59
IV. ANALYSIS OF AMERICAN OBSIDIANS BY X-RAY FLUORESCENCE
AND NEUTRON ACTIVATION ANALYSIS
F. H. Stross,* J. R. Weaver,*   G. E. A. Wyld,* R. F. Heizer,' J. A. Graham'
In recent years several studies have been published that were aimed at
characterizing obsidian by analyzing for elements present in small or trace
quantities. If obsidian rock can thus be characterized according to source,
correlation of an obsidian artifact with its source becomes possible. Medi-
terranean and Afro-Asian obsidians have been studied by Castiglioni et al.
(1963), Cann and Renfrew (1964), Renfrew, Cann and Dixon (1965), Renfrew,
Dixon and Cann (1966), and Dixon, Cann and Renfrew (1968). Green, Brooks
and Reeves (1967) have studied New Zealand obsidian types by emission spec-
troscopy. A similar though smaller study of American obsidians has been
published by Weaver and Stross (1965) and Heizer, Williams and Graham (1965).
The present paper is a continuation of the two latter studies.
Experimental
The samples reported here were analyzed by x-ray fluorescence using the
same instrument and technique described in the earlier study (Weaver and
Stross 1965). Values for the nine samples (with a few minor corrections)
together with an additional fifty-seven samples analyzed in 1965 are shown
in Table 1. The sample descriptions are given in Table 2. In addition to
the analyses made by x-ray fluorescence, manganese was determined by neutron
activation analysis. The x-ray values are in terms of counts-per-second-
ever-background and have no absolute quantitative significance; the manga-
nese values are given in terms of parts per million by weight.
Aluminum, chromium, and manganese have been disregarded in the x-ray
fluorescence determination.  These can normally be measured, but they were
judged to be of no value in this study for the following reasons:    (1) the
grinding device used to powder the samples was made of alumina and the
samples were unquestionably contaminated with aluminum by the grinding
operation; (2) the x-ray tube used had a chromium target which resulted in
a very large background signal for chromium; (3) the small manganese peak,
' Shell Development Company, Emeryville, California.
Department of Anthropology, University of California, Berkeley.
We wish to thank Shell Development Company for the time and facilities
made available to us for this study (P-1639). We also thank Mr. J. Holst,
who carried out most of the x-ray fluorescence analyses.
60
while detectable, was on the side of the large chromium peak, and hence
measurement was unreliable. However, manganese is considered a good
diagnostic element in this connection, and therefore we employed another
technique for obtaining this analysis.
The x-ray fluorescence work was performed over an extended period of
time, and it was necessary to adjust the conditions each time a lot of
samples was analyzed to make all the data comparable with each other.
Subsequent to the first lot, each time the instrument was used it was
adjusted to give, as closely as possible, the same counts-per-second for
each element in an arbitrarily chosen sample, namely sample 1-9. We in-
clude the data obtained on that sample at several points in Table 1 to
illustrate the precision that was obtained in this process.
For the neutron activation determination of manganese, 20-mg samples
were irradiated for 30 minutes in a thermal neutron flux of 1011 neutrons/
cm2/sec. in the Aerojet-General Nucleonics Industrial Reactor in San Ramon,
California. Ten micrograms of gold was added to each sample and standard
as an internal standard to compensate for flux variations. Gamma-ray
spectra were recorded by means of a solid, 3-inch sodium iodide detector
and a Nuclear Data, 512-channel analyzer. The only interference under
these irradiation conditions was sodium. A computer program was used to
remove the sodium interference by means of differences in the gamma-ray
spectra and half-lives.
Results
Artifacts from Mexico, Guatemala, Honduras, and some from California
and Nevada were analyzed. It has been suggested by Parks and Tieh (1966)
that the strontium/rubidium ratio is characteristic of origin and age of the
rock and could give an indication of its provenience. Among the other ele-
ments that showed the largest variation, the most useful for diagnostic
purposes were considered to be zirconium, manganese, and iron. Data for
these elements are displayed in a bar-graph (fig. 1) and in two ternary
plots (Zr-Sr-Rb and Sr-Rb-Mn, figs. 2 and 3).
