as well as the typical galleries of tube-like
pores. The morphology of these corals is in agreement with
that of the old Givetian populations from the Lažánky-Zrcadla
locality in Moravia. The presence of this species is quite inter-
esting from two points of view. First, this coral in Moravia
usually occurs on platforms and their slopes and, second, it is
rather indicative of earliest Givetian ages than the late Eife-
lian. As this coral most likely belongs to the very slowly and
consistently growing microsuspension feeders which can also
considerably exceed the territorial ranges of typical reef com-
munities (e.g. settling on slopes, and vice versa, in the shel-
tered environments only with amphiporids) it is not surprising
that these Scoliopora branches were also here preferentially
embedded in originally ?micritic—micropeloidal sediments
that have relatively low admixture of skeletal debris.
Rugose corals
There was a rich, moderately diversified assemblage of
these corals in the materials collected from the fragmentary
bioherm—biostrome structures in the centre of the type Odive-
las Limestone locality. Corals which were determined as
Pseudamplexus? sp. (Fig. 8F—I) are slightly dominant. Most
of these corals occur in clusters and accumulated in lenses,
where complete specimens are more abundant than millime-
ter to centimeter detritus of their calices. Typical original
sediments were most likely ?ostracod packstones/wacke-
stones, although more diversified skeletal packstone variet-
ies occur as well. It seems that some populations differ in
shape, as we can find longer conical shapes with less ce-
mented skeleton and also forms with deeper and more
opened calices where the skeletons were filled and coated by
early cements, but the more detailed taxonomic conclusions
are restricted by poor preservation of most of the internal
structures.
Among well represented groups mainly the Digonophylli-
nae must be mentioned. Large conical to keg-shaped corals
filled by large dissepiments are labelled as Cystiphylloides?
sp. (Fig. 8K). Large rugose corals with relatively well indi-
cated length and arrangement of septa were determined as
Mesophyllum? sp. (Fig. 8L).
The presence of other genera, such as the phillipsastreids
Disphyllum? sp., locally also Thamnophyllum? sp. and Pe-
neckiella? sp. is quite possible due to observed general
growth forms but the evidence based on preserved internal
skeletal structures is lacking. The same is true for possible
but not definitely confirmed occurrences of Acanthophyl-
lum? sp.
On the other hand, the sub random preservation and sec-
tioning of limestones provided tentative evidence for the
presence of various other rugose corals: for example, Cal-
ceola cf. sandalina (Linné, 1771) – Fig. 8M, Pseudo-
digonophyllum? sp. – Fig. 8N, Holmophyllum? sp.
(Holmophyllum? cf. uralicum Zhavoronkova, 1972) –
Fig. 9A, or Cyathopaedium? sp. – Fig. 9B.
Occurrences of Pseudamplexus, Cystiphylloides and Mes-
ophyllum correspond well to the Eifelian—Givetian ages, and
the occurrences of other very briefly mentioned genera are
not in conflict with this age determination. In addition, the
single finds and determinations of other rugose corals sup-
port these ideas about the age of this fauna. Calceola san-
dalina, although relatively rare, is an important cosmopolitan
marker for these ages and a very characteristic species of
Rhenish and adjacent seas. Pseudodigonophyllum? sp. and
Holmophyllum? cf. uralicum also confirm these ages, and
Cyathopaedium? sp. shows a parallel to the occurrences of
Cyathopaedium paucitabulatum (Schlüter, 1879) in the up-
per part of the Newberria Formation, lower Givetian of west-
ern Sauerland, Germany (May 2003).
Fig. 6. Continued from previous page. D—L – Thamnopora cf. irregularis Lecompte, 1939. Tabulate coral. The variability of the colony
and corallite growth shapes is illustrated using eleven, relatively undeformed coral fragments in rock slabs. D – The thamnoporid displays
its former capability of easy overgrowing of damaged/attacked parts in the apical part of the branch as well as on its sides. E – A consider-
able irregularity in budding and arrangement of corallites is regularly present, and according to these relatively well preserved specimens
this cannot be alternatively ascribed only to possible environmental extremes or effects of tectonic deformation. F—G – The irregularity of
budding is directly reflected by irregular shapes of the corallites that also differ in the number of neighbouring corallites (number of wall
parts) and also in corallite diameters. H—I – Also the pseudo-arching of parts of corallite walls in transverse or oblique sections is indica-
tive of incongruent growth domains and layers in the skeleton of the colony. J—L – The terminal parts of the densely branched coralla have
regularly the shapes and lengths which can be best described as the shape of a “human thumb”.
