Textile fabrics, pseudomorphs

As a form of direct fabric evidence, the physical shapes of textile fabric pseudomorphs have been studied to identify fiber type and yam and fabric construction. Pseudomorphs of paired filaments in mineralized fabric formations found on Shang-period bronze weapons were determined to be replaced silk (I, 2) S-and Z-twisted silk staple yarn pseudomorphs were identified as well as fabric constructions, including float yams and a ribbed weave. 

In addition to the analysis of physical structural characteristics of textile fabric pseudomorphs, chemical information has been obtained. On bronze and copper artifacts, the pseudomorphs are composed of malachite, tenorite, and cuprite (I, 2), the formation of which probably requires moist conditions, a corrosive metal, and optimum fiber-metal contact (I). Trace elements in their structure vary from object to object and site to site (1-3), but the relationship of these elements and the fiber, metal, and soil composition is not yet known. 

Little published information exists about textile fabric pseudomorphs. For the most part, those interested in the phenomenon have been concerned with the pseudomorph as textile evidence rather than with the process of its formation. There is no established methodology for examining the pseudomorph either as mineral or as textile. 

The UMC halberd exhibits corrosion products along much of its surfaces, and these differ markedly in texture, color, and depth. Dimensions of the halberd are approximately 23.8 X 5.8 cm (Figure 1). For the purpose of this research, the sides of the blade were designated as side A and side B. The tong, or handle, bears an inscription, which has not been translated, as well as the typical hole for insertion of the halberd onto a pole. Sections of the corroded areas on side A exhibit textile fabric pseudomorphs these are the focus of this research. 

Two categories of pseudomorphic textile fabric formations were identified. One, the yam type, moves in and out of the second, the fabric type. At least six areas of the latter are apparent. 

Questions that remain concerning the process of silk fabric pseudomorph formation on the bronze halberd will be resolved with further study of pseudomorphic formations, particularly on objects whose provenance is documented precisely. A more complete description of the microenvironment of the buried objects as well as a quantitative analysis of the mineral composition of the pseudomorphs is necessary for the development of equations for the chemical equilibria involved. Future work is planned to study pseudomorphs as mineralogical structures and pseudomorphs as evidence of textiles. This work includes examination of two additional Shang bronze objects currently on loan to one of the authors. 

Archaeological textiles occasionally occur in forms that mislead the analyst. The mineralized fabric evidence known as pseudomorphs after fabric is one such form. Fabric remains may be recovered in pieces crumpled together and may exhibit pronounced structural variation. In such instances, one cannot rely on a series of tests from one area of the fabric to identify characteristics of the entire fabric. 

Of 101 sampling units drawn, 11 revealed no pseudomorphs after fabrics present, and two points had pseudomorphic evidence that could not be identified because of blurring of the photomicrograph. Only the remaining 88 location points yielded textile information. 

Just as baffling is the presence of pseudomorphs after feathers in conjunction with spaced weft twined fabric and fine yams yet, no interworking of feathers into either fabric or yam structures could be ascertained. The significance of the feathers is pertinent here. Their position only on the underside of the plate near its center may mean that the feathers were placed there for a special mortuary purpose and bear no relation to the fabric. On the other hand, the pseudomorphs after feathers could be part of one of the fabrics, surviving only because of their association with the copper. Fabric, feathers, and copper plate may be parts of ceremonial garb. The ornaments were not placed next to the skeleton, but rather they were beneath its remains and separated from it by soil fill. Church (18) also points out the presence of textiles or preserved textiles adhering to copper plates found on chest or loins of human remains in the Ohio Hopewell finds. She does not mention feathers as part of the plate-textile finds. Scholtz (12) has found feathers used in yams recovered from the Ozark Bluff shelters, but the manipulation of the feathers appears to be closer to the Etowah fabric No. 1145 than to the feather pseudomorphs of Tunacunnhee. 

Pseudomorphs on a bronze Shang Dynasty halberd (ca. 1300 b.c.) were subjected to mineralogical analysis to determine their structure and composition. X-Ray diffraction, scanning electron microscopy, and energy dispersive analysis of x-rays were used in these analyses. Photomicrographs of pseudomorphs also were studied for fiber, yam, and fabric formations that give evidence of textiles. A model describing the process of silk pseudomorph formation was proposed. 

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