1 Isotopic Analysis of Laurion Lead Ores I. L . B A R N E S , W . R. S H I E L D S , and T. J. M U R P H Y
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Analytical Chemistry Division, Institute for Materials Research, National Bureau of Standards, Washington, D. C. 20234 R. H . B R I L L The Corning Museum of Glass, Corning, Ν. Y. 14830
The lead isotopic ratios of a carefully selected suite of ore samples from the Laurion
region have been determined
by a precise mass spectrometric procedure.
The ores were
taken from various levels in mines, some known to have been worked in ancient times. All are nearly indistinguish able
isotopically
(±0.05%),
within
the
precision
of
and they closely match leads from
objects found in Greece.
A comparison
for ores from other mining
method
with isotopic data
regions in the ancient world
has been made. The uniformity tates the interpretation
the
archaeological
of the Laurion ores facili
of lead isotope data for
archaeo
logical objects from Greece.
c h e m i c a l analysis of a r c h a e o l o g i c a l objects has b e e n d o n e for m a n y ^
years a n d , w h e r e p r a c t i c e d w i t h care, has r e s u l t e d i n i n f o r m a t i o n
of great v a l u e . T h i s has b e e n a m p l y i l l u s t r a t e d at several s y m p o s i a over the past decade.
W h i l e there p r o b a b l y w i l l n e v e r b e a n e n t i r e l y satis
f a c t o r y substitute f o r c o m p l e t e c h e m i c a l analysis to c h a r a c t e r i z e e a r l y objects, this m e t h o d alone does not o r d i n a r i l y t e l l us a l l w e w o u l d l i k e to k n o w a b o u t date, o r i g i n , a u t h e n t i c i t y , or m e t h o d
of
manufacture.
O t h e r approaches are e q u a l l y v a l u a b l e , a n d there is a g r o w i n g r e c o g n i t i o n of the c o m p l e m e n t a r i t y of c h e m i c a l analysis, p h y s i c a l testing, m i c r o scopic
e x a m i n a t i o n , a n d other s p e c i a l i z e d t e c h n i q u e s
appropriate
for
p a r t i c u l a r m a t e r i a l s . A s t r i k i n g e x a m p l e of this a p p r o a c h is the i n v e s t i g a t i o n of the famous b r o n z e horse i n t h e c o l l e c t i o n of the M e t r o p o l i t a n M u s e u m of A r t . It has b e e n s u b j e c t e d to a d o z e n or m o r e different types of e x a m i n a t i o n s , as d e m o n s t r a t e d i n a recent e x h i b i t i o n at t h e M u s e u m . 1 Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
2
ARCHAEOLOGICAL
CHEMISTRY
Lead Isotopic Analysis L e a d i s o t o p i c analysis ( I , 2, 3, 4, 5) is a r e l a t i v e l y n e w m e m b e r of this e x p a n d i n g g r o u p of c o m p l e m e n t a r y m e t h o d s . has its o w n p e c u l i a r i t i e s , advantages,
L i k e the others, i t
a n d disadvantages w h i c h
have
b e e n d e s c r i b e d . L e a d isotope studies h e l p to i d e n t i f y possible g e o g r a p h i c a l origins of the ores f r o m w h i c h a n c i e n t leads w e r e smelted.
Even
w h e r e specific m i n e s cannot b e i d e n t i f i e d , the objects c a n s t i l l be classified as to w h i c h c o u l d or c o u l d not h a v e h a d a c o m m o n o r i g i n . T h e m e t h o d
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r e q u i r e s o n l y s m a l l s a m p l e sizes, a n d the results are i n d e p e n d e n t of the histories of the objects s t u d i e d . T h e usefulness of l e a d isotope studies is t h e fortunate result of a threefold coincidence.
H i s t o r i c a l l y , l e a d was
one
of
the
first
metals
m i n e d — i t s first use d a t i n g b a c k at least i n t o the f o u r t h m i l l e n n i u m . T h u s , i t occurs i n artifacts associated w i t h m a n y h i s t o r i c a l places a n d periods.
