Content uploaded by José Francisco Santos
Author content
All content in this area was uploaded by José Francisco Santos on Jan 07, 2015
Content may be subject to copyright.
Versão online: http://www.lneg.pt/iedt/unidades/16/paginas/26/30/185 Comunicações Geológicas (2014) 101, 1, 29-37
ISSN: 0873-948X; e-ISSN: 1647-581X
Sr isotopic signatures of Portuguese bottled mineral waters
and their relationships with the geological setting
Assinaturas isotópicas de Sr em águas minerais de Portugal e sua
relação com o enquadramento geológico
S. Ribeiro1*, M. R. Azevedo1, J. F. Santos1, J. Medina1, A. Costa2
Recebido em 25/01/2013 / Aceite em 24/09/2014
Disponível online em Dezembro de 2014 / Publicado em Dezembro de 2014
© 2014 LNEG – Laboratório Nacional de Geologia e Energia IP
Abstract: This work presents the 87Sr/86Sr isotope compositions of nine
samples of bottled waters from several regions of Portuguese mainland. The
Sr isotopic variability displayed by the analysed waters is strongly
correlated with the age and mineralogical composition of the aquifer source
rocks, suggesting that the 87Sr/86Sr isotope signatures of these mineral
waters are dominantly controlled by fluid-rock and/or fluid-mineral
interaction processes. The lowest 87Sr/86Sr ratios are found in water samples
from the Monchique aquifer (87Sr/86Sr = 0.70447), located in Late
Cretaceous alkaline magmatic rocks of mantle origin. The Vimeiro waters
hosted in carbonate and evaporite formations of Jurassic age have 87Sr/86Sr
values of 0.70808 and appear to have reached bulk isotopic equilibrium
with whole-rock, whereas the waters sourced in Cenozoic siliciclastic
sediments tend to exhibit 87Sr/86Sr ratios close to the rainwater value (São
Silvestre; 87Sr/86Sr = 0.71078). Finally, the waters coming from granitic
and/or metamorphic terrains of the Iberian Variscan basement (Vitalis,
Luso, Carvalhelhos, Fastio and Serra da Estrela) display the most
radiogenic Sr isotopic signatures (87Sr/86Sr > 0.7136). In the modern
commercial context, the differences encountered provide a powerful tool for
fingerprinting the mineral water origin and may be used for purposes of
mineral water authentication. The results obtained also show the relevance
of Sr isotopes as geochemical tracers in hydrogeology.
Keywords: 87Sr/86Sr isotopic ratios, natural mineral waters, water-rock
interaction processes.
Resumo: Neste trabalho, apresentam-se e discutem-se as razões
isotópicas 87Sr/86Sr obtidas em nove amostras de águas engarrafadas
provenientes de vários pontos do território continental português. A
variabilidade isotópica encontrada nas águas analisadas relaciona-se com
a idade e com a composição mineralógica das rochas do aquífero de
origem, o que sugere que as razões isotópicas de Sr são fortemente
controladas por processos de interacção água - rocha e/ou água -
minerais. Os valores mais baixos de 87Sr/86Sr encontram-se nas águas do
aquífero de Monchique (87Sr/86Sr = 0,70447), que estão associadas a
ocorrências magmáticas alcalinas do Cretácico superior. As águas de
Vimeiro, captadas em formações carbonatadas e evaporíticas do
Mesozoico apresentam valores de 87Sr/86Sr de 0,70808, sugerindo que
estas águas alcançaram o equilibrio isotópico com as rochas do aquífero,
enquanto as águas associadas a rochas sedimentares siliciclásticas de
idade cenozóica possuem razões isotópicas muito próximas dos valores
que se encontram na água da chuva (São Silvestre; 87Sr/86Sr = 0,71078).
Por último, as águas procedentes de rochas graníticas e/ou metamórficas
do soco varisco (Vitalis, Luso, Carvalhelhos, Fastio e Serra da Estrela)
apresentam composições isotópicas de Sr mais radiogénicas (87Sr/86Sr >
0,7136). Num contexto comercial as diferenças encontradas
proporcionam uma ferramenta que poderá ser usada para fins de
certificação da proveniência de águas minerais. Os resultados obtidos
também mostram a importância dos isótopos de Sr como traçadores
geoquímicos em hidrogeologia.
Palavras-chave: Razões isotópicas 87Sr/86Sr, águas minerais
engarrafadas, processos de interação água-rocha.
1Geobiotec, Departamento de Geociências da Universidade de Aveiro, Campus de
Santiago, 3810-193 Aveiro, Portugal.
2Geodiscover – Consultores em Hidrogeoloogia, Lda.. Rua José Cardoso Pires, Lote 32,
2890-119 Alcochete, Portugal.
*Corresponding author / Autor correspondente: sararibeiro@ua.pt
1. Introduction
In the past decades, the European market of bottled mineral
waters and spring waters has been steadily growing due to the
progressive increase in the water consumption per capita (from
30 L to 108 L per year over the period 1997-2004) (Euzen, 2006;
Brach-Papa et al., 2009). As reported by Brach-Papa et al. (2009)
and references therein, the European legislation on this subject is
very strict and contains precise specifications on several
parameters such as the maximum concentrations of the major
constituents, the type of processes authorized for bottling and the
labelling information that should be provided to the consumers
by the producers. From the large number of requirements of a
‘‘Natural Mineral Water’’, the source provenance is one of the
most important. Only mineral waters with clear details of
provenance are included in the list of ‘‘Natural Mineral Waters’
recognised by the European Union state members.
Recent studies have demonstrated that Sr isotopes provide a
way of fingerprinting different mineral waters and may therefore
be applied, in combination with other chemical and isotope data,
for source authentication purposes (e.g. Négrel et al., 1997;
Montgomery et al., 2006; Voerkelius et al., 2010; Marques et al.,
2012). Since water is completely bio-available to plants and
animals and can be transferred to any organic material without
significant fractionation of Sr isotopes, the determination of
87Sr/86Sr isotope ratios has also been widely used to trace the
geographic origin of a large variety of food products (e.g. wine,
milk, butter and fruit juices) (Horn et al., 1993; 1998; Aberg,
1995; Rossmann et al., 2000; Almeida and Vasconcelos, 2001;
Barbaste et al., 2002; Crittenden et al., 2007; Rummel et al.,
2008).
Strontium is a divalent cation that can easily substitute Ca2+
in the crystal lattice of Ca-bearing minerals, such as plagioclase
feldspar, apatite, titanite, calcite, aragonite and dolomite. It has
four naturally occurring isotopes 84Sr, 86Sr, 87Sr and 88Sr. 84Sr,
86Sr and 88Sr are stable, whereas 87Sr derives from the radioactive
decay of 87Rb (Faure and Mensing 2005). As a result, the
87Sr/86Sr ratios in rocks and minerals tend to increase with time.
Artigo original
Original article
30 S. Ribeiro et al. / Comunicações Geológicas (2014) 101, 1, 29-37
Unlike strontium, rubidium is incorporated in K-bearing silicate
minerals, including K-feldspars, micas and clay minerals. Of the
two naturally occurring Rb isotopes (85Rb and 87Rb), 87Rb is
radioactive and decays to radiogenic 87Sr by - emission. Thus,
the age and the Rb content of a rock are the major factors
controlling its present day 87Sr/86Sr ratio. Old sialic crustal rocks
with high Rb/Sr ratios have the most radiogenic Sr isotopic
signatures (87Sr/86Sr > 0.709). In contrast, geologically young Rb-
depleted basaltic rocks typically display the lowest 87Sr/86Sr
ratios (0.703 - 0.706), whilst Sr-enriched calcareous sediments
and limestones are generally characterized by 87Sr/86Sr values
ranging between 0.706 and 0.709.
