deformation, including folding and thrusting. Thus,these undeformed mineralized veins are most probablyrelated to the rejuvenation and repeated reopening ofpre-existing fractures during late Variscan extensionaltectonics.
Both the Puebla de Guzma´n and the Calan˜as-
Valverde del Camino anticlines host some prominentmassive sulfide deposits. The giant Tharsis deposit,with reserves of about 115 Mt (Sa´ez et al. 1999), islocated some 10 km southwest of Nero´n and about7 km north of Aurora, and the Sotiel-Migollas Groupof massive sulfide deposits (reserves of 117 Mt) liesanother 10 km SE of the Silillas. No published infor-mation is available on possible indications of massivesulfide bodies buried below the Culm sediments in theNero´n-Silillas-Aurora area, whereas east of Valverdethe giant Masa Valverde deposit (120 Mt) has beendiscovered quite recently under Culm sediment cover(Toscano et al. 1993).
Analytical methods
Fluid inclusions were studied in quartz and barite in transmittedlight, and in stibnite in near-infrared light using a U.S.G.S. heating-freezing system. The thickness of doubly polished wafers for mic-rothermometric studies was between 200 and 250 lm for quartzand barite, and for stibnite between 100 and 120 lm. For cali-
Fig. 2 a Banded quartz–stibnite ore from Mina Nero´n (sample
bration, synthetic standards and natural inclusions were used.
10000 in Tables 2 and 3) b Photomicrograph of halite-bearing fluid
Hydrogen isotope ratios on bulk fluid inclusions in quartz were
inclusions in a clear zone of late-stage chevron quartz from Mina
measured by mechanical crushing of about 5 g of quartz grains of 1
Nero´n (sample 16041 in Tables 2 and 3). c Infrared photomicro-
to 5 mm in size, according to the method described in detail by
graph of a primary two-phase fluid inclusion in stibnite (sample
Simon (2001). The released water was trapped, reduced to H2 by
16039 in Tables 2 and 3) orientated parallel to {010}
zinc (Bloomington, Indiana University, USA), and measured on aFinnigan MAT 251 gas source mass spectrometer. The absoluteerror of determination is about 5 to 10&.
Oxygen isotope ratios were measured by the laser ablation
edo Vara 1963) and N100E (Routhier et al. 1980) strike.
continuous flow technique described in Fiebig et al. (1999) and
The mineral paragenesis comprises quartz, barite, galena
Wiechert et al. (2002). A 300-lm spot size was ablated by a 193-nm
and sphalerite.
ArF Excimer laser (Lambda Physik), with an average energy of
In terms of their structural and lithostratigraphic
20 J/cm2 on the sample surface. The resulting oxygen was analyzedby a Finnigan Delta plus mass spectrometer.
position, all three vein deposits occur at or near to the
Sulfur isotope analyses of sulfides were performed by preparing
flanks of anticlines and are hosted either by the Basal
sulfur dioxide through combustion at 1,000 C with V2O5. Sulfur
Shaly Formation (Moreno and Sequeiros 1989; Moreno
isotopic analyses of sulfates were carried out on H2S prepared by
1993) of the Culm Group, which overlies the third and
reaction at 350 C with Kiba solution. H2S is precipitated as CdS,converted to Ag
uppermost volcanic sequence of the VS Complex, or by
2S, and oxidized with V2O5 at 1,000 C to produce
SO2 which was used for the mass spectrometer measurements.
the first turbidite facies of the Culm Group.
Sulfur isotope ratios are reported as d34S relative to the Can˜on
Wipfler and Sedler (1995) have demonstrated that
Diablo Troilite (CDT).
the strike direction of undeformed quartz veins is ap-
Chemical analysis of the fluid inclusions was carried out at the
proximately parallel to the main foliation in the study
University of Leeds using the bulk crush-leach method as detailed inBanks et al. (2000a). Quartz, barite and stibnite samples were crushed
area. Structural analysis of the central part of the Py-
to 1–2 mm grain size and the quartz samples cleaned in aqua-regia,
rite Belt by Routhier et al. (1980) indicated a time se-
followed by nitric acid. All samples were then boiled several times in
quence of fractures and related veins from N90/100E
18.2 MW water and dried prior to analysis. Approximately 0.5 to 1 g
to N40/60E and finally N140/150E. In addition, a
of material was crushed, transferred to a suitable container and lea-ched with 18.2 MW water for anion and Na, K and Li analysis, or
close temporal and spatial relationship between the
with acidified LaCl3 solution for the analysis of other cations. Anions
observed Variscan folding phases and their subsequent
were determined by ion chromatography, Na, K and Li by flame
relaxation periods, represented by fractures, was as-
emission spectroscopy, and other cations by inductively coupled
sumed by Routhier et al. (1980). However, neither the
plasma emission spectroscopy. Replicate analyses show the precisionto be on average 5% RSD for the analysis of these samples. The 35Cl
Pb-Cu-barite veins nor the quartz-Sb veins which, ac-
and 37Cl isotopes were determined by thermal ionization mass
cording to the Routhier scheme, would belong to the
spectrometry on aliquots of the water-extracted salts, following the
oldest fracture generation, are affected by polyphase
method of Banks et al. (2000b).
phase and a vapor bubble at room temperature. Some
well-crystallized, late-stage quartz samples from MinaNero´n, with chevron structures, contain two-phase fluid
inclusions in the milky growth zones and polyphaseinclusions, i.e., two-phase fluid inclusions with cubes of
Milky gangue quartz samples from quartz–stibnite
halite crystals and/or other daughter minerals of un-
banded ores from Mina Nero´n and from the studied
known composition, in their clear zones (Fig. 2b). The
occurrences contain numerous fluid inclusions, but their
inclusions are preferentially orientated in milky growth
sizes generally do not exceed 2 lm. Due to the high
zones or arranged parallel to crystal planes in clear
number of fluid inclusions in milky quartz, a clear
zones and, therefore, they appear to be of primary or-
classification, i.e., primary vs. secondary origin of the
igin (Roedder 1984). They are highly variable in size
inclusions, is impossible. The shapes of the inclusions
(20–100 lm) and shape (irregular and rounded–elon-
are irregular or rounded and they either consist of a
gated forms). Barite samples from Mina Aurora always
liquid phase and a vapor bubble or, in the case of Mina
contain monophase aqueous fluid inclusions. They
Nero´n, they are often vapor-rich. Only a few combined
generally have a rounded–elongated form and sizes be-
microthermometric data of Tmice and Th were obtained
tween 10 and 30 lm.