T e c h n o l o g i c a l l y , i t w a s easily w o n f r o m its major ore, g a l e n a ,
a n d was q u i c k l y f o u n d to b e u s e f u l i n m a n y f o r m s : alloys, p i g m e n t s , cosmetics, m e d i c i n e s , glasses, glazes, a n d others. d u c e d i n l a r g e amounts as a b y - p r o d u c t
S i n c e it w a s also p r o
of s i l v e r e x t r a c t i o n , i t w a s
a b u n d a n t a n d r e l a t i v e l y i n e x p e n s i v e . G e o l o g i c a l l y , a n d most i m p o r t a n t l y , l e a d is one of the f e w c h e m i c a l elements w h i c h varies m a r k e d l y i n its i s t o t o p i c m a k e u p a c c o r d i n g to its g e o l o g i c a l o c c u r r e n c e .
Putting
these
three factors together, one has the basis of a v e r y u s e f u l a r c h a e o m e t r i c tool. T h e e l e m e n t l e a d is c o m p o s e d of f o u r i s t o t o p e s — and
2 0 4
Pb.
208
Pb,
2 0 7
Pb,
2 0 6
Pb,
T h e first three are the stable e n d p r o d u c t s of t h e r a d i o a c t i v e
d e c a y of u r a n i u m a n d t h o r i u m . 238TJ 235JJ 2 3 2
T h —->
Pb 207ρ^
4.4683 Χ 0.70381 Χ 14.01 Χ
2 0 6
2 0 8
Pb
10 10 10
9 9 9
years years years
B e c a u s e of the significant differences i n the h a l f - l i v e s of the a b o v e r e a c tions, leads i n different g e o l o g i c a l e n v i r o n m e n t s a c q u i r e different t h o u g h not necessarily u n i q u e )
(al
i s o t o p i c c o m p o s i t i o n s , w h i c h are c o n
t i n u o u s l y c h a n g i n g . I n a d d i t i o n , different a n d v a r y i n g amounts of l e a d , u r a n i u m , a n d t h o r i u m i n different g e o l o g i c a l e n v i r o n m e n t s t h r o u g h o u t g e o l o g i c a l t i m e r e s u l t e d i n e v e n l a r g e r changes.
H o w e v e r , i f d u r i n g the
process of ore f o r m a t i o n t h e l e a d separates f r o m its p a r e n t u r a n i u m a n d t h o r i u m (as almost a l w a y s h a p p e n s ) , its i s o t o p i c c o m p o s i t i o n becomes " f r o z e n " a n d ceases to change, l e a d i n g to a fixed c o m p o s i t i o n w i t h i n a g i v e n deposit. sufficient
W h e n the v a r i o u s i s o t o p i c ratios c a n b e m e a s u r e d w i t h
p r e c i s i o n , different
ore
deposits
can
be
distinguished and
m a t c h e d w i t h objects m a d e f r o m or c o n t a i n i n g leads f r o m those sources.
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
1.
BARNES
E T
AL.
Isotopic Analysis
of
3
Lead
T h e v a l u e of this t e c h n i q u e has b e e n firmly e s t a b l i s h e d e v e n t h o u g h the earliest w o r k w a s h a m p e r e d b y i n s t r u m e n t a t i o n a n d m e t h o d s w h i c h c o u l d not y i e l d h i g h l y precise d a t a a n d w e r e tedious a n d t i m e - c o n s u m i n g experimental procedures. W o r k b y C a t a n z a r o et al. i n 1968 ( 6 )
l e d to a n e w a n a l y t i c a l p r o
c e d u r e p e r m i t t i n g the m e a s u r e m e n t of isotopic ratios to a b o u t
±0.05%
( 9 5 % L . E . ) ; this r e s u l t e d i n the a v a i l a b i l i t y of three s t a n d a r d reference m a t e r i a l s , so t h a t results c o u l d b e p l a c e d o n a n absolute basis.