It is commonly assumed that Sr isotopes are not significantly
affected by mass fractionation during chemical weathering
processes (Shand et al., 2009). Therefore, the Sr released to the
water is a function of both the composition and the stability of
the aquifer bedrock forming minerals (Faure, 1986; Négrel et al.,
1993; 2001). As the reaction kinetics of mineral dissolution may
vary over several orders of magnitude, the Sr isotope signature
recorded in the water is dominantly controlled by the most easily
weathered minerals and does not always reflect the bulk isotopic
composition of the parent rock (e.g. Blum et al., 1993; Aberg,
1995, Jacobson et al., 2002; Bau et al., 2004, Montgomery et al.,
2006; Shand et al., 2009). For water reservoirs interacting with
silicate lithologies, isotope equilibrium with whole-rock is rarely
achieved, because the reactivity rates of their rock-forming
minerals are widely variable. In contrast, the waters sourced in
carbonate environments often show close to equilibrium Sr
isotope compositions due to the high solubilities of carbonate
minerals. More complex distribution patterns occur when water
systems receive Sr inputs from various sources with contrasting
87Sr/86Sr ratios (e.g. Négrel, 1999; Négrel et al., 2001; Barbieri
and Morotti, 2003). The final isotopic characteristics of these
waters will be determined by the compositions and the relative
contributions of the different end-members involved in the
mixture.
Natural waters have short residence times (maximum 103
years) compared to the half-life of 87Rb (48,8x109 years) and
suffer no influence of the 87Rb radioactive decay. Weathering
of carbonate minerals is generally very rapid, but the 87Sr/86Sr
ratios in waters from non-carbonate aquifers can be strongly
affected by the timescale at which water-rock interaction
processes take place. Longer residence times tend to favour the
hydrolysis reactions of silicate phases (plagioclase feldspar,
followed by K-feldspar and micas), allowing groundwater to
approach the equilibrium with the crystalline host rocks (Bullen
et al., 1996; Frost e Toner, 2004; Blum e Erel, 2005).
According to Frost and Toner (2004), the permeability
associated with igneous and metamorphic rocks can also
influence the weathering process, with low permeabilities
slowing groundwater equilibration rates.
In addition to natural causes, the use of fertilizers
(including dolomite, potash, nitrogen and phosphate materials)
may produce changes in the rates of release and exchange of Sr
in soils and significant variations in the 87Sr/86Sr ratios of
shallow groundwaters and streams draining these regions.
Groundwater contamination by agricultural activities or other
pollutant sources can disturb their original chemical and
isotopic characteristics and add further complexities to the
investigation of their source provenance (e.g. Bohlke e Horan,
2000; Soler et al., 2002; Jiang et al., 2009).
A valid interpretation of water Sr isotope signatures
requires therefore a thorough knowledge of the potential
hydrogeochemical processes operating along water flow paths,
because the Sr isotope composition of natural waters is not
always a conservative property and may be highly influenced
by the following factors: (a) reaction kinetics of mineral
dissolution and exchange efficiency; (b) thermodynamic
equilibrium; (c) water residence time; (d) mixing of waters of
distinct provenance and (e) addition of natural or anthropogenic
contaminants.
The aim of the present investigation is to determine the Sr
isotope composition of natural mineral waters from different
geologic environments in Portuguese mainland and assess the
extent to which the Sr radiogenic isotopes can be used to trace
their origin.
2. Geological setting
Portuguese mainland is located in the western and southwestern
sector of Iberia, at latitudes between 42.2°N to 36.92°N and
longitudes between 9.61° W to 6.07° W (Fig. 1). In broad terms,
it comprises terrains of the Variscan basement, occupying
extensive areas in the inner part of the country and a Mesozoic–
Cenozoic sedimentary cover, particularly well exposed along its
western and southwestern margins (Fig. 1). The Variscan
basement, also known as Iberian Massif, is composed of
thrusted, folded and metamorphosed rocks of Late Proterozoic
and Paleozoic age and large granitoid batholiths intruded in the
last stages of the Late Paleozoic Variscan oblique continent-
continent collision (e.g. Ribeiro et al., 1979; Matte, 1986;
Quesada, 1991).
Fig.1. Schematic geological map of Iberia with the main structural units (adapted from
Vera et al., 2004).
Fig.1. Mapa simplificado da Península Ibérica com as principais unidades estruturais
(adaptado de Vera et al., 2004).
During Mesozoic times, extensional tectonics related to the
opening of the North Atlantic Ocean resulted in the development
of the Lusitanian and the Algarve rift basins along the western
and southwestern borders of Iberia (Ribeiro et al., 1979; Wilson
et al., 1989; Rasmussen et al., 1998; Terrinha, 1998). The
stratigraphic record preserved in these fault-bounded basins
includes Late Triassic red fluvial siliciclastics, Hettangian
evaporites and Jurassic to Lower Cretaceous limestones,
sandstones and shales, documenting the occurrence of several
rifting episodes from early Triassic to early Cretaceous (Wilson
et al., 1989; Pinheiro et al., 1996).
Continental breakup was accompanied by three cycles of
magmatic activity. The first cycle is represented on-shore by
basaltic and dolerite dykes of tholeiitic affinities intruded at
around 200 Ma. This episode was followed by the emplacement
of Late Jurassic-Early Cretaceous intrusives with transitional
characteristics, at approximately 140 Ma (Ferreira e Macedo,
1979; Martins, 1991; Martins et al., 2008; Verati et al., 2007).
Sr isotopic signatures of Portuguese bottled mineral waters 31
The last magmatic cycle took place between 100 and 70 Ma and
includes the NNW-SSE aligned subvolcanic alkaline complexes
of Sintra, Sines and Monchique, the volcanic complex of
Lisbon and other minor alkaline intrusions (Miranda et al.,
2009).
Finally, the Cenozoic evolution of Iberia was strongly
controlled by Alpine compression, involving distinct periods of
crustal deformation, fault reactivation, and halokinesis related to
multiple episodes of collision between Iberia, Eurasia and Africa
(e.g. Mougenot, 1986; Malod and Mau¡ret, 1990; Srivastava et
al., 1990; Rosembaum et al., 2002; Alves et al., 2003). These
tectonic events are well expressed by a series of unconformity-
bounded Cenozoic sequences. Basin infilling resulted from the
interplay between alluvial fan, lacustrine, fluvial and shallow
marine sedimentation and consists of major siliciclastic facies
assemblages associated with minor carbonates (Antunes et al.,
1999, Pais et al., 2010).
3. Sampling and analytical techniques
The samples analysed in this study were collected from 250 -
1500 mL water bottles from different brands, purchased in
grocery stores. Only mineral waters with clear details for
provenance, mineral content values and physical parameters
were selected for analysis. Their geographical origin was
determined through the address labelled on the bottle and
further confirmed by direct contact with the technical director
of each mineral water company. Many of the waters now
exploited on a commercial basis have a long documented
history of use and are believed to be endowed with healing
properties. Of the nine samples analysed, eight are classified as
‘‘Natural Mineral Waters’’ and one as “Spring Water”. In order
to assess the effects from mixing of water from several
boreholes, filtering and bottling processes and potential
seasonal variations of strontium isotope ratios, the
characterization of each type of water involved the
measurement of two / three replicate samples with different
bottling dates and serial numbers. For comparison purposes,
samples of rainwater and snow were also collected and
analysed. To minimize contamination, snow samples were
collected approximately 0.1 - 0.2 m below the snow surface and
stored into pre-cleaned containers.
Sample preparation involved previous filtering of rainwater
and snow samples through a pre-washed 0.5 m Millipore
filter. All water samples were then acidified to pH 2 with
redistilled concentrated HNO3. A volume of 250 mL for
rainwater and snow samples and 10 - 50 mL for bottled waters
was measured into pre-cleaned Teflon beakers and evaporated
to dryness. The residue was subsequently acidified with 1mL
sub-boiled HF and 0.5 mL sub-boiled HNO3 and dried. Each
sample was then dissolved using 1 mL of sub-boiled 6.2N HCl
and evaporated to dryness. Strontium was collected using
conventional AG8 50W Bio-Rad resin ion exchange methods
and loaded on single tantalum filaments with H3PO4.
The Sr isotope compositions were determined using a VG
Sector 54 multi-collector mass spectrometer in the Laboratory
of Isotope Geology of the University of Aveiro. All 87Sr/86Sr
ratios were corrected for instrumental mass fractionation and
normalized to 86Sr/88Sr = 0.1194. The in-run precision of each
analysis lies between 30 to 50 ppm, with two standard
deviations from the mean (2 error) and Sr blanks are less than
250 pg. The international standard SRM-987 gave an average
value of 0.710249 6 (n = 18) during this study.