from such samples (Fig. 3 and Table 2). Fluid inclu-
FTIR spectroscopic investigations of stibnite samples
sions in younger quartz crystals, in small vugs within
from Mina Nero´n indicate a transmittance of 15–25% to
milky quartz, are considerably larger (up to 15 lm) and
near-infrared radiation in the studied wavelength range
show rounded to elongated forms, consisting of a liquid
between 880 and 1,300 nm. Under the IR microscope,
Fig. 3 Tmice vs. Th diagram offluid inclusions in stibnite,quartz, and barite from vein-type mineralization in theIberian Pyrite Belt. Note: baritecontains only monophaseaqueous inclusions, probablydue to low formationtemperatures
Table 2 Summary of microthermometric data derived from studies of fluid inclusions in quartz, stibnite, and barite (m massive quartz, xcrystallized quartz)
Locality Sample no. Material Te (n)
Mean Tmclath/hydr. (n)
)2.5 11.3 to 14.7 (6) 153 to 200 (19) 178
)3.6 to )0.8 (17)
141 to 217 (17) 176
)62 to )44 (14) )49.3 to )19.7 (27) )29.2 0.1 to 16.3 (4)
125 to 152 (27) 142
)3.2 to )1.1 (10)
133 to 192 (10) 165
)20.8 to )14 (5) )7.3 to )0.6 (15)
)3.7 )2.1 to )1.5 (5) 142 to 189 (15) 165
)30 to 24.3 (13) )16 to 13.9 (13)
)23.1 to )7.8 (7)
the samples mostly show striation in the direction of
homogenization temperatures and halite dissolution
growth. Primary two-phase fluid inclusions are elon-
temperatures (Bodnar and Vityk 1994).
gated (Fig. 2c), and orientated parallel to crystallo-
Fluid inclusions in quartz from Mina Silillas have
graphic planes, {110} and/or {010}, as observed in
moderate to high salinity but lower homogenization
stibnite from other occurrences (Lu¨ders 1996; Bailly et al.
temperatures compared with the fluid inclusions from
2000). The size of primary fluid inclusions in stibnite
Mina Nero´n, whereas fluid inclusions in quartz from
varies between 30 and 70 lm. Secondary fluid inclusions
Mina Aurora have slightly lower salinities but the
of smaller size (<25 lm) occasionally occur along trails
highest homogenization temperatures of the three oc-
crosscutting the samples in various directions.
currences (Fig. 3). Monophase aqueous inclusions inbarite from Mina Aurora have ice melting temperaturesvarying between )16 and )1.5 C. The absence of a
vapor bubble in fluid inclusions in barite may be indi-cative of a low formation temperature of <80 C.
The results of fluid-inclusion studies in quartz, stibniteand barite are shown in Fig. 3 and Table 2. From the Thvs. Tm diagram (Fig. 3), two groups of fluid inclusions
Crush-leach analyses
can be distinguished: (1) low-salinity fluid inclusionswith homogenization temperatures between 150 and
The results of the crush-leach analysis are presented in
245 C, and (2) high-salinity fluid inclusions with
Table 3. The data show the fluids to be dominated by
homogenization temperatures between 100 and 150 C.
Na and Cl with significant but variable amounts of Ca
Some fluid inclusions in quartz and monophase inclu-
and K, and lesser amounts of Li, Mg and Br. Fluorine
sions in barite from Mina Aurora vary in salinity
was not detected and, although SO4 was present, there
between that of these two groups.
was a strong possibility that the analyses were influenced
All fluid inclusions in stibnite from Mina Nero´n have
by oxidation of sulfides during crushing and leaching,
low salinities, i.e., 1.6–4.9 wt% equivalent NaCl. The
and so the data have been omitted.
first melting of ice was observed at about )20 C, close
There is a large variation in the Cl/Br ratio of the
to the eutectic of the pure H2O–NaCl system. Addi-
fluid inclusions (Fig. 4). Quartz and stibnite (paired
tionally, the melting of clathrate between 10 and 14 C
samples) have similar Cl/Br and Na/Br ratios, but within
in a few inclusions indicates traces of a dissolved gaseous
the whole sample suite the fluid inclusions have a large
component in the fluid. Final homogenization temper-
range of values. This is despite the samples having es-
atures were not obtained from these gas-bearing inclu-
sentially the same gross salinity. There is a correlation
with salinity, as can be seen from the bulk analyses of
homogenization. The homogenization temperatures of
quartz sample 16041 (*), where selective cutting and
aqueous two-phase inclusions in stibnite were generally
analyzing parts of this sample which contains different
observed between 150 and 200 C.
salinity inclusions (a=high salinity+halite, b=high
Fluid inclusions in milky gangue quartz from Mina
salinity, c=dominantly low-salinity fluids) was carried
Nero´n, which is associated with stibnite (Fig. 2a), have
out. Halite-bearing inclusions are the most Br-enriched
similar salinities and homogenization temperatures as
and the lowest-salinity fluid inclusions (salinity equiva-
the fluid inclusions in stibnite (Fig. 3). Melting of
lent to that of the quartz–stibnite mineralization) the
clathrate was not observed in low-salinity inclusions in
least. However, the range of Cl/Br and Na/Br ratios, in
milky quartz. Fluid inclusions in euhedral late-stage
the whole sample suite, is much larger than that covered
quartz crystals with chevron structures (quartz II in
by these three different salinity fluids in sample 16041.
Fig. 3) from vugs contain low-salinity fluid inclusions in
Quartz and barite from Mina Aurora have different Cl/
milky growth zones whereas clear zones contain high-
Br and Na/Br ratios, the fluid inclusions in quartz being
salinity or even halite-bearing fluid inclusions (Fig. 2b).
more Br-rich, and are within the range of values from
The high-salinity fluid inclusions show ice melting tem-
Mina Nero´n. The quartz from Mina Silillas has Cl/Br
peratures as low as )27 C. In some of these inclusions,
and Na/Br ratios which are the same as those of the
melting of hydrate was observed between )2 and +4 C
halite-bearing fluid from Mina Nero´n.
(metastable?). The homogenization of the vapor phase in
Cation ratios, Na/K, Na/Li and Na/Ca also show
halite-bearing inclusions occurs at temperatures of
considerable variation (Figs. 5 and 6). Low-salinity fluid
about 150 C, always prior to the homogenization of the
inclusions from the quartz–stibnite mineralization of
daughter mineral (170 to 175 C). From the final melting
Mina Nero´n have lower Na/K and Na/Li ratios com-
temperatures of halite daughter crystals, a salinity of up
pared to the high-salinity fluids, and are especially dis-
to about 30.5 wt% equiv. NaCl can be inferred for these
tinct in terms of their Na/K ratios. The fluid inclusions
inclusions (Bodnar 1994). Although this salinity estimate
in quartz and barite from Mina Aurora have the same
is only valid for inclusions where Th vapor and Tm
Na/K ratios but markedly different Na/Li ratios, with
halite occur at the same temperature, the error range
fluids in barite being depleted in Li relative to the other
from an underestimate of salinity will be less than
samples. There is no correlation of Cl/Br with Na/K
1.3 wt% for the measured difference between vapor
(Fig. 7) or Na/Li. However, fluid inclusions in quartz
Table 3 Crush-leach analyses of fluid inclusions hosted by the different vein minerals with the d37Cl, dD and d34S of the fluids and minerals(anion and cation data reported in ppb (as analyzed); n.a. not analyzed, cont. analyses contaminated by minerals not removed prior tocrushing)
Locality Sample no. Mineral Na
d37Cl FIs. dD FIs.
(&)CDT (&)SMOC (&)SMOW
4,900 18.2 n.a.
<20 3,909 23.1 n.a.
127 <20 8,925 47
2,100 33.2 105 35
59 <20 17,429 127.2 333
58 cont. 3 cont. <20 15,371 33.6 cont.
1,764 50.5 126 42
113 <20 24,029 61.2 915
30 cont. 11 cont. <20 5,122 17.2 cont.
126 <20 51,264 639.4 cont.
