A Definition of Debitage

Why Do Archaeological Sites Have So Many Little Rock Fragments?

Flint Knapping at Archeon 2016
A group of reenactors practice flintknapping at the Archeon Living Museum in the Netherlands.  Hans Splinter

Debitage, pronounced in English roughly DEB-ih-tahzhs, is an artifact type, the collective term used by archaeologists to refer to the sharp-edged waste material left over when a flint knapper creates a stone tool (that is, knaps flint). The process of making a stone tool is rather like sculpture, in that it involves whittling down a block of stone by removing unwanted pieces until the sculptor/flint knapper achieves the final product. Debitage refers to those unneeded stone fragments.

Debitage is the French term for this material, but it is commonly used in the scholarly literature in most other languages, including English. Other terms in English include waste flakes, stone chips, and chipping debris; all of these refer to the stone fragments left over as a waste product created when a worker produces a stone tool. Those terms also refer to chipping debris left over when a stone tool is repaired or refined.

Why is Debitage Interesting?

Scholars are interested in the stone flakes left behind by flintknappers for a number of reasons. The pile of debris is the location where stone tool production took place, even if the tool itself was taken away: that alone tells archaeologists about where people lived and worked in the past. The flakes also hold information about the type of stone used to make a stone tool, as well as the technology, the steps taken in the manufacturing process.

Some of the waste flakes may be used as tools themselves, to scrape plants or cut meat for example, but by and large, the word debitage refers to those pieces which have not been reused. Whether the flakes were used as a tool or not, debitage accounts for the oldest evidence discovered for human-like behaviors: we know ancient people were making stone tools because we have found purposeful flaking debris even if we don't know what was being made. And as such, they have been recognized as an artifact type since the first decades of the 20th century.

Analyzing Debitage

Debitage analysis is the systematic study of those chipped stone flakes. The most common study of debitage involves simple (or complex) cataloging of the flakes' characteristics, such as source material, length, width, weight, thickness, flaking scars, and the evidence of heat-treatment among many others. Given that there can be thousands or tens of thousands of pieces of debitage from a site, data from all of those flakes definitely qualifies as "big data."

In addition, analytical studies have attempted to classify the flakes by step in the tool-making process. In general, a stone tool is made by removing the largest pieces first, then the pieces get smaller and smaller as the tool gets refined and shaped. A popular tool-based debitage typology in the late 20th century consisted of categorizing flakes into three stages: primary, secondary, and tertiary flakes. These rough categories were thought to reflect a very specific set of flake removal processes: primary flakes were removed from a block of stone first, then secondary, and finally tertiary flakes.

Defining those three categories was based on size and the percentage of cortex (unmodified stone) left on the waste flake. Refitting, putting the stone pieces back together whether simply one flake to another or reconstructing an entire stone tool, was originally quite pain-staking and labor-intensive. More recent tool-based imaging processes have refined and built on this technique considerably.

Other Analytical Types

One of the problems with debitage analysis is there is just so much debitage. The construction of one tool from a block of stone can produce hundreds if not thousands of waste flakes of all shapes and sizes. As a result, studies of debitage as part of the study of all stone artifacts at a given site are frequently completed using mass analysis techniques. Size grading by using a set of graduated screens to sort debitage is often used. Researchers also sort the flakes into categories on a variety of attributes and then count and weigh the total in each category to estimate types of flaking activities.

Piece-plotting of the distribution of debitage has been used, when it can be determined that the scatter of flakes has laid relatively undisturbed since its deposition. That study informs the researcher about the mechanics of flint-working activities. As a parallel study, experimental reproduction of flint knapping has been used to build a suitable comparison of debitage scatters and production techniques.

Microwear analysis is the study of the edge damage and pitting of debitage using a low- or high-power microscope, and it is generally reserved for debitage that has likely been used as a tool.

Sources and Recent Studies

A great source for information about all types of Lithic Analysis is Roger Grace's Stone Age Reference Collection.

The late Tony Baker's excellent lithics site while now outdated still contains buckets of useful information based on his understanding of the mechanical processes he learned in his own flintknapping experiments.