The graph and plots bring out the fact that the samples seem to fall
into three groups:
Group "O", which comprises the greater part of source and site samples,
is the group that clusters around the center of both of the ternary plots,
and is characterized by approximately equal relative amounts of strontium,
rubidium, zirconium, and manganese. This group, we believe, is inadequately
differentiated; that is, there are probably several source types which are
sufficiently similar to be included in this general group. On logical
61
grounds, the El Chayal and Ixtepeque (=Papalhuapa) sources in Guatemala may
be suggested as providing the obsidian for most of the Maya site artifacts
analyzed here (samples 1-5, 2-4 /2-9, 2-14/ 2-19, 2-23 / 2-30, 2-32 / 2-48),
and in addition, the Salvador sample (2-11) and those from Copan, Honduras
(1-5, 1-13, 3-4).   Stephens (1963:II:232), in the early eighteen-forties',
may have been correct when he described a pottery jar from Kantunile,
Yucatan, as "filled nearly to the top with arrow-heads, not of flint, but
of obsidian; and as there are no volcanoes in Yucatan from which obsidian
can be procured, the discovery of these proves intercourse with the volcanic
regions of Mexico." The Otumba, Mexico, source (samples 2-20 3-5A, 3-5B)
probably provided the material for artifacts (2-21, 2-33) from Teotihuacan.
The La Venta samples (2-1, 2-2) may have been derived from either the Guate-
mala highland, the Mexican highlands, or some as yet unknown source. The
intermediate geographical position of La Venta, vis-a-vis Guatemala and
Hidalgo, makes any guess based upon geographical proximity impossible. Only
further artifact and source collecting and analysis will provide the data to
differentiate Group 0.
Group "2" is distinguished by a very low value for strontium, a high
Zr/Rb ratio (4 to 6), and a high value for manganese. This group includes
all "green" obsidians in the collection of samples analyzed. The only
Mexican source represented in this group is the Pachuca quarry, Hildalgo
(samples 1-3, 3-6A, 3-6B), which is well known for its green obsidian
deposit and is thought to have supplied the raw material for most, perhaps
all, of the green artifacts found in Mesoamerica. Sample 1-7 is a surface
artifact from the La Venta site, and its age is therefore not determinable.
In January-February 1968, excavations at La Venta in La Venta period refuse
deposits yielded a number of obsidian blades of green color, and these may
be presumed to have come from the Pachuca source. Drucker (1952:145) ob-
served that he found no green obsidian in the test pits and trenches dug by
him in 1942. It can now be said that the green obsidian from Pachuca was
being traded as far south as La Venta in Middle Pre-Classic times, and as
far as the Peten and highland Guatemala in Early Classic times.
It is remarkable that a blade found in Lovelock Cave, Nevada (sample
2-49) gave values that placed it clearly in Group 2; this specimen also
seemed to have the greenish translucency that is characteristic of the
Pachuca deposit. It is highly improbable that this artifact should have
been traded the long distance from Pachuca- to Lovelock, and consequently
this finding is of special interest. The Department of Anthropology at
Berkeley provided additional specimens (arrow points) of green obsidian
which had been found at sites near Lovelock Cave. Eleven of these were
analyzed and, without exception, gave analytical results that were consist-
ent with the unusual analysis found for the first artifact. These analyses
were compared with those obtained by the University of California (Berkeley)
62
Department of Geology (R. Jack, personal communication) for California and
Nevada artifacts and sources.   These included a few artifacts from Buck-
brush Springs, Humboldt County, Nevada, which gave analyses similar to our
Lovelock analyses. Since these two sites are not a great distance apart
(about 65 airline miles), a common source of the obsidian is suggested.
No deposit with the characteristic composition is now known, and it will
be of interest to find the source from which the Lovelock Cave-Buckbrush
Springs type green obsidian was obtained.
The remaining samples have been classed separately and are designated
Group "1". They have in common a low strontium content and a much lower
Zr/Rb ratio (approximately 1). The samples indeed appear as a generally
homogeneous group in the ternary plot (Zr-Sr-Rb, fig. 2). This group in-
cludes the two samples from Napa County, California. Many obsidian samples
from the same region have been analyzed independently by the Department of
Geology (Jack, Le Joie and Carmichael 1967), and were found to give values
on the Zr-Sr-Rb plot similar to those obtained on our samples.    The latter,
however, were further analyzed for manganese, and are distinguished by their
very low manganese content, as is evident in Figures 1 and 3. Only one
Mesoamerican sample (2-47, an artifact from Chichen Itza) exhibits a simi-
larly low manganese content. We have called this subgroup "lA." Here again,
as in the Group 0 series, there must be at least two sources represented -
one Californian and one Mesoamerican.