<20 9,385 131.6 115
<20 2,855 27.9 142
<20 13,730 89.9 173
<20 3,859 24.4 n.a.
<20 34,097 99.2 n.a.
<20 1,125 14.9 n.a.
<20 1,161 14.4 n.a.
Fig. 4 Fluid-inclusion compositions compared to the trend shown
Fig. 5 Comparison of the fluid-inclusion temperatures using the
by evaporating seawater. Sample marked * is the bulk analysis of
crush-leach analyses and equations for the Na/K and Na/Li
fluid inclusions in sample 16041 which contains halite daughter
geothermometers derived by Verma and Santoyo (1997). Samples
crystals. Samples marked a–c represent halite-bearing, high-salinity
designated by *, a, and c belong to the different portions of sample
and low-salinity portions of sample 16041
16041 as identified in Fig. 4. Sample b contained too little K foranalysis and is not shown
from Mina Nero´n show a good correlation of Cl/Br andNa/Ca, with the most Br-rich fluids having the lowest
an excellent correlation with Cl/Br (r2=0.91). The halite-
Na/Ca ratio.
bearing fluid is quite distinct from these others, having a
The d37Cl values of fluid inclusions in quartz (Fig. 8)
much lower Cl/Br ratio and a d37Cl value which is within
cover a large range from )1.8 to +3.2& (SMOC). The
the range expected from evaporation of seawater. Saline
low-salinity fluids associated with the mineralization have
brines trapped in quartz from other Spanish Pb–Zn
Fig. 6 The Na/Ca vs. Cl/Br ratios of quartz-hosted fluid inclusions
Fig. 8 Cl/Br vs. d37Cl. The d37Cl values of fluid inclusions in
from Mina Nero´n show a good correlation which may indicate
massive gangue quartz from Mina Nero´n plot on a trend line
either fluid mixing or immiscibility. Only the bulk analysis of
typical for fluids which underwent two-phase separation, as
sample 16041 is shown, plotting at one extreme. However, because
observed for seafloor mineralization (Lu¨ders et al. 2002). Samples
of its d37Cl value (Fig. 8), the highest-salinity inclusions found in
with vapor-rich inclusions have negative d37Cl values whereas the
this sample could not be involved, either through mechanical
residual fluid becomes more enriched in 37Cl. Evaporation alone
mixing or by dilution with other fluids, in producing the observed
would only result in d37Cl fractionation of ±0.5& (shown by the
correlation of the other samples
two dashed lines). The bulk analysis of sample 16041 from MinaNero´n (identified by *), which is dominated by high-salinity, halite-bearing fluid inclusions in late-stage quartz, had a different originto the other fluids or different formation conditions. Forcomparison, high-salinity fluid inclusions in quartz from SpanishPb–Zn brines in the Maestrat Basin (Banks 2001) differ clearlyfrom the data in this study. The error bars represent 2r errors
provide information on the origin of the salinity. In theabsence of evaporite minerals, Cl and Br behave con-servatively during fluid flow because they are not sig-nificantly involved in fluid–rock interactions (Banks et al.
1991; Bohlke and Irwin 1992). In addition, they can beused to determine if fluid mixing or evaporation duringfluid flow and mineral deposition has occurred. The Cl/Br and Na/Br ratios of fluid inclusions in differentminerals from the studied deposits are shown in Fig. 4relative to the seawater evaporation line based on datacompiled by Fontes and Mattray (1993). The dashed line
Fig. 7 Na/K vs. Cl/Br ratios of the fluid inclusions relative to the
in the Na/Br versus Cl/Br plot represents Na to Cl ratios
trend expected for evaporating seawater. Samples designated by *,
of 1, and any removal or addition of halite produces a
a, and c belong to the different portions of sample 16041 as
data array parallel to this line.
identified in Fig. 4. Sample b contained too little K for analysis and
High-salinity and halite-bearing inclusions from
is not shown. The variation in Cl/Br at constant Na/K for somequartz and stibnite samples from Mina Nero´n is due to fluid
Mina Silillas and Mina Nero´n (late fluids in vug quartz)
immiscibility. Other samples which contain variable proportions of
plot close to the seawater evaporation line, with Cl/Br
the late high-salinity fluid have quite different ratios
and Na/Br ratios which would be generated whenalmost all the halite had been precipitated from sea-
mineralization, in the Maestrat Basin, have quite different
water. The lower-salinity fluids, associated with the
distributions of Cl/Br ratios and d37Cl values, and show
quartz–stibnite mineralization and quartz from Mina
no correlation between the chlorine isotopic composition
Aurora, also plot close to or on the seawater evapora-
and the Cl/Br ratios (Banks 2001).
tion line, albeit with higher Cl/Br and Na/Br ratios.
However, the salinity of these fluid inclusions is too lowfor them to represent only evaporated seawater, and
Origin of the fluids
they would have to have been diluted by a low-salinityfluid. Fluids which plot on the seawater evaporation line
Determination of halogen concentrations, especially Cl
at these points should have approximately 35 wt% total
and Br, and their ratios in fluid inclusions can be used to
dissolved solids, whereas the salinity of these fluids is less
than 5 wt%. To maintain these Cl/Br and Na/Br ratios,
are much higher, between 300 and 450 C but most are
the diluting fluid must have had a very low salinity.
close to 350 C. Fluid inclusions in quartz and stibnite
Quartz samples and the barite from Mina Aurora have
at Mina Nero´n have homogenization temperatures of
Cl/Br and Na/Br ratios which are close to seawater
about 185 C, and the late-stage high-salinity fluids
values, and their salinity would be consistent with such
have halite dissolution temperatures of about 170 C.
an origin. Other samples have significantly higher Cl/Br
At Mina Aurora, homogenization temperatures of ca.
and Na/Br ratios which would be consistent with a
240 C were recorded for fluid inclusions in quartz.
contribution from the dissolution of halite in the fluid.
The two mineral geothermometers give different tem-
However, an origin for the fluids which involves sea-
peratures, and this may be due to the fluids not
water evaporation, halite dissolution and dilution by a
achieving equilibrium with the appropriate mineral
low-salinity fluid is not compatible with the Cl isotope
assemblages. However, it is also possible that both are
data (Fig. 8). d37Cl values should be within the range of
correct but reflect the temperature at different stages of
+0.3 to )0.5& if the fluids were derived by evaporation
the fluid's history. The temperatures obtained from
of seawater or dissolution of halite (Eggenkamp et al.
