Boletín de la Sociedad Geológica Mexicana Volumen 76, núm. 2, A081223, 2024 http://dx.doi.org/10.18268/BSGM2024v76n2a081223

Clasificación semi-supervisada de mezclas de distribuciones para determinar procedencias de artefactos de obsidiana en Izapa, Chiapas

Semi-supervised classification of distribution mixtures to determine the sources of obsidian artifacts at Izapa, Chiapas

Pedro A. López García¹, Denisse L. Argote Espino^2,*, Alejandro J. Uriarte Torres²,

Ivonne A. Pérez Alcántara³, Gerardo Cifuentes Nava⁴

¹ Posgrado de Arqueología, Escuela Nacional de Antropología e Historia. Periférico Sur y Zapote s/n, Colonia Isidro Fabela, 14030 Tlalpan, CDMX, México.

² Dirección de Estudios Arqueológicos, Instituto Nacional de Antropología e Historia. Calle Tacuba 76, 4to piso, Colonia Centro, 06000 Cuauhtémoc, CDMX, México.

³ Centro INAH San Luis Potosí. Arista No. 933, Colonia Tequisquiapan, 78230 San Luis Potosí, San Luis Potosí , México.

⁴ Instituto de Geofísica, Universidad Nacional Autónoma de México. Circuito de Investigación, Ciudad Universitaria, 04510 Coyoacán, CDMX, México.

* Autor para correspondencia: (D.L. Argote Espino) This email address is being protected from spambots. You need JavaScript enabled to view it.

Cómo citar este artículo:

López García, P.A., Argote Espino, D.L., Uriarte Torres, A.J., Pérez Alcántara, I.A., Cifuentes Nava, G., 2024, Clasificación semi-supervisada de mezclas de distribuciones para determinar procedencias de artefactos de obsidiana en Izapa, Chiapas: Boletín de la Sociedad Geológica Mexicana, 76 (2), A081223. http://dx.doi.org/10.18268/BSGM2024v76n2a081223

Manuscrito recibido: 12 de Septiembre de 2023; manuscrito corregido: 8 de Octubre de 2023; manuscrito aceptado: 12 de Octubre de 2023.

ABSTRACT

The chemical characterization of materials recovered from archaeological sites has been used to relate artifacts to their respective sources of raw material. For this, conventional methods of classical statistics are commonly used, such as bivariate graphs, cluster analysis and linear data transformations. Those who have applied these methods claim to have a high degree of confidence in the correct assignment of materials to their respective sources. However, if empirical data deviate from theoretical assumptions, classical statistical techniques can produce incorrect assignments. In this paper, we propose a semi-supervised learning procedure using clustering and classification based on models of mixtures of multivariate asymmetric exponential power distributions. The objective is to trace the origin and provenance of obsidian archaeological materials from the archaeological zone of Izapa, Chiapas, significantly optimizing the result of the correct allocation of unlabeled data by employing only limited supervision in the form of labeled instances. The effectiveness of the proposed method was evaluated by a controlled experiment using data from a set of geological samples from obsidian deposits. Subsequently, the method was applied to analyze a set of obsidian artifacts collected in excavations within Izapa dated for the Classic period. In both cases, well-defined classifications were obtained that, in the case of Izapa, allowed to determine the consumption of materials from Guatemalan sources, as well as some relationship with sources from western and central Mexico.

Keywords: Obsidian provenance analysis; Archaeological zone of Izapa; Portable X-ray fluorescence; Semi-supervised classification; Model-based clustering; Finite mixture models.