Isotopic Analysis of Laurion Lead Ores

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


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 .


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


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


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


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


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


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


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


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 .


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 .


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.



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.


Isotopic Analysis of Laurion Lead Ores

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