Na/K ratios are almost identical to the fluid-inclusion
1995). However, the values of the fluids are between )1.8
temperatures, and we suggest they may be reflecting
and +3.2& and show an excellent correlation with the
equilibration of the fluid at the site of mineral depo-
Cl/Br ratios. The linear regression through the data in
sition. Sodium and K are more readily re-equilibrated
Fig. 8 passes within error of each sample and of sea-
than Li which is essentially conservative once in solu-
water. The late quartz, which contains the highest-sa-
tion (Fontes and Matray 1993). Therefore, the tem-
linity halite-bearing fluid inclusions, does not plot close
peratures obtained from the Na/Li ratios may be
to the other samples. This has the lowest Cl/Br ratio and
reflecting the maximum temperature reached by the
a d37Cl value both of which are consistent with a sea-
fluid prior to its ascent. We believe that the initial
water evaporation origin for the fluid. The same origin is
temperature of the ore-forming fluids was approxi-
likely for the quartz-hosted fluid inclusions from Mina
mately 300 C, and that the Na/K geothermometer
probably indicates the true temperature of the mineralformation whereas the Na/Li geothermometer morelikely reflects the initial temperature of the hydrother-
mal fluids. Consequently, if the mineralization occurredin a near-surface environment (<500 m), as indicated
Unlike the halogens, the cation content of the fluid is
by the stratigraphic position of the deposits, it is very
more likely to reflect some degree of re-equilibration
likely that the ascending fluids locally underwent par-
with rocks along the flow path and at the site of min-
tial two-phase separation.
eralization, and ultimately may bear no resemblance to
We suggested above that the highest-salinity fluid
its original composition. An assessment of the closeness
inclusions were derived from seawater which evaporated
to equilibration can be made by comparing tempera-
past the point of halite precipitation. If this were the
tures derived from mineral geothermometers and
case, then the fluid should contain little Ca and large
amounts of Mg. However, we observe the opposite
homogenization temperatures are the minimum tem-
(Table 3), and this is common for most high-salinity,
peratures of the fluid and corrections for pressure have
low-temperature brines where dolomitization controls
to be applied, which are often difficult to determine
the Ca and Mg contents of the fluids. In Fig. 8 there is a
exactly. The temperatures obtained from mineral geo-
good correlation between the highest-salinity fluid
thermometers are only valid if the fluid has reached
(marked with *) and the lower-salinity mineralizing
equilibrium with the appropriate mineral assemblage
fluids. We assume that in these fluids the variation in Cl/
and, using only one geothermometer, this is difficult to
Br ratios was due to phase separation. It is possible the
assess. In this study (Fig. 5) we have used the Na/K and
correlation of Cl/Br and Na/Ca was caused by this
Na/Li geothermometers of Fournier (1979) and Fouillac
process, but we are unaware of data on the behavior of
and Michard (1981), which have improved equations
Ca in these circumstances. However, in Fig. 7 there is
determined by Verma and Santoyo (1997) to estimate
not a similar correlation of Na/K and Cl/Br for the
the temperature of the different fluids. None of the
fluids we suggest have undergone phase separation. It is
samples plot on the combined geothermometer line, and
not possible that the correlation is caused by the pres-
the Na/K and Na/Li geothermometers give markedly
ence of small amounts of the late highest-salinity fluids
(as secondary inclusions) which were mixed with the
The majority of quartz and stibnite from Mina
low-salinity fluids during crushing, based on the evi-
Nero´n, and of quartz and barite from Mina Aurora
dence from the Cl isotopes. If the highest-salinity fluids
give temperatures of between 250 and ca. 180 C using
at Mina Nero´n represent evaporated seawater, they
the Na/K geothermometer. Halite-bearing fluid inclu-
should plot on the seawater evaporation trend line in
sions from Mina Nero´n have much larger Na/K ratios
Fig. 7. They clearly do not, as they have ca. 7 to 9 times
which are outside the validity of the geothermometer.
less K than expected. This could be explained if, for
Temperatures obtained with the Na/Li geothermometer
example, illite was produced from the fluid.
Fig. 9 Cl/Br vs. dD diagram
Deuterium and oxygen isotopes
Fig. 10 d18O distribution in a chevron quartz of the late
The dD values of fluid inclusions hosted in quartz and
mineralization stage from Mina Nero´n (sample 16041x in Tables 2
stibnite from Mina Nero´n, obtained by mechanical ex-
traction, fall within a narrow range of )24.7 to )8.9&and are not correlated with the Cl/Br ratios (Fig. 9).
known massive sulfide deposit in the IPB with negative
Considering a 2 sigma uncertainty of 5 to 10& (Simon
sulfur isotopic signatures, the d34S values are between
2001), all samples could have formed from a single fluid
)10.7 and +1.3& (Tornos et al. 1998). At some mas-
with a mean dD composition of about 15&.
sive sulfide deposits, the d34S values of barite lie between
A profile through a well-crystallized quartz sample
+15 and +20&, which leads to the assumption that
from Mina Nero´n indicates a correlation between the
sulfate was derived from seawater. By contrast, sulfur
salinity of fluid inclusions, in distinct growth zones, and
isotopes in barite from Mina Aurora have d34S values
the d18O isotopic composition (Fig. 10). The lowest d18O
between )0.2 and +6.4&, indicating a different source
values of 19.3 to 20.7& were measured in growth zones
containing low-salinity fluid inclusions which have a Cl/Br ratio of 153. By contrast, growth zones containinghigh-salinity fluid inclusions without a halite daughter
mineral have a lower Cl/Br ratio of 103 and d18O valuesbetween 20.8 and 21.6&. In the uppermost zone of the
The differences in sulfur isotopic compositions indicate
quartz crystal where high-salinity fluid inclusions pre-
that stibnite, galena, and barite either derived their sul-
dominantly contain halite daughter crystals, a further
fur from distinctly different sources, or formed under
increase of the d18O values up to 23.4& occurs, ac-
quite different physico-chemical conditions. Sulfur iso-
companied by a decrease of the Cl/Br ratio to 72.
topic fractionation in hydrothermal ore deposits is afunction of temperature, pH, ƒO2, isotopic compositionof the ore-forming fluid, and/or dissolved element spe-
Sulfur isotopes in galena and stibnite
cies in the fluid (Ohmoto and Rye 1979). Assuming ahomogeneous sulfur source for all three deposits, sig-
Stibnite samples from Mina Nero´n have d34S values
nificant changes in ƒO2 and pH would have been re-
from )1.45 to )2.74&, and clearly differ from the d34S
quired to change the d34S values of sulfides and barite
values of galena samples from Mina Silillas and Mina
during ore deposition. Ohmoto (1972) has demonstrated
Aurora which have considerably lower d34S values
that for a fluid with d34SSS=0& and T=250 C, the
(Table 3). Galena from Mina Silillas has d34S values of
d34S values for sphalerite could vary between +5.8 and
about )15.5&, and galena from Mina Aurora between
)24&, and for coexisting barite between 0 and +24.2&,
)17.6 and )19.6&, the latter being lower than the within geologically reasonable limits for ƒO2 and pH. Atreported d34S values of )15 to +10& from sulfides of
low ƒO2 and pH values, the d34S values of sulfides will be
the massive sulfide deposits in the IPB (Sa´ez et al. 1999).
similar to d34SSS whereas at high ƒO2 values, the d34S
For example, at the Tharsis deposit, which is the only
values of minerals can differ significantly from d34SSS.