Sr concentrations in the water samples were obtained by
inductively coupled plasma mass spectrometry (ICP-MS) in the
University of Aveiro.
4. Results and discussion
The location of the studied samples is shown in the simplified
geological map of Portugal of figure 2. Chemical and Sr isotopic
data for rainwater and snow samples are given in table 1. General
information for the analysed bottled mineral waters, including
source, water type, mineral content values and pH are presented
in table 2, whilst their Sr contents and 87Sr/86Sr isotopic ratios are
compiled in table 3. Thorough reviews on the main chemical
characteristics of Portuguese bottled mineral waters can be found
in Lourenço et al. (2010).
Fig.2. Simplified geological map of Portugal with the geographic distribution of bottled
water samples (adapted from geological map of Portugal 1/500 000).
Fig.2. Mapa geológico simplificado de Portugal com a indicação da distribuição
geográfica das amostras de águas engarrafadas samples (adaptado da carta geológica de
Portugal 1/500 000).
4.1 Rainwater and snow
The Sr isotopic ratios for rainwater (87Sr/86Sr = 0.709287 -
0.710345) and snow samples (87Sr/86Sr = 0.708415 - 0.710805)
show a considerable degree of overlap (Tab. 1). Despite the small
number of samples collected and their scattered spatial and
temporal distribution (2005, 2006, 2009 and 2010), the data
obtained in this study lie within the range of values published in
the literature for rainwater in Portugal and other European
countries, such as Spain, France, Germany, Switzerland and
Scotland (Fig. 3). The average value (87Sr/86Sr = 0.70951
0.00033) provides therefore a rough estimate for the isotopic
composition of rain in Portugal.
32 S. Ribeiro et al. / Comunicações Geológicas (2014) 101, 1, 29-37
As pointed out by Négrel et al. (2007), the Sr isotopic signature
of rainwater is dominantly controlled by the nature of the
atmospheric aerosol sources, including sea salts, crustal dust,
volcanic dust, biogenic material and anthropogenic emissions. In
the present case, most of the rainwater and snow samples have
87Sr/86Sr ratios similar or slightly higher than that of seawater
(87Sr/86Sr = 0.70918 ± 1, Faure and Mensing, 2005) revealing that
sea salts are probably the major source of dissolved species for
rain and snow falls in Portugal. A significant contribution of
continental dusts from silicate terrains of the Variscan basement
(e.g. granite, gneiss, metasediments) and/or Cenozoic cover
deposits is strongly suggested for the rain and snow samples with
more radiogenic compositions (87Sr/86Sr > 0.709).
Table 1. Strontium contents (ppb) and 87Sr/86Sr isotopic ratios for rainwater and
snow samples.
Tabela 1. Concentrações de Sr (ppb) e razões 87Sr/86Sr em amostras de água da
chuva e de neve.
(a)Andrade, (2002); (b) Pacheco et al. (2009); n.d. – not determined.
Fig.3. Range of 87Sr/86Sr isotopic ratios for rainwater. Legend: (a) Bacon and Basin
(1995); (b) Hindshawa et al. (2011) (c) Wiegand (2009), (d) Négrel et al. (2007); (e)
Probst et al. (2000); (f) Chiquet et al. (1999); (g) Andrade (2002); (h) This study.
Fig.3. Intervalos de variação da razão isotópica 87Sr/86Sr na água da chuva. Legenda:
(a) Bacon and Basin (1995); (b) Hindshawa et al. (2011) (c) Wiegand (2009), (d) Négrel
et al. (2007); (e) Probst et al. (2000); (f) Chiquet et al. (1999); (g) Andrade (2002); (h)
Este trabalho.
4.2 Bottled mineral waters
Sr concentrations and 87Sr/86Sr ratios for the analysed bottled
mineral waters are presented in table 3. The lack of significant
differences in the isotopic compositions of replicate samples
from the same brand, pumped and bottled at distinct dates,
demonstrates that the potential influence of mixing between
waters from different boreholes, filtering and bottling processes
and/or seasonal variations of strontium isotope ratios can be
neglected.
Figure 4 shows that the nine samples of Portuguese mineral
waters are clearly distinguished on the basis of their 87Sr/86Sr
signatures. The Monchique water drawn from Late Cretaceous
alkaline magmatic aquifer rocks is the least radiogenic (87Sr/86Sr
= 0.70447) of the analysed mineral waters. The water samples
hosted in Jurassic limestones (“Vimeiro”) and Miocene
sandstones (“São Silvestre”) have average 87Sr/86Sr isotopic
ratios of 0.708086 and 0.71077, respectively, which, in the latter
case, are very close to rainwater values. Finally, all the remaining
bottled mineral waters come from areas of the Variscan basement
and yield very radiogenic isotopic compositions (87Sr/86Sr >
0.713). As discussed below, the stratigraphic age of the aquifer
host rocks and their mineralogical composition appear to be the
main factors governing the water Sr isotope signatures.
Table 2. Main characteristics of the samples of Portuguese bottled mineral waters.
Tabela 2. Principais características das amostras de águas minerais engarrafadas
Portuguesas.
(a)Information from bottle labels;
(b)Maximum temperatures from Lourenço and Cruz (2010).
Table 3. Sr contents and 87Sr/86Sr isotopic ratios for samples of Portuguese bottled
mineral waters and information on aquifer geology.
Tabela 3. Concentrações e razões isotópicas de Sr das amostras de águas minerais
engarrafadas e informação geológica do aquífero.
(a)Mean value and error presented with an confidence limit of 95%;
(b)References in the main text.
Cenozoic cover deposits - “São Silvestre” water
The São Silvestre water is sourced from two similar deep wells
(more than 176 m depth) in the Santarém region (Fig. 2). The
aquifer (82 - 176 m depth) is located in continental siliciclastic
units of Miocene age (Burdigalian - Helvetian), known as the
detrital complexes of “Ota” and “Arneiro de Milhariças”, which
are overlain by marls and carbonate sediments from the
Sarmatian - Pontian complex. The three sedimentary complexes
are part of the infilling deposits of a large basin differentiated at
middle Eocene times, as a result of the reactivation of NE-SW
fractures - the Lower Tejo Cenozoic basin (Figs. 1 and 2).
Sr isotopic signatures of Portuguese bottled mineral waters 33
In terms of Sr isotopic composition, there are strong
similarities between the São Silvestre water (87Sr/86Sr = 0.710754
- 0.710785) and rainwater (Fig. 4). This suggests that the Sr
isotopic signature of this water was probably controlled by direct
rainfall recharge of the aquifer and has not suffered significant
influence of water-rock interaction processes. According to
Albino de Medeiros (oral communication), technical director of
this water, the admitted short residence time and high velocity
flow of water on São Silvestre aquifer may therefore have
prevented groundwater from equilibrating with the host rocks.
The nature of the bedrock (sandstones) can also have contributed
to inhibit extensive interaction between groundwater and the
surrounding reservoir rocks, because the main mineral
constituents in these deposits (quartz ± K-feldspar + micas ± clay
minerals; Manuppella et al., 2006) are not easily dissolved
(Bullen et al., 1996; Frost and Toner, 2004; Blum and Erel,
2005).
Fig.4. The average 87Sr/86Sr isotope composition of bottled waters and respective
main geological environments. The shaded area represents the range of rainwater in
Portugal from 0.7084 to 0.7114 (data from this study and presented by Andrade,
2002).
Fig.4. Razões isotópicas 87Sr/86Sr das águas engarrafadas com indicação do
respectivo ambiente geológico. A área sombreada indica o intervalo de variação da
água da chuva em Portugal, de 0,7084 a 0,7114 (dados deste estudo e de Andrade,
2002).
However, the relatively high mineralization content and pH
value recorded in the São Silvestre waters (181 mg/L, pH =
7.13; Tab. 2) and, particularly their elevated Sr concentrations
(Sr = 64 ppb, Tab. 2), point to some ion input from the marls
and carbonate sediments from the overlying Sarmatian -
Pontian formations along their flow path. As, on the other hand,
the clastic component of the Cenozoic sediments is mostly
derived from weathering of strongly radiogenic Precambrian
and Palaeozoic rocks and would therefore have produced
waters with relatively high 87Sr/86Sr isotopic ratios, an
alternative scenario can be proposed. In this model, the isotopic
signature of the São Silvestre water could have resulted from
mixing of distinct Sr sources (meteoric water, carbonates with
low 87Sr/86Sr isotopic ratios and sandstones with high 87Sr/86Sr
isotopic ratios).
