using portable xrf for elemental analysis of obsidian, metals
TRANSCRIPT
Using Portable XRF for Elemental Analysis of Obsidian, Metals, Ceramics, and Other Archaeological Materials
Robert H. Tykot, University of South Florida
email: [email protected]
Monte ArciLipari
Pantelleria
Palmarola
Melos Gia
Sardinia
Corsica
Antiparos
Mediterranean Sources, and Archaeological Sites
with Obsidian Artifacts (Sardinian, Aegean,
Carpathian sites not shown)
Obsidian from Primary Deposits at Conca Cannas (SA)
easily collectible
Monte Arci (Sardinia) Obsidian
Four main subsource groups: SA, SB1, SB2, SC
with further subgroups identifiable SB1a, SB1b, SB1c, SC1, SC2
Visual and Physical Differences
Density Measurements
Useful
Density
Lipari
Palmarola
Pantelleria
Sardinia A
Sardinia B1
Sardinia B2
Sardinia C
2.3 2.35 2.4 2.45 2.5 2.55
Electron Microprobe Discrimination of Monte Arci Subsources
multivariate statistical analysis provides even clearer distinctions
5 5.5 6K O (%)
12.5
13
13.5
14
14.5
Al O
(%
)
SASB1SB2SC
23
2
Obsidian from Filiestru Cave (Sardinia) over 4 Neolithic Periods
published in Journal of Mediterranean Archaeology (1996)
Cardiale Filiestru Bonu Ighinu Ozieri0
20
40
60
80
100%
SCSB2SB1SA
20 29 1027
Laser Ablation ICP-Mass Spectrometry (with Michael Glascock & Jeff Speakman)
Laser ablation trace200 wide
microscopic signature left
Laser ablation sample holder
and instrument
Laser Ablation Inductively Coupled Plasma Mass
Spectrometer (LA-ICP-MS) at U Missouri
X-Ray Fluorescence Spectrometer
modern XRF instrument: needs liquid nitrogen to maintain vacuum and analyze lower Z elements
automated sample system
non-destructive, if sample fits in the sample holder
X-Ray Fluorescence
An electron in the K shell is ejected from the atom by an external primary excitation x-ray, creating a vacancy
An electron from the L or M shell "jumps in" to fill the vacancy, and emits a characteristic x-ray unique to this element
When a vacancy is created in the L shell, an electron from the M or N shell "jumps in" to occupy the vacancy. In this process, it emits a characteristic x-ray unique to this element
Multiple X-rays are produced, with characteristic energies, for each element in the sample
Overlaps are minimized by using filters, and different beam settings (voltage and current)
Portable X-Ray Fluorescence Spectrometer (pXRF)
Advantages Non-destructiveAny size sample Quantitative analysis Low Z elements (w/ vacuum)
Settings for pottery analysis no filter 40 kV, 1.5 μA, 180 seconds results calibrated against standards
250 Km
Passo di Corvo
Acconia
Grotta dell'Uzzo
Tas-Silg
GaioneSan PoloArene
Candide
Isolino di Varese
GiribaldiLa Cabre
Ste. Catherine
Les Terres Blanches
Combes
PietracorbaraStrette
Monte Grosso
St. Pancrace-TiggianeseBasi
I Calanchi
Liscia PilastruMonte d'AccoddiGrotta Sa Corona
Sa Ucca de su Tintirriolu Grotta FiliestruMolia
Cuccuru s'Arriu
Buon CamminoBarbusi
Su CarroppuTracasi
Paduletto di CastagnetoCasa Querciolaia
Mt. Arci
Palmarola
Lipari
Pantelleria
Casale del Dolce
Lumaca
Pianosa
Cuccuru Craboni
Duos Nuraghes
Antigori
Ortu ComiduSerra Cannigas
Domu Beccia
Mursia
Bova Marina
Susac
Fornace Cappuccini
Santo StefanoLa Marmotta
Zembra
Contraguda
Poggio OlivastroGiglio
Catignano
Ustica
Cardiccia
Sarra Cinescu
5 sites
Pulo di Molfetta
Colle Cera
S. Caterina di Pittinurri
Hergla
Monte Ortu, A Fuata, Carcu
Monte Lazzu
A Petra
Castellare
Is Solinas
Cuccuru Ibba
San Gemiliano
Grotta all’Onda
Brochtorff Skorba
Orbetello
Tavoliere
DaniloPokrovnic
Istria sites
Zagreb area
Obsidian analyses by:
• Acquafredda & Muntoni, in press• Ammerman et al. 1990• Ammerman & Polglase 1997• Barca et al., in press• Berton et al. 2004 • Crisci et al. 1994• Crummett & Warren 1985• de Francesco & Crisci 2000• Francaviglia & Piperno 1987• Lugliè et al. 2007a; 2007b• Mello 1983• Michels et al. 1984• Pessina & Radi 2006• Petrassi & Zarattini 1997• Tykot 1995…2009
