Glazed calcareous clay ceramics from critille, Turkey Essay Example For Students

Glazed calcareous clay ceramics from critille, Turkey Essay The twelfth and thirteenth centuries constitute a high point in the history of Islamic ceramics, with finely pot ted and decorated fritwarrs produced in both Syria and Iran. The widespread production of fine-lxdicd fril wares (also known as artificial paste or stonepaste-bodicd ceramics) and techniques either new (nnderglac paint ing. ajourc. and mina^i) or refined to new heights (luster and molded wares) base focused deserved attention on these two areas. Here we will examine the production of glazed ceramics in Svria and thejazira in the twelfth and thirteenth centuries by examining pan of a sample of glazed ceramics found during excavations at the south eastern Turkish site of Gritille. Until its recent flooding by the waters of the Ataturk Dain, Gritille was a small mound on the right bank of the Luphratcs River soon af ter it came down from the Anatolian highlands. 1 It was located some five miles tq »streain from Samsat, the prin cipal site in the region, which served to guard the major river crossing on the route from Syria to the eastern Ana tolian plateau, and dominated a small vallev surround ing it. The Sarnsat region was peripheral to both Anato lia and Syria, although it had participated more in the history of north Syria and the Ja/ira. Gritille itself was pe ripheral to Samsiit. in that it guarded a minor river cross ing at the uppet end of the valley that wasSamsafs hin terland. Gntillc was first foruficd in the medieval period in the mid eleventh century and soon abandoned, only to be rcfortificd about a century later near the end of the Cru sader county of Edcssa. Thereafter, from the mid twelfth century through the early to mid thirteenth cen tury. Gritille scivcd as a rural agrRu1lui.il settlement with largely domestic architecture. To examine the production of glazed ceramics, a sub set of 168 sherds from medieval levels at Gr itille were sampled anti chemically analyzed using instrumental neutron activation analysis (INAA). This study corre- lates visual categories of Islamic glacd fritwarcs (derived mainlv from decorative technique) with categories of chemical composition to answer questions relating to glazed ceramic production in Syria and the Jaira in the   twelfth and thirteenth centuries. The project is still in progress, but it has already yielded an unexpec ted result that we will prevent in this paper. Of the 168 glazed ceramics sampled. 37 were found not to Ikfiitwares at all. but instead had calcareous clay bodies as determined by chemical analysis. Figure I contains drawings of indi cator sherds (rims and bases) in the calcareous clay ceramic sample. The sherds consututing this sample wcre of small open form vessels. The one exception to this is a vessel (ID # GT14S) whose shac and glaze indi cated that it belonged to a closed form vessel The indi cator sherd drawings show these open form vessels to be small bowls with rim diameters of approximately ten cen timeters. The sample contains tw o distinct rim shapes, a flared everted rim and a squared head rim. Ihose sherds large enough to show more body shape point to carina tion a few centimeters below the rim. There are also tw4 liases, one of which belongs to an oil lamp. Most of the sherds arc of turquoise or blue-green glaze, with three manganese purple glazed sherds and two with turquoise glaze on the exterior and manganese on the interior. Chemical analysis. The sherds were sampled for chemical analysis by drilling with tungsten carbide drill bits. Approximately 200 milligrams were extracted, dried, and 100 milligram siibsamplcs taken for analysis. Analy sis was conducted by INAA at the Smithsonian Institu tion Conservation Analytical laboratorys INAA facility using the National Institute of Standards and Technolo gys 20 megawatt research reactor. The analytical proto col was similar to that described in Blackman 1984 For the calcareous clay bodied ceramic 28 elements were quantifiable. The chemical data from the 37 calcareous clay sherds were first processed with the hierarchical aggregative clustering program AGCI,US using a nearest neighbor clustering algorithm on a squatrd mean Euclidean dis tance matrix based on the elements listed in figure. Clustering analysis divided the sample into five groups with one outlier displayed in figure 2. Chemical groups 1 through 4 all contained calcium in excess of 10 percent   Ml body colors rang ed from pale yellow through white. Chemical group 5, containing only two samples, aver aged about 7.5 percent calcium and the bodies displayed a brown color. Group 5. distinctive in both chemistry and body color, and probably better classified as an earthen ware. was excluded from further statistical analysis. Principal components analysis was carried out on the remaining four groups using the elements Na. Cr. Fe. Rb. and la. Figure 3 is a plot of the second and third principal components for the four groups, with the ellipses around the samples in each group representing the 93 percent confidence intervals. The Oldest Ceramics EssayQuite the contrary, it represents the survival of an earlier technique in an era when a new- technology had seemingly carried the field. With the rise and spread of fritwarc production in the eleventh or twelfth centu ries,4 the making of fine vessels with calcareous clay bod ies fell out of favor, as the whiteness of the fabric and fineness of potting available from an artificial paste body made it more attractive. The knowledge and exploita tion of beds of white clay would not have ceased, how ever. despite the overwhelming popularity of fntwares in the medieval and late medieval Middle Fast. White calca reous day continues to be used as a small pan of the frit ware process. Interestingly, however, the dominance of fritwarc in inland Syria and the Jazira in the twelfth cen tury is threatened at the turn of the century, not by a resurgence of interest in calcareous clay vessels, but by another kind of pottery production — glazed earthen ware and sgr afTiato. In our opinion,  «hen. the observable wide variety in fineness of polling, glazing, firing, and decoration of latc-twcltth and earlythirtccnthentury Syrian ceramics must be due to many production cen ters, in as small and peripheral areas as the Samsat valley. The production of calcareous clay vessels is part of the wide variety of ceramic production that goes with this decentralization. Until activation analysis is performed on them, these vessels, with calcium contents of between 10 and 17 percent, are visually indistinguishable from the lower end of the spectrum of fntware production occur ring at the same lime.