Irrespective of the model assumed, the available data
suggest that the São Silvestre mineral aquifer corresponds to a
semi-confined aquifer in which water flows on the Miocene
detrital formation but also receives water, by leakage, from the
overlying carbonates.
Late Cretaceous alkaline magmatic rocks – “Monchique” water
The Late Cretaceous Monchique alkaline subvolcanic complex
crops out in the southwest corner of Portugal (Fig. 2) and consists
of two concentric bodies of nepheline syenites and minor
occurrences of mafic and ultramafic rocks (Rock, 1978; Miranda
et al., 2009). These alkaline magmas of deep mantle origin were
intruded into Carboniferous slates and quartzites from the
Brejeira Formation, at around 72 Ma (MacIntyre and Berger,
1982, Rock, 1976; Bernard Griffiths et al., 1997; Valadares,
2004).
The Monchique water flows through a highly fractured
bedrock, taps a deep aquifer (at least several hundred meters
deep) and is recovered from drill holes at temperatures of 27 -
31.5 ºC (Lourenço and Cruz, 2010; Tab. 2). Its Na-HCO3
chemical character and high pH values (total mineral contents =
295 mg/L, pH = 9.13; Tab. 2) indicate that groundwater has
significantly interacted with the main mineral phases (K-feldspar
+ albite + nepheline) present in the nepheline syenite host rocks.
Progressive dissolution of Na-silicates (albite and nepheline) was
probably the major cause for the increase of sodium
concentration and alkalinity in the Monchique water. However, it
is likely that ion exchange reactions between groundwater and
Na-rich clays produced by weathering of primary minerals along
fracture zones has also contributed to the chemical signature of
the Monchique water (Venturelli et al., 2003). Also relevant for
the geochemical composition of the Monchique water is the
contribution of other deep-origin components (CO2, H2S, NaCl
and N2) (Calado and Vieira da Silva, 2003).
From the group of samples of bottled mineral waters analysed
in this study, the Monchique water is the least radiogenic
(87Sr/86Sr = 0.704448 - 0.704486; Fig. 4). The 87Sr/86Sr isotopic
ratios for this sample lie within the range of present-day whole-
rock values displayed by the nepheline syenites (87Sr/86Sr =
0.703674 ± 52 - 0,705189 ± 56, Valadares, 2004), revealing that
groundwater appears to have reached almost complete
equilibrium with the aquifer host rocks. Both the bulk chemistry
and the Sr isotopic composition of the Monchique water may
therefore result from long-term fluid-rock interaction
mechanisms, at relatively high temperature.
Mesozoic Limestones – “Vimeiro” water
The Vimeiro mineral water comes from a deep-seated confined
aquifer ( 200 m) of Late Jurassic karstified limestones (Upper
Kimmeridgian), located in the southern sector of the Lusitanian
Basin (Fig. 1). At the presently exposed level, the limestones
occur at the flanks of a NNE-SSW salt anticline structure
(Maceira diapir) with a core composed of Late Triassic
mudstones, carbonates and evaporites from the “Dagorda
Formation” (Hettangian) (Manuppella et al., 1999). The region is
famous for its thermal bath resort and highly mineralized springs.
The water is heated by circulation down to 1000 m in depth
reaching temperatures of 35 ºC and discharges in a valley situated
on the eastern flank of the diapir zone, with temperatures up to
26°C (Costa, 1982).
The chemical composition (Na-Ca-Cl-HCO3) and high total
dissolved solids content (1112 mg/L) of the Vimeiro bottled
mineral water (Tab. 2) can be attributed to intense dissolution of
carbonates (calcite/dolomite), sulphates (anhydrite/gypsum) and
chloride salts (halite) from the buried Mesozoic carbonate and
evaporite formations during deep groundwater flow and mostly
during ascending terminal fluxes. Widespread water–rock
interaction processes involving highly soluble minerals with
typically low Rb/Sr values would have enabled groundwater to
equilibrate chemically and isotopically with the aquifer host
34 S. Ribeiro et al. / Comunicações Geológicas (2014) 101, 1, 29-37
rocks, explaining the low 87Sr/86Sr ratios found in the sample of
the Vimeiro water (87Sr/86Sr = 0.708084 - 0.708087, Fig. 4).
Assuming that the Sr isotopic composition of the Vimeiro
groundwater is inherited from the evaporite/marine carbonate
rock system with which it interacts, its isotope ratio should
encompass the 87Sr/86Sr seawater curve for Late Triassic and/or
Late Jurassic times. However, the average Sr isotopic ratio
obtained in the sample of the Vimeiro natural mineral water is
slightly higher than the values reported in the literature for
Hettangian and Upper Kimmeridgian seawater (87Sr/86Sr =
0.7077 and 0.7069 respectively; Jones and Jenkyns, 2001). As
such, it is possible that the observed increase reflects changes in
the Sr isotopic signatures of the reservoir rocks induced by post-
depositional diagenetic processes or derive from mixing with
more radiogenic non-marine waters. Irrespective of the factors
controlling this subtle shift towards more elevated 87Sr/86Sr
ratios, the Sr isotopic composition of the Vimeiro groundwater is
entirely consistent with the published data for aquifers associated
with Mesozoic marine carbonates (87Sr/86Sr = 0.7070 - 0.7090;
Voerkelius et al., 2010).
Variscan granitoids – “Carvalhelhos”, “Fastio”, “Serra da
Estrela” mineral waters
The water samples included in this group are all hosted in
granitoid intrusions from Northern/Central Portugal (Fig. 2).
Most of these plutons were emplaced into metasediments of Late
Proterozoic to Paleozoic age, during or slightly after the last
Variscan deformation event (D3). Based on their structural,
petrographical and geochemical characteristics, the Portuguese
Variscan granitoids have been classified into four main suites: a)
early, syn-D3 granodiorites and biotite monzogranites; b) strongly
peraluminous syn-D3 leucogranites and two-mica granites; c)
late-post-D3 calc-alkaline granodiorites and biotite monzogranites
and (d) late-post-D3, slightly peraluminous, biotite-muscovite
granites (Azevedo and Valle Aguado, 2013 and references
therein). It is generally accepted that the synkinematic
leucogranites and two-mica granites have S-type signatures
(87Sr/86Sri > 0.708) and should therefore have derived from
partial melting of middle crustal metasedimentary sources
(Azevedo and Valle Aguado, 2013 and references therein). In
contrast, a major contribution from metaigneous lower crust
materials and/or interaction with mantle derived magmas appears
to be required to produce the least radiogenic I- and H-type syn-
D3 and late-post-D3 granodiorite-monzogranite suites (87Sr/86Sri <
0.708) (Azevedo and Valle Aguado, 2013 and references
therein).
The Carvalhelhos water has very peculiar characteristics. It
comes from a large hydrologic province of hot and cold CO2-rich
thermal and mineral springs, located in the Galicia-Trás-os-
Montes para-autochthonous terrains of NE Portugal. Many of
these CO2-rich waters are issued from granitic aquifers, at the
intersection of major fault systems, reactivated during Alpine
compression (e.g. Marques et al., 2006; Marques et al., 2010;
Lourenço, 2010). According to several authors, their high CO2
contents result from fluids of deep-seated (upper-mantle) origin,
carrying a CO2-rich gaseous phase, that have migrated towards
the surface through the regional fault network (e.g. Marques et
al., 2006; Carreira et al., 2008; Marques et al., 2010).
In the Carvalhelhos area, the spring emergences occur close
to the contact between the Barroso syn-D3 two-mica granite and
the Silurian metasedimentary sequences, with a temperature of
22°C, a total mineralization of 230 mg/L and a pH of 7.3. The
relatively low outflow temperatures suggest that these Na-HCO3-
CO2 cold waters represent infiltrating meteoric waters with deep
circulation paths (at least 200 m deep), mineralized by water–
gas–rock interaction processes. According to Vieira da Silva (oral
communication), technical director of this water, the absence of
tritium in samples of the Carvalhelhos water collected in 1996,
means that infiltration of meteoric water occurred more than 44
years before that date. Carbon isotopes analysis were
inconclusive concerning dating of this water, since it is suspected
that there is a deep mantle CO2 contribution to its final
composition.