Lum
aca
Piet
raco
rbar
a
Stre
tte
A P
etra
Sa C
oron
a - F
ilies
tru
Filie
stru
- EN
Filie
stru
- Fi
liest
ru
Sant
a C
ater
ina
Su C
arro
ppu
0
20
40
60
80
100%
Sardinia CSardinia BSardinia A
27101021 2026 963542
Monte Arci Subsource Distribution Early Neolithic Sites in Sardinia and Corsica
Lisci
a Pila
stru
Li M
uri
Cont
ragu
da
Mon
te d'A
ccod
di
Filie
stru
Sa U
cca
Moli
a
S. Ge
milia
no
Cucc
uru I
bba
Is So
linas
Barb
usi
Trac
asi0
20
40
60
80
100%
Sardinia CSardinia BSardinia A
10 181 93 11 62 17 83 22 29 24 11 10
Monte Arci Subsource Distribution Late Neolithic Sites in Sardinia & Corsica
Stre
tte
Mon
te G
ross
o
Sain
t Pan
crac
e
Bas
i
I C
alan
chi
Lum
aca
A F
uata
Cas
tella
ri
Mon
te L
azzu
0
20
40
60
80
100%
Sardinia CSardinia BSardinia A
12 20 10 125 59 20 17 21 5
Open-air, Late Neolithic site of Contraguda
Areas excavated at Contraguda (above); Structural feature A-B (left)
Area 3 Area 3 Str. A Area 3 Str. B Area 3 Tumulo B0
10
20
30
40
50
60
70
80
90
100
%
SCSB2SA
45 22 81 5
unlisted Area 3 Area 4 Area 19 Area 200
10
20
30
40
50
60
70
80
90
100
%
SCSB2SA
47 152 9 28 10
Comparison of subsources present in different areas of the Contraguda site (combined LA-ICP-MS and pXRF data)
Comparison of subsources present within Area 3 at Contraguda (combined LA-ICP-MS and pXRF data)
Contraguda Results (246 analyses)
Sardinia (Italy)
Obsidian from 15 sites in the Museo Pigorini collections tested here, plus from open-air site of Contraguda
Previous analytical studies mostly in northern (e.g. Filiestru Cave)
Pigorini CollectionS. Bartolomeo & S. Elia cave artifacts acquired in 1880s by Francesco Orsoni; Oristano area surface finds collected in 1899 by T. Zanardelli
Monte Arci
Nghe. Tiria
Sant’Elia
Frumini
La Gumarense
Simaxis
San Bartolomeo
Is Arrius
Mes’e ArriusPalas de Casteddu
Nghe. Loddu
Nghe. Nieddu
Palmas Arborea
Triarzu
Su Casteddu BecciuSerra de Castius
Grotta Filiestru
Contraguda
Examples of Obsidian Artifacts Tested from Museo Pigorini
Note some visual differences in transparency, luster, inclusions
Archaeological Sites in Sardinia from Pigorini Museum collection
SiteTime VisualpXRFSu Cuccuru de Is Arrius (Cabras) Middle Neolithic 13420Grotta San Bartolomeo (Cagliari) Late Neolithic 15440Grotta Sant'Elia (Cagliari) Neolithic? 2110Simaxis Neolithic 1010Palas de Casteddu (Cabras) Late Neolithic 1010Mes'e Arrius (Cabras) Late Neolithic 5910Stazione La Gumarense (Santa Giusta) Late Neolithic-Chalcolithic 99Domus de janas di Triarzu (Paulilatino) Neolithic-EBA 1010Cantoniera Frumini (Sili) Chalcolithic 1010Palmas Arborea (Oristano) Chalcolithic 44Serra de Castius (Sili) Chalcolithic 1010Su Casteddu Becciu (Fordongianus) Chalcolithic-EBA? 88Nuraghe Tiria (Villaurbana) Nuragic 1010Nuraghe Loddu (Fordongianus) Nuragic 98Nuraghe Nieddu (Oristano) Nuragic 109
total 468178
High Rb relative to low Sr
Roughly equal Rb and Sr
Using Rb, Sr, Y, Zr, Nb to identify obsidian sources
pXRF Discrimination of Monte Arci Subsources and Assignment of Artifacts
multivariate statistical analysis provides even clearer distinctions
SASB
SC
Map of Sardinia
shows obsidian source area (MonteArci) and the area of Nuragic siteswith obsidian tested
Central Marghine Region in Sardinia
large cluster of Nuragic sites occupies about 40 sq km in Borore and adjacent comuni
Excavations near Tower A at Duos Nuraghes
In the mid-1980s led by Penn State faculty Joseph Michels & Gary Webster
Only about 90 artifacts tested in total for six other Nuragic sites
Duo
s Nur
aghe
s
Oth
er S
ites
0
20
40
60
80
100%
SASB1SB2SC
228 71
Nearly 300 artifacts tested for these 5 Marghine sites
Nur
aghe
A
Nur
aghe