This
p r o c e d u r e , s t i l l the most precise a n d a c c u r a t e one a v a i l a b l e , r e q u i r e s Downloaded by UNIV OF NEWCASTLE on February 26, 2017 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0138.ch001
about 1 m g of l e a d for a n analysis. A second p r o c e d u r e developed
(7)
has b e e n
w h i c h u t i l i z e s s i l i c a g e l as a n i o n i z a t i o n enhancer.
m e t h o d p e r m i t s the m e a s u r e m e n t of i s o t o p i c ratios to a b o u t ( 9 5 % L . E . ) , b u t i t r e q u i r e s o n l y 0.1
This
±0.1%
of l e a d p e r analysis. I n a d d i t i o n ,
the i n s t r u m e n t a t i o n a n d d a t a h a n d l i n g h a v e b e e n v a s t l y i m p r o v e d
so
that m a n y samples c a n b e s t u d i e d q u i c k l y a n d c o n v e n i e n t l y . Our
Lead Studies T h e s e d e v e l o p m e n t s h a v e e n c o u r a g e d us to u n d e r t a k e a l o n g t e r m
s t u d y of objects, b o t h of k n o w n a n d u n k n o w n o r i g i n s , a n d of l e a d ores f r o m m i n i n g areas w o r k e d i n a n c i e n t times. O u r research is n o w r a n g i n g into a l l sorts or a r c h a e o l o g i c a l a n d h i s t o r i c a l materials—e.g.,
glasses,
glazes, b r o n z e coins, w h i t e - l e a d p i g m e n t s , traces of l e a d i n silver a n d g o l d , C h i n e s e b r o n z e s , a n c i e n t E g y p t i a n k o h l , a n d the earning i n m e d i e v a l stained glass w i n d o w s . T h i s has a l l b e e n m a d e possible b y the d e v e l o p m e n t of h i g h p r e c i s i o n i n s t r u m e n t a t i o n . W e h a v e a n a l y z e d l e a d ores ( m o s t l y g a l e n a s ) f r o m m a n y c o u n t r i e s , b u t o u r ore d a t a are s t i l l f e w e r t h a n d e s i r e d . T h e p r o b l e m is to o b t a i n w e l l - d o c u m e n t e d ore samples f r o m areas k n o w n or suspected to h a v e b e e n e x p l o i t e d i n a n c i e n t times. T h e present s t u d y is a n effort to correct this, a l o n g w i t h another r e l a t e d facet of the ore p r o b l e m — i . e . , just h o w m u c h i s o t o p i c v a r i a t i o n exists w i t h i n g i v e n m i n i n g regions.
W h i l e our
c h o i c e of a r e g i o n m a y not be representative, i t does p r o v i d e d a t a o n one of the most i m p o r t a n t l e a d m i n i n g regions of the a n c i e n t w o r l d , the L a u r i o n mines i n G r e e c e . W e h a v e b e e n fortunate i n a c q u i r i n g a suite of c a r e f u l l y selected ore specimens
f r o m three m i n i n g sites w i t h i n the r e g i o n c u s t o m a r i l y
d e s c r i b e d as " L a u r i o n . " T h e s e samples, i n c l u d i n g sulfide a n d oxide ores, w e r e c o l l e c t e d to represent the g e n e r a l area a n d v a r i o u s contact levels w i t h i n the m i n e s s a m p l e d .
T h e m i n e s , l o c a t e d a b o u t 20 k m s o u t h of
A t h e n s , are d e s i g n a t e d b y the present operators as the P l a k a , Espérance, a n d K a m a r i s a m i n e s a n d are s e p a r a t e d b y a f e w k i l o m e t e r s . O f the 17 ore specimens a n a l y z e d , a b o u t o n e - h a l f are f r o m occurrences a t e l y adjacent to a n c i e n t w o r k i n g s .