However, at high ƒO2 values the proportion of aqueous
Metallogenic model
sulfate in the fluid will increase significantly with respectto H2S in the fluid, and considerable amounts of sulfates
The data obtained from studies of sulfur isotopes and
should precipitate. Small changes in ƒO2 and pH would
fluid inclusions in quartz, stibnite and barite show there
cause large changes in the d34S values of either sulfate or
to be different sources of metals and sulfur, and different
sulfide (Ohmoto and Lasaga 1982). Assuming a com-
depositional conditions for some vein-type mineraliza-
mon sulfur source for all three deposits, the variations of
tions in the IPB. Vein-type deposits in the study area are
the d34S values can be explained by changes in ƒO2 and
situated along E-W-striking (normal) fault zones which
pH. The variation of the large negative d34S values of
were active during the transition from Hercynian uplift
galena (Table 2) from Mina Aurora and Mina Silillas
to extensional tectonism. Therefore, the vein mineral-
can be attributed to a significant increase in ƒO2, con-
ization seems to be related to a late stage of metamor-
sidering an initial d34SSS=0& for the parental ore-
phism (Routhier et al. 1980). Extensional tectonics
forming fluid (Ohmoto 1972). The small negative d34S
allowed fluids from deeper reservoirs to ascend along
values of stibnites from Mina Nero´n would have re-
faults to higher crustal levels, accompanied by fluctua-
quired only a slight increase in ƒO2 or a decrease in pH.
tions in pressure and temperature (Cathelineau et al.
The positive d34S values of barite samples from Mina
2000). However, it should be noted that rocks of the
Aurora (Table 3) could also have resulted from signifi-
uppermost VS Complex and of the Culm sequence host
cant changes in ƒO2. However, the data from quartz-
all the studied vein-type deposits. The thickness of flysch
hosted fluid inclusions (associated with galena) and
sediments in the eastern part of the IPB (in the Huelva
massive barite from Mina Aurora (Fig. 3) do not sup-
province) certainly does not exceed some 500 m, ac-
port the contemporaneous formation of both minerals
cording to Schermerhorn and Stanton (1969). Therefore,
from the same fluid.
it can be considered that mineral deposition occurred
Alternatively, the observed variation in the sulfur
close to the paleosurface, in the upper 1 km of the crust
isotopic compositions of galena, stibnite, and barite
where the hydrothermal fluids were likely to have been
could indicate different sources of sulfur. The large
hydrostatically pressured (Hedenquist and Henley 1985).
negative d34S values of the galena samples from Mina
At Mina Nero´n, banded quartz–stibnite ore (Fig. 2a)
Aurora and Mina Silillas (Table 3) are comparable to
was deposited from low- to moderate-salinity fluids
d34S values of sediment-hosted massive sulfide deposits
probably containing small proportions of dissolved
(Sa´ez et al. 1999) and sedimentary sulfides in the Iberian
gases. Similar fluids are present in late metamorphic-
Pyrite Belt (Routhier et al. 1980). Therefore, deeply
stage quartz from dissolution vugs and small veinlets
circulating fluids could have derived sulfur as well as
within the massive sulfide orebodies, where it is associ-
metals by alteration of sedimentary rocks and/or pre-
ated with polymetallic sulfide assemblages, and/or late
existing sediment-hosted massive sulfide deposits. Mar-
chlorite and carbonates (Cathelineau et al. 2001). The
coux et al. (1994) and Wipfler and Sedler (1995) have
precipitation of milky gangue quartz seems to have oc-
shown that galena samples from late vein-type miner-
curred at temperatures similar to that of stibnite. A
alization have a more radiogenic Pb isotopic composi-
similar low-salinity fluid precipitated gangue quartz at
tion than the massive sulfide mineralization. At Mina
Mina Aurora but at slightly higher temperatures
Aurora, barite seems to have precipitated at a late stage
(Fig. 3). By contrast, well-crystallized quartz with
of mineralization. The variations in sulfur isotopic
chevron structures from Mina Nero´n contains low-sa-
compositions between )0.2 and 6.4& can be explained
linity fluid inclusions with Th values generally above
by mixing of a cold SO2 -dominant fluid, probably re-
150 C in the milky zones, and high-salinity fluid in-
sidual evaporated seawater, with variable amounts of
clusions with lower Th values in the clear zones. Fluid
dissolved biogenic sulfide with ascending, hydrothermal
inclusions with halite daughter crystals can be found in
Ba-bearing fluids.
the outermost parts of the quartz crystals (Fig. 2b). Such
The small negative d34S values of the stibnite samples
a significant variation in salinity of the fluid inclusions
from Mina Nero´n are similar to those of volcanic-hosted
within a single deposit can either be produced by con-
massive sulfide deposits in the IPB (Routhier et al. 1980;
tinuous, non-adiabatic boiling in the vein structure, thus
Sa´ez et al. 1999). These deposits are characterized by
indicating near-surface depositional conditions, or it is a
anomalously high concentrations of mobile elements
result of fluid mixing. In the latter case, a high-salinity
such as As, Sb Tl, and F (Mo¨ller et al. 1983) which are
fluid (>30 wt% NaCl equiv.) must have been the
assumed to be secondary dispersion haloes from un-
dominant fluid which mixed with the metal-bearing low-
derlying orebodies resulting from the action of diage-
salinity fluid. Both scenarios are discussed in the light of
netic or metamorphic fluids. Therefore, it seems
the results of fluid-inclusion studies.
plausible that the stibnite mineralization at Mina Nero´nwas deposited from fluids which altered the volcanic-hosted massive sulfides and derived metals and sulfur
Fluid mixing model
from deeper orebodies, under the assumption that onlysmall isotopic fractionation occurred from the leaching
A simple mixing model requires at least two fluids, with
stage to the deposition stage.
different compositions, from different sources to explain
the observed variations in temperature, salinity, and
hosted in barite from the Mina Aurora. Furthermore,
isotopic compositions. It is likely that the ore-forming
the strong fractionation of the d37Cl values cannot be
fluids ascended from depth due to the opening of the
explained by evaporation and mixing alone. Solomon
shear zones during late stages of metamorphism. In the
et al. (2002) suggested that brine pools developed by
case of fluid mixing this hot, metal-bearing fluid must
exsolution of supercritical fluids from magmas during
have mixed in differing proportions with a colder (de-
the main period of volcanism in the Spanish Pyrite Belt.
scending?), highly saline brine. The source of this brine
The origin of highly saline fluids in such brine pools at
in the study area is unclear. However, the Cl/Br ratios of
depth is reasonable. However, in our case, these brines
the high-salinity inclusions exclude the dissolution of
must have formed by seawater evaporation rather than
evaporites and strongly indicate that the fluid was a re-
magmatic fluids. In the latter case, the Cl/Br ratios of the
sidual brine derived from seawater evaporation past the
brines should be considerably higher than observed
point of halite precipitation (Fig. 4). If these brine-type
(Bohlke and Irwin 1992), and the chlorine isotopic
fluids were derived from evaporated seawater, from a
composition should show a magmatic signature (Banks
near-surface reservoir such as a sabkha, one would ex-
et al. 2000b).