130
MACHADO, HLADIL, KOPTÍKOVÁ, FONSECA, ROCHA and GALLE
Fig. 7. A—F – Heliolites cf. porosus bilsteinensis? Iven, 1980 (? = Heliolites Typus C Hubmann, 1991). Small bulbous and domical colony
shapes prevail, both usually a little protracted, as it is seen in their longitudinal, oblique and transverse sections (A, B and C), A and C are
slabs, B is a broken and weathered colony. D – Close views on two other weathered sections (transverse and longitudinal, left and right in this
picture. E—F – Rare silicified areas found in the thin sectioned colonies give more contrast to the skeleton details, but there is also evident that
the deformation locally caused some breakage and secondary reduction of the coenenchyme width. G—I – Caliapora? cf. plagiosquamata
Hladil, 1981. Tabulate coral. G – The transverse section shows regular arrangement of corallites with only slight rotation of corallites, so that
an overall appearance is somewhere among usual favositid, caliaporid and alveolitid appearances. H – The slabs are indicative of the presence
of pores in short distances and only rudimental squamulae (longitudinal sections) and some transverse sections have rotated, four to six walled
corallites, even though they grew parallel to the growth of their neighbours, without any strong lateral increase of the colony.
131
MIDDLE DEVONIAN REEF SYSTEM IN OSSA-MORENA ZONE (PORTUGAL)
Fig. 7. Continued from previous page. I – Some slightly bent parts of the wall seem to be thicker than the other parts, resembling the “bat-
ten” structures of caliaporids. J—M – Squameoalveolites cf. fornicatus (Schlüter, 1889). Tabulate coral. Coating and low domical colonies.
J—K – The bent upper walls are undoubtedly dominant, being regularly, unidirectionally arranged in the colony. L – The longitudinal sec-
tion cutting the lateral walls with pores suggests the regular presence of the couples of squamula-like swellings of wall, alternating with
these mural pores. M – An oblique section of a colony gives other evidence about presence of thick spines and squamula-like swellings on
the corallite walls.
Stromatoporoids (and amphiporids)
The stromatoporoids are certainly an important faunal com-
ponent of the bioherm—biostrome structures in the central part
of the Odivelas Limestone type locality, but their originally
aragonitic to Mg-calcitic skeletons were recrystallized during
both the diagenesis and slight metamorphosis to a degree
which even precludes their generic identification. Only some
of the observed relict structures allow us to speculate about
possible occurrence of Actinostroma? (or Plectostroma?)
[thick, well separated pillars], Salairella? [preponderance of
regular coenosteles], Atelodictyon? [strongly expressed lami-
nated features of coenosteum] and Clathrocoilona? [very
densely structured coatings on corals]. However, this must be
considered only in a category of tentative and disputable opin-
ions, not of facts which could be supported by unequivocal
evidence.
It is significant that the abundance of stromatoporoids and
their overall shape diversity rapidly increased at the transition
between the bioherm—biostrome structures and overlying
tempestites and calciturbidites. Judging only on the basis of
coenosteal outer morphologies in the rock slabs, we can
speculate about the possible presence of ?Stachyodes together
with massive and coating coenostea of the genera with easily
recrystallizable skeletons (e.g. ?Stromatopora, ?Taleastroma,
?Stromatoporella, ?Anostylostroma, etc.).
The poor preservation of this fauna therefore means nothing
more than that stromatoporoids are certainly present, but we
can hardly use them for any detailed estimates in terms of sys-
tematics, stratigraphy and paleogeography.