B
Vill
age
0
20
40
60
80
100
%
SASB1SB2SC
1539 168
Over 200 tested from specific contexts within Duos Nuraghes
Other Nuragic Sites Tested
Tiri
Lodd
u
Nie
ddu
Duo
s Nur
aghe
s
Mar
ghin
e
Dom
u B
ecci
a
Ortu
Com
idu
Ant
igur
i0
20
40
60
80
100%
SASBSC
810 9 10 145 13228 71
(extraction)Acquisition
Reduction
Transport
Production
Use
Deposition
Modification
Exchange
Re-use
The Chaîne Opératoire
Greenstone and Copper Artifacts from Florida tested
Pure copper, consistent with native (natural) copper, rather than smelted from copper ore. From the Blueberry Site
Malta National Museum of Archaeology, Valletta
tested obsidian from residential site of Skorbaand mortuary complex of Brochtorff Circle
Tested wooden sculpture to see if there was gold paint on surface...
...and there was!
Tested statue to see if modern or ancient gold alloy...
...and it appears to be truly ancient
Malta National Museum of Archaeology, Valletta
Analysis of Copper-Based Artifacts from Morocco, at University of Siena, Italy
Specifically testing to see whether objects were brass (containing zinc), rather than pure copper or bronze (containing tin)
At USF - testing human bone samples to look at diet(differences between terrestrial plants/animals and seafood)
need to use vacuum to detect phosphorus (P) –important for comparison with calcium (Ca), strontium (Sr), and barium (Ba) values
Human bone sample from inland site of Scab'e Arriu, Sardinia
note lower Sr peak
remember, this is just the visual concentration peaks; calibrated numeric values are what is significant
For homogeneity, powder samples removed by drilling...
...while analyses of clean surfaces also shown to be consistent and reliable
Rb/Sr
Zr/S
r
Check Stamped
Fort Walton Incised
Lake Jackson Incise
Lake Jackson Plain
Lamar Complicated S
Marsh Island Incise
Sand Tempered Plain
0.9 1 1.1 1.2 1.3 1.4 1.50.6
0.8
1
1.2
1.4
1.6
pXRF of inner surface of Yon Mound ceramics (2009)
note cluster of Lamar Complicated Ware samples, while probably multiple sources of Fort Walton and Marsh Island incised wares
13
203
23824
29
31 4658
83
93
100 110 120 130 140 150
Strontium (ppm)
80
90
100
110
120
130
140
150
160
170
180
Zirc
oniu
m (p
pm)
Ceramic Samples from Kolomoki (Georgia)
note: one or two central groups (local?), plus several outliers (from other sources?)
0 0 .5 1 1 .5
R b /S r
0
0 .5
1
1 .5
2
Zr/S
r
C h e c k S ta m p e dF o r t W a lto n In c is e dL a k e J a c k s o n In c is e dL a k e J a c k s o n P la inL a m a r C o m p lic a te d S ta m p e dM a rsh Is la n d In c is e dS a n d T e m p e re d P la inC la ib o rn e - P P OC la ib o rn e - S t. Jo h n sP o v e r ty P o in t - P P OP o v e r ty P o in t - S t . J o h n sA p a la c h ic o la - P P OT ic k Is la n d - P P OT ic k Is la n d - S t. Jo h n sT ic k Is la n d - W a lle r
Poverty Point & St. Johns Pottery from Florida and Louisiana
Many possible applications, but need to ...... have specific purpose for the testing; ... know what elements should be tested;... have other data to compare with... remember that analysis is of surface (if sample not powdered)
Florida possibilities include: ... sourcing ceramics;... sourcing recently found obsidian; ... identifying native vs. historic metals;... composition of metal alloys (ancient and modern tools, jewelry); ... soil testing (ancient activities, modern contamination);... seafood consumption (by testing bones)
Samples can be solid, powder, or liquid
Portable and precise... but not inexpensive!
And does require use by someone trained in X-ray analysis and data processing
If interested in collaborative research projects, I can be contacted at:
813 974-7279 (office phone)[email protected] (email)
http://shell.cas.usf.edu/~rtykot (website)
or just google “Tykot”
Thank you!