Four other Mesoamerican samples of Group 1 (samples 3-1, 3-2, 3-3, 2-10)
have a manganese content intermediate between subgroup 1-A and most of
Group 0, and are classed as subgroup 1-B. All of the subgroup 1-B samples
date from the Pre-Classic. The source of the artifact material is not known,
but we would guess that it will be found to exist in the Central Mexican
highland.  If there are two sources, one of which supplied Cuicuilco and the
other southern Veracruz, both remain to be located.
The iron content generally varies with the groups (Group 0 has the lowest,
Group 2 the highest iron content), but this does not seem, at least at the
present time, to offer additional insight.
This study, in our opinion, serves mainly to point up the desirability
of carrying out large scale studies of this kind, which, potentially at least,
have been made possible by the efficient (but not inexpensive) analytical
techniques developed in recent years. The crucial question concerning the
divergence from source to source can be answered completely only be analyzing
a sufficiently large number of samples from each of the individual sources.
A substantial step in this direction has been made in the study already men-
tioned (Jack, Le Joie and Carmichael 1967), in which the similarity of com-
position (using the Zr-Sr-Rb ternary as criterion) within one lava flow was
63
found to be satisfactory.  In our case, we can get information on this
question from a few samples collected at the same sources at different
instances.  Thus, samples 1-4 and 1-8 are from the same source-the deposit
at Papalhuapa, Guatemala. One sample   is red, the other black.  The analy-
ses are seen to compare quite closely.  Samples 1-3, 3-6A, and 3-6B are all
from the Pachuca deposit (Group 2), and again give very similar analyses.
Samples 1-9 (our reference sample for x-ray fluorescence) and 2-31 are from
El Chayal, Guatemala, and they compare quite well with each other.  Samples
2-20, 3-5A, and 3-5B are from the source deposit at Otumba, Mexico, and
again the comparison is satisfactory.  It should be noted, however, that of
the four Mesoamerican sources only one (Pachuca) is different enough from
the others to be clearly distinguishable. On the other hand, the samples in
Group 1 are distinct from both Group 0 and Group 2; two of these samples are
from California. No obsidian rock was found that corresponds to the Meso-
american samples of Group 1, and it is thus not unlikely that these artifacts
were made from obsidian obtained from at least one source as yet unknown to
us,
The published literature on Mesoamerican obsidian working techniques,
mining, and quarrying, and implement manufacturing techniques is large and
scattered. We have not made any special effort to compile a bibliography on
this subject, but have encountered some published data which we cite here in
the hope that other workers may find them useful.
Stoll (1886:432-434) mentions the El Chayal source. It is also described
by Holmes (1919:227) and by Coe and Flannery (1964). Thompson (1963:207)
mentions a "vast deposit of obsidian" at Zacapa, Guatemala. We now know that
this is in error, and that the obsidian seen along the railroad at this place
is roadbed ballast carried there from El Chayal. Villacorta (1927) first
mentions, although very casually, the obsidian at the site of Papalhuapa,
Guatemala. This locality has been described geologically by Williams,
McBirney and Dengo (1964).
The obsidian mines in southern Hidalgo, Mexico, were described by Holmes
(1900, 1919) and Breton (1902), and more recently by Spence and Parsons (1967)
and Spence (1967).; Breton (1902) also provides brief descriptions of obsid-
ian workshop-quarry sites at Zinepecuaro, Michoacan, and near Guadalajara,
Jalisco. Known or reported obsidian sources in Mexico are listed and mapped
in Heizer, Williams -and Graham (1965:98,map 5). The statement by Lunardi
(1948:290) that obsidian is common in the vicinity of La Esperanza and
Intibucao Honduras, has not been verified, and judging from what is known of
the geology of this area, the claim is probably incorrect. Hints of other
Mesoamerican and Central American obsidian sources are contained in an article
by Washington (1921).
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69
Table 2
Sample Identification*
(Obsidians are black or gray unless otherwise noted)
Sample |
No.                          Source Locality
1-1  | Glass Mt., near St. Helena, Napa Co., Calif. Sample from
1 quarry. Collected by R. F. Heizer, 1959.