In comparison with the major part of these undeterminable
stromatoporoid skeletons, the preservation of some rare am-
phiporids is better. They occur only in relicts of some biostro-
mal structures, in the centre of the limestone body and close to
the basalts, and they were locally preserved in a very specific
way. The coating by algal-bacteria? “stockings” together with
burial in the lime-mud led to a post-mortem concentration of
the organic matter in the porous but closed skeleton resulting
in a reduced carbonate cementation and increased silicifica-
tion. The analysis of weathered silicified fragments in combi-
nation with unsilicified accumulations of these fossils in rock
slabs and thin sections suggests the presence of Amphipora?
cf. spissa Yavorsky, 1957 (Fig. 9C—K). Concerning the stock-
ing-like coatings we must consider both the cyanobacteria and
algal coatings, i.e. Wetheredella? sp. (sensu Kazmierczak &
Kempe 1992) and Gymnocodium? sp., respectively. Relicts of
both structures were preserved. Particularly the silicified frag-
ments and some of the appropriately weathered surfaces pro-
vided an undoubted image of the amphiporid skeleton
structures. The quite regular internal structures, large size of
these branches and irregular occurrences of axial canals in
them actually point to Amphipora? spissa or closely related
forms. These forms are particularly common in the Eifelian-
Givetian limestones, where they are either accompanied or al-
ternated by the cosmopolitan species A. ramosa (Phillips,
1841). Several small silicified fragments of thin cylindrical
specimens with roughly structured skeleton tissues (indicating
the “sabre”-shaped pillars), regular axial canal and well separat-
ed outer gallery of chambers were also found, but it is difficult
to decide whether they really represent A. ramosa or only some
morphological extremes within the population of A. spissa (or
other amphiporid). It is possible, that a few stachyodid or coral
branches were also admixed in the more recrystallized accumu-
lations of these ca. 0.5 cm wide cylindrical fossils.
Amphiporids dominated the sheltered areas of platforms,
but in small amounts they were also found on isolated, drown-
ing elevations with basalts (e.g. at Horní Benešov in Moravia;
Galle et al. 1995).
Brachiopods
The accumulations of brachiopod shells are relatively com-
mon at the base of biohermal structures, and were observed in
several places in the centre of the type locality. Rare fragments
of these coquinas (together with coral and coral-stromato-
poroid facies) were also found in rock fragments around the
eastern Odivelas Limestone body, although this body is char-
acterized by preponderance of crinoidal calciturbidites. In
spite of their relatively common occurrences we cannot con-
firm according to our newly collected material the presence of
Athyris concentrica (von Buch, 1834) reported by Conde &
Andrade (1974).
Especially the largest and thickest brachiopod shells (7 to
12 cm long specimens) have internal structures which cannot
be compared with this species, and in addition they do not cor-
respond to the basic structures of many of the commonly
known brachiopod genera (consulted with by U. Jansen 2007).
We report these brachiopod shells under the working name
Brachiopoda gen. et sp. indet. (Type Y) – compare Fig. 9L—O.
These very thick shells are preferentially preserved, and this
corresponds to the assumption that they were thicker and larg-
er than the opposite valves, so that one can speculatively infer
that they were most likely pedicle valves on the ventral side of
the brachiopod. The most spectacular feature of these valves is
the presence of extremely thick ventral medium septa. The
cross-sections of their posterior parts, where these shells have
typically a width of 3—5 cm, show commonly a thick septum
which is closely connected with other connate skeletal ele-
ments, forming the typical bulky shapes of “capital Y”. It is
interesting that these brachiopod shells were not yet docu-
mented by systematic paleontology. These shapes were ob-
served on two localities of the Czech and Polish Sudetes, and
132
MACHADO, HLADIL, KOPTÍKOVÁ, FONSECA, ROCHA and GALLE
Fig. 8. A—D – Scoliopora denticulata denticulata (Milne-Edwards & Haime, 1851) cf. “alpha morphotype” Hladil, 1985). Tabulate coral.
Small, thick-walled corallites are elongated to 0.5 ratio in the transverse section and tend to be sub-parallel near the colony surface. Wall
thickening from axial to peripheral zone of the branch is gradual. Arrangement of pores in galleries is visible, as well as swelling of walls
between them. Rugose corals. E—I – Pseudamplexus? sp. E—F – Sparite-filled calicional parts of this coral in brachiopod skeletal pack-
stone. Slab and weathered rock surface (E), weathered surface (F). G—I – The higher and not so steeply conical specimens from ostracod
packstones/wackestones are congeneric but do not necessarily belong to the same species. K—L – Examples of two possible digonophyl-
lids (Digonophyllinae Wedekind, 1923). K – Cystiphylloides? sp.; a conical (and then keg-shaped) coral specimen on weathered rock sur-
face typically shows large and dish arranged, bubble shaped dissepiments. L – Mesophyllum? sp. Transverse section, weathered surface.
