Accessing the ephemeral using multiscale 3D microscopy of bone microwear

Abstract

Ancient people used perishable resources much as people do today. Such materials do not preserve well in the archaeological record, and so there are types of items that would have been made from animal skins or vegetal matter like clothing, footwear, and containers that are not present in many assemblages. Direct evidence for such items is often lacking, but indirect evidence in the form of microwear traces can be found on more durable materials, such as bone tools, that interacted with these less permanent items prior to deposition. In this study, 3D microscopic methods are applied to quantitatively evaluate traces from three perishable materials (semi-fresh animal skin, processed split leather, and dry bark) on experimental bone tools. Bones were scanned on two objectives (20x and 100x) with a confocal disc-scanning microscope and evaluated using 3D surface texture parameters. Quantitative measurements of the bone surfaces varied at the different scales, but material wear patterns were evident and indicative of the differences in properties of the three materials. This study indicates that the use of 3D microscopic methods on bone tools at multiple scales is useful for understanding how contact with perishable materials affects bone surfaces. This method has the potential to indirectly evaluate ephemeral resources that once came into contact with ancient bone artifacts and reconstruct some of the less tangible aspects of ancient human behavior.