1-2  | Site CA-Sol-2, Solano Co., Calif. Artifact in Lowie
Museum of Anthropology
1-3 - Green obsidian.   Pachuca, Hidalgo, Mex. Sample from
| quarry. Coll. by W. H. Holmes.
1-4  | Papalhuapa, Depto. Jutiapa, Guatemala.   Sample from quarry.
| Coll. by H. Williams, J. Graham, R. Heizer, 1964.
1-5  | Copan.  Artifact in Peabody Mus. Coll., Harvard University
1-6  j Green obsidian.  Teotihuacan, Mex.   Surface artifact.
1-7  | Green obsidian.  La Venta, Tab.   Surface artifact.
1-8  j Red obsidian.  Papalhuapa, Depto. Jutiapa, Guatemala.
| Sample from quarry.
1-9  | El chayal, Depto. Guatemala, Guatemala.   Sample from quarry.
2-1    La Venta, Tab.  Surface artifact.
2-2    La Venta, Tab.  Surface artifact.
2-3  | Green obsidian.  Texcoco, Valley of Mexico, Los Melones Md.
Artifact in Peabody Mus. Coll., Harvard University.
2-4  | Yaxun, Lower Lacantun R., Chiapas, Boco or Jimba Phase.
Artifact in Peabody Mus. Coll., Harvard University.
2-5  | Cave of Loltun, Yucatan.  Entrance to Chamber 1. Artifact
-  (c/1998) in Peabody Mus. Coll., Harvard University.
2-6  | Cave of Loltun, Yucatan, Sec. 1, Chamber 3.   Artifact
| (c/2023) in Peabody Mus. Coll., Harvard University.
2-7  | Labna, Yucatan, Md. 6 Late Classic Period.   Artifact
| (c/2262) in Peabody Mus. Coll., Harvard University.
2-8  | Green obsidian, Mitla, Oaxaca.   Artifact (c/5917) in
| Peabody Mus. Coll., Harvard University.
sit
on
.e No. I
Map 1 1
21    1
31
I
21     I
23    I
I
51
19.    1
3     1
10,.   1
21     1
1
23
10
10   I
12    |
I
13.    1
I
I'
14     1
I
7     1
I
Table 2 (cont'd.)
Site No.   Sample I
on Map 1     No.                         Source Locality
11        2-9    San Lorenzo, Lacantun R., Chiapas. Artifact in Peabody
Mus. Coll., Harvard University.
6        2-10 | Cuicuilco, D.F., Mexico. TIalpan Phase (field cat. 769).
|        1 University of California Collection.
20    |   2-11   "El Salvado."   Artifact (30.0/2863) in Amer. Mus. Nat.
|        | Hist. Collection.
2        2-12 | Green obsidian, Tula, Hidalgo. Mexico. Surface artifact.
1        I Artifact in Amer. Mus. Nat. Hist. Collection.
19    |   2-13 | Copan, Honduras. Artifact in Peabody Mus. Coll., Harvard
|        | University.
34    |   2-14 j Uaxaxtun, Depto. Peten, Guatemala. Stela A-7 cache, Late
I  Classic Period. Artifact (33-99-20/3393) in Peabody Mus.
I -      | Coll., Harvard University.
17    j   2-15 | Benque Viejo, British Honduras. Artifact in Peabody Mus.
I        | Coll., Harvard University.
31    |   2-16 | Seibal, Depto. Peten, Guatemala. Collected by J. Graham,
1965.
25    |   2-17 | Iximche, Late Post Classic. Depto. Chimaltenango. Surface
I        I artifact collected by J. Graham and R. Heizer, 1965.
18    1   2-18 | Nohoch Ek, Cayo Dist., British Honduras, Periods 4 and 5.
Artifact in Peabody Mus. Coll., Harvard University.
14    |   2-19   Weston site 6, near Belize, British Honduras. Terminal
I  Classic. Artifact (3-20232) in Peabody Museum Coll.,
|        | Harvard University.
4    |   2-20 | Obsidian source locality ("Mine") 2 km. NE of San Marcos,
I        | near Otumba, Estado de Mexico. Collected by M. Spence, 1966.
3    1   2-21   Teotihuacan, Tlamimilolpa Phase. Site sector 21E:N5Wl.
1        I Collected by J. Bennyhoff.
3    |   2-22 | Teotihuacan, Tzacualli phase, Zona 5-9, Calle de los Muertos
I        | 0.199. Collected by Florencia Muller.