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
immedi
4
ARCHAEOLOGICAL
T h e s e samples
CHEMISTRY
are p a r t i c u l a r l y v a l u a b l e for this s t u d y since
the
area is u n d o u b t e d l y the s o u r c e of m u c h of the l e a d u s e d i n e a r l y times. It is n o t k n o w n exactly w h e n m i n i n g first b e g a n there, b u t i t was a b l y b e f o r e 1000 B . C . M a r i n o s a n d P e t r a s c h e c k ( 8 )
prob
have described
the
g e o l o g y of t h e r e g i o n , the n a t u r e of the ore deposits, a n d the h i s t o r y of m i n i n g at L a u r i o n . A c c o r d i n g to t h e m , t h e m o s t i m p o r t a n t p e r i o d e x p l o i t a t i o n was f r o m 483 B . C . o n w a r d , w h e n the deposits at day K a m a r i s a were discovered.
T h e y state that there are t o d a y
of
present more
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t h a n 1000 ancient m i n e shafts a n d galleries, some of w h i c h are m o r e Table I. NBS No.
Brill No.
383 384 385 386 388 387 389 390 391 392 393 394 395
850 851 852 853 854 855 856 857 858 859 860 861 862
1 1 2 2 3 3 3 3 4 4 4 4 4
sulfide A sulfide Β sulfide A sulfide Β sulfide A sulfide Β oxide A oxide Β sulfide A sulfide Β sulfide C oxide A oxide Β
396 397 398 399
863 864 865 866
5 5 5 6
sulfide sulfide sulfide sulfide
No.
Sample a
6
A Β C A
Mine Plàka Plaka P l a k a 33 P l a k a 33 Espérance P l a k a 33 Espérance Espérance Plaka Filon Plaka Filon Plaka Filon Plaka Filon Plaka Filon Sklives Kamarisa Kamarisa Kamarisa Kamarisa
80 80 80 80
Lead
Level
208/206
145 145 110 110 96 110 103 103 85 85 85 135 80
2.0600 2.0604 2.0605 2.0602 2.0611 2.0637 2.0600 2.0606 2.0596 2.0591 2.0598 2.0590 2.0614
135 135 135 104
2.0593 2.0594 2.0580 2.0579
Major lead mineral in the ore samples identified as "sulfides" is galena (PbS). Ore samples identified as "oxides" are highly oxidized or gossan ores in which the major lead mineral is also galena. α
6
t h a n 100 m d e e p a n d that m i n i n g was c a r e f u l l y p l a n n e d since the ancient m i n e r s q u i t e e a r l y u n d e r s t o o d that the ore was to be f o u n d i n the m a r bles, e s p e c i a l l y at t h e i r c o n t a c t planes w i t h the schists.
S o m e other k e y
references o n the h i s t o r y of t h e area are those of A r d a i l l o n ( 9 ) , (10), Boulakia ( I I ) , and Hopper
Davies
(12).
Experimental T h e ore samples w e r e c a r e f u l l y c r u s h e d i n a m o r t a r a n d w e i g h e d into T e f l o n beakers. T h e y w e r e d i s s o l v e d i n 10 m l of 1:1 ( v o l ) p e r c h l o r i c a c i d ; this a c i d s o l u t i o n was d i l u t e d w i t h w a t e r to 100 m l , a n d
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
1.
BARNES E T A L .
