Use-Alteration Analysis of Fire-Cracked Rocks

Abstract

Although it is now commonplace for archaeologists to study use-alteration patterns on ceramics, the same cannot be said of one of the most ubiquitous classes of hunter-gatherer artifacts, fire-cracked rocks (FCR). It can be shown, however, that many of the same methods and theories applied to the study of cooking ceramics are also relevant to the investigation of rocks used as heating elements. Because use alteration analyses of FCR are so scarce, I describe a range of attributes with the goal of helping researchers identify use alterations (e.g., sooting, reddening, various fracturing patterns) on lithic artifacts from sites worldwide and evaluate their potential function in various cultural practices. These attributes are also outlined in order to create a standardized terminology for describing FCR use-alteration patterns. I discuss my analysis of FCR from three Late Archaic sites (Duck Lake, 913, and 914) on Grand Island in Michigan's Upper Peninsula, followed by an interpretation of their cooking contexts, as a case study. The results indicate great intersite variability among FCR characteristics, cooking methods, and cooking facilities (earth oven, stone boiling, and rock griddle). This use alteration analysis can be applied in archaeological contexts worldwide where similar materials are recovered.

Identifying Heated Rocks Through Feldspar Luminescence Analysis (pIRIR290) and a Critical Evaluation of Macroscopic Assessment

“…A review of the literature (Online Resource 1: Table A) shows that there is no uniform nomenclature to describe heated stones (although attempts are made to change this; e.g. Neubauer, 2018) and that descriptions of macroscopic traces of heating are usually very general and often lack images to support descriptions. In addition, it is not always clear whether descriptions are based on experiments or assumptions about archaeological material based on circumstantial evidence.…”

“…Unfortunately, systematic, experimental research into thermal alterations of stone is very limited (Neubauer, 2018), and an independent, objective method for their direct identification is still lacking. As it stands, the identification of heated stones from archaeological sites is primarily based on a combination of a visual, macroscopic, assessment of rocks (i.e.…”

“…However, some progress has been made in recent years. Neubauer (2018) has addressed the issue of coherent terminology for heated fine-grained rocks, while Bentsen and Wurz (2019) presented work on the standardisation of the use of colour to identify heated stones. Nevertheless, visual, macroscopic criteria remain problematic, as many of these characteristics are comparable with those resulting from post-depositional surface modifications, like frost action or mechanical weathering agents (Backhouse & Johnson, 2007;Deal, 2012), and therefore result in equifinality.…”

Alteraciones térmicas en guijarros costeros en la localidad de Las Grutas (Río Negro). Discutiendo sus implicancias para la interpretación del registro arqueológico lítico

“…Sin embargo, las piezas con indicios de alteración térmica no fueron contempladas en el análisis debido a que ciertos efectos de la misma pueden imitar las trazas y características originadas por corrasión (abrasión eólica) sobre la superficie de los artefactos, como por ejemplo la presencia de brillo, pulido y redondeamientos de aristas (Carranza, 2017). Asimismo, por exposición no controlada al fuego se pueden generar también fracturas y pseudoartefactos (sensu Borrazzo, 2011Borrazzo, , 2016Neubauer, 2018Neubauer, , 2019, difíciles de distinguir de aquellos generados por otros efectos tafonómicos. Esto puede llevar a una identificación errónea de la alteración térmica en artefactos líticos en la medida en que estos pudieron haber estado expuestos al fuego en algún momento luego de su descarte, por lo que los efectos que se registran en la actualidad pueden tener diferentes orígenes.…”