33    |   2-23 | Tikal, Depto. Peten, Guatemala, Early Classic. Artifact
|        I (12C-408/29) in Univ. of Pennsylvania Mus. Collection.
71
Table 2 (cont'd.)
Sample
No.                         Source Locality
2-24 | Tikal, Depto. Peten, Guatemala, Early Classic.  Artifact
| (12K-164-18) in Univ. of Pennsylvania Mus. Collection.
2-25   Tikal, Depto. Peten, Guatemala, Late Preclassic.  Artifact
| (12P-167/89) in Univ. of Pennsylvania Mus. Collection.
2-26 | Tikal, Depto. Peten, Guatemala, Late Preclassic.  Artifact
I (12P/138) in Univ. of Pennsylvania Mus. Collection.
2-27   Tikal, Depto. Peten, Guatemala, Middle Preclassic.
Artifact (12P/152) in Univ. Penn. Mus. Collection.
2-28   Tikal, Depto. Peten, Guatemala, Early Classic. Artifact
I (127-226C/33) in Univ. Penn. Mus. Collection.
2-29 | Tikal, Depto. Peten, Guatemala, Late Classic. Artifact
| (41F/2) in Univ. of Pennsylvania Mus. Collection.
2-30 | Tikal, Depto. Peten, Guatemala, Early Post Classic.
Artifact (98L/10) in Univ. Penn. Mus. CollecLion.
2-31   El Chayal, Depto. Guatemala, Guatemala.  Sample from quarry.
2-31 | Bilbao (Sta. Lucia Colzumahualpa), Depto. Escuintla, Guate-
I mala. Surface artifact coll. by Graham, Heizer & Williams 1965.
2-33 | Uaxactun, Tepeu phase, Depto. Peten, Guatemala.  Artifact
in Guatemala Museum of Archaeology Collection.
2-34 J Uaxactun, Tepeu phase, Depto. Peten, Guatemala. Artifact
in Guatemala Museum of Archaeology Collection.
2-35   Zacualpa, Depto. Quicha, Guatemala, Post Classic Period.
Artifact in Peabody Mus. Coll., Harvard University.
2-36 J Zacualpa, Depto. Quiche, Guatemala, Post Classic Period.
Artifact in Guatemala Museum of Archaeology Collection.
2-37   Poptun, Depto. Peten, Guatemala.  Late Classic Period.
Artifact in Guatemala Museum of Archaeology Collection.
2-38 J Utatlan, Depto. Quiche, Guatemala. Classic Period.
| Artifact in Peabody Mus. Coll., Harvard University.
2-39   Nebaj, Depto. Quiche, Guatemala. Classic Period.
Artifact in Peabody Mus. Coll., Harvard University.
Sil
on
te No. I
Map 1 |
33     I
33     I
33 -   I
33     I
33     I
33
I
33     1
23
24     I
34     1
34     I
28
28     1
30     I
27    1
29    1
72
Table 2 (cont'd.)
Site No. I Sample I
on Map 1   No.   j                     Source Locality
32       2-40    Altar de Sacrificios, Depto. Pet'n, Guatemala.   Artifact
1-in Guatemala Museum of Archaeology Collection.
19    j 2-41   | Piedras Negras, Depto. Peten, Guatemala.   Classic Period.
|-       | Artifact in Guatemala Museum of Archaeology Collection.
26    |2-42    | Agua Escondida, near lake, Depto. Solola, Guatemala.
Artifact in Guatemala Museum of Archaeology Collection.
22    j 2-43   j Kaminaljuyu, Depto. Guatemala, Guatemala.  Artifact col-
1        | lected by R. Heizer and J. Graham, 1966.
2-2      2-45  | Green obsidian, Kaminaljuyu, Depto. Guatemala, Guatemala.
Early Classic (Tomb A-V).  Artifact in Guatemala Museum
|  of Archaeology Collection.
Cenote of Sacrifice, Yucatan, Mexico.   Artifact in Peabody
Museum Collection, Harvard University.
15    | 2-46     Green obsidian, Chichen Itza, Yucatan, Mexico.  Artifact
|  (c/5042) in Peabody Mus. Coll., Harvard University.
15    | 2-47   | Chichen Itza, Yucatan, Mexico.  Artifact (c/5038) in
|  Peabody Museum Collection, Harvard University.
