Hunter–gatherer mobility and technological landscapes in southernmost South America: a statistical learning approach

The present work aims to quantitatively explore and understand the relationship between mobility types (nautical versus pedestrian), specific technological traits and shared technological knowledge in pedestrian hunter–gatherer and nautical hunter–fisher–gatherer societies from the southernmost portion of South America. To that end, advanced statistical learning techniques are used: state-of-the-art classification algorithms and variable importance analyses. Results show a strong relationship between technological knowledge, traits and mobility types. Occupations can be accurately classified into nautical and pedestrian due to the existence of a non-trivial pattern between mobility and a relatively small fraction of variables from some specific technological categories. Cases where the best-fitted classification algorithm fails to generalize are found significantly interesting. These instances can unveil lack of information, not enough entries in the training set, singular features or ambiguity, the latter case being a possible indicator of the interaction between nautical and pedestrian societies.HAR-2009-06996, CSD2010-00034, HAR2017- 90883-REDC, CULM-HAR2016-77672-P (Ministerio de Ciencia e Innovacio´n de Espan˜ a); PIP-0706, PIP-0348 (Consejo Nacional de Investigaciones Cientı´ficas y Tecnolo´gicas-Argentina) and PICT 2012-2148 (Ministerio de Ciencia, Tecnologı´a e Innovacio´n Productiva de la Repu´ blica Argentina); PROC/12-120610-A (SESAR WPE Long Term and Innovative Research-European Commission); and Project GR-7846 (Wenner-Gren Foundation for Anthropological Research

Distribución espacial y uso prehistórico de las materias primas líticas del chorrillo Miraflores en el norte de la Isla Grande de Tierra del Fuego (Argentina)

Lithic raw materials employed by hunter-gatherers who inhabited the northern portion of Isla Grande de Tierra del Fuego (southern extreme of South America) since the Early Holocene come mainly from sedimentary deposits of gacial, fl uvial and/or marine origin available within the region. Th e recent identifi cation of a primary lithic source in the chorrillo Mirafl ores valley (Prieto et al. 2004), which presents distinctive lithologies and evidences of its prehistoric exploitation, provides an opportunity to assess circulation and use of rocks with a focal  availability within the fueguian landscape. Th e goals of this paper are: 1) to introduce the fi rst petrographic and geochemical characterization of Mirafl ores lithic raw materials; 2) to inform on its distribution and frequency among  archaeological assemblages recovered in the Argentine portion of the Island comprised between Espíritu Santo and San Sebastián capes; 3) to present the technological analysis of those artifacts. Petrographic studies allowed the identifi cation of the two Mirafl ores rocks as riolitic tuff and silicifi ed tuff . Geochemical analysis showed that all artifacts recovered within study region are geochemically similar to the Chorrillo Mirafl ores raw materials. We conclude that hunter-gatherers that inhabited the fueguian steppe used and transported Mirafl ores rocks several tenth of kilometers from the Chorrillo Mirafl ores source.Key words: lithic technology, Tierra del Fuego, hunter-gatherers.Las materias primas líticas empleadas por los cazadores-recolectores que poblaron el norte de la isla Grande de Tierra del Fuego (extremo meridional de Sudamérica) desde el Holoceno temprano proceden principalmente de los depósitos de origen glacifl uvial y/o marino de la región. La reciente identifi cación de una fuente primaria en el valle chileno del chorrillo Mirafl ores (Prieto et al. 2004), con litologías distintivas y evidencias de su explotación prehistórica, constituye una oportunidad sin precedentes para evaluar la circulación y uso de rocas con una distribución puntual en el paisaje fueguino. Los objetivos de este trabajo son: 1) presentar la primera caracterización petrográfica y geoquímica de las materias primas disponibles en Mirafl ores; 2) informar sobre su distribución y frecuencia en conjuntos arqueológicos recuperados en el sector argentino de la Isla, comprendido entre los cabos Espíritu Santo y San Sebastián; 3) caracterizar tecnológicamente dichos artefactos líticos. Los estudios petrográfi cos identifi caron las materias primas del chorrillo Mirafl ores como toba riolítica y toba silicifi cada. Los análisis geoquímicos muestran una marcada afi nidad geoquímica entre los artefactos y las rocas de la fuente chilena. Los resultados obtenidos indican que los cazadores-recolectores fueguinos han utilizado y trasladado a varias decenas de kilómetros las materias primas del chorrillo Mirafl ores.Palabras clave: tecnología lítica, Tierra del Fuego, cazadores-recolectores

Expanding the scope of Actualistic Taphonomy in Archaeological Research

This chapter presents the application of actualistic taphonomy to the study of one of the inorganic remains produced by hominins since 3 million year BP up to historical times: lithic artifacts. As rocks are among the most durable raw materials employed by modern humans and their ancestors, differential preservation has conferred a leading role in archaeological research upon lithic artifacts. Indeed, lithics -flaked artifacts in particular- are the proxy for culture or anthropic presence most commonly used by scholars all over the world. This artifact-human relationship promoted actualistic research on flintknapping in archaeology but no similar effort was devoted to assessing alternative non-cultural (i.e. taphonomic) sources for flaked stone objects. Even though actualistic studies have already shown that taphonomic processes may produce lithic pseudomorphs, this fact is only rarely considered in archaeological practice and research design. Furthermore, it is commonly assumed that human products are different enough from any natural specimen to be detected by lithic analysts. However, the current lack of knowledge on non-cultural flaking processes and their byproducts prevents their identification in the archaeological record, thus undermining the accuracy and reliability of archaeological interpretations. This paper illustrates the contribution of actualistic taphonomy to study the inorganic remains of the archaeological record and its critical role in assessing the cultural vs natural origin of lithic specimens in Fuego-Patagonia (South America). Naturalistic and experimental research on rockfall and trampling presented here suggests that the effects of these taphonomic processes result in pseudoartifacts that progressively incorporate to the regional archaeological record.Fil: Borrazzo, Karen Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; Argentin