The Sr isotopic ratios for the Carvalhelhos water (87Sr/86Sr =
0.726255 - 0.726485), though more radiogenic than rainwater
(Fig. 4), do not lie within the range of present-day values
reported by Saraiva et al. (2007) for samples of the host granite
(87Sr/86Sr = 0.749238) and the Silurian formations (87Sr/86Sr =
0.760103 - 0.782684) (Tab. 3), indicating that the bulk
equilibrium between rocks and fluids was not attained. In granitic
and metamorphic environments, the isotopic exchange between
rocks and fluids is highly dependent on the relative leaching
stabilities of the different silicate phases (plagioclase feldspar
dissolves first than biotite, K-feldspar or muscovite), which may
therefore lead to some decoupling of their Sr isotopic
compositions (Stettler and Allégre, 1978; Lasaga, 1984, Marques
et al., 2006). As, on the other hand, the most easily weathered
silicate mineral is plagioclase feldspar, which is Sr-enriched and
far less radiogenic than K-feldspar or micas (Tab. 3), it is likely
that the 87Sr/86Sr ratios of the Carvalhelhos mineral waters have
been essentially controlled by the dissolution of Na-feldspar, as
proposed by Saraiva (2006) and Saraiva et al. (2007). The high
degree of overlap between the Sr isotopic ratios of the
Carvalhelhos water and the results obtained by Brough (1990) in
plagioclases from similar granitoids (87Sr/86Sr = 0.716873 -
0.736393) supports this assumption.
The samples of the Fastio and Serra da Estrela bottled
mineral waters can be clearly distinguished from the
Carvalhelhos water by their lower concentrations of dissolved
solids (< 52 mg/L), pH values (5.8 - 6.9) and average Sr isotopic
ratios (Fastio: 0.71369, Serra da Estrela: 0.71982). Their
physico-chemical characteristics and Sr isotopic compositions
point to shallower groundwater circulation paths, shorter
residence times and less effective fluid-rock (fluid-plagioclase)
interaction mechanisms. It should be noted, however, that the
aquifer source rocks are in both cases late-post-D3 Variscan
granitoids with younger ages, lower Rb/Sr ratios and less
radiogenic Sr isotopic signatures than the S-type granite hosting
the Carvalhelhos water.
The Gouveia Massif (Serra da Estrela water) displays a U-Pb
zircon age of 301 2.6 Ma and a Sr isotopic ratio of 0.74421
(Neiva et al., 2009), whereas the Agrela Massif (Fastio water) is
306 3.5 Ma old and shows present-day 87Sr/86Sr ratios ranging
from 0.720803 to 0.732505 (Dias et al., 1998; 2002). A
comparison of water and whole-rock isotope ratios is of little
relevance, because full isotope equilibrium with the surrounding
country rocks is rarely achieved (Négrel et al., 2001; Shand et al.,
2009). Nevertheless, differences in the age and nature of granite
reservoirs will have strong effects on the 87Sr/86Sr ratios of their
silicate minerals, being therefore possible that the Sr isotopic
variability recorded in the three types of granite waters analysed
in this study reflects contrasts in the exchange rates and 87Sr/86Sr
compositions of the plagioclase with which they have interacted,
as also demonstrated by Marques et al. (2012).
Ordovician quartzites – “Luso”, “Ladeira de Envendos”,
“Castelo de Vide” mineral waters.
The natural mineral waters of Luso, Ladeira de Envendos and
Castelo de Vide are low mineralised water types (Tab. 2), derived
from infiltration of meteoric water along a highly fractured
Sr isotopic signatures of Portuguese bottled mineral waters 35
bedrock, consisting mainly of quartzites of Lower Ordovician age
(Arenigian). The Ordovician sequences are exposed in the core of
a series of NW-SE trending synclines, formed during the first
Variscan deformation event (Buçaco, Envendos-Pinhal and
Castelo de Vide synclines, respectively).
In a geological environment dominated by quartz-rich
lithologies with little or no Sr-bearing minerals, a close match
between the 87Sr/86Sr ratios of groundwater and rainfall should be
expected. However, the average Sr isotopic compositions of the
three mineral water samples (Luso: 0.71525; Ladeira de
Envendos: 0.71700; Castelo de Vide: 0.77701) are distinctly
more radiogenic than rainwater (Fig. 4), suggesting that the
isotopic composition of the recharge waters was substantially
modified by the input of easily accessible Sr with high 87Sr/86Sr
ratios from external sources.
For the Luso and Ladeira de Envendos hydrologic systems,
the increase in the 87Sr/86Sr ratios relative to rainwater may have
resulted from chemical weathering of silicate minerals present
either in arkosic / pelitic intercalations within the Arenigian
quartzite succession or in the underlying red bed and
conglomerate deposits of presumed Tremadocian age (Teixeira,
1981; Oliveira et al., 1992). These low-grade metasedimentary
rocks contain, in addition to quartz, variable amounts of feldspar
and phylossilicates (muscovite and chlorite) and may thus have
supplied radiogenic Sr to groundwater.
The Luso and Ladeira de Envendos mineral waters flow
through deep-seated fractures (> 100 m) and discharge with
moderate temperatures (Luso: 27 ºC; Envendos: 22 ºC), pH
ranging from 4.8 to 5.7 and very low mineralization contents
(Tab. 2). Under these conditions, partial equilibrium between
silicic rocks and fluids could have occurred and Sr may have
been progressively released to the solution from the primary
reacting minerals (feldspar, muscovite, chlorite) and neo-formed
clay minerals, promoting the elevation of the 87Sr/86Sr ratios in
the waters. Their overall chemistry and relatively high silica
concentrations are consistent with a chemical evolution primarily
controlled by water-rock interaction processes involving acidic
weathering of aluminosilicates. In the case of the Serra do
Buçaco aquifers (Luso region), Vieira da Silva et al. (2000)
showed that there is a direct correlation between discharge
temperature, silica content, maximum depth of circulation and
tritium content (residence time).
As first pointed out by Voerkelius et al. (2010), the Castelo
de Vide mineral water exhibits anomalously high 87Sr/86Sr ratios
(0.776543 - 0.777268). The water is sourced from an Ordovician
aquifer system (the “Castelo de Vide” syncline) showing the
same broad stratigraphic units that the Luso and Ladeira de
Envendos synclines. However, the Ordovician sequences of the
Castelo de Vide syncline are in contact with strongly deformed
pre-Variscan granitoids (Portalegre orthogneisses), related to an
old episode of magmatic activity (493 ± 3.5 Ma; Solá, 2007). In
keeping with their old age and extreme differentiated character,
the Portalegre orthogneisses have 87Sr/86Sr ratios ranging from
0.9573 - 1.4985 (Solá, 2007). Because the Sr isotope ratios in
granite rock forming minerals depend on the age and Rb/Sr ratio
of the host, it may be presumed that dissolution of radiogenic
plagioclase (and to a lesser extent, K-felspar and biotite) from the
Portalegre orthogneisses could have provided a supplementary
source of radiogenic Sr for the Castelo de Vide mineral water.
