Geofacts - Naturally Formed Artifacts That Fool the Eye

When is a Broken Rock NOT an Artifact?

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Hirst, K. Kris. "Geofacts - Naturally Formed Artifacts That Fool the Eye." ThoughtCo, Feb. 23, 2016, Hirst, K. Kris. (2016, February 23). Geofacts - Naturally Formed Artifacts That Fool the Eye. Retrieved from Hirst, K. Kris. "Geofacts - Naturally Formed Artifacts That Fool the Eye." ThoughtCo. (accessed October 19, 2017).
Natural Limestone Pavement, Malham Cove, Yorkshire
Malcom Cove is a curved crag of carboniferous limestone eroded naturally at the end of the last ice age.

A geofact is a piece of rock that has been naturally broken or eroded, as opposed to one that was broken by purposeful human agency. The word is what linguists call a 'back formation' from the word artifact, of course; artifacts are products of human behaviors, while geofacts are products of natural forces.

Natural forces which can create geofacts include erosion, stream bed turbation, and animal trampling.

It's also true that entire landscapes, like the one in the photo, can be created by nature that fool us into thinking they were created by people. But most geofact/artifact studies are focused on determining whether a piece of rock was broken as a result of deliberate stone tool production (flint-knapping), or by the forces of nature.

Flint-Knapping and Geofacts

Flint-knapping, using hard-hammer or soft-hammer percussion and/or pressure flaking to break down a piece of raw lithic material and create a stone tool, has a byproduct which is one of the most frequently found type of artifact: debitage. Debitage is all the little fragments of stone created during stone tool making, and it is the focus of most archaeological geofact/artifact studies.

Determining whether stone flakes are artifacts or geofacts is important in particular at very very old sites, where the implications of misidentifying broken rock as artifacts are pretty serious.

As a result, there are a few rules archaeologists use to sort out geofacts from artifacts. By the way, the flip side of identifying geofacts is identifying systematic flaking--the characteristics of human working.

Evidence of Geofacts

The main analytical techniques still used today are based primarily on the characteristics identified by Evan Peacock (1997).

These characteristics include qualities associated with bulbs of percussion (a bump created when a stone breaks having been struck with another), the striking platform (which is created by the knapper to control the flaking and faceted by subsequent strikes), and the dorsal surface (the opposite side from the bulb, which shows various types of evidence of flakes having been removed. Read some of the literature below to gain a greater understanding of these technologies.

In general, though, your artifact is probably a geofact if two or more of the following are true.

  • There are four or fewer flake scars. A flake (aka waste flake or debitage) is what archaeologists call a tiny fragment of stone broken off a larger stone. A flake scar is the dent made on a piece of rock from where a small fragment was removed. Flake scars can occur naturally, when rocks bang against each other in a rock slide or within a stream bed; but more than four begins to look intentional.
  • There is no platform preparation. Precise control of stone flaking is an important part of stone tool manufacture. Evidence that a flat place was created on a piece of stone from which to knock off additional flakes is a sure sign of human activity.
  • The flake scars are weathered at different rates. Weathering is the term used to describe the effects of long-term exposure to climatic events. All exposed surfaces of an untouched stone should weather at the same rate. Depending on the climate and the type of rock, it takes many centuries or millennia for weathering to be apparent. If a stone has several flakes removed, and the flake scars are differently weathered, you know there was a large quantity of time passed between flaking events, and so not likely human.
  • The flake scars occur randomly on the rock. Flaking scars made on stone by human beings are likely to be patterned, rather than random.

For More Information

There are several good resources on geofacts that I can recommend. Texas Beyond History has a picture of geofacts that shows how tricky they can be to identify; I also like the Museum of Stone Tools in the UK.

More generally, Roger GraceTony Baker and Hugh Jarvis are my go-to guys for all things lithic. 

This article is a part of the guide to the Stone Tool Types, and the Dictionary of Archaeology.

Austin RJ. 1999. Technological characterization of lithic waste-flake assemblages: Multivariate analysis of experimental and archaeological data. Lithic Technology 24(1):53-68.

Bisson MS. 2001. Interview with a Neanderthal: an experimental approach for reconstructing scraper production rules, and their implications for imposed form in middle Palaeolithic tools. Cambridge Archaeological Journal 11(2):165-184.

Bradbury AP, and Carr PJ. 1995. Flake typologies and alternative approaches: An experimental assessment. Lithic Technology 20(2):100-115.

Bradbury AP, and Carr PJ. 2014. Non-metric continuum-based flake analysis. Lithic Technology 39(1):20-38.

Collins MB. 1994. Comprehensive lithic studies: Context, technology, style, attrition, breakage, use-wear, and organic residues. Lithic Technology 18(1&2):87-94.

Cyrek K, and Sudol M. 2012. Artefacts or geofacts? Presenting a dilemma basing on the Early Vistulian finds from the Bisnik Cave, Poland. Anthropologie (Brno) 50(3):323-344.

Gillespie JD, Tupakka S, and Cluney C. 2004. Distinguishing between naturally and culturally flaked cobbles: A test case from Alberta, Canada. Geoarchaeology 19(7):615-633.

Lopinot NH, and Ray JH. 2007. Trampling Experiments in the Search for the Earliest Americans. American Antiquity 72(4):771-782.

Lubinski PM, Terry K, and McCutcheon PT. 2014. Comparative methods for distinguishing flakes from geofacts: a case study from the Wenas Creek Mammoth site. Journal of Archaeological Science 52:308-320.

Mercader J, Barton H, Gillespie J, Harris J, Kuhn S, Tyler R, and Boesch C. 2007. 4,300-Year-old chimpanzee sites and the origins of percussive stone technology. Proceedings of the National Academy of Sciences 104(9):3043-3048.

Peacock E. 1991. Distinguishing between Artifacts and Geofacts: A Test Case from Eastern England.

Journal of Field Archaeology 18(3):345-361.

Pelcin AW. 1997. The formation of flakes: The role of platform thickness and exterior platform angle in the production of flake initiations and terminations. Journal of Archaeological Science 24:1107-1113.

Wallace IJ, and Shea JJ. 2006. Mobility patterns and core technologies in the Middle Paleolithic of the Levant. Journal of Archaeological Science 33:1293-1309.

Wisniewski A, Badura J, Salamon T, and Lewandowski J. 2014. The alleged Early Palaeolithic artefacts are in reality geofacts: a revision of the site of Konczyce Wielkie 4 in the Moravian Gate, South Poland. Journal of Archaeological Science 52:189-203.