Transcript Correlation of Physical Properties for Aeginetan Ware with Compositional and Chemical Data from the Clay Source Deposit Shriner, C1, Douglas, B1, Elswick, E1,

Correlation of Physical Properties for Aeginetan
Ware with Compositional and Chemical Data
from the Clay Source Deposit
Shriner, C1, Douglas, B1, Elswick, E1, Brophy, J1,
Christidis, G2, Hasaki, E3, and Murray, H1
1Dept.
of Geological Sciences, Indiana University, Bloomington, IN
2 Dept. of Mineral Resources Engineering,
Technical University of Crete, Greece
3Dept. of Classics, University of Arizona, Tucson, AZ
Archaeological Problem
• Aeginetan Ware was
distributed in the 2nd
Millennium BC (ca. 22001200 BC) in large
numbers throughout the
Aegean Complex.
• Archaeologists consider
Kolonna, the large fortified
site on the east coast of
Aegina, Greece, the
production center for the
Ware.
Aeginetan Ware
● Aeginetan Ware
was produced in two
fabrics:
(1) a fine to medium
coarse, buff yellow to
red firing clay for table
wares and storage
vessels
Aeginetan Ware
2) a medium coarse to
coarse red-brown to
gray-brown firing clay
for structural wares.
● In a pivotal 150 year
period (2150-2000 BC)
coarse Aeginetan Ware
production began to be
more visible and abruptly
dominated at the beginning
of the Middle Helladic (MH)
(2000-1650 BC).
● The rapid predominance
of coarse ware over fine
ware is considered by
archaeologists a significant
ceramic production change
with cultural implications.
Methodology
● The source clays for this important and long-lived Greek Bronze
Age ceramic, Aeginetan Ware, have been provenanced using a
comparative analytical approach (Shriner et al. 2003, 2005).
● Our integrated approach requires the comparison of quantitatively
provenanced samples of Aeginetan Ware with the source clays.
● Samples of EMPA provenanced Aeginetan Ware from Asine, a MH
coastal site on the Argolic Gulf, Greece, were analyzed using multiple
analytical techniques to determine the degree of vitrification.
Asine 5231 (Plain)
Asine 5409 (Red Slipped)
Asine 1237 (Kitchenware)
Results of Previous Study
● Asine sample set appears to substantiate that both fine
and coarse varieties of Aeginetan Ware were derived
from our proposed volcanoclastic coastal plain deposits.
● Low-fired coarse ware is the technological innovation.
Vitrification doesn’t seem to be the reason for lower firing
range. Firing condition is still unknown.
• With its known mineralogical composition, it will be
possible to develop a R&D project for this archaeological
clay deposit.
Strength vs Vitrification
Heimann et al. (1980) showed different phases in oxidized and
reduced firing of a calcareous illitic clay
Modulus of Rupture
(MOR) Study
Reduced Firing Kiln
Modulus of Rupture (MOR) Study
Oxidized Firing Oven
Modulus of Rupture (MOR) Study
Universal Testing Machine and 3-Point Loading Jig
MOR – Experimental Firing of
Aeginetan Clay Deposit
20
18
16
MOR (MPa)
14
12
ACD-O
10
ACD-R
ACD-TGF
8
6
4
2
0
0
5
10
Num ber of sam ples
15
20
MOR – Aeginetan Sherd Material
30
800º C
25
MOR (MPa)
20
Experimental Range - Oxidized
AKW
15
AP
ARS
10
Green
5
0
0
5
10
Num ber of sam ples
15
Modulus of Rupture (MOR) Results
• Use of sherd material for MOR strength tests provides a
useful diagnostic tool for distinguishing sherd types.
• The strength range (5-30 MPa) appears to be
comparable for both the clay source and the Asine
samples.
• Maximum strength is associated with high temperature
phases produced during firing.
• Surface flaws in the experimental samples initiated
fractures which appear to have limited the strength of the
samples.
Research Questions
● Vitrification is assumed to be an indication of ceramic
strength and durability. Is any clay characteristic other
than vitrification developed?
● Could reduction firing and strategies that optimize the
natural fluxing potential of the raw material achieve the
properties of strength and durability?
● What chemical and mineralogical characteristics of this
archaeological clay deposit impart strength to Aeginetansourced Ware?
Acknowledgements
The National Endowment for the Humanities
The Cotton Foundation (UK)
Indiana Academy of Science
Schrader Archaeological Endowment Fund (IU)
The Institute of Aegean Prehistory (INSTAP)
The Department of Geological Sciences, Indiana University
Ruth Droppo, Visual Consultant, Indiana University
Bill Carty and Hyojin Lee, School of Ceramic Engineering
And Material Science, NYSCC at Alfred University
Anna Sliva, Geoarchaeology Intern, Indiana University