M—N – Other fragmentary rugose corals. M – Calceola cf. sandalina (Linné, 1771). N – An oblique section across a calicional margin
of a coral. Possibly Pseudodigonophyllum? sp.
133
MIDDLE DEVONIAN REEF SYSTEM IN OSSA-MORENA ZONE (PORTUGAL)
Fig. 9. A—B – Other fragmentary rugose corals (continuation). A – Holmophyllum? sp. (Holmophyllum? cf. uralicum Zhavoronkova, 1972).
Well separated, flabellacanthine-like trabeculae are indicated on the images. B – An undeterminable rugose coral, tentatively a young
specimen of Cyathopaedium? sp. attached on a broken part of an amphiporid stem. Amphiporids. C—K – Amphipora? cf. spissa Yavorsky,
1957. C – Some broken parts of amphiporid stems were silicified. D—E – The stems (branches) of typical 5 mm width are locally coated by
thickened vesicular and/or multiple-tube structures which may be compared with cyanobacteria and algal products Wetheredella? sp. (sensu Ka-
zmierczak & Kempe 1992) and Gymnocodium? sp., respectively. Separation of these coatings is seen on figure E. F—I – Four slabs illustrate that
growth of such a bacteria-algal stocking can also continue on necrotic amphiporid tissues. J—K – Some terminations of these stockings show fea-
tures of division. This morphology must rather be ascribed to unknown temporary inhabitants of these hollows than to the self-organizing capabil-
ity of the bacteria-algal structures. Brachiopods. L—O – Brachiopoda gen. et sp. indet. (Type Y). P—Q – Small, undetermined brachiopod valves
as they were leached by natural weathering on the rock surfaces. R – An accumulation of thick brachiopod shells. Different types of shell mor-
phologies prevail. Presence of fragmentary Kaplex and Stringocephalus shells is possible, but any strong evidence for this assumption is absent.
134
MACHADO, HLADIL, KOPTÍKOVÁ, FONSECA, ROCHA and GALLE
both of these localities have very similar successions of
Givetian limestones deposited on submerging basalt seafloor
highs (Padouchov in the Ještěd Mountain Ridge – Chlupáč &
Hladil 1992; and Mały Bożków in Klodzko area – Hladil et
al. 1999). Similarity of these brachiopods within this Variscan
belt structure resembles the conclusions which can be reached
on the basis of the Odivelas coral faunas.
The small brachiopod shells found as positive relief on the
weathered rock surfaces (Fig. 9P—Q) were left without deter-
mination, because there is no more than one shell. Very specu-
latively, there is a possibility to compare these shells with
Cranaena? sp. or similar brachiopods. With similarly low va-
lidity of assumptions we can speculate about the presence of
Kaplex or Stringocephalus shells in the deformed brachiopod
coquinas (e.g. Fig. 9R), but also without any direct evidence.
It is caused mainly by the tectonic deformation of these shell
accumulations which make it difficult to successfully recon-
struct the shapes of the valves on the basis of such haphazard-
ly oriented and deformed sections.
Micropaleontology
The site was sampled for conodont and palynology studies.
For the palynology analysis several samples were collected
from the site, mostly from the calciturbidite limestone (Fig. 3).
HCl attack destroyed nearly all the mineral fraction. Concen-
trated HF attack was performed but it had little effect on the
residue. The organic residue was quite abundant. Black
opaque heavily thermally altered (sensu Batten 1983) amor-
phous organic matter was the most abundant component of the
residue. Rare complete leiosphere-type palynomorphs were
observed. Skeletal remains of acritarchs and grey organic tis-
sues were more commonly seen. None of these could be as-
signed to a specific genus or group. It is difficult to exercise
on the original palynological assemblage, but the relative
abundance of prasinophyte and acritarch fragments suggests a
rather diversified assemblage that was partially destroyed due
to the long exposure to high pH geological environments
(Traverse 2007) and the metamorphism and deformation that
affected the limestones.
