Using Portable XRF for Elemental Analysis of Obsidian, Metals, Ceramics, and Other Archaeological Materials

Robert H. Tykot, University of South Florida

email: rtykot@cas.usf.edu

Monte ArciLipari

Pantelleria

Palmarola

Melos Gia

Sardinia

Corsica

Antiparos

Mediterranean Sources, and Archaeological Sites

with Obsidian Artifacts (Sardinian, Aegean,

Carpathian sites not shown)

Typical neolithic obsidian toolsMost sites also have flakes and tools less formal

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

Major and minor elements only

1-inch disks with 14-16 samples

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

Missouri University Research Reactor

Instrumental Neutron Activation Analysis (INAA)

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 XRF Systems

ElvaX Niton

Bruker, with vacuum Bruker, on tripod

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

Nuraghi in the Marghine Area

Excavations near Tower A at Duos Nuraghes

In the mid-1980s led by Penn State faculty Joseph Michels & Gary Webster

Excavations done first in the village area outside of the nuraghi…

AB

…followed by excavations within the nuraghi

Sr/Nb

Rb/

Nb

SA SB1 SB2 SC

0 3 6 91

4

7

10

13

Distinctions visibly clearer using multiple elements

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

Soil Samples

Use in lab, field, museums……on stone, metals, ceramics, etc.

Orlando Museum of Art – South American Collections

More Examples of Testing at the Orlando Museum of Art

Tampa Museum of Art – Classical Period Metal Artifacts

More Examples of Metal Artifacts Tested at Tampa Museum of Art

Silver object in Tampa Museum of Art

Brass object in Tampa Museum of Art

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 coastal site of Is Arrutas, Sardinia

note Sr peak

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

Yon Mound (Apalachicola, Florida)

excavations by Nancy White & Jeff DuVernay (USF)

Fort Walton Incised

Lamar Ceramic Types

For homogeneity, powder samples removed by drilling...

...while analyses of clean surfaces also shown to be consistent and reliable

pXRF of Yon Mound Ceramics

Florida Ceramics(tested samples for Tom Pluckhahn)

Differences in ceramic composition for Sr, Zr

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

Kolomoki (Georgia)(excavations by Tom Pluckhahn)

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)rtykot@cas.usf.edu (email)

http://shell.cas.usf.edu/~rtykot (website)

or just google “Tykot”

Thank you!