pect that such a brine was enriched in heavy isotopes Dand 18O, as illustrated by water from the Red Sea (Craig1966). For oxygen such a trend can be observed by the
Phase-separation model
clear zones in quartz hosting highly saline fluid inclu-sions with heavier d18O values, compared to milky zones
Under a hydrostatic pressure regime, an ascending fluid
which host fluid inclusions with considerably lower sa-
with a salinity of about 3 wt% NaCl equiv. and an ini-
linity (Fig. 10) whereas no positive dD values were
tial temperature of about 300 C (mean temperature
measured (Fig. 9 and Table 3). If we assume that quartz
derived from Na/Li and Na/K geothermometers) would
precipitated under a hydrostatic pressure regime at a
start boiling at a depth of about 900 m (Cunningham
depth of about 500 m, a pressure correction for the
1978). In any case, if the pressure at the site of miner-
mean Th values of about 180 C for the low-salinity
alization was less than 90 bar, as indicated by the
fluid inclusions would be negligible. The mean d18O
stratigraphic position of the deposits (<500 m), the
value of quartz in the growth zone hosting this type of
hydrothermal fluid responsible for the vein-type deposits
inclusions is about 20&, and the d18O value of water in
must have undergone phase separation into a low-sa-
equilibrium with the quartz at 180 C would be about
linity vapor and a saline brine (Fig. 11). In the temper-
7.0& (Zheng 1993). By contrast, clear zones in the
ature range under consideration for the ore-forming
studied chevron quartz sample, hosting the high-salinity
fluid (250±50 C), any dD variation will be less obvious
fluid inclusions which were trapped at minimum tem-
and fractionation scatters around 0±10& (Driesner and
peratures of about 175 C (as indicated by halite disso-
Seward 2000). If some equilibration with the country
lution after homogenization of the vapor phase), are
rock and boiling processes had occurred, a variation of
associated with a fluid which had an initial d18O value of
10& of the dD values is possible.
about 10&. The fractionation between quartz and pure
A phase-separation model would also account for
water is 13& at 170 C, and 13.8& at 180 C (Zheng
both the observed variations in the Cl/Br ratios and the
1993). High concentrations of salts such as NaCl and/or
KCl would lower the fractionation to about 0.5&(Horita et al. 1993). If high amounts of CaCl2 are con-tained in the fluid, the fractionation between quartz andthe fluid can be lowered to about 2& (Horita et al.
1993). However, the initial d18O value of the brine can beassumed to be between 8.5 and 10&. Thus, the initiald18O values as well as the dD values of both fluids aretypical for formation waters or metamorphic fluids, andtherefore have probably been modified by water–rockinteractions in the sub-surface from the typical valuesexpected of sabkha-type fluids. A mixing model where ahot, low-salinity fluid mixes with considerable amountsof a cold, near-surface brine would not account for thevariations in the d18O of the quartz and temperatures of175 C indicated by the high-salinity fluid inclusions. Ifwe assume that the temperature of the high-salinity fluid
Fig. 11 Temperature–pressure–depth diagram showing the two-
was less than 50 C, the fluctuation in temperature must
phase boundary for a H2O–NaCl solution of seawater salinity
be considerably higher than observed. Such a mixing
(3.2 wt% NaCl equiv.; modified after Cunningham 1978; Bischoff
model would only account for the observed variations in
and Pitzner 1985). The shaded field marks the range of trappingtemperature fluid inclusions in quartz and stibnite from Mina
salinity and temperatures (indicated by the presence of
Nero´n. High-salinity fluids are probably the product of extreme
monophase, aqueous inclusions) of fluid inclusions
boiling (for details see text)
exception of the sample which contains halite daughter
different sources of sulfur (and metals) as well as dif-
crystals in the fluid inclusions, all the other four quartz
ferent depositional conditions.
samples from quartz–stibnite ores from Mina Nero´n
There is strong evidence that quartz–stibnite miner-
have a large variation in chlorine isotopes which corre-
alization is the product of a non-adiabatic phase-sepa-
lates with a large variation in Cl/Br ratios (Fig. 8). A
ration (boiling) process under a hydrostatic pressure
similar correlation was first observed for sphalerite-
regime (<100 bar). Phase separation caused pro-
hosted fluid inclusions from modern seafloor mineral-
nounced fractionation of chlorine isotopes which cor-
ization, where fluid-inclusion microthermometric data
relate with the fractionation of Cl/Br ratios. The
have revealed compelling evidence for two-phase sepa-
chlorine isotope data clearly differ from other Spanish
ration (Lu¨ders et al. 2002). However, negative d37Cl
Pb–Zn mineralization which is assumed to have depos-
values were not measured in fluid inclusions from sea-
ited from brines similar to those in this study.
floor mineralization, due to the escape of significant
The sources of antimony and sulfide are assumed to
amounts of vapor from the systems. At the Mina Nero´n
come from a hidden, underlying volcanic-hosted massive
site, it seems that considerable amounts of vapor (and
sulfide orebody. High-salinity fluids which are involved
condensed vapor?) are trapped as fluid inclusions in vein
in the formation of late-stage quartz, and the Pb–Zn
quartz, as indicated by the presence of numerous, small
mineralization at other localities, are not derived from
vapor-rich inclusions besides aqueous two-phase inclu-
dissolution of evaporites. They most closely resemble
sions. These samples have negative d37Cl values and
formation waters which originated as residual brines.
larger Cl/Br ratios when compared with the aqueous
The sulfur isotopic compositions of galena samples
two-phase fluid inclusions (Fig. 8). In this scenario, the
from two occurrences indicate a sedimentary source of
most saline fluids should have the most positive d37Cl
sulfide, as it is also proposed for the metals from the Pb
values. This is not the case at the Mina Nero´n where the
isotopic signatures in galena (Marcoux et al. 1994). It is
late-stage fluid trapped in clear zones of chevron quartz
also likely that boiling occurred during the formation of
has the lowest Cl/Br ratio and a d37Cl value close to 0&.
quartz–galena mineralization. Barite is thought to have
This fluid clearly originated from a different source or
formed by mixing of the ascending fluids with meteoric
was produced by a different process, and indicates that
at least two different fluid sources were involved during
From detailed studies of vein-type deposits in the
the formation of late-stage quartz II at the Mina Nero´n
Iberian Pyrite Belt, it may be possible to trace deeper-
site. The halogen data are most consistent with its origin
lying massive sulfide orebodies. Although there are dif-
being that of a highly evaporated seawater, but there is
ferent sources for the metals and sulfur and different
still the question of how the fluid became so hot. As
depositional conditions for the polymetallic ores, their
mentioned above, a simple mixing model where a cold,
origin is apparently linked to the older massive sulfide
near-surface brine mixed with an ascending hydrother-
mal fluid should have produced a larger temperaturedecrease than observed. Therefore, the mixed brine ap-
Acknowledgements We are particularly indebted to I.K. Sedler and
pears to have had a temperature similar to that of the
E.L. Wipfler for providing sample material from the studied vein
ascending fluid. This brine may represent a formation
mineralizations. We are grateful to M. Cathelineau and another
water heated by the escape of steam from the upflowing
anonymous Mineralium Deposita referee for their constructivereviews of the manuscript and useful comments.
fluid. The large bromine enrichment in the fluid mayhave been caused by halite precipitation. However, wecan exclude the possibility that this saline brine wasderived from the same ascending hydrothermal fluid
which underwent extreme boiling at higher levels closeto the surface. If this had occurred, the d37Cl values
Bailly L, Bouchot V, Be´ny C, Mile´si JP (2000) Fluid inclusion study
of stibnite using infrared microscopy: an example from the
would be expected to be even more positive than those
we recorded in other samples, which is not the case.
France). Econ Geol 95:221–226
Therefore, these high-salinity fluids did not play an im-
Banks DA (2001) The applicability of Cl-isotopes to determining
portant role in the formation of quartz–stibnite miner-
the source of salinity. In: Noronha F, Do´ria A, Guedes A (eds)XVI ECROFI European Current Research on Fluid Inclusions,
alization, but seem to have had a greater role in the
Porto, 2001. Fac Cieˆ Porto Dep Geol Mem 7:33–36
formation of galena and quartz mineralization at the
Banks DA, Davies GR, Yardley BDW, McCraig AM, Grant NT
Mina Silillas site.