Three samples from different outcrops (two from the bio-
herm type and one from the calciturbidite type) were collected
for conodont studies and dissolved with 10% acetic acid. The
30 and 120 µm fractions were thoroughly examined after ace-
tic acid dissolution but none produced conodont elements.
Rare ghosts of conodont elements found by means of thin-sec-
tioning were partly dephosphatized and fragmented. The resi-
due was composed of a carbonaceous material, probably
organic matter. Small amounts of quartz crystals were present
as well as pyrite (heavily corroded). From the calciturbidite
sample, the coarser fraction (> 120 µm) was dominated by
black prismatic particles, usually less than 2 cm in length (see
petrographic analyses).
Discussion and conclusions
From the described fauna it is possible to constrain the age
of the Odivelas Limestone to an interval between the upper-
most Eifelian and lowermost Givetian. The most frequently
indicated ages of the sediments dominate the main body of
the classical Odivelas Limestone and seem to be centred
roughly about stratigraphic equivalents of the Polygnathus
hemiansatus Zone. However, it cannot be completely ex-
cluded that closely adjacent limestone occurrences would
also contain some subordinated, stratigraphically condensed
partial sequences (or lenses) of older (?Eifelian) and younger
(?Givetian) ages. The magnetic susceptibility results do not
clarify the stratigraphical positioning and their correlation
with the Kačák Event lowest MS magnitudes and possible pat-
terns is only tentative, having only slight supportive weight in
comparison with the biostratigraphical indications. It is main-
ly due to volcanic admixture in limestones and their slight
metamorphosis.
The field, petrographic and geochemical data indicate that
volcanic and subvolcanic activity took place before, during
and after the limestone deposition and that at least part of sub-
volcanic activity was syn or post-deformational.
The deposition of limestone was most likely dependant on a
volcanic structure, with the shallower areas supporting a bio-
herm-biostromal system with calciturbidite-type sedimenta-
tion on the flanks and in the surrounding deeper areas. The
described faunal assemblages dominated by crinoids, heliolit-
ids, solitary rugose corals and brachiopods are suggestive of
sedimentation on basalt seafloor highs developed along the in-
ner side of the central Variscan facies-tectonic belts as record-
ed elsewhere in Europe and particularly in the Rhenish facies
areas. The relevant paleogeographical constraints are inferred,
for example from the occurrences of Cupressocrinites, Cal-
ceola and spectrum of possible tabulate coral taxa.
The Odivelas material also revealed something about cli-
matic conditions. The numerous and highly diversified stro-
matoporoids, increased production of micrite and burial of
organic matter may be indicative of relatively high surface
water temperatures, and it may correspond to re-establishment
of reefal communities after the Kačák Event. The seasonal
growth rhythms observable on walls of rugose corals are
quasi-regular or regular, with rapid strangulations of “short
duration”. No double-monsoon yearly patterns have been ob-
served.
The Pedreira de Engenharia Formation (Évora-Beja Do-
main, Ossa-Morena Zone), comprising calciturbidites and pro-
viding Eifelian conodonts can tentatively be compared with
the Odivelas Limestone setting, but the paleogeography and
paleoenvironmental conditions of the latter are unknown and
contemporaneous volcanic activity in the area has not been
recognized. Further work in the Pedreira de Engenharia area is
needed to assess the relation between the two areas.
The new data presented here contributes to the better un-
derstanding of the paleogeography of the southern border of
the Ossa-Morena Zone and the Variscan deformation in SW
Europe.
Acknowledgments: We acknowledge George Sevastopulo
(Trinity College Dublin) for support in the initial stages of the
work. Funding was provided by the AS CR Projects
AV0Z30130516 “Earth System” and IAA300130702
“Growth Rhythms and Climates” (J. Hladil) and by the
135
MIDDLE DEVONIAN REEF SYSTEM IN OSSA-MORENA ZONE (PORTUGAL)
Fundaç
a
o para a Ci
ę
ncia e a Tecnologia, Portugal PhD.
Grant SFRH/BD/23787/2005 (G. Machado). P. Fonseca was
supported in the field work by LATTEX-Geodyn-Present to
Past POCTI-ISFL-5-32.
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