Isotopic Analysis of
5
Lead
the l e a d w a s r e m o v e d as P b 0 b y e l e c t r o p l a t i n g at 2.0 a m p s for 16 h o u r s . T h e l e a d was t h e n r e m o v e d f r o m the a n o d e w i t h 1 m l of a s o l u t i o n of n i t r i c a c i d ( 2 % ) a n d h y d r o g e n p e r o x i d e ( 0 . 3 % ) . A f t e r h e a t i n g to destroy the p e r o x i d e , t h e l e a d was t a k e n u p i n sufficient 2 % n i t r i c a c i d to m a k e a s o l u t i o n e q u i v a l e n t to 25 m g of l e a d p e r g r a m of s o l u t i o n , w h i c h was r e s e r v e d for mass s p e c t r o m e t r i c analysis. T h e a n a l y t i c a l p r o c e d u r e w a s the mass s p e c t r o m e t r i c t r i p l e filament p r o c e d u r e of C a t a n z a r o ( 1 3 ) . A d r o p of the s a m p l e w a s p l a c e d o n e a c h of t w o side filaments of r h e n i u m , l e a d h y d r o x i d e was p r e c i p i t a t e d o n the filaments b y a d d i n g a d r o p of a m m o n i u m h y d r o x i d e , a n d the p r e c i p i t a t e
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2
Isotopic Ratio Data Atom 207/206
204/206
208
207
Percent 206
204
0.83127 0.83143 0.83175 0.83196 0.83210 0.83201 0.83149 0.83128 0.83120 0.83044 0.83098 0.83131 0.83204
0.053005 0.053104 0.053103 0.053134 0.053099 0.053100 0.053061 0.053047 0.053030 0.052984 0.052975 0.053049 0.053054
52.228 52.229 52.226 52.219 52.229 52.261 52.224 52.234 52.223 52.228 52.229 52.214 52.234
21.075 21.076 21.082 21.087 21.086 21.070 21.080 21.072 21.076 21.064 21.071 21.081 21.083
25.353 25.349 25.346 25.347 25.340 25.324 25.351 25.349 25.356 25.365 25.357 25.359 25.339
1.3439 1.3461 1.3460 1.3468 1.3455 1.3447 1.3452 1.3447 1.3446 1.3439 1.3423 1.3453 1.3443
0.83218 0.83165 0.83170 0.83083
0.053129 0.053073 0.05298 0.053011
52.205 52.214 52.198 52.208
21.097 21.086 21.095 21.078
25.351 25.354 25.364 25.370
1.3469 1.3456 1.3438 1.3449
was d r i e d a n d m o u n t e d i n the i n s t r u m e n t a l o n g w i t h a p l a t i n u m i o n i z i n g filament. A t least 10 measurements of e a c h of the three ratios w e r e m a d e i n a 1 2 - i n c h r a d i u s mass spectrometer. A l t h o u g h w i t h samples as l a r g e as these, b l a n k s are so s m a l l as to b e n e g l i g i b l e , p r e c a u t i o n s w e r e t a k e n to p r e v e n t unnecessary c o n t a m i n a t i o n . A l l p r o c e s s i n g w a s c a r r i e d out i n a C l a s s 100 c l e a n l a b o r a t o r y , a n d subsequent h a n d l i n g w a s d o n e i n s m a l l C l a s s 100 c l e a n a i r hoods. A l l e q u i p m e n t w a s s p e c i a l l y c l e a n e d , a n d a l l reagents w e r e p u r i f i e d b y a s u b - b o i l i n g d i s t i l l a t i o n t e c h n i q u e k n o w n to r e d u c e l e a d c o n t a m i n a t i o n to v e r y l o w levels (14). T h e n o r m a l l a b o r a t o r y l e a d b l a n k is 1-2 n g p e r analysis. Results D a t a o b t a i n e d f o r the 17 samples are s h o w n i n T a b l e I , a l o n g w i t h the c o m p u t e d compositions ( a t o m p e r c e n t ) of e a c h s a m p l e . T h e d a t a
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
6
ARCHAEOLOGICAL CHEMISTRY
are also s h o w n i n F i g u r e 1 as a p l o t of t h e 2 0 8 / 2 0 6 vs. 2 0 7 / 2 0 6 ratios. N o t e the r e m a r k a b l e u n i f o r m i t y s h o w n b y a l l of these samples.
The
m a x i m u m v a r i a t i o n of the 2 0 8 / 2 0 6 ratios is less t h a n 0 . 3 % w h i l e that of the 2 0 7 / 2 0 6 ±0.05%,
ratios is less t h a n 0 . 2 % .
W i t h our expected
p r e c i s i o n of
this i n d i c a t e s that w h i l e the samples s h o w s m a l l b u t statis
t i c a l l y significant differences, t h e y are v e r y s i m i l a r a n d m u s t h a v e b e e n d e r i v e d f r o m the same or v e r y s i m i l a r source rocks i n a r e l a t i v e l y short time.