5. Conclusions
Based on the results obtained for nine samples of bottled mineral
waters from Portuguese mainland, it is possible do draw the
following conclusions:
(a) each of the analysed water samples exhibits a distinctive
Sr isotope signature that does not change significantly with time
and can therefore be used for purposes of mineral water
authentication;
(b) the Sr isotope ratios of the analysed waters are
dominantly controlled by both the nature and stratigraphic age of
the aquifer host rocks. The least radiogenic waters are related to
Jurassic carbonates / evaporites (87Sr/86Sr = 0.70808) and Late
Cretaceous alkaline igneous sources (87Sr/86Sr = 0.70447),
whereas the Cenozoic siliciclastic sediments host waters with
87Sr/86Sr values of 0.71078 and the waters coming from granitic
and/or metamorphic terrains of the Iberian Variscan basement
display highly radiogenic Sr isotopic compositions (87Sr/86Sr
varying between 0.7136 and 0.7770);
(c) fluid-rock and fluid-mineral interaction processes
involving lithologies composed by easily soluble minerals
(calcite/dolomite, anhydrite/gypsum and halite) promote bulk
isotope equilibrium between groundwater and parent rock
(Vimeiro water). For water reservoirs interacting with silicate
rocks, isotopic equilibrium with the whole-rock is rarely achieved
due to the variable reactivity rates of their mineral constituents
(Carvalhelhos, Fastio, Serra da Estrela, Castelo de Vide, Luso,
Ladeira de Envendos waters) and can only be approached by
long-term fluid-rock interaction mechanisms at high temperatures
(Monchique water);
(d) in non-carbonate environments, the input of radiogenic Sr
to the water is a function of the stability, age and Rb/Sr ratios of
the aquifer bedrock silicate minerals and appears to be mainly
provided by the hydrolysis of plagioclase feldspar and, to a lesser
extent, primary phylossilicates or neo-formed clay minerals.
Finally, the presence of significant differences in the Sr
isotope composition of the Portuguese bottled mineral waters
provides a powerful tool for fingerprinting their origin and to
trace the hydrogeochemical processes operating along water flow
paths.
Acknowledgements
The authors wish to thank Eugenio Soares, Joana Coimbra and
Lina Carvalho, from the ICP Laboratory (Laboratório Central de
Análises - University of Aveiro) for the Sr concentration data.
We are also grateful to Vieira da Silva, Antunes da Silva, Albino
de Medeiros and Manuela Azevedo, who gave us detailed and
actual data concerning the exploitation of each mineral water
involved in this study. The authors also like to thank the two
anonymous reviewers for their helpful comments. This research
was financially supported by FCT (Science and Technology
Foundation, Portugal) through the following projects:
POCTI/CTE-GIN/60043/2004, PTDC/CTE-GIX/112561/2009
and PEst-C/CTE/UI4035/2011.
References
Aberg, G., 1995. The use of natural Sr isotopes as tracers in
environmental studies. Water, Air & Soil Pollution, 79, 309-322.
Almeida, C. M. R., Vasconcelos, M. T. S. D., 2001. ICP-MS
determination of strontium isotope ratio in wine in order to be used as
a fingerprint of its regional origin. Journal of Analytical Atomic
Spectrometry, 16, 607-611.
Alves, T., Gawthorpe, R. L., Hunt, D. W., Monteiro, J. H., 2003.
Cenozoic tectono-sedimentary evolution of the western Iberia margin.
Marine Geology, 195, 75-108.
Andrade, M. P. L., 2002. A Geoquímica isotópica e as águas
termominerais. Contribuição dos isotópos do Sr (87Sr/86Sr) e do Cl
(37Cl/35Cl) na elaboração de modelos de circulação. O caso de algumas
águas gasocarbónicas do N de Portugal. MSc Thesis (unpublished),
Instituto Superior Técnico, Univ. Técnica de Lisboa, Lisboa, 104.
36 S. Ribeiro et al. / Comunicações Geológicas (2014) 101, 1, 29-37
Antunes, M. T, Elderfield, H., Legoinha, P., Nascimento, A., Pais, J., 1999.
A stratigraphic framework for the Miocene from the Lower Tagus Basin
(Lisbon, Setúbal Peninsula, Portugal) depositional sequences,
biostratigraphy and isotopic ages. Revista de la Sociedad Geológica de
España, 12, 1.
Azevedo, M. R., Valle Aguado, B., 2013. Origem e instalação de
granitóides variscos na Zona Centro-Ibérica. In: Dias, R., Araújo, A.,
Terrinha, P. e Kullberg, J. C. (Eds) Geologia de Portugal, Escolar
Editora, 1, 377-401.
Bacon, J. R., Bain D. C., 1995. Characterization of environmental water
samples using strontium and lead stable isotope compositions.
Environmental Geochemistry and Health, 17, 39-49.
Barbaste M., Robinson K., Guilfoyle S., Medina B., Lobinski R., 2002.
Precise determination of the strontium isotope ratios in wine by
inductively coupled plasma sector field multicollector mass spectrometry
(ICP-SF-MC-MS). Journal of Analytical Atomic Spectrometry, 17, 135-
137.
Barbieri, M., Morotti, M., 2003. Hydrogeochemistry and strontium isotopes
of spring and mineral waters from Monte Vulture volcano, Italy. Applied
Geochemistry, 18, 117-125.
Bau, M., Alexander, B., Chesley, J. T., Dulski, P., Brantley, S. L., 2004.
Mineral dissolution in the Cape Cod aquifer, Massachusetts, USA: I.
Reaction stoichiometry and impact of accessory feldspar and glauconite
on strontium isotopes, solute concentrations, and REY distribution.
Geochimica et Cosmochimica Acta, 68, 1199-1216
Bernard Griffiths, J., Gruau, G., Cornen, G., Azambre, B., Mace, J., 1997.
Continental lithospheric contribution to alkaline magmatism: isotopic
(Nd, Sr, Pb) and geochemical (REE) evidence from Serra de Monchique
and Mout Ormonde complexes. Journal of Petrology, 38, 115-132.
Blum, J. D., Erel, Y., Brown, K., 1993. 87Sr/86Sr ratios of Sierra-Nevada
stream waters – implications for relative mineral weathering rates.
Geochimica et Cosmochimica Acta, 57, 5019-5025.
Blum, J. D. and Erel, Y., 2005. Radiogenic isotopes in weathering and
hydrology. In: Drever, J.I. (Ed), Surface and Ground Water, Weathering,
and Soils. Treatise on Geochemistry, Elsevier, 365-392.
Bohlke, J. K. and Horan, M., 2000. Strontium isotope geochemistry of
groundwaters and streams affected by agriculture, Locust Grove, MD.
Applied Geochemistry, 15, 599-609.
Brach-Papa, C., Cocxtaele, M. V., Ponzevera, E., Quétel C. R, 2009. Fit for
purpose validated method for the determination of the strontium isotopic
signature in mineral water samples by multi-collector inductively
coupled plasma mass spectrometry. Spectrochimica Acta, B 64, 229-234.
Brough, N., 1990. Peraluminous granite magmatism in Central Northern
Portugal. PhD Thesis (unpublished), Department of Earth Sciences,
Open University, U.K., 434.
Bullen, T. D, Krabbenhoft, D. P., Kendall, C., 1996. Kinetic and
mineralogic controls on the evolution of groundwater chemistry and
87Sr/86Sr in a sandy silicate aquifer, northern Wisconsin, USA.
Geochimica et Cosmochimica Acta, 60, 1807-1821.
Carreira, P. M., Marques, J. M., Graca, R., Aires-Barros, L., 2008.
Radiocarbon application in dating "complex" hot and cold CO2-rich
mineral water systems: A review of case studies ascribed to the northern
Portugal. Applied Geochemistry, 23, 10, 2817-2828.
Calado, C., Vieira da Silva, A. M., 2003. As águas minerais de Monchique.
Proposição de um modelo hidrogeológico conceptual. Jornadas Luso-
Espanholas sobre as Águas Subterrâneas no sul da Peninsula Ibérica,
APRH, Faro.
Chiquet, A., Michard, A., Nahon D., Hamelin, B., 1999. Atmospheric input
vs in situ weathering in the genesis of calcretes: an Sr isotope study at
Gálvez (Central Spain), Geochimica et Cosmochimica Acta, 63, 311-
323.
Crittenden, R. G., Andrew, A. S., LeFournour, M., Young, M. D.,
Middleton, H., Stockmann, R., 2007. Determining the geographic origin
of milk in Australasia using multi-element stable isotope ratio analysis.
International Dairy Journal, 17, 5, 421-428.
Costa, A.M., 1982, Estudo hidrogeológico das Nascentes termo-minerais de
Vimeiro e Cucos. Relatório de final de curso FCUL, Lisboa.
Dias, G., Leterrier, J., Mendes, A., Simões, P. P., Bertrand, J. M., 1998. U-
Pb zircon and monazite geochronology of post-collisional Hercynian
granitoids from Central Iberian Zone (Northern Portugal). Lithos, 45,
349-369.
