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Correlation of Physical Properties for Aeginetan Ware with Compositional and Chemical Data from the Clay Source Deposit. Shriner, C 1 , Douglas, B 1 , Elswick, E 1 , Brophy, J 1 , Christidis, G 2 , Hasaki, E 3 , and Murray, H 1.
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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. 2200-1200 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.
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
MOR – AeginetanSherd Material 800º C Experimental Range - Oxidized Green
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 Aeginetan-sourced 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