T h e r e a l differences
observed
are most l i k e l y r e l a t e d to s l i g h t
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2.066 ρ
2.064
S
Οβ57 Ο 850 Ο 858
2.060
ο
8 5 1
Ο 56 8
Ο 864
Ο 861 2.058
2.056
1
1
.8310
' .8312
' .8314
• .8316
207 /206 pb
• .8318
' .8320
•
pb
Figure 1. wpb/ *Vb vs. Pb/ Pb for some Laurion lead ores. Numbers for each point are given in Table I. Error bars represent the 95% limit of error for each analysis. 20
207
206
v a r i a t i o n s i n the source of the ore fluids, c o n t a m i n a t i o n of t h e ore
fluids
b y c o u n t r y rock, a n d to slight v a r i a t i o n s i n t i m e of the e x t r a c t i o n of the ore fluids. F i g u r e 2 is a p l o t of 2 0 8 / 2 0 6 r a t i o vs. the d e p t h of the deposit f r o m w h i c h the s a m p l e was o b t a i n e d a n d for e a c h of the three separate areas. N o r e a l correlations are o b v i o u s , n o r is there a n y m a r k e d difference b e t w e e n the sulfide a n d o x i d e ores. T h e n a r r o w r a n g e of l e a d i s o t o p i c a b u n d a n c e s i n the L a u r i o n area as s h o w n i n this s t u d y a n d the fact that major amounts of l e a d f r o m this area w e r e m i n e d a n d u s e d i n a n c i e n t times i n d i c a t e that these ratios s h o u l d serve as a reasonable tracer. T h e d a t a also justify the a s s u m p t i o n p r e v i o u s l y m a d e , b u t u n t i l n o w u n p r o v e d , that the l e a d o u t p u t of t h e L a u r i o n m i n e s was essentially of one u n i f o r m a n d r e c o g n i z a b l e t y p e . W e h a v e a n a l y z e d a b o u t 20 ancient objects, w h i c h w e k n o w ( w i t h near c e r t a i n t y ) w e r e m a d e of L a u r i o n l e a d . F o r e x a m p l e , one of o u r
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
1.
BARNES
E T
Isotopic Analysis
A L .
7
of Lead
reports ( 1 5 ) gives t h e a n a l y t i c a l results o f a series of seven e a r l y coins minted i n Athens.
W e h a d concluded
t h a t these p r o b a b l y
contained
l o c a l l y o b t a i n e d l e a d , a n d w e are n o w confident that this u n q u e s t i o n a b l y is true. I t also appears t h a t L a u r i o n l e a d w a s e x p o r t e d since some 2 n d c e n t u r y B . C . coins m i n t e d i n A l e x a n d r i a a n d S y r i a c o n t a i n this same type o f l e a d . O t h e r objects w e h a v e a n a l y z e d i n d i c a t e that L a u r i o n l e a d was u s e d i n t h e 6 t h c e n t u r y B . C . M a t e r i a l f r o m t h e h a n d l e s o f b r o n z e vessels d a t e d f r o m t h e 6 t h , 5 t h , a n d 4 t h centuries B . C . a l l s h o w
isotopic
ratios i n t h e n a r r o w r a n g e c h a r a c t e r i s t i c o f this l e a d ( J ) . O n e i n p a r Downloaded by UNIV OF NEWCASTLE on February 26, 2017 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0138.ch001
t i c u l a r , w h i c h h a d b e e n a t t r i b u t e d t o either S p a r t a o r s o u t h e r n I t a l y shows
l e a d ratios n e a r l y i d e n t i c a l to t h e average
for Laurion
leads
r e p o r t e d here a n d m u c h different f r o m a n y ratios w h i c h w e h a v e f o u n d i n I t a l i a n leads. A f e w earlier specimens, o f M y c e n a e a n date, a r e also o f the L a u r i o n type.
