An Encyclopaedia of Indian Archaeology v1.c21.s15.t1.3

v1.c21.s15.t1.3

Generally normal microscopic techniques are used in microwear analysis. Scanning Electron Microscopy (SEM) has also gained importance in this field in recent years. This provides a method to scan the surface of the tool even at a very high magnification (× 100000) with an adequate depth of field. For normal microscopy the samples to be examined are thoroughly cleaned and coated with suitable colourizers to increase their opacity. For SEM studies one has to prepare a replica of the surfaces to be examined or one can mount the samples directly on SEM stubs, if they are small enough to be accommodated on them. In both the cases the surfaces to be examined have to be coated with a thin conducting layer. After giving proper surface treatment the surfaces are scanned from one end to the other and the microwear recorded. The most common types of microwear are: sheen, rounding of friction areas, striations and microscars. All these use-caused deformities appear on the functional parts of the tools in different combinations and orientations and vary in their intensity from tool to tool. Disposition and orientation of these marks on the tools are important to determine the direction of tool movement, the angle at which it contacted the object of work, its depth of penetration and also the mode of its utilization indicating the hafting methods used, etc. On the basis of these marks alone one can conclusively say whether the tool was used as an axe or an adze or it was used as a knife or scraper irrespective of tool morphology. As a result we could show that morphologically similar-looking Neolithic artefacts [4.6] were used for different purposes and vice versa. Similarly we could distinguish between the Mesolithic [4.5] and Chalcolithic [4.14] microliths on functional grounds. This could be achieved with the help of control samples. Control samples are prepared by replicating the artefacts using the same raw material as that of the original. The control samples are then used against different materials (viz., wood, meat, grass, earth, etc.) and in different ways (as a saw, axe, scraper, hoe, chopper, sickle, etc). The resultant use-caused deformities produced on these control samples are then compared with those appearing on the artefacts. This helps us in identifying the functions of Stone Age tools. We could also determine the life history of individual tools by using these techniques.