(1991) The chemistry of brines from an Alpine thrust system inthe Pyrenees: an application of fluid inclusion analysis to thestudy of fluid behaviour in orogenesis. Geochim CosmochimActa 55:1021–1030
Banks DA, Giuliani G, Yardley BWD, Cheilletz A (2000a) Em-
erald mineralisation in Colombia: fluid chemistry and the role
Detailed studies of sulfur isotopic compositions of sul-
of brine mixing. Miner Deposita 35:699–713
fides and fluid inclusions hosted in various minerals
Banks DA, Green R, Cliff RA, Yardley BWD (2000b) Chlorine
isotopes in fluid inclusions: determination of the origins of
from late Hercynian vein-type mineralization in the
salinity in magmatic fluids. Geochim Cosmochim Acta
central part of the IPB have revealed evidence for
Bischoff JL, Pitzer KS (1985) Phase relations and adiabats in
Leistel JM, Marcoux E, Thie´blemont D, Quesada C, Sa´nchez A,
boiling seafloor geothermal systems. Earth Planet Sci Lett
Almodo´var GR, Pascual E, Sa´ez R (1998) The volcanic-hosted
massive sulphide deposits of the Iberian Pyrite Belt. Review and
Bodnar RJ (1994) Synthetic fluid inclusions. XII. The system H2O-
preface to the thematic issue. Mineral Deposita 33:2–30
NaCl. Experimental determination of the halite liquidus and
Lescuyer JL, Leistel JM, Marcoux E, Mile´si JP, Thie´blemont D
isochores for a 40 wt.% NaCl equiv. solution. Geochim Cos-
(1998) Late Devonian-Early Carboniferous peak sulphide
mochim Acta 58:1053–1064
mineralization in the Western Hercynides. Miner Deposita
Bodnar RJ, Vityk MO (1994) Interpretation of microthermometric
data for NaCl-H2O fluid inclusions. In: De Vivo B, Frezotti ML
Lu¨ders V (1996) Contribution of infrared microscopy to fluid
(eds) Fluid inclusions in minerals: methods and applications.
inclusion studies in some opaque minerals (wolframite, stibnite,
Short Course Working Group IMA Inclusions in Minerals,
bournonite): metallogenetic implications. Econ Geol 91:1462–
(Pontignano-Siena, 1–4 September 1994, pp 117–130
Bohlke JK, Irwin JJ (1992) Laser microprobe analyses of Cl, Br, I
Lu¨ders V, Banks DA, Halbach P (2002) Extreme Cl/Br and d37Cl
and K in fluid inclusions: implications for sources of salinity in
isotope fractionation in fluids of modern submarine hydro-
some ancient hydrothermal fluids. Geochim Cosmochim Acta
thermal systems. Miner Deposita 37:765–771
Marcoux E, Moe¨lo E, Leca X, Leistel JM, Lescuyer JL, Mile´si JP
Bonijoly D, Deschamps Y, Leistel JM, Joubert M, Sobol F (1994)
(1994) Mineralogy, geochemistry, and Pb-isotopic compositions
Structural criteria and paleostructural context. In: Leistel JM
of the massive sulphide deposits. In: Leistel JM et al. (eds) The
et al. (eds) The massive sulphide deposits of the South Iberian
massive sulphide deposits of the South Iberian Pyrite Province:
Pyrite Province: geological setting and exploration criteria.
geological setting and exploration criteria. BRGM Doc 234:99–
BRGM Doc 234:109–137
Cathelineau M, Boiron MC, Banks DA, Vallance J, Fourcade S
Mo¨ller P, Lu¨ders V (eds) (1993) Formation of hydrothermal vein
Marignac C (2000) Fluid mixing and gold deposition during the
deposits. A case study of the Pb-Zn, barite and fluorite deposits
uplift of the Hercynian Belt. In: Symp Metallogeny 2000, Re-
of the Harz Mountains. Monogr Ser Miner Deposits 30
view and Perspectives, in honour of the retirement of Bernard
Mo¨ller P, Dieterle MA, Dulski P, Germann K, Schneider HJ,
Poty, Nancy, France, 7–8 December 2000, pp 33–34
Schu¨tz W (1983) Geochemical proximity indicators of massive
Cathelineau M, Marignac C, Diagana B, Boiron MC, Banks DA,
sulphide mineralization in the Iberian Pyrite Belt and the East
Fourcade S, Martineau F (2001) P-T-X fluid evolution during
Pontic Metallotect. Miner Deposita 18:387–398
the deformation and the metamorphism of the south Iberian
Moreno C (1993) Postvolcanic Paleozoic of the Iberian Pyrite Belt:
Pyrite Belt. In: Noronha F, Do´ria A, Guedes A (eds) XVI
an example of basin morphologic control on sediment distri-
ECROFI European Current Research on Fluid Inclusions,
bution in a turbidite basin. J Sediment Petrol 63:1118–1128
Porto, 2001. Fac Cie´ Porto Dep Geol Mem 7:85–88
Moreno C, Sequeiros L (1989) The Basal Shaly Formation of the
Craig H (1966) Isotopic composition and origin of the Red Sea and
Iberian Pyrite Belt (South-Portuguese Zone): Early Carbonif-
Salton Sea geothermal brines. Science 154:1544–1548
erous bituminous deposits. Palaeogeogr Palaeoclimatol Palae-
Cunningham CG (1978) Pressure gradients and boiling as mecha-
oecol 73:233–241
nisms for localizing ore in porphyry systems. J Res US Geol
Munha´ J (1990) Metamorphic evolution of the South Portuguese/
Pulo do Lobo Zone. In: Dallmeyer RD, Martinez E (eds) Pre-
De la Rosa JD, Rogers G, Castro A (1993) Relaciones 87Sr/86Sr de
Mesozoic geology of Iberia. Springer, Berlin Heidelberg New
rocas ba´sicas y granitoides del batolito de la Sierra Norte de
York, pp 363–368
Sevilla. Rev Soc Geol Esp 6:141–149
Munoz M, Courjault-Rade´ P, Tollon F (1992) The massive stibnite
Driesner T, Seward TM (2000) Experimental and simulation study
veins of the French Palaeozoic basement: a metallogenic marker
of salt effects and pressure/density effects on oxygen and hy-
of Late Variscan brittle extension. Terra Nova 4:171–174
drogen stable isotope liquid-vapor fractionation for 4–5 molal
Ohmoto H (1972) Systematics of sulfur and carbon isotopes in
aqueous NaCl and KCl solutions to 400 C. Geochim Cos-
hydrothermal ore deposits. Econ Geol 67:551–579
mochim Acta 64:1773–1784
Ohmoto H, Lasaga AC (1982) Kinetics of reactions between
Eggenkamp HGM, Kreulen R, Koster van Groos AF (1995)
aqueous sulfates and sulfides in hydrothermal systems. Geo-
Chlorine stable isotope fractionation in evaporites. Geochim
chim Cosmochim Acta 46:1727–1745
Cosmochim Acta 59:5169–5175
Ohmoto H, Rye RO (1979) Isotopes of sulfur and carbon. In:
Fiebig J, Wiechert U, Rumble III D, Hoefs J (1999) High-precision