15    | 2-48   | Chichen Itza, Yucatan, Mexico. Artifact (c/4919) in
| Peabody Museum Collection, Harvard University.
| 2-49   | Green obsidian, Lovelock Cave, Churchill Co., Nevada.
I        1 Artifact (1-19208) in Univ. Calif. Lowie Mus. Collection.
8    | 3-1    j Tres Zapotes, Veracruz, Mexico.  Preclassic Period (?)
I  (sub-ash cultural level Trench 26).  Collected by P.
I        | Drucker and R. Heizer, 1967.
9    | 3-2      Site buried in sand dune near Roca Partida, Tuxtla Mts.,
I        I Veracruz, Mexico.  Probably Preclassic.  Collected by
I        I J. Graham, R. Heizer, H. Williams, 1967.
9    j 3-3    j Eroded site on beach near Punta Roca Partida, Tuxtla Mts.,
I        I Veracruz, Mexico.  Probably Preclassic.
19    1 3-4    j Copan, Honduras.  Classic Period.  Surface artifact col-
|        | lected by R. Heizer, J. Graham, H. Williams, Feb. 1967.
4
I
73
Table 2 (cont'd.)
Site No.   Sample I
on Map 1 |                                Source Locality
4       3-5A   | Otumba, Estado de Mexico, Mexico.   Mine No. 1.  Collected
1 by Michael Spence, 1965.
4       3-5B   | Otumba, Estado de Mexico, Mexico.  Mine No. 1.   Collected
by Michael Spence, 1965.
1    | 3-6A    | Green obsidian, "Pachuca Mine No. 2," near Huasca, Hidalgo,
Mexico.  Collected by Michael Spence, 1965.
1    | 3-6B    | Green obsidian, "Pachuca Mine No. 2,," near Huasca, Hidalgo,
Mexico.  Collected by Michael Spence, 1965.
*
We wish to thank the following persons for supplying obsidian samples:
Drs. W. R. Coe and H. Moholy-Nagy of the University of Pennsylvania Museum
(samples 2-23/ 2-30);
Dr. Harry Pollock, Peabody Museum, Harvard University (samples 1-5, 2-3/ 2-9,
2-13/ 2-15, 2-18, 2-19);
Dr. Gordon Ekholm, American Museum of Natural History (samples 2-11, 2-12);
Sr. Gustavo Espinosa, Guatemala Museum of Archaeology (samples 2-33, 2-34,
2-36, 2-37, 2-40, 2-41, 2-45);
Drs. J. A. Bennyhoff and Michael Spence, and Dra. Florencia Muller,
Proyecto Teotihuacan (samples 2-2C / 2-22, 3-5Al 3-6B);
Dr. Clifford Evans, U.S. National Museum (samples 1-3).
74
89-C
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75
Sr
Group 0:
1 - 4, 5, 8, 9
2- 1, 2, 4, 5, 6, 7, 9, 11,
13-27, 29-44, 48
3 - 4, 5A and 5 B
Group 1:
1 - 1, 2
2 - 10, 47
3- 1, 2, 3
Group 2:
1 - 3, 6, 7
2 - 3, 8, 12, 28, 45, 46, 49
3 - 6A and 6B
Black Points are
Source Samples
Group 0
/   -  O     _0
_ Oc _0
0
Group I
/
'0P
O "
0   0 I
NORMALIZED RATIOS OF Zr-Sr-Rb
/
Rb
Group 2
/ 0? E
Zr
%.f
I
I
l
Figure 2.
76
Sr
Group 0:
1 - 4, 5, 8, 9
2- 1, 2, 4, 5, 6, 7, 9, 11,
13-27, 29-44, 48
3 - 4, 5A and 5B
Group 1:
Subgroup 1A:
1 - 1, 2
2 - 47
Subgroup 1B:
2 - 10
3 - 1, 2, 3
Group 2:
1 - 3, 6, 7
2 - 3, 8, 12, 28, 45, 46,
3 - 6A and 6B
Black Points are
Source Samples
/
I
/
Group I B
.,    _ ..
Group IA
/
I
Ilo0
/
0      l
Group 0
Q  "
'\\ ? 1
00
1  0  ~0
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Figure 3. NORMALIZED RATIOS OF Mn-Sr-Rb
I
/
/
Group 2
0
/ 0
ll
.
\
I
77.
