Social network analysis of obsidian artefacts and Māori interaction in northern Aotearoa New Zealand

Abstract

Over the span of some 700 years the colonizing populations of Aotearoa New Zealand grew, with subsequent changes in levels of interaction and social affiliation. Historical accounts document that Māori society transformed from relatively autonomous village-based groups into larger territorial lineages, which later formed even larger geo-political tribal associations. These shifts have not been well-documented in the archaeological record, but social network analysis (SNA) of pXRF sourced obsidian recovered from 15 archaeological sites documents variable levels of similarity and affiliation. Three site communities and two source communities are defined based on the differential proportions of obsidian from 13 distinct sources. Distance and travel time between archaeological sites and obsidian sources were not the defining factors for obsidian source selection and community membership, rather social considerations are implicated. Some archaeological sites incorporated material from far off sources, and in some instances geographically close sites contained material from different sources and were assigned to different communities. The analytical site communities constitute relational identifications that partially correspond to categorical identities of current Māori iwi (tribal) territories and boundaries. Based on very limited temporal information, these site communities are thought to have coalesced sometime after AD 1500. By incorporating previously published and unpublished data, the SNA of obsidian artefacts defined robust network communities that reflect differential levels of Māori interaction and affiliation.

Artefact Categories, Artefact Assemblages and Ontological Alterity

“…As noted above, many of these objects derive from different raw material ‘classes’, the most numerous of which at both sites is flaked obsidian. This obsidian comes from a variety of sources, primarily Tuhua (Mayor Island) in the Bay of Plenty and several sources on the Coromandel Peninsula as well as those in Northland (Furey et al 2017; Ladefoged et al 2019; McBride 2019) (Fig. 1).…”

“…Moore (2012) describes the contexts as in situ , colluvial, and detrital. It is not surprising, therefore, that Tuhua obsidian is overwhelmingly present in archaeological obsidian assemblages from the North and South Islands (Ladefoged et al 2019; McCoy & Carpenter 2014; McCoy & Robles 2016; Moore 2012; Moore & Coster 2015; Phillipps et al 2016; Sheppard 2004; Sheppard et al 2011; Walter et al 2010). In comparison, the Coromandel and Northland sources also represented at Waitapu and Houhora respectively are smaller and more limited in both raw material form and abundance, with only colluvial and detrital materials present, and of a quality Moore (2012) categorizes as ‘good’.…”

“…In one sense it is therefore not surprising that artefacts made from Coromandel and Northland obsidian are less abundant in archaeological assemblages (e.g. Ladefoged et al 2019), if for no other reason than that the cobbles at these sources are smaller and hence capable of yielding fewer flakes (we discuss this further below). Ethnohistoric records suggest some Māori distinguished between four types of obsidian based on colour with certain colours used for particular tasks (White 1875).…”

“…Functionally defined locations relate to functional site types and from this regional settlement patterns follow. A structured, bounded, organizational use of space results from which inferences of bounded social groups follow (Ladefoged et al 2019).…”

On provenance studies of New Zealand obsidians: A pXRF‐based geochemical reference dataset and a review of analytical methods

“…Cruickshank ; Cruickshank & McAlister ; Kneebone ; Ladefoged et al . ; Lawrence et al . ; McCoy & Robles ; McCoy et al .…”