Dias, G., Simões, P. P., Ferreira, N., Leterrier, J., 2002. Mantle and crustal
sources in the genesis of late-Hercynian granitoids (NW Portugal):
geochemical and Sr-Nd isotopic constraints. Gondwana Research, 5, 2,
287-305.
Euzen, A., 2006. Bottled water, globalization and behaviour of consumers.
Journal Europeen d'Hydrologie, 37, 143-155.
Faure, G., 1986. Principles of Isotope Geology. John Wiley & Sons, 2nd
edition, New York, 589.
Faure, G., Mensing T. M., 2005. Isotopes, principles and applications. John
Wiley & Sons, 3th edition, 897.
Ferreira, M. R. P., Macedo, C. R., 1979. K-Ar Ages of the Permian-
Mesozoic Basaltic Activity in Portugal. Abstracts VI. Europ. Col.
Geochron., Cosmochron. and Isotope Geology, Norway, 26-27.
Frost, C. D., Toner, R. N., 2004. Strontium isotopic identification of water–
rock interaction and groundwater mixing. Ground Water, 42, 418-432.
Hindshawa R. S., Tipperc E. T., Reynoldsa B. C., Lemarchanda E.,
Wiederholda J. G., Magnussond J., Bernasconie S. M., Kretzschmarb R.,
Bourdona B., 2011. Hydrological control of stream water chemistry in a
glacial catchment (Damma Glacier, Switzerland), Chemical Geology,
285, 215-230
Horn, P., Schaaf, P., Holbach, B., Hoelzl, S., Eschnauer, H., 1993. 87Sr/86Sr
from rock and soil into vine and wine. Zeitschrift fur Lebensmittel-
Untersuchung und Forschung, 196, 407-409.
Horn, P., Hoelzl, S., Todt, W., Matthies, D., 1998. Isotope abundance ratios
of Sr in wine provenance determinations in a tree-root activity study and
of Pb in a pollution study on tree rings. Isotopes in Environmental and
Health Studies, 34, 31-42.
Jacobson, A. D., Blum, J. D., Chamberlain, C. P., Poage, M. A., Sloan, V.
F., 2002. Ca/Sr and Sr isotope systematics of a Himalayan glacial
chronosequence: carbonate versus silicate weathering rates as a function
of landscape surface age. Geochimica et Cosmochimica Acta, 66, 13-27.
Jiang, Y., Wu, Y., Yuan, D., 2009. Human impacts on karst groundwater
contamination deduced by coupled nitrogen with strontium isotopes on
the Nandong underground river system in Yunan, China. Environmental
Science and Technology, 43, 7676-7683.
Jones C. E., Jenkyns H. C., 2001. Seawater strontium isotopes, oceanic
anoxic events, and seafloor hydrothermal activity in Jurassic and
Cretaceous. American Journal of Science, 301, 112-149.
Lasaga, A. C., 1984. Chemical kinetics of water-rock interactions. Journal
of Geophysical Research, 89, 4009-4025.
Lourenço, C., Cruz, J., 2010. Cátalogo de Recursos Geotérmicos. LNEG -
Laboratório Nacional de Energia e Geologia, I.P.
http://geoportal.lneg.pt/index.php?option=com_content&id=59#page=0
Lourenço, C., Ribeiro, L., Cruz, J., 2010. Classification of natural mineral
and spring bottled waters of Portugal using Principal Component
Analysis. Journal of Geochemical Exploration, 107, 362-372.
MacIntyre, R. M., Berger, G. W., 1982. A note on the geochronology of the
Iberian Alkaline Province. Lithos, 15, 133-136.
Malod, J. A., Mauffret, A., 1990. Iberian plate motions during the
Mesozoic. Tectonophysics, 184, 261-278.
Manuppella, G., Antunes, M. T., Pais, J., Ramalho, M. M., Rey, J., 1999.
Notícia Explicativa da Folha 30-A Lourinhã da Carta Geológica de
Portugal à escala 1/50000. Instituto Geológico e Mineiro, Lisboa, 83.
Manuppella, G., Barbosa, B., Azeredo, A. C., Carvalho, J., Crispim, J.,
Machado S., Sampaio J., 2006. Notícia Explicativa da Folha 27-C
Torres Novas da Carta Geológica de Portugal à escala 1/50000, 82.
Instituto Nacional de Engenharia, Tecnologia e Inovação, Lisboa, 79.
Marques, J. M., Carreira, P. M., Goff, F., Eggenkamp H. G. M., Antunes da
Silva, M., 2012. Input of 87Sr/86Sr ratios and Sr geochemical signatures
to update knowledge on thermal and mineral waters flow paths in
fractured rocks (N-Portugal). Applied Geochemistry, 27, 1471-1481.
Marques, J. M., Andrade, M., Carreira, P. M., Eggenkamp, H. G. M., Graça,
R. C., Aires-Barros, L. A., Antunes da Silva, M., 2006. Chemical and
isotopic signatures of Na/HCO3/CO2-rich geofluids, North Portugal.
Geofluids, 6, 273-287.
Marques, J. M., Matias, M. J., Basto, M. J., Carreira, P. M., Aires-Barros, L.
A., Goff, F. E., 2010. Hydrothermal alteration of Hercynian granites, its
significance to the evolution of geothermal systems in granitic rocks.
Geothermics, 39, 152-160.
Martins, L. T., 1991. Actividade Ígnea Mesozóica em Portugal
(contribuição petrológica e geoquímica). Tese de Doutoramento não
publicada. Faculdade de Ciências da Universidade de Lisboa, 418.
Martins, L. T., Madeira, J., Youbi, N., Munhá, J., Mata, J., Kerrich, R.,
2008. Rift-related magmatism of the Central Atlantic magmatic province
in Algarve, Southern Portugal. Lithos 101, 102-124.
Sr isotopic signatures of Portuguese bottled mineral waters 37
Matte, P., 1986. Tectonics and plate tectonic model for the Variscan Belt of
Europe. Tectonophysics, 126, 329-374.
Miranda, R., Valadares, V., Terrinha, P., Mata, J., Azevedo, M. R., Gaspar,
M., Kullberg, J. C., Ribeiro, C., 2009. Age constraints on the Late
Cretaceous alkaline magmatism on the West Iberian Margin. Cretaceous
Research, 30, 575-586.
Montgomery, J., Evans, J. A., Wildman, G., 2006. 87Sr/86Sr isotope
composition of bottled British mineral waters for environmental and
forensic purposes. Applied Geochemistry, 21, 1626-1634.
Mougenot, D., Vanney, J.-R., Mau¡ret, A., Kidd, R., 1986. Les montagnes
sous-marines de la marge continentale nordportugaise: morphologie et
evolution structurale. Bull. Soc. Geol. Fr., 2, 401-412.
Négrel Ph., Allègre C. J., Dupré B., Lewin E., 1993. Erosion sources
determined from inversion of major, trace element ratios and strontium
isotopic ratio in riverwater: the Congo Basin case. Earth and Planetary
Science Letters, 120, 59-76.
Négrel, Ph., Fouillac, C., Brach, M., 1997. A strontium isotopic study of
mineral and surface waters from the Cezallier (Massif Central, France):
implications for the mixing processes in areas of disseminate
emergences of mineral waters. Chemical Geology, 135, 89-101.
Négrel, Ph., 1999. Geochemical study in a granitic area, the Margeride,
France: chemical element behaviour and 87Sr/86Sr constraints. Aquatic
Geochemistry, 5, 125-165.
Négrel, Ph., Casanova, J., Aranyossy, J. F., 2001. Strontium isotope
systematic used to decipher the origin of groundwater sampled from
granitoids: the Vienne case (France). Chemical Geology, 177, 287-308.
Négrel, Ph., Guerrot, C., Millot, R., 2007. Chemical and strontium isotope
characterization of rainwater in France: influence of sources and
hydrogeochemical implications. Isotopes in Environmental and Health
Studies, 43, 3, 179-196.
Neiva A. M. R., Williams I. S., Ramos J. M. F., Gomes M. E. P., Silva M.
M. V. G., Antunes I. M. H. R., 2009. Geochemical and isotopic
constraints on the petrogenesis of Early Ordovician granodiorite and
Variscan two-mica granites from the Gouveia area, Central Portugal.