Bibliography
Azurdia, Carlos Enrique
1927    Las Ruinas de Papalhuapa. Anales de la Sociedad de Geograffa
e Historia, 4: 1:65-70.
Breton, A.
1902
Some Obsidian Workings in Mexico. 13th Intern. Cong. Amer.,
265-268. New York.
Cann, J. R. and C. Renfrew
1964    The Characterization of Obsidian and Its Application to the
Mediterranean Region. Proc. Prehistoric Soc. for 1964,
30:111-133.
Castiglioni, 0. C., F. Fussi and G. D'Agnolo
1963    Indagini sulla provenienza dell' ossidiana utilizzata nelle
industrie preistoriche del Mediterraneo Occidentale. In
Atti della Societa Italiana di Scienze Naturali e del Museo
Civico di Storia Naturale in Milano, Vol. CII, Fasc. 111,
310-322.
Coe, M. D and K. V. Flannery
1964    The Pre-Columbian Obsidian Industry of El Chayal, Guatemala.
American Antiquity, 30:43-49.
Dixon, J. E., J. R. Cann and C. Renfrew
1968    Obsidian and the Origins of Trade.   Scientific American,
218: 3:38-46.
Drucker, Philip
1952    La Venta, Tabasco.   A Study of Olmec Ceramics and Art.
Bureau American Ethnology, Bulletin 153. Washington, D.C.
Green, R. C., R. R. Brooks and R. D. Reeves
1967    Characterization of New Zealand Obsidians by Emission Spectro-
scopy.  New Zealand Journ. Sci., 10: 3:675-682, Wellington.
Ueizer, R. F., H. Williams and J. A. Graham
1965    Notes on Mesoamerican Obsidians and Their Significance in
Archaeological Studies. Contributions of the Univ. Calif.
Archaeol. Res. Facility, No. 1:94-103, Berkeley.
78
Holmes, W. H.
1900    The Obsidian Mines of Hidalgo, Mexico.    American Anthropologist,
2: 3:405-416.
1919    Handbook of Aboriginal American Antiquities.    Bureau American
Ethnology. Bulletin 60. Washington, D.C.
Jack, R. N., K. R. Lajoie and I. S. E. Carmichael
1967    "Finger-Printing" of Obsidian and Pumice from the Western
United States. Proc. 80th Ann. Meeting, Geol. Soc. of America,
New Orleans, La., Nov. 20-22, 1967 (p. 107).
Lunardi, Federico
1948    Honduras Maya:   Etnologfa y Arqueologla de Honduras.
Tegucigalpa, Honduras.
Parks, George A. and T. T. Tieh
1966    Identifying the Geographical Source of Artefact Obsidian.
Nature, No. 5046:289-290.
Renfrew, Colin, J. R. Cann and J. E. Dixon
1965    Obsidian in the Aegean.   The Annual of the British School of
Archaeology at Athens, 60:225-247, Oxford.
Renfrew, Colin, J. E. Dixon and J. R. Cann
1966    Obsidian and Early Cultural Contact in the Near East.    Proc.
Prehistoric Soc. for 1966, 32:30-72.
Spence, Michael W.
1967    The Obsidian Industry of Teotihuacan.    American Antiquity,
32: 4:507-514.
Spence, Michael and J. Parsons
1967    Prehispanic Obsidian Mines in Southern Hidalgo.    American
Antiquity, 32: 4:542-543.
Stephens, J. L.
1962    Incidents of Travel in Yucatan.   2 vols.   Norman, Oklahoma.
Stoll, Otto
1886    Guatemala, Reisen und Schilderungen aus den Jahren 1878-1883.
Leipzig.
79
Thompson, J. E. S.
1963    Maya Archaeologist.   Norman, Oklahoma.
Villacorta Calderon, J. A. and Carlos A. Villacorta
1930    Arqueologia Guatemalteca.   Guatemala.
Washington, H. S.
1921    Obsidian from Copan and Chichen Itza.   Journ. Washington
Acad. Sci., 11:481-487,
Weaver, J. R. and F. H. Stross
1965    Analysis by X-Ray Fluorescence of Some American Obsidians.
Contributions of the Univ. Calif. Archaeol. Res. Facility,
No. 1:89-93, Berkeley.
Williams, H., A. R. McBirney and G. Dengo
1964    Geologic Reconnaissance of Southeastern Guatemala.    Univ.
Calif. Publs. Geol. Sci., Vol. 50, Berkeley.