Barnes HL (ed) Geochemistry of hydrothermal ore deposits,
in situ oxygen analysis of quartz using an ArF laser. Geochim
2nd edn. Wiley, New York, pp 509–567
Cosmochim Acta 63:687–702
One´zime J, Charvet J, Faure M, Chauvet A, Panis D (2002)
Fontes JC, Matray JM (1993) Geochemistry and origin of forma-
Structural evolution of the southernmost segment of the West
tion brines from the Paris Basin, France. 1. Brines associated
European Variscides: the South Portuguese Zone (SW Iberia). J
with Triassic salts. Chem Geol 109:149–175
Struct Geol 24:451–468
Fouillac C, Michard G (1981) Sodium/lithium ratio in water ap-
Pinedo Vara J (1963) Piritas de Huelva Su historia, minerı´a y ap-
plied to geothermometry of geothermal reservoirs. Geothermics
rovechamiento. Summa, Madrid
Quesada C (1998) A reappraisal of the structure of the Spanish
Fournier RO (1979) A revised equation for the Na/K geother-
segment of the Iberian Pyrite Belt. Miner Deposita 33:31–44
mometer. Geotherm Res Coun Trans 3:221–224
Roedder E (1984) Fluid inclusions. Mineral Soc Am Rev Mineral
Gumiel P, Arribas A (1987) Antimony deposits in the Iberian
Peninsula. Econ Geol 82:1453–1463
Routhier P, Aye F, Boyer C, Le´colle M, Moliere EP, Picot P,
Hedenquist JW, Henley RW (1985) Effect of CO2 on freezing point
Roger G (1980) La Ceinture Sud-Ibe´rique a amas sulfure´s dans
depression measurements of fluid inclusions: evidence from
sa partie espagnole me´diane. Me´m BRGM 94:1–265
active geothermal systems and implications for epithermal ore
Sa´ez R, Pascual E, Toscano M, Almodo´var GR (1999) The Iberian
deposition. Econ Geol 80:1379–1406
type of volcano-sedimentary massive sulphide deposits. Miner
Horita J, Wesolowski DJ, Cole DR (1993) The activity-composi-
Deposita 34:549–570
tion relationship of oxygen and hydrogen isotopes in aqueous
Schermerhorn LJG (1971) An outline stratigraphy of the Iberian
salt solutions. I. Vapor-liquid water equilibration of single salt
pyrite belt. Bol Geol Mineral Spain 82:238–268
solutions from 50 to 100 C. Geochim Cosmochim Acta
Schermerhorn LJG, Stanton WI (1969) Folded overthrusts at
Aljustrel. Geol Mag 106:130–141
Schu¨tz W, Ebneth J, Meyer K-D (1987) Trondhjemites, tonalites
Toscano M, Ruiz de Almodo´var G, Pascual D, Sa´ez R (1993)
and diorites in the South Portuguese Zone and their relations to
Hydrothermal alteration related to the ‘‘Masa Valverde'' mas-
the vulcanites and mineral deposits of the Iberian Pyrite Belt.
sive sulphide deposit, Iberian Pyrite Belt, Spain. In: Fenoll
Geol Rundsch 76/1:201–212
Hach-Ali P, Torres-Ruiz J, Gervilla F (eds) Current research in
Sedler IK (1989) Die Manganlagersta¨tten Pancho und Santiago
geology applied to ore deposits. University of Granada
und ihr geologischer Rahmen Provinz Huelva, Andalusien,
Verma SP, Santoyo E (1997) New improved equations for Na/K,
Spanien. Diploma Thesis, Freie Universita¨t Berlin
Na/Li and SiO2 geothermometers by outlier detection and
Silva JB, Oliveira JT, Ribeiro A (1990) South Portuguese zone.
rejection. J Volcanol Geotherm Res 79:9–23
Structural outline. In: Dallmeyer RD, Martı´nez Garcı´a E (eds)
Wagner T, Cook NJ (2000) Late-Variscan antimony mineralisation
Pre Mesozoic geology of Iberia. Springer, Berlin Heidelberg
in the Rheinisches Schiefergebirge, NW Germany: evidence for
New York, pp 348–362
stibnite precipitation by drastic cooling of high-temperature
Simon K (2001) Does dD from fluid inclusion in quartz reflect the
fluid systems. Miner Deposita 35:206–222
original hydrothermal fluid? Chem Geol 177:483–495
Wiechert U, Fiebig J, Przybilla R, Xiao Y, Hoefs J (2002) Excimer
Solomon M, Tornos F, Gaspar OC (2002) Explanation for many of
laser isotope-ratio-monitoring mass spectrometry for in situ
the unusual features of the massive sulfide deposits of the Ibe-
oxygen isotope analysis. Chem Geol 182:179–194
rian pyrite belt. Geology 30:87–90
Wipfler EL (1989) Geologie und Lagersta¨tten in einem Teilbereich
Thie´blemont D, Stein G, Leistel JM (1995) New findings on the
des SW-iberischen Pyritgu¨rtels westlich von Calan˜as mit einem
magmatism related to massive sulfide deposits in the South
Beitrag zu Eigenschaften und Entstehung der Sb-Gang-
Iberian pyrite belt. In: Pasˇava J, Krˇı´bek B, Zˇa´k K (eds) Mineral
lagersta¨tte Nero´n Provinz Huelva, Andalusien, Spanien. Di-
deposits from their origin to their environmental impacts.
ploma Thesis, Freie Universita¨t Berlin
Balkema, Rotterdam, pp 245–247
Wipfler EL, Sedler IK (1995) Vein mineralizations in the Iberian
Tischendorf G, Schwab G (1989) Metallogenesis of the transition
Pyrite Belt, SW. In: Pasˇava J, Krˇı´bek B, Zˇa´k K (eds) Mineral
period between Hercynian orogenesis and subsequent platform
deposits from their origin to their environmental impacts.
stage in Central Europe. Z Geol Wissen 17:815–842
Balkema, Rotterdam, pp 405–408
Tornos F, Gonza´lez Clavijo E, Spiro B (1998) The Filo´n Norte
Zheng YF (1993) Calculation of oxygen isotope fractionation in
orebody (Tharsis, Iberian Pyrite Belt): a proximal low-temper-
ature shale-hosted massive sulphide in a thin-skinned tectonic
belt. Miner Deposita 33:150–169
Source: http://www.see.leeds.ac.uk/see-research/essi/people/banks/papers/md38.pdf
1ASSAY TECHNOLOGIES Anuradha RoyDel Shankel Structural Biology Center, High Throughput Screening Laboratory, Lawrence, Kansas Gerald H. LushingtonMolecular Graphics and Modeling Laboratory, University of Kansas, Lawrence, Kansas; LiS Consulting, Lawrence, Kansas James McGee Quantitative Biology, Eli Lilly and Company, Indianapolis, Indiana
Pre-IBC Special • September 2009 Cooke First Look: Cooke Panchros Like the Phoenix rising in Harry Potter, the venerable Cooke In September 9, 1926, Kinematograph Weekly reported: "Over Panchro name is being revived, or should we say, reinvented. a hundred Taylor-Hobson Cooke lenses of various focal lengths Film and Digital Times has learned that Cooke is working on a