H o w e v e r , l e a d deposits i n t h e n e a r b y G r e e k i s l a n d s ,
f o r e x a m p l e o n K e a , m i g h t h a v e ratios v e r y close to those o f the L a u r i o n ores. U n t i l w e a n a l y z e samples f r o m s u c h sites, w e cannot assume e i t h e r
ο
2 . 0 6 3 I-
Ο
ESPERANCE
Ο
KAMARISA OXIDE
φ
PLAKA
•
ORE
Ο
Û. 2
ο
2.060 ο ο
8
DEPTH
(METERS)
Figure 2. wpb/ ?b ratio vs. the depth in meters for the Laurion lead ore samples. Points surrounded with a hexagon represent oxide ores. Other samples are sulfide ores. 20e
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
8
ARCHAEOLOGICAL CHEMISTRY
that t h e y differ s i g n i f i c a n t l y f r o m those d i s c u s s e d here or t h a t t h e y are i d e n t i c a l to t h e m . Future
Work
A n o t h e r area i n n e e d of i n v e s t i g a t i o n is n o r t h e r n G r e e c e , b u t
we
h a v e b e e n u n a b l e to o b t a i n s u i t a b l e ore specimens f r o m that r e g i o n .
Downloaded by UNIV OF NEWCASTLE on February 26, 2017 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0138.ch001
L e a d s h e a t h i n g f r o m the roof of t h e m o n a s t e r y at I v i r o n o n M t . A t h o s
LAURIUM EGYPT GERMANY ENGLAND TURKEY IRAN SARDINIA ITALY
CP I
I
I
.80
I
I
.82
I
.84 207
•
•
.86
•
.88
Pb/ Pb 206
Figure 3. Retotionship between the ores of Launon and those of other areas are shown in a plot of Pb/ Pb vs. Pb/ Pb ratios. Each point represents the approximate size of the 95% limit of error for the individual analysis. 208
206
207
206
has a n i s o t o p i c c o m p o s i t i o n u n l i k e t h e L a u r i o n l e a d ; this fact r e m i n d s us that just because a l e a d is f o u n d w i t h i n the p r e s e n t - d a y p o l i t i c a l b o u n d a ries of G r e e c e , i t n e e d not b e of the L a u r i o n t y p e . T h i s l e a d looks m u c h m o r e l i k e a g r o u p of leads w e Istanbul.
associate w i t h the g e n e r a l r e g i o n
of
T h e sheer massiveness of the m o n a s t e r y s h e a t h i n g s t r o n g l y
suggests t h a t it p r o b a b l y is a p r o d u c t of the nearest m i n e s , either i n n o r t h e r n G r e e c e or the m i n e s s u p p l y i n g the environs of I s t a n b u l .
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
1.
BARNES
E T A L .
Isotopic Analysis
9
of Lead
A l t h o u g h i t is m o r e i n t e r e s t i n g to a n a l y z e l e a d f r o m a c t u a l objects of a r c h a e o l o g i c a l i m p o r t a n c e r a t h e r t h a n p e r f o r m i n g r e p e a t e d analyses of g a l e n a , i n a n y s t u d y w h i c h attempts to define the o r i g i n of r a w m a t e rials m u c h effort m u s t b e spent i n d e t e r m i n i n g the l o c a t i o n a n d t h e expected
v a r i a t i o n of t h e m a t e r i a l f r o m t h e source area.
T o date w e
h a v e b e e n able to d o this f o r o n l y a f e w areas—e.g., E n g l a n d , to a lesser extent, T u r k e y , a n d n o w q u i t e t h o r o u g h l y f o r L a u r i o n .
O u r knowledge
of t h e i s o t o p i c c o m p o s i t i o n o f l e a d ores f r o m I t a l y , n o r t h e r n G r e e c e , S p a i n , M e s o p o t a m i a , I n d i a , a n d C h i n a is s t i l l i n a d e q u a t e — a s i t u a t i o n Downloaded by UNIV OF NEWCASTLE on February 26, 2017 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0138.ch001
w e h o p e to correct.
L a u r i o n leads a r e c o m p a r e d i n F i g u r e 3 w i t h those
f o u n d i n some of these other areas. P r e v i o u s l y w e h a v e t e n d e d to treat o u r findings o n objects e m p i r i c a l l y , n o t i n g w h i c h objects a p p e a r e d to h a v e c o m m o n origins a n d w h i c h d i d not. A s o u r c a t a l o g of ore d a t a grows, w e are m o r e confident i n a t t r i b u t i n g objects to specific m i n i n g regions.