Lithos, 111, 186-202.
Oliveira, J. T., Pereira, E., Piçarra, J. M., Young, T., Romano, M., 1992. O
Paleozóico Inferior de Portugal: Síntese da estratigrafia e da evolução
paleogeográfica. In: Gutiérrez Marco, J. G., Saavedra, J., Rábano, I.
(Eds) Paleozóico Inferior de Ibero-América. Universidad de
Extremadura, 359-375.
Pais, J., Cunha, P. P., Legoinha, P., 2010. Litostratigrafia do Cenozóico de
Portugal. In: Neiva, J. M. C., Ribeiro, A., Victor, L. M., Noronha, F.,
Ramalho, M. (Eds) Ciências Geológicas: Ensino e Investigação, I: 365-
376.
Pacheco F. A. L., Medina, J., Ribeiro, S., Van der Weijden C. H., 2009.
Duration of weathering episodes in small watersheds: implications on
plagioclase weathering rates. Abstract book, VII Congresso Ibèrico X
Congresso Nacional de Geoquímica, Soria, 282-292.
Pinheiro, L. M., Wilson, R. C. L., Reis, R. P., Whitmarsh, R. B., Ribeiro,
A., 1996. The western Iberia margin: a geophysical and geological
overview. Proceedings of the Ocean Drilling Program, Scientific
Results, 149, 3-23.
Probst, A., Gh'mari, E., Aubert, D., Fritz, B., McNutt, R., 2000. Strontium
as a tracer of weathering processes in a silicate catchment polluted by
acid atmospheric inputs, Strengbach, France. Chemical Geology, 170,
203-219.
Quesada, C., 1991. Geological constraints on the Palaeozoic tectonic
evolution of tectonostratigraphic terranes in the Iberian Massif.
Tectonophysics, 185, 225-245
Rasmussen, E. S., Lomholt, S., Andersen, C., Vejbæk, O. V., 1998. Aspects
of the structural evolution of the Lusitanian Basin in Portugal and the
shelf and slop offshore Portugal. Tectonophysics, 300, 199-225.
Ribeiro, A., Antunes, M. T., Ferreira, M. P., Rocha, R. B., Soares, A. F.,
Zbyszewski, G., Moitinho de Almeida, F., Carvalho, D., and Monteiro,
J. H., 1979. Introduction à la Géologie generale du Portugal. Serviços
Geológicos de Portugal. 114.
Rock, N. M. S., 1976. The comparative strontium isotopic composition of
alkaline rocks: new data from Southern Portugal and East Africa.
Contributions to Minerology and Petrology, 56, 205-228.
Rock, N. M. S., 1978. Petrology and petrogenesis of the Monchique
alkaline complex, Southern Portugal. Journal of Petrology, 19, 171-214.
Rosembaum, G., Lister, G. S., Duboz, C., 2002. Relative motions of Africa,
Iberia and Europe during Alpine orogeny. Tectonophysics, 359, 117-129.
Rossmann, A., Haberhauer, G., Hoelzl, S., Horn, P., Pichlmayer, F.,
Voerkelius, S., 2000. The potential of multielement stable isotope
analysis for regional origin assignment of butter. European Food
Research and Technology, 211, 1, 32-40.
Rummel, S., Hoelzl, S., Horn, P., Rossmann, A., Schlicht, C., 2008. The
combination of stable isotope abundance ratios of H, C, N and S with
87Sr/86Sr for geographical origin assignment of orange juices. Food
Chemistry, doi: 10.1016/j.foodchem.2008.05.115.
Saraiva, M. A., 2006. Caracterização geoquímica dos granitos variscos,
metasedimentos silúricos e águas da região de Boticas. Aplicação de
isótopos de Sr. MSc Thesis (unpublished), Univ. Trás os Montes e Alto
Douro, Vila Real, 156.
Saraiva, M., Gomes, M. E. P., Azevedo, M. R., 2007. Sr isotopic
composition in Variscan granitoids, Silurian metasediments and waters
from the Boticas area (Northern Portugal). Goldschmidt Conference
Abstracts, Cologne, Germany, A877
Shand, P., Darbyshire, D. B. F. Love, A. J., Edmunds, W. M., 2009. Sr
isotopes in natural waters: Applications to source characterisation and
water–rock interaction in contrasting landscapes. Applied Geochemistry,
24, 574-586.
Solá, A. R., 2007. Relações petrogeoquímicas dos maciços graníticos do
Nordeste Alentejano. PhD thesis (unpublished), Fac. Ciências, Univ.
Coimbra, 405.
Soler, A., Canals, A., Goldstein, S. L., Otero, N., Antich, N., Spangleberg,
J., 2002. Sulfur and strontium isotope composition of the Llobregat
River (NE Spain): tracers of natural and anthropogenic chemicals in
stream waters. Water, Air, & Soil Pollution, 136, 207-224.
Srivastava, S. P., Schouten, H., Roest, W. R., Klidtgord, K. D., Kovacs, L.
C., Verhoef, J., Macnab, R., 1990. Iberia plate kinematics: a jumping
plate boundary between Eurasia and Africa. Nature, 344, 756-759.
Stettler, A., Allégre C.J., 1978. 87Sr/86Sr studies of waters in a geothermal
area, the Cantal, France. Earth and Planetary Science Letters, 38, 364-
72.
Teixeira, C. 1981. Geologia de Portugal. Precâmbrico e Paleozóico.
Fundação Calouste Gulbenkian, Lisboa, I, 622.
Terrinha, P., 1998. Structural Geology and Tectonic Evolution of the
Algarve Basin, South Portugal. PhD Thesis (unpublished), Imperial
College, University of London,430.
Valadares, V., 2004. O Complexo Alcalino de Monchique: novos dados de
cartografia, geoquímica e geocronologia. MSc Thesis (unpublished), Fac.
Ciências, Univ. Lisboa, 248.
Vera, J.A., Ancochea, E., Barnolas, A., Bea, F., Calvo, J.P., Civis, J., De
Vicente, G., Fernández-Gianotti, J., Garcia-Cortéz, A., Pérez-Estaún, A.,
Pujalte, V., Rodríguez-Fernández, L.R., Sopena, A., Tejero, R., 2004.
Introducción. In: Vera, J.A. (Eds). Geología de España. SGE-IGME,
Madrid, 3-17.
Venturelli, G., Boschetti, T., Duchi, V., 2003. Na-carbonate waters of
extreme composition: Possible origin and evolution. Geochemical
Journal, 37, 351-366.
Verati, C., Rapaille, C., Féraud, G., Marzoli, A., Bertrand, H., Youbi, H.,
2007. 40Ar/39Ar ages and duration of the Central Atlantic Magmatic
Province volcanism in Morocco and Portugal and its relation to the
Triassic–Jurassic boundary. Palaeogeography, Palaeoclimatology,
Palaeoecology, 244, 308-325.
Vieira da Silva, A. M., Condesso Melo, M. T., Marques da Silva, M. A.,
2000. Modelo conceptual e caracterização hidrogeológica preliminary do
sistema aquifer da Serra do Buçaco. Actas das Jornadas
Luso
‐
Espanholas sobre As Águas Subterrâneas no Noroeste da
Peninsula Ibérica, La Coruña (España), 3-6 Julho, Ed. ITGE.
Voerkelius, S., Lorenz, G. D., Rummel, S., Quétel, C. R., Heiss, G., Baxter,
M., Brach-Papa, C., Deters-Itzelsberger, P., Hoelzl, S., Hoogewerff, J.,
Ponzevera, E., Van Bocxstaele, M., Ueckermann, H., 2010. Strontium
isotopic signatures of natural mineral waters, the reference to a simple
geological map and its potential for authentication of food. Food
Chemistry, 118, 933-940.
Wiegand B. A., 2009. Tracing effects of decalcification on solute sources in
a shallow groundwater aquifer, NW Germany. Journal of Hydrology,
378, 1-2, 62-71
Wilson, R. C. L., Hiscott, R. N., Willis, M. G. and Gradstein, F. M., 1989.
The Lusitanian basin of west-central Portugal: Mesozoic and Tertiary
tectonic, stratigraphy, and subsidence history. AAPG Memoir, 46, 341-
361.