W e h o p e t h a t geologists
or archaeologists w h o h a v e access to ore specimens w i l l c o n t r i b u t e to this c a t a l o g . Acknowledgment T h e authors are i n d e b t e d to the m a n y persons w h o h a v e p r o v i d e d samples f o r analysis. W e p a r t i c u l a r l y t h a n k J . M . L a m b e r t , D i r e c t o r C o m p a g n i e Française D e s M i n e s D u L a u r i u m a n d h i s colleagues, M r . P a p a t h a n a s s i o u , M r . M i r e t , a n d M r . S y c h o w i c z w h o p r o v i d e d t h e ex c e l l e n t ore samples a n d to the persons m e n t i o n e d i n o u r p r e v i o u s catalogs w h o p r o v i d e d t h e a n c i e n t specimens.
W e also t h a n k G . N . H a n s o n w h o
p e r f o r m e d m a n y of the analyses w h i l e a guest w o r k e r at N B S .
Literature
Cited
1. Brill, R. H . , Wampler, J. M . , "Isotope Studies of Ancient Lead," Amer. J. Archaeol. (1967) LXXXI, 63-77. 2. Brill, R. H . , Wampler, J. M . , "Isotope Ratios in Archaeological Objects of Lead," in "Application of Science in Examination of Works of Art," W . J. Young, E d . , pp. 155-66, Boston Arts Museum, Boston, 1967. 3. Brill, R. H . , "Lead Isotopes in Ancient Glass," Ann. Congr. Journees Int. Verre, 4th, (International Association for the History of Glass), Liège, 1969, 255-51. 4. Brill, R. H . , "Lead and Oxygen Isotopes in Ancient Objects," in "The Im pact of the Natural Sciences on Archaeology," T. E. Allibone et al., Eds., pp. 143-64, London, 1970; same paper in Phil. Trans. Roy. Soc. Lond. A. (1970) 269, 143-64. 5. Brill, R. H . , Shields, W . R., Wampler, J. M . , "New Directions in Lead Isotope Research," in "Application of Science in Examination of Works of Art," W . J. Young, E d . , Boston Arts Museum, Boston, 1971. 6. Catanzaro, E . J., Murphy, T. J., Shields, W . R., Garner, E . L . , J. Res. Nat. Bur. Stand., Sect. A (1968) 72A (3), 261-267.
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
Downloaded by UNIV OF NEWCASTLE on February 26, 2017 | http://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0138.ch001
10
ARCHAEOLOGICAL
CHEMISTRY
7. Barnes, I. L . , Murphy, T. J., Gramlich, J. W., Shields, W . R., "Lead Sepa ration by Anodic Deposition and Isotope Ratio Mass Spectrometry of Microgram and Smaller Samples," Anal. Chem. (1973) 45, 1881-1884. 8. Marinos, G . P., Petrasheck, W . E . , Geol. Geophys. Res. (Athens) (1956) 4, 223-36. 9. Ardaillon, E . , "Les Mines du Laurion dans l'Antiquité," Paris, 1897. 10. Davies, O., "Roman Mines in Europe," Oxford, 1935. 11. Boulakia, J., "Lead in the Roman World," Amer. J. Archaeol. (1972) 76 (2), 139-44. 12. Hopper, R. J., "The Laurion Mines: A Reconsideration," Ann. Brit. School Athens (1968) 63, 293-326. 13. Catanzaro, E . J., Earth Planet. Sci. Lett. (1967) 3, 343-46. 14. Kuehner, E . C., Alvarez, R., Paulsen, P. J., Murphy, T. J., Anal. Chem. (1972) 44, 2050-56. 15. Brill, R. H . , Shields, W . R., "Lead Isotopes in Ancient Coins," in "Methods of Chemical and Metallurgical Investigations of Ancient Coinage," Ε. T. Hall, D . M . Metcalf, Eds., pp. 297-304, Royal Numismatic Society, London, 1972. RECEIVED July 9, 1973.
Beck; Archaeological Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1974.